POLYALKYNYL PHTHALOCYANINES BOHDAN BOB SUCHOZAK …€¦ · POLYALKYNYL PHTHALOCYANINES BOHDAN BOB SUCHOZAK A thesis submitted to the Faculty of Graduate Studies in partial fulfilment

POLYALKYNYL PHTHALOCYANINES

BOHDAN BOB SUCHOZAK

A thesis submitted to the Faculty of Graduate Studies in partial fulfilment of the requirements

of the degree of

MASTER OF SCIENCE

Graduate Programme in Chernistry York University

Toronto, Ontario, Canada

Decernber 1 999

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Polyalkynyl Phthalocyanines

Bohdan Bob Suchozak

a thesis submitted to the Faculty of Graduate Studies of York University in partial fulfillment of the requirements for the degree of

MASTER OF SCIENCE

Permission has been granted to the LIBRARY OF YORK UNIVERSITY to lend or sel1 copies of this thesis, to the NATIONAL LIBRARY OF CANADA to microfilm this thesis and to lend or seIl copies of the film, and to UNIVERSITY MICROFILMS to publish an abstract of this thesis. The author reserves other publication rights. and neither the thesis nor extensive extracts from it may be printed or otherwise reproduced without the author's written permission.

Three, 4,5-di(phenylethynyl)phthalonitrile derivatives have been prepared,

characterized and subsequentl y mndensed to their corresponding phthalocyan ines

by reactian wïth lithium 1-octoxide in 1-octanol. The extreme insolubility of both

2,3,9,10,16, 17,23,24-octa(phenylethynyl)phthalocyanine and its octa(ptert-butyl-

phenylethynyl) derivative prompted the synthesis of 4,5-di@-neopentoxyphenyl-

ethyny1)phthalonitnle. The corresponding phthalocyanine was subsequently found

to possess a far greater solubility in most organic solvents. Due to increased

electron delocalization caused by the peripherai phenylethynyl groups, the UV-VIS

spectrum of the dilithio derivative of this Pc exhibited a Q-Band absorption

maximum which was found to be red-shifted by 20 nm relative to the dilithio

octaalkylethynyl phthalocyanine.

Additionally, the developrnent of a synthetic method towards 4,5-di(? ,3-buta-

diynyI) substituted phthalonitriles was established. This method involves the

synthesis of a substituted terminal 1,3-butadiyne followed by a palladium catalyzed

coupling with 4,5-diiodophthalonitrile. Previous attempts at synthesizing these

phthalonitriles using Eglinton, Glaser or Cadiot-Chodkiewicz coupling conditions

with 4,5-diethynylphthalonitrile and a terminal alkyne proved unsuccessful.

Reaction of 4,Mi(1,3-octadiyny1)-phthdonitrile with IithiumIDMAE did not give the

corresponding Pc due to the immediate decomposition of the starting material upon

contact with lithium alkoxide. Altematively, reaction of 4,5-di[4-(pneopentoxy-

phenyl)-l,3-butadiynylJph~alonitnle wïth lithium l-odoxide in l -octano[ gave a dark

green material, which men isolated under anhydrous conditions, gave what is

believed to be the conesponding dilithio Pc.

ACKNOWLEDGEMENTS

I wish to thank my supervisor, Dr. Clifford C. Leznoff for giving me the

opportunity to broaden my kncwiedge, and for his support and guidance during the

course of this challenging project. I would also Iike to thank the staff and faculty

members of the Chemistry Department at York University for their support during

this work. I am also grateful for the friendship, support and invaluble discussions

from past and present members of our group, in particular, Anna D'Ascanio, Namrta

Bhardwaj, Dr. Zhaopeng Li, Dr. S. Zeki Yildiz, Doron Betel, Dr. Ashot Khanamiryan,

Michelle Delaney-Luu, Kieran Nolan, Dmitri Terekhov, David Drew and Mougang

Hu. I would finally like to thank Amir Pesyan, Lucie Masciello, Dr. Henry T. Kruk,

Dr. Ben Khouw, Lisa Nelson, Dr. Svetoslav Bratovanov and especialiy Debasis

Mallik for his invaluble insights and suggestions.

TABLE OF CONTENTS

Paae ABSTRACT., ................................................................................................... iv

ACKNOWLEDGEMENTS-,--.------..-----. .................................................. ,,. ......... vi

TABLE OF CONTENTS..- ............................................................................. vii

LIST OF FIGURES-.. ........ -. .............................................................................. ix

UST OF SCHEMES ......... -. ............................................................................. x

UST OF ABBREWATIONS ............................................................................ xii

INTRODUCTION

Background ...... ....-. .............................................................................. 1

......................................................... Synthesis of Phthatocyani nes.. 3

..................................... Mechanism of Phthalocyanine Formation.. 6

............................................ Electronic Spectrai of Phthalocyanines 8

.......................... Synthesis of Alkyrnyl Substituted Phthalocyanines 1 0

Nonlinear Optics .................................................................................. 12

............ ..............................*.... Purpose and Goals of this Project .. 15

RESULTS AND DISCUSSION

........................ Synthesis of an Octaphenylethynylphthalocyanine 19

............................... Synthesis of 4,s-Dili(butadiynyl)phthalonitriIeses. 30

vii

Paae

55

LlST OF FIGURES

Paae

Figure 1 .

Figure 2 .

Figure 3 .

Figure 4 .

Figure 5 .

Figure 6 .

Figure 7 .

Figure 8-

Figure 9 .

Figure 10 .

Figure 1 1 .

Figure 12 .

General structures of phthalocyanine (1) and porphine (2) .......

UV-VIS absorption spectra for a) PcM and (b) PcH , ................. UV-Vis spectrum of a reaction probe monitoring the interconversion of 24 to 25b .....................................................

UV-VIS spectmm of Pc 34a .........................................................

UV-Vi S spectrum of Pc i 3W.. .......................................................

UV-VIS spectnim of Pc 34b ........................................................

UV-VIS spectral probe for Pc i3a .................................................

Variable temperature 'H-NMR spectra of Pc 34a (taken in toluene-d, at 1.0~1 o3 M concentration) ......................

UV-VIS spectral probe, condensation reaction of 69 to Pc 69b ...

........................ UV-VIS spectnim of acid treated reaction mixture

UV-VIS spectrurn of material believed to be Pc 69b ....................

Aromatic region of 'H-NMR spectrum of material believed to be Pc 69b (pyridined5 300Y 4.53~1 o4 M) ............................

Paae

Scheme 1. Various methods for preparing phthalocyanine ........................ 5

Scheme 2. Synthesis of diiminoisoindoiine .......................................... 6

Scheme 3. A proposed mechanism for Pc formation ................................. 7

Scheme 4. Synthesis of octaal kynyl phthalocyanines. ............................ 8

Scheme 5. Proposed synthesis of 2,3,9,101 16,17,23,24-octa- (phenylethynyl)phthalocyanine(l7).. ........................................ 1 7

Scheme 6. Proposed synthesis of a 2,3,9,IO, 16,17,23,24-octa- (1 ,3-butadiyny1)substituted phthaiocyanine (19) ........................ 1 9

Scherne 7. Synthesis of 4,5-diwtert-butylphenylethynyl)phthalonitrile (24) 20

Scheme 8. Synthesis of 2,3,9,IO, 16,17,23,24-octa(p-tert-butylphenyl- ethyny1)phthalocyanine (25a). ........................................... 21

Scheme 9. Synthesis of 4,5-di(p-neopentoxyphenylethynyl)phthalonitrile 23

Scheme 10. Synthesis of 2,3,9,lO, 16,17,23,24-octa(pneopentoxyphenyl- ethyny1)phthalocyanine (34a) and its dilithium derivative (34b) 24

Scheme 11. Various alkyne coupling reactions ........................................... 31

.................................... Scheme 12. Synthesis of 4,5-diethynylphthalonitrile 32

Scheme 13. Attempted synthesis of 4,5-di(l,3octadiynyl)phthalonitrile (42) . - using Glaser conditions ............................................................. 32

Scheme 14. Synthesis of 1,4-di(3,4-dicyanophenyl)-l,3-butadiyne (45) ...................................................... utilizing Eglinton conditions 33

Paae

Scheme 15 . Synthesis of 4.5.di(I. 3.octadiynyl)phthalonitrile using . . Eglinton conditions .................................................................... 35

Scheme 16 . Attempted Cadiot-Chodkiewicz coupling of 40 with 47 ............ 36

Scheme 1 7 . Attempted Cadiot-Chodkiewicz coupling of 49 with 15 ............. 37

Scheme 18 . Attempted coupling between 40 and 47. and behnreen 49 and ............. 15 using Cul and Pd(PPh&C12 catalysts in pyrrolidine 38

Scheme 19 . Proposed alternative approach to the synthesis of 18 ............... 39

Scheme 20 . Synthesis of 4,s-di(4-phenyl-l,3-butadiyn yl)phthalonitrile (50) 40

Scheme 21 . Attempted preparation of 1. 3.octadiyne (57) ........................... 42

Scheme 22 . Synthesis of 4.5.di(l1 3.octadiynyl)phthalonitrile (42) ............. 43

Scheme 23 . Attempted synthesis of 59 ......................................................... 44

Scheme 24 . Synthesis of 1 .(p4ert.butylphenyl)~i,3.butadiyne. and structure of proposed phthaionitrile 63 ...................................... 46

Scheme 25 . Synthesis of 4,5.di[[email protected]).l, 3.butadiynylI phthalonitrile (68) ....................................................................... 68

Scherne 26 . Attempted synthesis of Pcs 69a and 69b .................................. 49

LIST OF ABBREVlATlONS

1 3 C - ~ M ~

'H-NMR

Anal, Calcd.

br

C

cm-'

d

dd

DBN

DBU

DIPA

DMAE

DMF

El

EtNH2

Et20

FAB

FT

carbon nuclear magnetic resonance

proton nuclear magnetic resonance

elemental analysis calculated (96)

broad

Celsius

wave number

doublet

doublet of doublets

1,5-diazabicyclo[4.3.0]non-5-ene

1,8-diazabicyclo[5.4.0&mdec-7-ene

diisopropylarnine

2-N, N-dimethylaminoethanol

N, N-dimeth ylformamide

eiectron impact

ethylamine

diethyl ether

fast atom bombardment

Fourier transforrn

9

h

HOAc

HRMS

Hz

IR

3

K

1 it.

m

m/z

M

M+

MeOH

mg

min

ml,

mm01

mP

MS

NLO

grams

hours

acetic acid

h igh resolution mass spectrometry

Hertz

infrared

coupling constant

Kelvin

literature

multiplet

mass to charge ratio

metal

rnolecular ion

methanol

miIligram

minute

milliIitres

millimoles

melting point

mass spectrum

nonlinear optics

S..

mil

nm

OAc

OMe

W s )

PPrn

PYf-

9

R

r. t,

S

t

TBAF

TEA

THF

TLC

TMS

UV

VIS

nanometres

acetate

methoxy

phthaiocyanine(s)

parts per million

gyridine

quartet

substituent

foom temperature

singlet

triplet

tetrabutylammonium fluoride

triethylamine

tetra hydrofuran

thin layer chromatography

tetramethylsilane

ultraviolet

visible

xiv

INTRODUCTION

Background

The fi~st recorded synthesis of phthalocyanine (Pc) (1 a) was made in 1907

by Braun and Tchemiac [Il at the South Metropolitan Gas Company in London. It

was discovered as an insoluble, dark blue by-product during the preparation of o-

cyanobenzamide (3) from phthalimide and acetic acid. Further discoveries of

metallated derivatives of Pc were made alrnost a quater of a century fater,

beginning with de Diesbach and von der Weid 121 in 1927. By reacting o-

dibrmobenzene (4) wïih copper cyanide in refiuxing pyridine, they obiained in 23%

yield, an exceptionally stable blue material, now known to be copper Pc.

Approximatety a year later at Scottish Dyes Ltd., the iron derivative of Pc was also

accidentally discovered during the industrial preparation of phthalirnide from

phthafic anhydride and ammonia. This iron containing by-product was irnmediately

examined for its potential as an exceptionally stable and insoluble pigment. Further

research by tinstead r3-81 in the 1930's culminated in a propoçed stnrdure for this

new class of compounds, which he narned "phthalocyaninesn from the Greek

naphtha. meaning "rock oit" and cyanine, meaning "blue". He proposed that Pc is

a symmetrical macrocycle composed of 4 iminoisoindoline units with a central cavity

of sufficient size to accomodate various metal ions. This structure was confirmed

by Robertson 191 a short time later using x-ray diffraction techniques. It was noted

that the structure of Pc is closely related to the naturally occuring porphyrin ring

system and similarly contains an 18n electron inner w re (Figure 1).

1 (a) M = H, 1 (b) M = metal

Figure 1. General structures of phthalocyanine (1) and porphine (2)

As a result of the four peripheral benzo groups on the Pc rnacrocycle, the n electron

density of the inner a r e is delocalized more extensively than in the porphyrins.

This delocalization causes a shift to lower energy (red shift) in the electronic

spectrum of the Pc relative to the porphyrin. The extended electronic conjugation

of phthalocyanine can also present problems resulting from n stacking

(aggregation) between Pc macrocycles. One of the greatest inconveniences

2

presented by this phenornenon is its effect in Iowering the solubiMy of Pcs in water

and most organic solvents. The most common approach used to alleviate this

problem is to functionalize the peripherat benzo units with variaus substituents

which can interact with the solvent. Depending on the nature of these substituents,

the Pc can become either -ter soluble (ie: SO,H groups) [Iq or soluble in organic

solvents (ie: neopentoxy groups) [Il].

Since their first discovery almost a œntury ago, researchers have discovered

countless applications for these rernarkable molecules, many lying beyond their

traditional uses as dystuffs and pigments. Phthalocyanines have found use as

catalysts in sulfur oxidation in the petroleum industry, as laser dyes, as lubricants,

and among many others, in applications relating to optical computer disk

technology, photography and xerography. More recently, interest in Pcs as

potential drugs in the photodynaniic therapy of cancer and their potential

applications in non-linear optics has generated new interest in the development of

novel substituted Pcs [12-161.

Synthesis of Phthalocyanines

A wide variety of methods for synthesizing phthalocyanines are availabfe to

the organic chemist, two of which have already been diswssed above frorn a

historical perspective. The first method involves the reaction of o-cyanobenzamide

3

(3) in refluxing ethanol from wtiich a blue i (a) is recovered in low yield [1] (Scheme

1). The other method, also outlined in Scheme 1, yields PcCu upon reflwting o-

dibromobenzene (4) with copper cyanide in pyridine 121. These classical fow-

yielding methods have generally been replaced by a more convenient laboratory

scale synthesis based on phthalonitrile (51, a method first developed by Linstead

151- Phthalonitrile is heated with lithium pentoxide in 1-pentanol or another high

boiling alcohol to give PcLi,, which could either be wnverted to the metal free Pc

by treatment th acid or metallated with the addition of a M2+ salt (Scheme 1).

Similarly, substitution of 1,8-diazabicyclo[5.4.~undec-7-ene (DBU) or 1,5-

diazabicyclo[4.3.0]non-5-ene (DBN) as bases for alkoxides, in the presence of a

metal salt and an alcohol [17] has also been found to give the metallated Pc 1 (b)

in good yield (Scheme 1). Another method, although less convenient, involves

fusing the phthalonitrile with magnesiurn or sodium metal above 200°C to give

metallophthalocyanines (MPcs), from which PcH, can be liberated [18] (Scheme 1).

Phthalonitrile can also be readily converted to diiminoisoindoline (6), an

intermediate which can then be easily condensed with itself to give Pc. This

method involves bubbling gaseous ammonia through a solution of phthalonitrile in

methanol and sodium methoxide at room temperature 1191 (Scheme 2). The

resulting diiminoisoindaline can be isolated and then converted to Pc by simply

refluxing it in 2-N,N-dirnethylaminoethanol (DMAE) as shown in Scheme 1. In a

variation of this procedure, the Pc can be obtained directly by bubbling ammonia

4

through a refluxing solution of the phthalonitrile in DMAE. In either of these

methods, a metallated Pc can also be obtained by simply adding an appropriate

metal salt to the refluxing reaction mixture.

EtOH reflux

D

CuCN / pyndine refiux

Li / 1-pentanol reflux

DBU or DBN / alcohol M(I1) salt *

reflux

DMAE reflux

t

1 (a) M = H 2 1 (b) M = metal

Scheme 1. Various rnethods for preparing phthalocyanine

aCN NaOMe / NH3 CN

MeOH

5 6 NH

Scheme 2. Synthesis of diiminoisoindoline

Mechanism of Phthalocyanine Formation

Over the last sixty years there have been only a few reports in the fiterature

[20, 211 concerning the mechanism of Pc formation. It is proposed that under Li

alkoxide conditions, the monomeric intemediate (7) is first fomed, and this

subsequently reacts with another phthalonitrile to fom a half-Pc intemediate (8)-

This intermediate can then self condense to give Pc or it may sequentially react

with phthalonitrile to give the trimeric intermediate (9) and then the tetrameric

intermediate ( IO) , which cyclizes to give Pc as outlined in Scheme 3. This final

cyclization step requires a two electron reduction of the macrocycie in order to

obtain the final 18n electron aromatic system, and under these conditions, this step

involves the oxidation of an alcohol to the aldehyde. This oxidation step generates

H' which is neutralized by the excess alkoxide in the reaction mixture.

a:::

Scheme 3. A proposed mechanisrn for Pc formation

The self-condensation reaction of diiminoisoindoline has not been

extensively explored from a mechanistic perspective. It is known however, that four

moles of NH, are liberated per moie of Pc famed, and that DMAE may act as the

two electron reducing agent and as the necessary base to remove the acid

generated by the final reduction step [Z].

Electronic Spectra of Phthalocyanines

Historically, the remarkably intense absorption of light by Pcs to give their

characteristic blue and green hues, had sparked considerable interest in their

applications as pigments and dyes. Examination of the UV-VIS absorption spectra

of phthalocyanines (Pcs) and metallophthalocyanines (MPcs) in solution reveals the

origin behind their attractive colours. The extended n conjugation of Pc

macrocycles give rise to strong absorption maxima in the region of 670 to 700 nm

(referred to as the Q-Band) and another in the ultraviolet region between 320 and

370 nm (known as the B-Band or Soret Band). It is this former absorption that is

responsible for the characteristic intense blue (or Mue-green) colour of the

compound. The structure of the Q-Band is highly dependent on the symmetry of

the molecule. Metallophthalocyanines such as PcZn belong to the D, symmetry

point group, and as such, display only a single absorption in this region (Figure 2a).

The split Q band obtained from PM, anses from its lower symmetry (D,,) compared

8

with that of planar MPcs (Figure 2b).

a 2-0

T - - a) PcM

4

œ O C+ 1-0.- .

\

Y l

a) PcM

œ O C+ 1-0

\

L

Figure 2. UV-VIS absorption spectra for a) PcM and (b) PcH,

Synthesis of Alkynyl Substituted Phthalocyanines

The importance of introducing substituents ont0 Pcs has been previously

discussed with regards to enhancing solubility, but it also has important

ramifications on their UV-VIS absorption spectra. Substituents on the peripheral

benzo groups which can further delocalize the n system usually have the effect of

shifting the Q-Band to longer wavelengths. Arnong a Mole host of other groups,

alkynes are known to induce these red shifts, the effects of which have recently

been studied in our laboratory [23]. A series of 4,5-dialkynylphthalonitriles (1 2) was

prepared from 4,5diiodophthalonitriie (11) and a terminal alkyne via palladium

catalyzed cross-coupling reactions [24, 251. Condensation of each of these

phthalonitriles with lithium l -pentoxide in 1 -pentanol gave after acid workup,

2,3,9, A 0,16,17,23,24-octaaIkynylphthafocyanines (1 3b), while intervention of the

intemediate dilithium Pcs (13a) wïth zinc acetate gave the related Zn(ll) Pcs (14)

(Scheme 4). It was found that in the metal free Pcs, each triple bond appeared to

cause the Q-Band region to red shift by 4-5 nm, and in the ZnPcs, by 1-2 nrn. This

wark has demonstrated that the Q-Band of the electronic spectrum of a Pc can be

fine tuned by introducing triple bonds into their peripheral benzo units.

lnterest in these alkynyl-substituted phthalocyanines was originally kindled

by the description of hexaalkynylbenzenes as possible compounds for use in

nonlinear optics [26a]. Metallophthalocyanines themselves are known to exhibit

10

nonlinear optical (NLO) properties 1121, and it was hoped that these effects might

be enhanced by structurally modifying the peripheral benzo groups with alkynyl

substituents.

11 R = n-hexyi n-pentyl n-butyl n-propyl terf-büty l

Pd(PPh&C12 Cul, TEA

12

la) CH3(CH2)40Li

b) H+

13a' M = Li2 , R = n-propyl 13b M=H2 l 3 b U M = H 2 , R=n-propyl

R 14 M=Zn

Scheme 4. Synthesis of octaalkynyl phthalocyanines

Nonlinear Optics

Nonlinear optics is the study of phenomena that occur as a consequence of

the modification of the optical properties of a material system by the presence of

light. In order to understand the origins behind nonlinear optical phenomena, one

must first distinguish between linear and nonlinear behaviour. At the relatively low

Iight intensities that normally occur in nature, the optical properties of materials are

quite independent of the intensity of illumination. If light waves are able to

penetrate and pass through a medium, this occurs without any interaction between

the waves. These are the Iinear optical effects with wtiich we are familiar through

our visual sense. However, if the illumination is made sufficiently intense, as with

a laser, the optical properties begin to depend on the intensity and other

characteristics of the Iight. The Iight waves may then interact with each other as

well as with the medium. It is these interactions that lead to what are known as

nonlinear optical effects.

Light, on passing through a medium, induces an oscillating polarisation (P)

which is usually regarded as Iinearly proportional to the Iight's electric field 0, and

is simply defined by Equation 1 ., in which is the polarizability of the medium and

c is a proportionality constant:

P = cxE (1)

However, for higher light intensities, such as those obtained from laser light

12

sources, deviation from this linear relationship o m r s and higher powers of the

electric field becorne important. Equation 1. can then be expressed as a power

series in the field strength E:

P = c(X"'E + f ) E 2 + f)E3 ..3 (2)

The t e n s f ) and f ) are known as the second-order and third-order hyperpolar-

izabilities, respectively. An important consequence of this nonlinearity becomes

apparent when one considers the refractive index of the material. For light of low

intensity, the refractive index (nJ is roughly related to the polarisability by equation

3:

However, for high iight intensities, and for materials significantly large values

of (such as phthalocyanines), the effective refractive index (nd) ceases to obey

this relationship. It then follows from Equations 2 and 3 that:

Therefore, if f ' can be neglected, the effective refractive index can be expressed

by Equation 5, where n, is proportional to f ) , and is therefore dependent on the

intensity of Iight (4:

nfl = n,+nJ (5)

Many potentially useful optical properties result from an intensity-dependent

refractive index. For example, optical switches, analogous to electronic transistors

can be constructed in which an intense external light source is used to control the

passage of an optical signal through a waveguide such as a fibre-optic cable [16].

Another property of materials posessing large third order hyperpolarizabilities is

frequency tripling of the incident Iight (third harmonic generation). Some examples

of organic materials wïth high f j values include diphenylbutadiyne, hexaphenyl-

ethynylbenzene, polydiacetylenes, polythiophenes and ferrocenyl compounds,

among many others [26b]. Similarly, materials posessing large second order

hyperpolarizabilities, such as quartz, have the ability to double the frequency of

incident light (second hamonic generation), and in some cases, frequency mixing

of two Iight sources of different wavelengths is also possible. The majority of

organic compounds which have already been explored for second-order nonlinear

optics fall into the categories of substituted: benzenes, biphenyls, stilbenes,

tolanes, chalcones and related structures. Some promising second order NLO

materials currently under investigation include lithium niobate, potassium titanyl

phosphate, as well as derivatives of both N,N-dirnethyl-2-acetamido-4-nitroaniline

and N-(4-nitropheny1)-(a-prolinol [26b]

Another nonlinear optical effect, optical Iimiting, arising from the excited state

having a greater absorption coefficient than the ground state, is useful for the

construction of optical filters to protect the human eye against high-intensity Iight

sources such as laser wapons. Phthalocyanine compounds, including lead octa-

(cumy1phenoxy)- and chloro-aluminum phthalocyanine have been studied for this

purpose and have already been found to be among the most promising organic

materials for use as optical limiters [27]-

For an organic material to exhibit large nonlinear hyperpolarizabilities, it

should possess a molecular structure with a large potarisable n-system. In order

to possess significant values of second-order molecular hyperpolarizabilities, a

permanent molecular dipole moment must be associated with the n system.. Since

most Pcs do not formally possess a permanent dipole moment, they are mainly of

interest as third-order nonlinear optical materiais.

Purpose and Goals of this Project

Much attention has reœntly been devoted to the search for organic materials

having large third-order nonlinearity because of their potential utility in optical

switching and processing applications. However, materials with sufficiently high

nonlinearities for tbese applications have not yet been identified. In contrast to the

relatively =Il-defined structure-property relationships used to guide the design of

molecules for second-order nonlinear optical applications, such relationships for

third-order nonlinear optical chromaphores are stifl lacking. It is known however,

that most of the third-order nonlinearity relies on the ri-conjugated double-bond

framework of the molecuie. Recent theoretical and experimental studies have

suggested that bond-length alternation is a useful structural parameter to Vary in

15

attempts to optimize the secondurder hyperpolarizabilities. Theoretical

mlculations also predict that thirdorder hyperpolarizabilities should follow a similar

trend [28, 291.

Phthafocyanines substituted with alkynyl groups fit these criteria in that the

n-electron system wouid become further delocalized, and if these triple bonded

units are used as a bridge bet\irieen 2 rrconjugated systems, the altemation in bond

lengths may lead to enhancements in nonlinear effects. Although a series of

alkynyl substituted Pcs have already been synthesized in our laboratory, their

potential as NLO materials have not, to our knowledge, yet been studied. Not

included in this series of wmpounds w r e phenyfalkynyl substituted Pcs. Using the

same methodology, it was our intention to synthesize 4,5-di(phenylethyny1)

phthalonitrile (1 6) and subsequently, 2,3,9, 10, 16,17,23,24-octa(phenylethynyl)-

phthalocyanine (17) in order to further broaden this series and to observe what

effects the substituents might have on red-shifting its UV-VIS spectrum (Scheme 5).

An extension of this work is to increase the bond length alternation by

introducing conjugated triple bonds ont0 a Pc7s peripheral benzo groups. The main

goal of this project was the synthesis of such a compound, specifically, a

2,3,9,10,16,17,23,24-octabutadiynyl substituted phthalocyanine. The proposed

approach was to synthesize a 4,54i(butadiynyl) substituted phthalonitrile (18)

which could then be condensed to the corresponding phthalocyanine (19) by

reaction lithium 1 -octoxide in 1 -octano1 (Scheme 6).

26

Scheme 5. Proposed synthesis of 2,3,9,10,16,17,23,24-octa(pheny1ethynyl) phthalocyanine (1 7 )

R = alkyl, aryl

Scheme 6. Proposed synthesis of a 2,3,9,lO, 16117123,24-octa(butadiynyl) substituted phthalocyanine (1 9)

RESULTS AND DISCUSSION

Synthesis of an Octaphenylethynylphthalocyanine

The synthetic method used to prepare 2,3,9,.10,16, i 7,23,24-octa(pheny1-

ethyny1)phthalocyanine (17) is outlined in Scheme 5, and is based on a general

method for preparing octaethynyl Pcs, recently developed in our laboratory [23].

The desired phthalonitrile 16, was prepared in 70% yield by coupling 2 molar

equivalents of phenylacetylene (15) with 11, using catalytic quantities of

Pd(PPh&CI, and Cul in triethylarnine (TEA). Subsequent condensation of 16 wi-th

lithium 7-octoxide in 1-octanol gave after work-up, a dark green solid which was

extremely insoluble in most organic solvents. Purification of this product, which is

believed to be 17, was made extremely dificult due to its insolubility, and

consequently, a satisfactory NMR spectrum could not be obtained. In addition, this

product failed to afford a satisfactory FAB-MS analysis. However, a UV-VIS

spectrum of a probe from the reaction mixture at 20 h seems to suggest the

formation of an MPc, as evidenced by a strong absorption at 720 nm. This would

correspond to the expected Q-Band absorption of the dilithium Pc.

The high degree of insolubility displayed by the product of this reaction,

assuming that it is indeed 17, wuld probably be attributed to aggregation. In order

to complete the task of synthesizing and futly characterizing an octaphenyiethynyl

Pc, this problem would need to be addressed. The proposed approach to

rninimizing aggregation was to use a phenylacetylene fundionalized with a bufky

substituent such as a terf-butyl group. A route toward the synthesis of ptert-

butylphenylacetylene (23) was hence established, and is outlined in Scheme 7-

The first step involved wupling trimethylsilylacetylene (21) to 1 -bromo-4-te1t-

butylbenzene (20) using Pd(PPh,),CI, and Cul in TEA in a sealed tube at 95OC to

afford 1 -trimethylsilyl-2-@-fert-butylphenyl)acetylene (22) in 75% yield . This

cornpound was then deprotected by treatment with aqueous 5 M NaOH in methanol

to give the desired alkyne 23 in a crude yield of 98%. This was subsequently

coupled with 4,5-diiodophthalonitrile (1 l ) , again using Pd(PPh,),CI, and Cul, to

afford 4,5-di@tert-butylphenylethynyl)phthalonitrle (24) in 88% yield.

Pd(PPh3kC12, Cul, TEA

/ \ -fQ-ji-

5 M NaOH

Scheme 7. Synthesis of 4,5-di@-te&butylphenylethynyl)phthalonirle (24)

20

Condensation of this phthalonitrile to the wrresponding Pc (25a) was

performed using lithium 1 -octoxide in 1 -octano1 at 1 1 O°C (Scheme 8). A UV-VIS

probe of this readion after 22 hours revealed an absorption at 722 nm, bel ieved to

be the Q-Band absorption of the dilithiurn Pc (25b) (Figure 3). An acid work-up of

the reaction was performed to obtain the metal free Pc 25a, but the da&-green

product isolated frorn this reaction was found to be just as insoluble in organic

solvents as Pc 17. Similar difficulties were also encountered in trying to obtain

satisfactory NMR and mass spectra. If the phthalocyanine 2Sb had indeed formed

in this reaction, as suggested by the UV-VIS spectrum, then it seems evident that

the ted-butyl groups do little to enhance the solubility of these Pcs.

Scheme 8. Synthesis of 2,3,9,lO, 16,l 7,23,24-oda@terf-butylphenylethynyl) phthalocyanine (25a)

Figure 3. UV-VIS spectrum of a reaction probe monitoring the interconversion of 24 to 25b

Previous work in out laboratory has shown that neopentoxy groups are

highly effective at increasing the solubility of Pcs [Il]- It was therefore hoped that

by replacing the tert-butyl groups with neopentoxy groups, a more soluble

octaphenylethynyl Pc could be synthesized and full characterization might be

facilitated. The synthesis 4,5-di(p-neopento>cyphenylethynyl)phthaloitrile (33) was

therefore undertaken, and is outlined in Scheme 9. The first step required the

synthesis of neopentyl tosylate (28), which was obtained in 85% yield by reacting

neopentyl alcohol(26) with ptoluenesulfonyl chloride (27) in pyridine. Tosylate 28

then reacted wi-th piodophenol(29) to give p-iodoneopentoxybenzene (30) in

+ - 1 Pd(PPh3)2ClL t: - Si-

1 Cul l TEA (r. t )

21 31

Y-.- 5 M NaOH, MeOH (r, t)

31 32

I Pd(PPh3)2CI

I >"N+ ;-Ch+ ,,,TE&

11 32

Scheme 9. Synthesis of 4,s-di@-neopentoxyphenylethynyl)phthalonitrile

82% yield. This w s subsequently coupled with trimethylsilyl acetylene (21) using

Pd(PPh3),C12 to give 1-trirnethylsilyl-2-(p-neopentoxyphenyl)acelene (31) in 88%

yield. The trimethylsilyl group was then cleaved from 31 using 5M aqueous NaOH

in methanol to give, in 97% yield, p-neopentoxyphenylacetylene (32) . Terminal

alkyne 32 was then coupled Wth 4,5-diiodophthalonitn'le ( I l ) , again using

Pd(PPh3)2CI, as a catalyst, to give 4,5-di(p-neopentoxyphenylethynyl)phthalonitrile

(33) in 70% yield. For al1 of these intermediate compounds, satisfactory 'H-NMR,

13C-NMR, EI-MS, IR, and elemental analyses were obtained. Subsequent

condensation of 33 in LüûMAE at 1 OO°C (Scheme 1 O) yielded 2,3,9,lO, 16,17,23,24-

oda@neopentoxyphenylethynyl)phthalocyanine (Ma) as a dark green solid after

work-up. Although not exceedingly soluble, Pc 34a was found to dissolve

appreciably well in benzene, touene, CHCI,, CH,CI,, and THF. Purification of this

compound was aaxmplished by column chromatography using flash silica gel and

CH,CI, as eluent, followed by gel permeation chromatography using SX-2

Biobeadsg and THF as eluent. This was followed by reprecipitation from

benzenelethanol and then further chromatography, again using flash silica gel and

CH,CI,. After exhaustive purification, 34a was obtained in an overall yield of 8%.

Scheme 10.

A 1) Li/ DMAE (100oC) 2) H+

6- Li I THF (50 O C )

Synthesis of 2,3,9,101 16,17,23,24-octa@-neopentoxyphenyl- ethyny1)phthalocyanine (34a) and its dilithium derivative (34b)

The UV-VIS spedrclm of 34a exhibited a rather broad Q-Band absorption at

678 nm, with a shoulder at 720 nm (Figure 4). It was speculated that the broadness

may be due to aggregation, but m e n the spectnim was re-nin at higher tempera-

tures, no changes were obsewed from 25% to 60°C. Comparing this to other metal

free octaalkylethynyl Pcs previously synthesized in our laboratory (13b), the

terminal phenyl groups did not seem to red-shift the Q-Band region at all, in fact,

they appeared to cause a blue sh#t d approximately 20 nm (Figure 5). The

reasons behind this result are not clear since a shift to longer wavelengths would

Figure 4. UV-VIS spectnim of Pc 34a

Figure 5. UV-VIS spectnim of Pc 13b'

25

be expected with increased electronic delocalization.

ln order to confirrn that Pcs 25b and the dilithio forrn of 17 were in fact

formed in their respective reaction mixtures, Pc 34a was metallated using lithium

in THF to give 34b in 99% yield (Scheme 10). Tne UV-VIS spectrum of this

compound in THF, shown in Figure 6, displays the same sharp Q-Band absorption

at 720 nm, as seen in Figure 3, and seems to confirm the formation of the dilithium

Pcs in both of the aforementioned reactions. Also, a comparison of the UV-VIS

spectrum of 34b with unsubstituted dilithium phthalocyanine, which displays a Q-

Band absorption at 688 nm [18], suggests that the 8 peripheral pneopentoxy-

phenylethynyl groups impart a red-shift of approxirnately 32 nm. The zinc derivative

of 3431 was not prepared since the solubility of these phthalocyanines are typically

much lover than their metal free derivatives [30], although a comparison was made

with an octaalkylethynyl PcLi, (1 3a'). A W-VIS spectral probe of the condensation

reaction of 12 to 13a9 (Scheme 4) after 3 hours is shown in Figure 7. These

intemediate dilithium Pcs exhibit Q-Band absorptions at 700 nm, so it appears that

the 8 peripheral phenyl groups on 34b, have the effect of increasing the red shift

by an additional 20 nm-

Figure 6. UV-VIS spectrurn of Pc 34b

Figure 7. A UV-VIS spectral probe for Pc 13a'

Phthalocyanines 34a and 34b were also characterized by 'H-NMR

spectroscopy in toluene-d, at 300Y at a concentration of l .Oxl OJM. The spectrum

of 34a exhibited 3 broad signais in the aromatic region, one corresponding to the

protons on phthalocyanine itself, and the other tvm corresponding to the protons on

the peripheral neopentoxyphenyl rings. The outer neopentoxy groups were

obsewed as a pair of broad singlets, one at 3.48 ppm, corresponding to the OCH,

hydrogens and the other at 1.16 ppm, corresponding to the hydrogens on the

terminal C(CH,), groups. The 2 protons on the inner nitrogens however were not

observed, and a series of high-temperature 'H-NMR experiments were

subsequently conducted to determine whether aggregation may have any effect in

obscuring this signal. The same sample was re-mn at incrementally higher

temperatures, ranging from 300K to %3K, but the signal still remained absent.

Only after extreme vertical expansion of the spectra was a very broad singlet

detected at 4.8 ppm. Additionally, the previously broad aromatic singlets at 300K

began to sharpen, and eventually appeared as a pair of doublets (Figure 8). The

proton NMR spectmm of Pc 34b exhibited essentially the same features as those

for 34a, except for the expected absence of any signals from O to -6 ppm which

would correspond to protons on the internai nitrogen atoms.

FAB-MS analysis of 34a exhibited the parent ion (M + 1, mh = 2004), but the

elementai analysis exhibited somewhat low carbon values, typicai of some Pc

wmpounds. The FAB-MS spectmm for 34b did not show a mofecular ion peak, but

exhibited rather, 2 ion clusters that are consistent with the loss of one and two

lithium atoms; (M - Li) centred around mh = 201 0 and (M - 2Li) centred around m/z

= 2004-

Figure 8. Variable temperature 'H-NMR spectra of Pc 34a (taken in t01uene-d~ at 1 -0x1 O ~ M concentration)

Synthesis of 4,s-Di(butadiynyl)phthalonitn'les

The proposed route to synthesizing phthalocyanines functionalized ~ Ï t h

conjugated diakynyi groups has been outlined in Scheme 6, and is ultimately based

on the synthesis of 4,5di(butadiynyl) substituted phthalonitrile precursors (1 8).

Classical methods for synthesizing diynes usually involve the coupling of 2 terminal

alkynes. This can occur under a variety of conditions 1311, but particularly in

reactions involving copper derivatives. Two of the most commonly used methods

involving copper derivatives are the Glaser reaction [32], and the Cadiot-

ChodkiewiQ coupling [33]. In the former reaction, an alkyne (35) reacts with basic

aiprous chloride to give a diyne (36) upon air oxidation (Scheme 11 A). Under the

second set of conditions, a brornoalkyne (37) reacts with a rnonoalkyne in the

presence of cuprous chloride and an amine to give an unsymmetrical diyne (38)

(Scheme 1 1 C). Glaser type coupling of alkynes can be accomplished other

copper derivatives and bases other than hydroxide. One widely employed

variation, known as Eglinton conditions 1341, uses cupric acetate and pyridine as

the base (Scheme 1 1 B).

A) Glaser

B) Eglinton

2. air

- pyrid ine

C ) Cadiot-Chod kiewicz

35

The

Scheme i 1. Various alkyne coupling reactions

proposed approach toward synthesizing these 4,54i(butadiynyl)

phthalonitriles was therefore based on the direct coupling of 4,s-diethynyl

phthalonitrile (40) with another terminal alkyne. Recent work in our Iaboratory has

already established a facile synthetic route towards 4,5-diethynylphthalonitrile [35].

TrimethylsilytacetyIene (21) was coupled with 4,5-diiodophthalonitrile (1 l ) , in the

presence of Pd(PPh&CI, and Cul catalysts to afford 4,5-di(2-trimethylsilylethynyl)

phthalonitrile (39) in 70% yield (Scheme 12). This was followed by subsequent

deprotection with tetrabutylammoniurn fluoride (TBAF) in THFIH,O to give 40 in

85% yield.

3 1

NC al + H d i - Pd(PPh3)2C12 I Cul, TEA

NC (24h, r. t-) NC 1 4 21

TBAF _____Ct

THF / H20 NC

39 (1 hl r. L) 40

Scherne 12. Synthesis of 4,5diethynylphthaIonitrile

The first coupling reaction was attempted under acidic Glaser conditions,

using 10 equivalents of 1 -hexyne (41) in the presence of copper (1) chloride and

ammonium chloride in EtOH/THFlH,O at room temperature (Scheme 13). The

reaction was stirred for 18h Mi le a Stream of air was introduced through the

mixture, but a TLC probe using benzene as eluent revealed only unreacted starting

materials. This reaction was repeated at 60°C, and then using oxygen in place of

air, but the same results were obtained.

air or O2 r- t or 600C

Scheme 13. Attempted synthesis of 4,5-di(l,3-octadiynyl)phthalonitrile (42) using Glaser conditions

These conditions were subsequently abandoned in favour of Eglinton

cunditions, Mich have already been succeçsfulty ernployed in our Iaboratory in the

synthesis of 1 ,Qdi(3,4-dicyanop heny 1)-1.3-butadiyne (45) via oxidative cou pl ing of

4-ethynylphthalonitn'le (44) 1361 (Scheme 14). In this reaction it was noticed that 4-

(2-trimethytsilylethynyl)phthalonitrïle (43), under Eglinton conditions (Le.: dissolved

in a mixture of pyridine, methanol and wpper (Il) acetate), undergoes rapid

hydrolysis at room temperature to give 4-ethynylphthalonitrile (44) in high yield.

further heating of the reaction mixture to 55OC promoted dimerkation of 44 to give

45 in 70% yield.

Nc'

Scherne 14. Synthesis of 1,4-di(3,4-dicyanopheny1)-1,3-butadiyne (45) utilizing Eglinton conditions

The synthesis of 42 was then attempted once again using Eglinton

conditions. A variable excess of 1 -hexyne (41) (from 10-20 equivalents) was

reacted with 4,5di(2-tnrnethy1sifylethynyl)phthalonitrile (39) in a mixture of pyridine,

methanol and copper (II) acetate at 5S°C to give 42 in yields ranging from 5-12%

(Scheme 15). It was found that a greater excess of 1 -hexyne did not significantly

improve the yield, and served only to further contaminate the reaction mixture with

the homocoupled side-product, dodem-3,&diyne (46). The major product of this

reaction appeared to be an insoluble black material wtiich could not be

characterized. The reaction was repeated under the same conditions, using 40 in

place of 39, but similar results were obtained (Scheme 15). Another attempted

modifidion involved varying the reaction temperature from 0°C to 70°C, but it was

discovered that lower temperatures did not improve yields, and that higher

temperatures and longer reaction times led to to decomposition of the product.

Further modifications included varying the reaction concentration, its water content,

and the order and rate in which the starting materials were combined, but no

significant improvements were achieved under any conditions. Under some of

these readion conditions, 1 -hexyne (41) was replaced with 3,34Ïmethyl-1 -butyne

or 1 -phenylacetyIene, but again, no significant differences were observed.

Cu(0Ach / pyr, / MeOH *

55%

41

Scheme 15. Synthesis of 4,5-di(l,3-octadiynyl)phthalonitrile using Eglinton conditions

Both the Glaser and Eglinton methods are generally not well suited for

heterocoupling reactions due to, among other problems, the difFkulties offen

encountered in separating the inevitable mixture of products. It is also clear from

the results already obtained, that an alternate strategy was needed in order to

synthesize the desired diynyl phthalonitriles (18) in reasonable yield. A more

suitable approach to the synthesis of unsymmetrical diynes was thought to be with

the use of the Cadiot-Chodkiewicz method. As previously discussed, this involves

the cuprous salt catalyzed coupling of a terminal aikyne and a bromoalkyne

(Scheme 1 IC), but one disadvantage to this method is the additional step required

to synthesize a 1 -bromoalkyne.

Although nurnerous methods exist for the preparation of 1 -brornoalkynes

[371, the hypobromite method introduœd by Strauss [33, 38, 391 appeared to be the

easiest and most wnvenient. Phenylacetylene (15) was sonicated in a mixture of

KOH, H,O and Br2 for 18 hours at room temperature to afford 1 -bromophenylacetyl-

ene (47) in 87% yield (Scheme 16A). Subsequent reaction of 47 with 40 in the

presence of CUCI, NH,OH-HCI, EtOH, Y0 and ethylamine (Cadiot-Chodkiewicz

conditions) resulted only in the dewmposition of 40 to an unknown black product,

the recovery of 47, and the isolation of 1,4-diphenyl-1 ,Sbutadiyne (48), the

homocoupled product of 47 (Scheme 16B).

KOH / H20 1 Bi2 sonication, 1 8h - Q - B .

(r. f.) 47

CUCI / NH20i+ HCI EMH2 -

EtOH 1 H20

Scheme 16. Attempted Cadiot-Chodkiewicz wupling of 40 with 47

In a variation of the previous reaction, it was decided to attempt the same

coupling using 415-di(2-bromoethynyl)phthalonitrile (49) and phenylacetylene (15)

in place of 40 and 47 (Scheme 178). The hypobromite method used to synthesize

47 was unsuitable for the synthesis of 49 since the strongly alkaline conditions

wu ld likely muse hydrolysis of the nitrile groups. A more convenient method was

found using N-brornosuccinimide (NBS) and AgNO, in aœtone at room temperature

[40, 411 (Scheme 17A). After only 15 minutes, this reaction produced 49 cleanly,

in 91% yield. Subsequent reaction of 49 with 15 under Cadiot-Chodkiewicz

conditions, once again produced not 415-di(4-phenyl-l,3-butadiynyl)phthalonitrile

@O), but rather 48 in low yield as well as an unidentified black product. This

reaction was repeated using 1-hexyne (41) in place of 15 under the same

conditions, only to yield similar results

acetone 15 min. (r, t) NC

Scheme 17. Attempted Cadiot-Chodkiewicz coupling of 49 with 15

37

Since the Cadiot-Chodkiewïcz method had proved to be unsuccessful in

these reactions, alternative methods for synthesizing unsymmetrical 1 -3-diynes

were sought. It has been recently reported that similar unsymmetricsi couplings

have been performed between 1-haloalkynes and 1-alkynes using catalytic

quantlies of a copper (1) salt in pyrrolidine, with and without using Pd(PPh,),CI, as

w-catalyst [42]. The wupiing reactions between 40 and 47 and between 49 and

15 were subsequently repeated in pyrrolidine, using 1 0% Cul and 5% Pd(PPh,)&I,.

(Scheme 18). These reactions once again produced similar results to those

obtained under Cadiot-Chodkiewicz conditions, that is, the isolation of 48 and the

formation of an unidentified black material. It was speculated that this black

materiaf may be polymers of 40, the formation of which may be unavoidable under

these types of conditions.

5% Pd(PPh3)2C12 pyrrolidine *

Scherne 18. Atternpted wupling between 40 and 47, and between 49 and 15 using Cul and Pd(PPh,),CI, catalysts in pyrrolidine

If the polyrnerization of 40 or 49 does indeed act as a cornpetitive side-

reaction, then it became clear that an alternative approach to synthesizing 4,5-di-

(1 ,3-butadiyny1)phthalonitnleç (1 8) needed to be adopted. A proposed

methodology involved first, the synthesis of the 1,3-butadiynyl moiety, followed by

a palladium catalyzed cross-coupling wïth 4,5diiodophthaIonitrile (1 1) (Scheme

19B). To accomplish this, a Cadiot-Chodkiewïcz reaction c m be used to couple a

1 -bromoalkyne with trimethylsilyla~@lene (21 ), followed by de protection to liberate

the 1,3-butadiyne. (Scheme 19A).

A) Cadiot-

R B r + H - 1 Chodkiewicz - Si- R = = Si- I I

1 deprotection R = = Si- , R H

I

Pd(PPi13)~cl~ Cul / TEA

Scheme 19. Proposed alternative approach to the synthesis of 18

39

Coupling between 1 -bromophenylacetylene (47) and trimethylsilylacetylene

(21) was attempted under Cadiot-Chodkiewicz conditions, but resulted onIy in the

formation of 48. It has been suggested that 21 decomposes in the presence of Cu'

[31], so the reaction was repeated using the more robust fert-butyldirnethyl-

silylacetylene (51) to Mord 1 -phenyl4terf-butyidirnethyfsilyl-l,3-butadiyne (52) in

35% yield (Scheme 20A). This was followed by desilylation of 52 using TBAF to

give 1 phenylbuta-1,34iyne (53) in 55% yield (Scherne 208), and then CO upling this

to 1 1 using Pd(PPh&CI, and Cul in TEA, gave 4,5-di(4-phenyl-1,3-butadiyny1)-

phthalonitrile (50) in 25% yield (Scheme 20C).

A) CuCl I NH 20H- HCI EWH2

EtoH / H20 51 52

47

Scheme 20. Synthesis of 4,5-di(4-phenyl-1,3-butadiynyl)phthalonitrile (50)

Phthalmitrile 50 was not converted to its respective phthalocyanine because it was

speculated that, based on the extrerne insolubility of 17, this Pc would most likely

be just as insoluble. The synthesis of this mode1 compound was therefore used

onty to establish a feasible pathway through which to synthesize other 4,5-

butadiynyl substituted phthalonitriles. In fa&, 50 itself was rather insoluble in mostt

solvents, which made it difficult to purifi and as a wnsequence, acceptable 'H-

NMR and 1 3 C - ~ ~ ~ spectra could not be obtained. However, the El-MS of 50 d i a

show the parent ion (W, mh = 376) and signals consistent h t h charged fragments

arising from cleavage of the phthalonitrile moieties. Also, as is typical with somet

polyacetylene compounds, 50 did not exhibit a melting point, but rather charred tw

a black solid as the temperature was increased. Although, by dropping a crystall

onto a Kofler block heated at incrementally higher temperatures, it was found thaE

50 exhibits a sharp decomposition point at 265OC, at which it ignites with a flame.

One goal of this project was the synthesis of a 4,5-bis(4-alkyl-1,3-butadiynyl)t

phthalonitrile, such as 42, in a reasonabte enough yields to allow for its subsequent

condensation to the phthalocyanine. It was therefore decided that phf halonitrile 42:

be re-synthesized using this newly established route. The desired silyl-protected

oda-Il3-diyne (55) w s synthesized from terf-butyldirnethylsilyi-acetylene (51) and

1 -iodohexyne (54, which was itself prepared in 51 % yield by reacting l -hexyne

(41) with ethyl Grignard and iodine [37, 431 (Scheme ZIA). Cadiot-Chodkiewicz

conditions were once again employed for the wupling, to yield 1-(tert-

butyldimethylsil yl)-1 ,3uctadiyne (55) in 27% yield (Scheme 21 B), after repeated

chromatography using Rash silica gel and hexane as eluent. Difficulties w r e

encountered in purifying 55 since the two other side products, 1,4-bis(tert-

butyldimethylsilyl)-1,3-butadiyne (56) and 3,S-dodecadiyne (46) tended to co-

chromatograph with the product. Subsequent deprotection of 55 to give 1,3-

octadiyne (57) was attempted using TBAF in THF/H,O [44, 451, first at room

temperature, then at 70°C for 5 days, but without success (Scheme 21C).

Deprotedion w s also attempted using aqueous 5M NaOH in H20NeOHITHF 1461,

and weth HOAdTHFIH,O [44], but again without success.

1) EtMgBr / Et 2 0 H = n 1 = n

2) 12 , reflux, 1 h 41 54

CuCl/ NH 20H- HCI EtNH2

EtOH /H20 54

Scheme 21. Attempted preparation of Il3-octadiyne (57)

The exœptional stability of 55 to desilylation prompted further investigation

into alternative coupling procedures that would tolerate the more labile and less

expensive tnmethylsilyl protecting group. One such procedure, which claimed good

yields of I13-diynes, was based on a PdKu catalyzed crosscoupling between an

alkyne and an iodoalkyne [47, 481. The synthesis of 57 was attempted once again

using this procedure, as outlined in Scheme 22. lodoalkyne 54 reacted with

tnmethylsilylaœtylene (21) in the presence of Pd(PPh&CI, and Cul in triethylamine

to give 1-(trimethylsilyl)-l,3-octadiyne (58) in 47% yie!d after repeated flash

chromatography using silica gel and hexane as eluent. This compound was then

treated wïth 5M aqueous NaOH in MeOH for 15 minutes at room temperature

- n + = S i - Pd(PPh 3)2c12 m -si I = = 54 21 1 I 58

CUI 1 TEA 18h. r. t.

I -si = = 5M NaOH H z = l-7 1 MeOH 58 025h, r, t 57

Pd(PPh3)2C12 mi+,= = N 1 Cul l TEA 18h, r. t

11 57

Scheme 22. Synthesis of 4,5-di(l,3-octadiyny1)phthalonitrile (42)

[46] to give the desilylated product 57 in 70% yield. This crude product was

immediately wupled with 4,5diiodophthalonitrile (1 1 ), using Pd(PPh,),CI, and Cul

to give 4,5-di(l,3-octadiynyl)phthalonitrile (42) in 41 % yield (Scheme 22)

Condensation of 42 to 2,3,9,10,16,17,23,24-octa(1,3-octadiynyl)phthalo-

cyanine (59) was attempted using LVDMAE (Scheme 23), but this resulted only in

the formation of an insoluble black material immediately upon contact with the

alkoxide solution. It was speculated that the phthalonitrile may have become

deprotonated at the carbon alpha to the octadiynyl triple bonds, and that this may

have resulted in the formation of polymeric products.

U I DMAE +

Scheme 23. Attempted synthesis of 59

44

This problem led us to subsequenuy redired our focus back to the synthesis

of 4,5-di(4-ary~-1,3-butadiynyl)phthalonitriles, which do not possess these a

hydrogens- While wrking in parallel with the synthesis of 24 and 25a, attempts

were made to synthesize 4,s-di[4-(p-tert-butyf pheny1)-1,3-butadiynyllphthalonitrile

(63), using a similar methodology as that used for 42 (Scheme 24). Terminal

acetylene 23 was converted to 1 -iodo-2-@tefi-butyIpheny1)acetylene 60 in 70%

yield by reaction with ethyl Grignard and 1,. lodoacetylene 60 was then coupled

th 21 using Pd(PPh,),CI, and Cul as catalysts to give 1-@-tert-butylphenyl)4-

tn'rnethylsilyl-113-butadiyne (61) in 60% yield. This cornpound was then desilylated

using TBAF in THF/H,O to afford 1 -@-tert-butylpheny1)-1,3-butadiyne (62) in 88%

as a white solid, which gradually began to darken on exposure to air and Iight. It

was at this point that the extreme insolubility of 25a was discovered, and it was felt

that a Pcfrom 63 would be just as insoluble. The synthesis of phthalonitrile 63 was

therefore not attempted, and this scheme was abandoned in favour of the synthesis

of 4,5-di[4-(pneopentoxyphenyl)-ll3-butadiynyl]phthalonitrile (68). Based upon the

solubility of 34a1 it was hoped that the Pc of 68 muid possess the same favourable

solubility characteristics, which would eventually aid in its purification and

characterization.

2) 12, reflux, 1 h

/ \ I mql + H = Si- Pd(PP Cul /TEA h3)2C12 = = si- I I

60 21 (18h, r. t.) 61 I

Scheme 24. Synthesis of 1 -@-terf-butylpheny1)-1,3-butadiyne, and structure of proposed phthalonitrile 63

The synthesis is of 68 was based on the same methodology as that for 63,

and is outlined in Scheme 25. Alkyne 32, upon reaction wïth ethyl Grignard and 1,

gave 1 -iodo-2-(p-neopentoxyphenyl)acetylene (64) in only 26% yield. The major

product of this reaction was the hornocoupled dimer of 32, 1,4-di@-neopentoxy-

pheny1)-l,3-butadiyne (65). Although these types of dimerizations are not unknown

under these conditions [31], it w s unexpected, considering the high yietd obtained

1. Pd(PPhnhClz + H = SI- I Cul / DlPA

TBAF - THF / H20

66 (0.25h, r. t)

Scheme 25. Synthesis of 4,5-di[4-(p-neopentoxypheny1)-l,3-butadiynyl] phthalonitrile (68)

47

for 60. This was followed by coupling ~ A t h 21, again using Pd(PPh,),CI, and Cul

as catalysts in diisopropylamine (DIPA), to afford 1-@neopentoxyphenyl)-4-

(trïmethylsilyl)-113-butadiyne (66) in 29% yield. Subsequent desilylation using 5M

aqueous NaOH in MeOH at room temperature, gave 1-@neopentoxyphenyl)-1,3-

butadiyne (67) in 95% yield as a white solid, whi* rapidly darkened upon exposure

to air and Iight. This was followed immediately by a palladium catalyzed cross-

coupling with 11, to give 68 as a golden-yellow solid in 75% yield. Satisfactory 'H-

NMR, 1 3 ~ - ~ M R , IR and mass spectral data was obtained for this compound and for

its intermediates, but the elemental analysis for 68 exhibited low carbon values. As

with 50, this wmpound did not exhibit a rnelting point but rather, a sharp

decornposition point at 223OC, at which it became a black tar. It is possible that this

property may have contributed to the low carbon value as a result of incornplete

combustion. On the other hand, a higrh resolution mass spectrum (HRMS) of

phthalonitrile 68 exhibited as the base peak, an ion signal at m/z = 548.2464,

corresponding to the exact mass of the parent ion.

Condensation of 66 to 2,3,9, IO, 16,17,23,24-octa[4-@neopentoxyphenyl)-

1,3-butadiynyllphthaiocyanine (69a) was. attempted using lithium 1-octoxide in 1 -

octanol at 80°C (Scheme 26). After 18 hours, a UV-VIS probe of the dark-green

reaction mixture in THF revealed a sharp absorption ai 738 nm (Figure 9), which

is believed to correspond to the Q-Band absorption of

Scherne 26. Attempted synthesis of Pcs 69a and 69b.

dilithium-2,3,9,10, 16,17,23,24-octa[4-(pneopentoxyphenyl)-l,3-butadiynyl]-

phthalocyanine (69b). The reaction was wrked up by diluting with EtOHl3 M HCI,

centrifuging and collecting the precipitate (after several repeated

dissolutionlreprecipitation cycles from EtOWH,O). Unexpectedly, upon contact with

EtOHIH,O', the originally dark green suspension turned brown and formed an

insoluble precipitate. A UV-VIS spectmm of this material showed a marked

decrease in the intensity and sharpness of the absorption in the Q-Band region,

which suggests decompostion of the material (Figure 10).

Figure 9. UV-VIS spectral probe, condensation reaction of 68 to Pc 69b

Figure 10. UV-VIS spectrurn of acid treated reaction mixture

50

Thin-layer dirornatographic W C ) analysis of this brown material using 95:5

CH,CIJEtOH revealed a nurnber of bright yellow forerunning wrnponents (none of

which w r e starting material) and a brownlgreen matefial at the baseline. Column

chromatography on this material using fiash-grade silica gel and 955 CH,CIJEtOH

as eluent removed these forerunning wmponents, but the material at the baseline

could not be flushed from the column using benzene, toluene or THF. A Soxhlet

extraction of a portion of the silica gel from the column was perfoned using THF,

but a UV-VIS analysis of the resulting extract did not reveal any significant

absorption in the Q-Band region of the spednim. This reaction was repeated under

the same conditions, except that zinc acetate was added after 18 hours in an

attempt to isolate the zinc derivative of 69a [23]. It was hoped that the Zn(ll) Pc

might be more stable than 69b, but aqueous workup of this reaction similarly

resulted in the formation of an insoluble brown material.

Since the isolation of 69a was proving to be difficult, it was hoped that at

least 69b could be isolated with some success. Also, since the dilithio Pc 34b had

already been characterized, a direct cornparison of their UV-VIS spectra could still

be made. The absorption at 738 nm certainly suggested the presence of 69b, and

it was this peak that was used as a diagnostic aid during purification. The

condensation reaction was repeated under the same conditions as previously

reported, but was worked up by diluting ~ 4 t h anhydrous THF followd by

precipitation into hexane. This was repeated twice more and then the crude solid

51

was loaded onto a flash silica gel column packed in methylene chloride. Elution of

the column with the same solvent effected the separation of several unknown

bright-yellow components from the dark baseline material. A subsequent flush with

THF caused some of this dark material to elute from the wlumn as a brownlgreen

solution, from Mich precipitated out a brown solid upon standing. Analysis of these

solids by UV-VIS spectroscopy revealed the absence of any sharp absorptions at

738 nm, suggesting that the compound may have demetallated or decomposed

m i l e in contact with the silica gel.

The readion w s repeated once more using the same THFthexane workup

procedure as previously described, but the crude solid was loaded directly ont0 a

gel-pemeation column (SX-2 ~ i obeads~ ) packed in freshly distilled THF. Careful

elution of this column with dry THF resulted in the collection of a dark green

material over several small fractions. Analysis of these elutions by UV-VIS

spectroscopy revealed a sharp absorption at 738 nm in most fractions, as well as

absorptions of varying intensities in the 200-500 nm region. The fractions with the

least intense absorptions in the latter region were combined, and the solvent

evaporated to yield a dark green solid. A UV-VIS spectrum of this material,

beiieved to be Pc 69b, is shown in Figure 11. A comparison of this spectrum with

that for 34b (Figure 6) suggests that the additional 8 conjugated triple bonds on 69b

have the effect of increasing the red shift by an additional 18 nm. In comparison

with the spectrum for 13a (Figure 7), the imparted red shift appears to be 38 nm.

52

Figure 11. UV-VIS spectrum of material believed to be Pc 69b

Proton NMR analysis of this material in pyridine-d, at 300K, showed a

spectrum which was consistent with the structure of 69b. Two singlets were

displayed at 1 .O8 and 3.61 ppm, which would correspond to resonances arising

from the protons on the 8 neopentoxy groups. The aromatic signals arising from the

outer neopentoxyphenyl groups were found as 2 doublets centered around 6.92

and 7.67 pprn, and the 8 benzo protons on the Pc macrocycle were found as a

singlet at 9.98 pprn (Figure 12). Unfortunately, FAB-MS analysis of this material did

not exhibit any ion signals in the expected mass region, and sufficient quantities of

the purified sample w r e not available for elemental analysis. This compound was

not resynthesized due to time constraints, and remains without full characterization.

Figure 12. Aromatic region of 'H-NMR spectrum of material believed to be Pc 69b (pyridine-d, 300Y 4.53~1 O4 M)

The self-condensation of 4,5di(phenylethynyl)phthalonitrile (1 6) with lithium

1-octoxide in î-octanol gave what is believed to be the desired product,

2,3,9,10,16, .17,23,24-octa(phenylethynyl)phthaiocyanine (17) as a highly insoluble

green material. Attempts were made at increasing the solubility of this Pc by

functionalizing the peripheral phenylethynyl groups with bulky substituents. It was

found however, that the self-condensation of 4,5-di(p-te&butylphenylethynyl)-

phthalonitrile (24) produced a green material that was just as ins~iuble as 17,

although the same reaction with 4,5di(p-neopentoxyphenylethynyl)phthalonitrile

(33) produced an odaphenyiethynyl Pc (Ma) which was reasonably soluble in most

organic solvents. The UV-VIS absorption of 34b at 720 nm shows that the 8

peripheral phenyl groups have the effect of red-shifting the Q-Band absorption by

20 nm compared to that of 13a.

The synthesis of 4,5ai(butadiynyl)phthalonitriles by classical alkyne-alkyne

or alkyne-haloalkyne coupling methods showed little or no success when 4,5-

diethynylphthalonitrile (40) or 4,5-di(2-bromoethynyl)phthalonitrile (49) were used

as substrates. It was speculated that under Eglinton and Cadiot-Chodkiewicz

conditions, 40 undergoes rapid polymerization, leaving an insoluble black residue

as the major product.

It w s found howver that substituted 4,5-bis(butadiyny1)p hthaloni triles could

be successfully synthesized using a modified coupling procedure. A 1 -iodoalkyne,

coupleci with trÏmethylsilylacetylene (21) using a palladium catalyst has afforded 1 -

trimethylsilyl protected 1,3-butadiynes- Desilylation using aqueous base, followed

by palladium cross-mupling with 4,5-diiodophthalonitrile (11) has successfully

yielded alkyl- and aryl-substituted 4,5-di(butadiyny1)phthalonitriles 42 and 68

respectively. Attempts to convert 42 to its respective Pc (59) by reaction with

lithium/DMAE resulted in the immediate formation of an insoluble black material.

It was speculated that the phthalonitrile may have become deprotonated at the

carbon alpha to the octadiynyl triple bonds, and that this rnay have resulted in the

formation of polymeric products. The selfcondensation of 68 on the other hand,

using lithium 1 -octoxide and 1 -octano1 gave a dark-green product, presumed to be

dilithium Pc 69b. Unexpectedly, an aqueous workup of this product resulted, not

in demetallation to 69a, but rather in decomposition. Although the seeming

instability of these Pcs may preclude their use as potential candidates for third-

order nonlinear optical investigations, phthalonitriles 33 and 68 may themselves be

of interest as second order NLO materials [28$

General Methods

Unless otheMse noted, al1 reaction processes w r e perforrned using

rnagnetic stirring rnethods under an inert atmosphere of Matheson high-purily

argon. Water-woled condensers were used if reaction processes were held near,

or at reflux conditions and round bottomed glass vessels chosen such that the

quantity of reagents and solvent did not exceed half of the available volume. All

organic solvents were dried by appropriate methods and distilled before use.

Ultrasound activation was carried out using a Branson 1200 sonicator. Thin-layer

chromatography (TLC) was perfoned using Merck silica gel 60 F, polyester-

backed plates and column chromatography was perforrned using Caledon Rash

grade silica gel 60 of particle size 40 - 63 Mm. Gel permeation chromatography was

perforrned with Bio-Rad SX-2 ~iobeads~, using THF as the eluting solvent. lnfrared

(IR) spectra were recorded on a Unicam Mattson 3000 FT-IR spectrometer using

samples prepared as KBr discs, unless otheWse noted. Ultraviolet-visible (UV-

VIS) spectra were recorded on a Hewlett-Packard HP8451A diode array

spedrophotometer using M F as the solvent Melting points (mp) were determined

using a Kofier hot stage melting point apparatus and are reported uncorrected.

Nuclear magnetic resonance (NMR) spectra for proton and carbon were recorded

on a Bruker ARX 400 high field Fourier transform instrument at room temperature

57

unless otheMse stated. Chemical shifts are reported in parts per million relative

to a tetrarnethylsilane (TMS) intemal standard. Splitting patterns of proton

resonances are described as singlets (s), doublets (d), triplets (t), quartets (q),

doublet of doublets (dd), multiplets (m) or as broad signals (br). Coupling constants

for signals other than singlets and multiplets are reported in Herk Resonances are

reported as the proton decoupled chernical shifts for 13C NMR spectra. Electrm-

impact mass spectral analyses (El-MS) w r e perfomed by Dr. B. Khouw (York

University, North York, Ontario, Canada), Ms. Lisa Nelson (York University, North

York, Ontario, Canada) and Dr. R. Smith (McMaster University, Hamilton, Ontario,

Canada). Fast atom bornbardment (FAB) and high resolution mass spectrometric

analyses (HRMS) were performed by Dr. R. L. Cemy (Nebraska Center for Mass

Spectrometry, University of Nebraska-Lincoln, Lincoln, Nebraska, U. S. A.).

Elemental analyses were perfomed by Guelph Chemical Laboratories Ltd., Guelph,

Ontario, Canada).

Svnthesis of 4.5-diiodo~hthalonitrile (1 1).

This compound was prepared in three steps according to a published

procedure 1231 (overall yield 50% from phthalimide); mp 216-217°C (lit. [23], 216-

Svnthesis of 4.5-di(~henvlethvnvl~hthalonitrile (1 6) General Procedure.

To a solution of 200mg (0.53 mmol) of 4,5-diiodophthalon itrile (1 1 ) dissolved

in 30 mL of TEA were added 36 mg (0.051 mmol) of Pd(PPh,),CI,, 10 mg (0-051

mmol) of Cul, and then 0-13 m l (0.1 1 g, 1.2 mmot) of phenylacetylene. The

reaction was heated to 60°C for 2 fi under argon and then allowed to cool to room

temperature ovemight The reaction was analyzed by TLC using benzene as

eluent, and judged complete by the disappearance of the starting material. The

solvent was removed by rotary evaporation at 40°C, the residue was suspended in

ethyl acetate, suction filtered through d i t e and then the solvent was removed from

the filtrate in vacuo at 40°C. This brown residue was chromatographed with flash

grade silica gel using 982 hexane-ethyl acetate to afford 16 as a yellow solid (121

mg, 70% yield): mp 1 90-1 92%; IR (KBr) 221 7 (C=N) cm-' ; UV-VIS (THF) A- nrn

222,276, 301, 345; 'H-NMR (CDCI,) 5 7.93 (s, 2H), 7.59 (d, J = 7.1 HZ, 4H), 7.43

(m. 6H); 1 3 C - ~ ~ F 3 (CDCI,) 6 136.34, 132.22, 131 -09, 13021, 128.92. 121.72,

1 14.90, 1 l4.27, 1 UO.70, 85.74; El-MS m/z (%) 328 (M', 100). Anal. calcd. for

C,,H,,N,: C, 87.79; Hl 3.68; N, 8.53. Found: Cl 87.72; H, 3.66; NI 8.42.

59

Attem~ted synthesis of 2.3.9.10.16.1 7.23.2~ctaphenvlethynyI~hthalocvanine (1 7).

To a vigorously stirred suspension containing 50 mg (0.1 5 mmol) of 16 in 2

mL of l-octanol was added 20 mg (2.9 mmol) of lithium metal. The reaction mixture

was heated at 80°C for 6 hours, at which point a TLC probe using benzene as

eluent revealed complete consumption of the starting material. A UV-VIS probe of

the reaction in dry THF revealed absorptions at 720, 392 and 300 nm. The reaction

mixture was then diluted wïth 20% ethanollH2Q and centrifuged. This

dilutionlcentrifugation cycle was repeated several times until a solid dark green

material was colleded. Further purification or analysis of this material was not

compieted due to its extreme insolubility.

Svnthesis of 1 -trirnethvlsilvl-2-@-tert-butvl~henvI)acetvlene (22).

lnto a 100 mL pressure bottle was placed 0.87 mL (1.1 g, 5.0 mmol) of 1 -

bromo4terf-butylbenzeneI 0.23 g (0.32 mmol) of Pd(PPh,),CI,, 19 mg (0.1 0 mmol)

of Cul and 50 mL of I E A . This yellow suspension was degassed argon for

approximately 5 minutes, and then 1.5 mL (1 .O g, 10 mmol) of (trimethylsily1)-

acetylene was added. The bottle was sealed and heated in an oil bath at 95OC

ovemight The reaction mixture was allowed to cool to roorn temperature and was

then filtered through celite. The solids w r e washed vvith ethyl ether until the

washings wwe colourless and the filtrate was evaporated to dryness under reduced

pressure. The residue was chromatographed with flash grade silica gel using

60

hexane as the eluent to give 22 as a pale yellow oil (898 mg, 78% yield): 'fi-NMR

(CDCI,) 6 7.40 (d, J = 8.6 Hz, ZH), 7.31 (d, J = 8.5 Hz, 2H), 1.31 (s, 9H), 0.25 (s,

QH); ElMS mh (%) 230 (NT, 58), 21 5 (1 00). The 'H-NMR spectrum matched that

of the previously reported compound [49].

Svnthesis of ptert-bu@lphenvlamtylene (23).

To a stirred solution of 200 mg (0.87 mmol) of 1-trirnethylsilyf-2-(p-te&

butylpheny1)acetylene (22) dissolved in 1 0 mL of MeOH was added 0.5 mL (2.5

mmol) of 5 M NaOH. After 15 minutes, the reaction mixture was acidified with 1 M

HCI, extracted twice with hexane and the extracts were dried over MgSO,.

Filtration, followed by evaporation of the filtrate in vacuo gave 23 as a pale yellow

liquid (1 34 mg, 98%): IR (neat) 21 09 (C-C) cm-'; 'H-NMR (CDCI,) 6 7.44 (dl J = 8.6

Hz, 2H), 7.35 (dl J = 8.1 HZ, 2H), 3.03 (S. 1 H), 1 -32 (s, 9H). The ' H-NMR spectrurn

matched that of the previously reported compound 1491.

Svnthesis of 4.5dilo-tefi-butvlphenvlethynvI~~hthalontrfe 124).

The sarne procedure was used as for the synthesis of 16, using 1 .O g (2.6

mmol) of 11, 1 .O g (6.3 mrnol) of 23, 222 mg (0.32 mrnol) of Pd(PPh,),CI,, 30 mg

(0.16 mmol) of Cul and 30 mL of TEA to give 1.0 g of 24 in 88% yield: mp 168-

169OC; IR (KBr) 221 3 (C=N) cm-' ; UV-VIS (THF) A, nm 21 4,279, 309, 354;' H-

NMR (CDC13) 6 6-91 (S. 2H), 7.53 (dl J = 8.4 Hz, 4H), 7.43 (d, J = 8.6 Hz, 4H), 1.36

(s, 18H); ' 3 ~ - N ~ ~ (CDCI,) 6 153.81. 136.36, 132.09, 131.23, 125.96, 11 8.79,

1 15-04, 1 13.99. 101 -09, 85.45, 35.27, 31 -34; El-MS m/z (%) 440 (M', 60), 426

(1 00). Anal. calcd. for C,H,N,: Cl 87.24; HI 6-41 ; N, 6.36. Found: Cl 87.25; H,

6.42; N, 6.1 2-

Svnthesis of neopentyl tosvlate (28).

To a stirred, ice-water cooled solution of 50 g (0.57 mol) of neopentyl alcohol

in 350 mL of pyridine was slowfy added a solutiori of 162 g (0.85 mol) of p-

toluenesulfonyl chloride in 200 mL pyridine. The resulting cloudy brown mixture

was allowed to stir ovemight at room temperature, after which time the pyridine was

rernoved by rotary evaporation at 45OC. To the remaining residue was added 300

mL of ice-cold water, and the mixture was stirred for 1 hour. The mixture was

extracted 3 times with 200 mL portions of ethyl ether, and the combined organic

layers w r e washed with successive 200 mL portions of 1 M HCI, sat NaHCO,, H,O

and then brine. The extract was dried over MgSO,, filtered, and the solvent was

removed in vacuo to leave 28 as an amber oil. This crude product was crystallized

frorn MeOHfH,O to afford a white crystalline solid (1 16 g, 85% yield): mp 484g0C

(lit 1501, 47-4û°C); 'H-NMR (CDCI,) 6 7.76 (d, J = 8.4 Hz, 2H), 7.32 (dl J = 8.1 Hz,

2H). 3.63 (s, 2H). 2.42 (s, 3H), 0.87 (s, 9H); '3C-NMR (CDCld 6 144.75, 133.20,

129.91, 127.97, 79.59, 31.71, 26.10,21.69.

62

S~nthesis of piodoneo~entoxybenzene (30).

A mixture of 10 g (45 mmol) of 4-iodophenol (29), 12.1 g (50 rnmol) of

neopentyl tosylate (28) and 2.8 g (50 mmol) of potassium hydroxide in 30 mL of

hexamethylphosphoramide (HMPA) was vigorously stirred at 100°C for 3 days. This

mixture was then poured into 300 mL of H,O and extracted 3 times vvith 100 mL

portions of ethyl ether. The combined ether extracts were successively washed

vvith 100 mL portions of H,O, 1 M HCI, H,O, and then brine, followed by drying over

MgSO, filtration and removal of the solvent by rotary evaporation. The remaining

amber oil was chromatographed using silica gel and hexane as eluent to afford 30

as a clear, colourless liquid (10.8 g, 82% yield): UV-VIS (THF) A- nm 234, 282;

'H-NMR (CDCI,) 6 7.54 (dl J = 8.8 Hz, 2H), 6.68 (dl J = 8.8 Hz, 2H), 3.55 (s, 2H),

1.03 (s, 9H); 13C-NMR (CDCI,) 6 159.65, 138.27, 1A7.17, 82.50, 78.16, 32.05,

26.78; EI-MS mh(%) 290 (M', 60). 220 (100). Anal. calcd. for C,,H,,IO: CI 45.54;

H, 5.21 - Found: Cl 45.47; H, 5.36.

Svnthesis of 1 -trirnethvlsilvl-2-(p-ne0~ent0~~~henvI~acetylene (31 1-

The same procedure was used as for the synthesis of 16, using 8.0 g (28

mmol) of 30, 4.7 mL (3.3 g, 33 mmol) of trimethylsilylacetylene (21), 968 mg (1 -4

mmol) of Pd(PPh&CI,, 263 mg (1 -4 mmol) of Cul and 300 mL of TEA, except that

the entire reaction was carried out at room temperature. The crude product was

chromatographed using silica gel and hexane as duent to Mord 31 as a white solid

(6.3 g, 88% yield): rnp 78-7g°C; IR (KBr) 2157 (C-C) cm-'; UV-VIS (THF) A, nm

214,261 ; 'H-NMR (CDC13) 6 7.39 (d, J = 8.4 Hz, 2H), 6.81 (dl J = 8.6 Hz, 2H), 3.59

(s, ZH), 1.04 (s, 9H). 0.25 (s, 9H); 13C-NMR (CDCIJ 5 160.02, 133.62, 1 15.1 7,

1 14-60, 105.63, 92.39,78.08, 32-08, 26.80, 0.32; El-MS mh (%) 260 (M4, 40), 245

(20). 190 (50), 175 (1 00). Anal. mlcd. for Cl,H,OSi: Cl 73.79; Hl 9.29. Found: Cl

73.40; Hl 9.23.

Svnthesis of -p-neopentoxyphenvlacetviene (32).

The same procedure was used as for the synthesis of 23, using 10 g (38

mmol) of 31, 23 mL (1 15 mmoi) of 5 M NaOH, and 600 mL of MeOH to afford 32.

The crude product was chromatographed using silica gel and hexane as eluent

giving the title compund as a clear, colourless oil (6.5 g, 95% yield): IR (neat) 21 O7

(C=C) cm''; W-VIS (THF) nm 21 3,252,293,318, 343; 'H-NMR (CDCI,) 6 7.42

(dl J = 8-7 Hz1 2H), 6-84 (dl J = 8-6 Hz, 2H), 3.60 (s, 2H), 2.99 (s, 1 H), 1.04 (s, 9H);

13C-~MR (CDCI-J 6 160.21, 133.73, 114.71, 114.03, 84-05, 78.1 1, 75-81 , 32.08, 4'

26.78; EI-MS mh (%) 188 (M+, 1 O), 1 18 (1 00). Anal. cal&. for C,,H,,O: Cl 82.94;

Hl 8.57. Found: Cl 82.20; Hl 8.39.

Svnthesis of 4.5-dib-neopentoxyphenvlethvnvl)~hthal~ie (33).

The same procedure was used as for the synthesis of 16, using 760 mg (2.0

mmol) of 11,791 mg (4.2 mmol) of 32, 147 mg (0.32 mmol) of Pd(PPh,),CI,, 40 mg

(0.16 mmol) of Cul and 25 mL of TEA to give 700 mg of 33 in 70% yield: mp 168-

170°C; IR (KBr) 2209 (C-N) cme1; UV-VIS (THF) A, nrn 2?4,252, 284, 325, 366;

1 H-NMR (CDCI,) 6 7.87 (s, 2H). 7.51 (dl J = 8.6 Hz, 4H), 6.92 (dl J = 8.7 Hz, 4H),

3.64 (s, 4H). 1 -06 (s, 18H); 13C-NMR (acetone-d,) 6 162.37, 1 37.24, 1 34.80, 1 31 70,

116.33, 116.03, 114.91, 1 14.66, 101.51,86.12,79.12, 32-69, 27.02; El-MS m/z (%)

501 (M+, 1 8), 500 (55). 360 (1 00). Anal. calcd. for C,H,N,O,: C, 81 -57; HI 6.44;

NI 5.60. Found: CI 81 -00; H, 6.45; NI 5.44.

Svnthesis of 2.3.9.1 0.16.1 7.23.24scta~~neopento~~henvlethvn~l~phthalocvanine

(34a).

To 2.5 mL of dimethylaminoethanol (DMAE) was added 30 mg (4.3 mmol) of

lithium metal. After the metal had completely dissolved, 200 mg (0.4 mmol) of 33

was added to the wII-stinied alkoxide solution, and the reaction mixture was heated

to 1 OO°C for 15 hours. After this time, the reaction mixture was cooled to room

temperature and diluted with 10 mL of 20% MeOH/H,O. After being allowed to

stand for 90 minutes, the reaction mixture was centrifuged and the crude Pc was

collected, dissolved in M F and precipitated from hexane. This crude pigment was

chromatographed using silica gel and CH&!, as eluent, followed by gel permeation

chromatography. This material was further purified by reprecipitation from

benzendethanol and then by chromatography using silica gel and CH,CI, as eluent

to give 34a as a dark green solid (64 mg, 8% yield): UV-VIS (THF) Am,, nm (log e)

716 (6.08), 678 (6.19), 390 (6.18), 330 (6.41), 258 (6.14), 216 (6.23); 'H-NMR

(toIuene-&, 1 .O x 10" Ml 363K) 6 8.71 (br, 8H), 7.71 (d, J = 7.8 Hz), 6.81 (dl J = 8.1

Hz), 3.58 (s, 16H). 1.14 (s, 72H), -4.81 (br, 2H); FAB-MS 2004 (M + 1). Anal. calcd.

for Cl,Hl,N,O,: Cl 81.49; Hl 6.54; N, 5.59. Found: Cl 80.06; H, 5.80; N, 5.27.

Synthesis of 12.3.9.10.16.1 7.23.24-octa@-neopentoxy~vlethvnvl~ohthalocvan-

invl jdilithium (34b).

To a suspension of 10 mg (0.72 mmol) of lithium metal in 2 mL of dry THF

was added 2 mg (1 -0 x Io3 mmol) of Pc 34a. The mixture was stirred ai 50°C for

5 days, after Mich time the excess lithium was removed by filtration and the solvent

was removed in vacuo at 40°C to give 34b (2 mg, 100% yield): UV-VIS (THF) A,,

nm (log s ) 720 (6.89), 686 (6.04), 648 (6.07), 398 (6.52), 316 (6.40), 282 (6.35),

21 2 (6.40); 'H-NMR (pyridined, 4.0 x 1 Ml 33310 6 8.86 (br, 8H), 7.75 (br, 16H),

6.79 (dl J = 7.4 Hz), 3.53 (s, 16H), 1.12 (s, 72H); FAB-MS 201 0 (M - Li), 2004 (M -

2Li).

The same procedure was used as for the synthesis of 16, using 1 .O g (2.6

mmol) of 11,O.g mL (0.65 g, 6.6 mmol) of trimethylsilylacetylene (21), 231 mg (0.33

mmol) of Pd(PPhJ&I, 63 mg (0.33 mmol) of Cul and 60 mL of TEA, except that the

entire reaction was canied out at room temperature. The crude product was

diromatographed using silica gel and 9:l hexanelethyl acetate as eluent to afford

39 as a white solid (591 mg, 70% yiold): mp 157°C; IR (KBr) 2237 (C=N) cm"; UV-

VIS (THF) A,, nm 222,262, 309; 'H-NMR (CDCb) 6 7.84 (S. 2H), 0.29 (S. 18H);

13C-NMR (CDCIJ 6 136.96, 131 -01, 1 14.71, 1 14.52, 107.49, 99.84, -0.172; El-MS

nvt (%) 320 (M+, 90), 305 (1 00). Anal. calcd. for C,,H,N,Si,: C, 67.45; H, 6.29; N,

8.74. Found: Cl 67.51 ; Hl 6.47; N, 8.75.

Svnthesis of 4.5-diethynyl~hthalonitrile (40).

The same procedure was followed as previously reported from 4,s-bis(tert-

butyldimethylsilyl)phthalonitnle [35], using 100 mg (0.31 mmol) of 39, 1 O mL of THF

and using 0.31 mL (0.31 mmol) of TBAF (1 -0 M solution in THF) and 4 mL of H,O

rather than 2 drops and 5 drops respectiveiy. The reaction mixture remained clear

and colourless rather than turning black, as reported. After 15 minutes, the reaction

mixture was extracted 4 times with 20 mL CH#,, the combined extracts were

washed with H,O, dried over MgSO,, concentrated by rotary evaporation and then

chromatographed using siiica gel and CH,CI, as eluent. Evaporation of the

product-rich fractions gave 40 as a white solid (47 mg. 85% yield): rnp 187°C

(decomp) (lit [35], 135OC); 'H-NMR (CDCI,) 6 7.91 (s, 2H), 3.70 (s, 2H); 13C-NMR

(CDCI,) O 137.0, 130.4, 1 15.2, 1 14.2, 88.1 7, 78.63. The 'H-NMR and ' 3 ~ - ~ ~ ~

spectra metûhed that of the previously reported compound 1351.

Svnthesis of 4'5-di(l.3-octadivnvl~hthalonitrile (42).

Method 1.

Using the Eglinton terminal alkyne coupling procedure, 2.1 g (11 mmol) of

copper (II) acetate monohydrate was rnixed with 50 mL of pyridine and 10 mL of

methanol. The mixture was heated to 55°C and then a solution containing 101 mg

(0.32 mmol) of 39 and 257 mg (3.1 2 mrnol) of A -hexyne in 10 mL of pyridine wae

slowly added via syringe over 1 hour. The resulting black reaction mixture was

allowed to cool to room temperature ovemight and was then poured into 200 mL of

cold 5 M HCI and extracted 3 times with 100 mL portions of ethyl ether- The

combined ether extracts were washed with water until neutral, and then dried over

MgSO,, filtered and evaporated in vacuo. The rernaining residue was

chromatographed using silica gel and 9:l hexanelethyl acetate as eluent to give 42

as a pale yellow solid (1 1 mg, 10% yield).

Method 2-

The same proœdure was used as for the synthesis of 16, using 341 mg (0.90

mrnol) of 11, 200 mg (1 -9 mmol) of 1,3-octadiyne (S?), 66 mg (0.094 mmoI) of

Pd(PPh&CI, 18 mg (0.094 mmol) of Cul and 1 O mL of TEA, except that the entire

reaction was carried out at room temperature. The m d e product was

chromatographed with silica ge! using 04% ethyl acetatehexane as eluent to afford

42 as a pale yellow crystalline solid (1 24 mg, 41 % yield): mp 95-96OC; IR (KBr)

2234 (C=N) cm-'; UV-VIS (THF) A, nm 214, 235, 274, 291, 333, 3511 H-NMR

(aœtone-d,) 5 8.22 (s, 2H), 2.51 (t, J = 6.9 Hz, 4H), 1 58 (m, 4H), i -48 (m, 4H), 0.94

(t, J = 7.6 Hz, 6H); I3C-N~R (acetone-d,) 6 138.79, 131 -54, 1 16.12, 1 15-60.

92.1 23, 85-16, 70.96, 65.35, 30.98, 22.81, 1 9.93, 1 3.83; El-MS (%) 336 (M+,

100). Anal. calcd. for C,H,Ni C, 85.68; H, 5.99; N, 8.33. Found: Cl 86.10; Hl

6.21 ; N, 8.62.

Svnthesis of 1 -brornophenvlacetylene !47).

This compound vms prepared acwrding to a published procedure [37] using

16 mL of water, 5.5 g (98 mmol) of potassium hydroxide, 2.0 mL (6.2 g, 39 mmol)

of bromine and 2.2 mL (2.1 g, 20 mmol) of phenylacetylene (1 5) to give a pale

orange oily liquid (3.29, 87% yield): 'H-NMR (CDCI,) 6 7.45 (m, 2H), 7.25-7.35 (ml

3H); 13C-NMR (CDCIJ 6 432.1 6, 128.84, 128.50, 122.86, 80.27, 49.99. El-MS MZ

(%) 180 (M+, 100). The 'H-NMR and 1 3 C - ~ ~ ~ spectra matched that of the previous-

69

ly reported cornpound [51].

Svnthesis of 4.5-di(2-bromoethvnvl)~hthalonitrile (49).

To a solution of 100 mg (0.57 mmol) of 40 in 8 mL aœtone was added 60 mg

(0.35 mmol) of silver nitrate and 0.26 g (1.5 mmol) of NBS. After 15 minutes, the

cloudy white reaction mixture was poured into 50 mL of water, the resulting white

precipitate was collected by filtration and then dissolved in ethyl acetate. The

solution was washed th water and brine, then dried over MgSO,, filtered and

evaporated in vacuo to a beige coloured solid. This solid was dissolved in a

minimum volume of CH,CI, and chromatographed using siiica gel and CYCh as

eluent to give 49 as a white solid (1 74 mg, 91 % yield): IR (KBr) 2233 (C=N), 21 77

(C=C) cm-'; UV-VIS (THF) A, nm 260, 303; 'H-NMR (acetone-d,) b 8.23 (s); 13C-

NMR (aœtone4J 6 138.1 3, 131.37, 1 l6.08, 1 15.55, 76.93, 64.01 ; El-MS mh (%)

336 (M++4, 1 9), 334 (M++2, 50)) 332 (M', 14). 253 (34), 255 (23), 174 (1 00).

Synthesis of 4.5-di(4-phenvl-1.3-butadiynyI~~hthalonitrile (50).

The same procedure was used as for ihe synthesis of 16, using 69 mg (0.1 8

mrnol) of 11, 93 mg (0.74 mmol) of 1-phenyl-1,3-butadiyne (531, 26 mg (0.037

mmol) of Pd(PPh,),CI,, 7.1 mg (0.037 mmol) of Cul and 4 mL of TEA, except that

the entire reaction was carried out at room temperature. The crude produd was

chromatographed silica gel using hexane and then benzene as eluent to afford

50 as a pale yellow solid (1 7 mg, 25% yield): mp 265°C (decornp.); IR (KBr) 2204

(C=N) cm4; 'H-NMR (CDCI,) 6 7.94 (S. 2H), 7.62 (d, J = 7.1 HZ, 4H). 7.49 (t, J =

7.6 HZ, ZH), 7.42 (t, J = 7.5 HZ, 4H); Ei-MS mh (1) 376 (M+, 100).

Svnthesis of 1 -phenvl4-fert-butyldimethvlsily 1-1 .3-butadivne (52).

A solution containing 11 mg (0.1 1 mmol) of copper (1) chloride, 307 mg (4.4

mmol) of hydroxylamine hydrochloride, 2 mL of water, 1.0 mL of a 70% (w/w)

solution of ethylamine in water and 1.16 g (8.3 mmol) of tert-butyldimethylsilyl-

aœtylene were warmed to 50°C with vigorous stirring. To this mixture was slowly

added a solution of 1.0 g (5.5 mmol) of 1 -bromophenylacetylene (47) in 3 mL of

ethanol. The reaction mixture was allowed to stir at this temperatue overnight, after

which time it was neutralized by the addition of coid 1 M HCI. The reaction mixture

was then extracted using ethyl ether, the combined organic layers were washed

water, dried over MgSO,, and evaporated in vacuo. The residue was

chromatographed using silica gel and hexane as eluent to Mord 52 as a white solid

(464 mg, 35% yield): UV-VIS (THF) A,- nrn 203,218, 229, 251,264, 280, 297; 'H-

NMR (CDCI,) 6 7.50 (dl J = 7.7 HZ, 2H), 7.40-7.30 (ml 3H), 1.00 (s, 9H), 0.1 9 (s,

6H); "C-NMR (CDCI,) 6 132.91, 129.51, 128.63, 121 66, 89.57, 88.66, 76-46.

74.57, 26.30, 17.00, 4.59. The UV-VIS spectrum matched that of the previously

reported wmpound 1461.

71

Svnthesis of 1 -phkenvl butadivne (53).

To a solution of 51 mg (0.21 mmol) of 52 in 1 mL of THF and 0.1 mL H,O

was added 0.2 m L (0.2 mmol) of TBAF (1 .O M solution in THF). After 15 minutes,

the reaction mixture was diluted with 2 mL of H20 and extracted 3 times wïth 2 mL

of CH& The combined extracts were washed with H20, dried over MgSO,, con-

centrated by rotary evaporation and then chromatographed using silica gel and

hexane as eluent Evaporation of the product-rich fractions gave 40 as a pale

yellow liquid (1 9 mg, 71 % yield): UV-VIS (THF) Am nm 204, 21 9, 241, 254, 267,

283; 'H-NMR (CDCld li 7.1 -7.56 (m, 2H), 7.31-7.42 (ml 3H), 2.49 (s, 1 H). The UV-

VIS spectrum rnatched that of the previously reporîed wmpound [46].

Svnthesis of 1 -iodshexyne (54).

To 20 mL (3.06 moi) of ethylmagnesium bromide (3.0 M solution in ether)

was slowly added a solution of 4.1 g (50 rnmol) of 1 -hexyne in 15 mL of anhydrous

ether. The reactian mixture was then heated to reflux as 12.7 g (50 mmol) of

powdered iodine was slowly added through the top of the condenser. The solution

was refluxed for another hour, allowd to cool to room temperâture and then poured

into 150 m l of H20. The mixture was acidified with glacial acetic acid, the ether

layer was separateid and the aqueous layer was extracted hnnce with 50 mL portions

of ether. The combined organic extracts were washed with sat. Na2S20,, sat.

NaHC03, H,O and brÏne, Vien drïed over MgSO,, filtered and evaporated under re-

72

duced pressure. The crude product was distilled in vacuo to give 54 as a clear,

colourless Iiquid (5.3 g, 51 % yield): 'H-NMR (CDCI,) 6 2.37 (t, J = 6.9 Hz, 2H), 1-48

(m. 2H), 1 -42 (m. 2H), 0.91 (t, J = 6.9 Hz, 3H); l 3 C - ~ ~ R (CDCI,) O 94.98, 30.74,

22.06,20.70, 13.74, -7.41 ; El-MS mh (%) 208 (M*, 100). 166 (29). The 'H-NMR,

'3C-NMR and mass spedra matched that of the previously reported compound [52].

Svnthesis of 1 -(tefi-butvldimethvlsiIvI)-1 .S-octadivne (55).

The same procedure was used as for the synthesis of 52, using 0.84 g (6.0

mmol) of tert-butytdirnethylsilylaœ~lene, 0.83 g (4.0 mmol) of ?-iodohexyne, 8.0 mg

(0.08 mmol) of wpper (1) chloride, 0.22 g (3.1 rnmol) of hydroxylamine

hydrochloride, 0.65 rnL of a 70% (w/w) solution of ethylamine in water, 5 mL of

ethanol and 4 mL of H,O. The m d e product was ehromatographed 3 times using

silim gel and hexane as eluent to give 55 as a white solid (238 mg, 27% yield): mp

42-45OC; 'H-NMR (CDCI,) 6 2.28 (t, J = 6.9 Hz, 2H), 1.52 (ml 2H), 1.44 (m, 2H),

0.94 (s, 9H), 0.91 (t, J = 6.9 Hz, 3H), 0.12 (s, 6H); ' 3 ~ - ~ ~ ~ (CDCI,) 6 89.07, 84-22,

81 -74, 65-82, 30.37, 26.26, 22.16, 19.14, 16.96, 13.72, -4.65; El-MS m/z (%) 220

(M', 60), 163 (1 00).

Svnthesis of 1 -3-octadivne (57).

The same procedure was used as for the synthesis of 23, using 900 mg (5.0

rnmol) of 1 -(trimethylsilyl)octa-1,3-diyne (58), 3.0 mL (1 5 mmol) of 5 M NaOH and

40 mL of MeOH to afford 375 mg of 57 as a pale orange oil (70% yield). This

material was not chromatographed, but used immediately in its crude form in the

synthesis of 42: 'H-NMR (CDCI,) 6 2.27 (t, J = 6.9 Hz, 2H), 1.96 (s, 1 H), 1.60-1 -35

(m, 4H). 0.92 (t, J = 6.9 Hz, 3H). The 'H-NMR spectrum matched that of the

previously reported compound [53].

Svnthesis of .1 -ftrirnethvlsilvl)-1.3-octadivne (58).

To a solution containing 208 mg (1 -0 mmol) of 54 dissolved in 4 mL of TEA

were added 35 mg (0.05 mmd) of Pd(PPh,),CI,, 9.5 mg (0.05 mmol) of Cul, and

then a solution containing 1 18 mg (1 -2 mmol) of trimethylsilylacetyiene in 1 mL of

TEA The reaction mixture was allowed to stir ovemight at room temperature, after

which time the solvent was evaporated in vacuo, the residue was suspended in

hexane and then filtered through a bed of celite. The filtrate was concentrated

under reduced pressure and then chromatographed twke, using silica gel and

hexane as eluent to give 58 as a clear, colourless liquid (83 mg, 47% yield): IR

(neat) 2224, 2109, 1465, 1251, 1183, 840, 761, 701, 647, 630 cm-'; ' H-NMR

(CDCIJ 6 2.28 (t, J = 6.8 Hz, 2H), 1.52 (m. 2H), 1.43 (m, 2H), 0.91 (t, J = 7 Hz, 3H).

0.19 (s, 9H); I 3 C - ~ M ~ (CDCS) 6 88-71, 83.1 1, 80.35,65.65, 30.35, 22.1 1, 19.1 0,

13.68, -0.1 3; El-MS mh (%) 178 (M+, 1 1): 163 (1 00). The IR spectnim matched that

of the previously reported compound [SI].

Synthesis of 1 -iodo-2-la-te1f-butvIphenvl)acetvIene (60).

The same procedure was used as for the synthesis of 54, using 3.7 g (23

mmol) of ptert-butylphenyiacetylene (23), 9.4 mL (28 mmol) of a 3.0 M solution of

ethyimagnesium bromide in ether, 6.0 g (23 mmol) of powdered iodine and 12 mL

of dry ether. The title compound was obtained as a white solid (4.7 g, 70% yield):

mp 100-1 02°C; IR (KBr) 21 58 ( C S ) cm-'; UV-VIS (THF) A, nm 21 4,252; H-NMR

(CDCla 6 7.37 (dl J = 8.6 Hz, 2H), 7.33 (dl J = 8.2 Hz, 2H), 1.31 (s, 9H); 13C-NMR

(CDC13 6 lSî.l6, ?32.07, 125.25, 120.43, 34.83, 31 -16, 4.83; El-MS m/z (%) 284

(w 80), 269 (100). Anal. calcd. for Cl,Hl,I : Cl 50.73; Hl 4-67. Found: Cl 50.63;

Hl 4-52.

Svnthesis of 1 -(D-tert-butvlphenvI)-4-trimethvlsilvl-1 .bbutadivne 161 1.

The same procedure was used as for the synthesis of 58, using 156 mg (0.55

mmol) of 60, 10 mg (0.014 mmoi) of Pd(PPh,),CI,, 3 mg (0.1 58 rnmol) of Cui, 0.1

rnL (70 mg, 0.71 mmol) of trimethylsilylacetylene and 4 mL of TEA. The title

m p o u n d w s obtained as a white solid (83 mg, 60% yield): mp 91 -92°C; UV-VIS

(THF) & nm 221,233,254,268. 284,301; 'H-NMR (CDCI,) 6 7.43 (dl J = 8.6 Hz,

2H), 7.34 (dl J = 8.5 Hz, 2H), 1.31 (S. 9H), 0.24 (s, 9H); I3C-NMR (CDCI,) 6 153.06,

132.70, 125.70, 118.51, 90.34, 88.28,77.31, 73.77, 35-15, 31-31, 43-13; El-MS mh

(%) 254 (M', 70), 239 (1 00). Anal. calcd. for Cl,H,Si : C, 80.25; Hl 8.71. Found:

Cl 80.02; H, 8.25.

Synthesis of 1 -@-tefi-butvlphenvl)-l .Bbutadivne (62).

The same proœdure was used as for the synthesis of 53, using 50 mg (0.2

mmol) of 61, 0.2 mL (0.2 mmol) of TBAF (1 .O M solution in THF), 1 mL of THF and

0.2 mL of H,O. The title compound was obtained as a white solid which began to

darken on exposure to air and light (32 mg, 88% yield): IR (KBr) 2245, 2210, 1914,

1604,1502, 1460,1363, 1268,1237,1108,1018,835,735,639, 621 cm-'; UV-VIS

(THF) nm 224,246,259,273,289; 'H-NMR (CDCI,) 5 7.45 (dl J = 8.5 Hz, ZH),

7.35 (dl J = 8.6 Hz, 2H), 2.46 (s, IH), 1.32 (s, 9H); ',C-NMR (CDCI,) 6 153.27,

132.80, 125.72, 118.13. 75-87, 73.11, 71.11, 68.55, 35.15, 31.29; El-MS m/z(%)

182 (M', 65), 167 (1 00).

Svnthesis of 1 -iodo-2-@-neopentoxyphenvi~acety lene (64).

The same procedure was used as for the synthesis of 54, using 5.0 g (27

mmol) of pneopentoxyphenylacetylene (32), 1 1.5 mL (35 mmol) of a 3.0 M solution

of ethylmagnesium bromide in ether, 6.7 g (23 mmoi) of powdered iodine and 15 m l

of dry ether. The title cornpound (64) was obtained as a white solid after

recrystallization frorn MeOHIH,O (2.2 g, 26% yield): mp 5455OC; IR (KBr) 2166

( G C ) cm'; M S (THF) L n m 214,262; 'H-NMR (CDCI,) 6 7.36 (dl J = 8.7 Hz,

2H), 6.83 (d, J = 8.7 Hz, 2H), 3.59 (s, 2H), 1 .O3 (s, 9H); 13C-NMR (CDCI,) 6 160.26,

1 33.94, 1 15.45, 1 14-62, 94.38, 78.1 3, 32.08, 26.79, 3.56; El-MS m/z (%) 31 4 (M+,

351, 244 (IOO), 118 (65). Anal. calcd. for Cl,Hl,IO : Cl 49.70; H, 4.81. Found: C,

50.06; H, 4.78,

The by-product, 1 +di-(p-neopentoxyphenyl)-l , 3-butadiyne (65), was obtained in

59% yield (2.9 g) as a white solid: mp 189-1 91 O C ; IR (KBr) 2388, 21 39, 1601, 1503,

1291,1247, 1 166,1016,831 cm"; UV-VIS (THF) A, nrn 214,269,282, 300, 320,

343; 'H-NMR (CDCI,) 6 7.44 (dl J = 8.7 Hz, 2H), 6.85 (dl J = 8.7 Hz, 2H), 3.60 (s,

2H), 1 -04 (s, 9H); 1 3 C - ~ ~ R (CDCI,) 6 160.50, 134.19, 1 14.89, 1 1 3.85, 81 -59, 78-16.

73.10, 32.09, 26.78; El-MS m/z (%) 374 (M*, 50), 234 (100). Anal. calcd. for

C,,H,O, : C, 83.38; H, 8.07- Found: C, 82.90; H, 8.40.

Svnthesis of 1-(~~neopento~~henvI~4~trimethvlsil~l-l.3-butadivne (66).

To a solution containing 200 mg (0.64 rnmol) of 64 dissolved in 5 mL of THF

w r e added 22 mg (0.032 mmol) of Pd(PPh,),CI,, 3.0 mg (0.01 6 mmol) of Cul, 0.1 6

rnL (1 16 mg, 1.15 mmol) of diisopropylamine (DIPA), and then 0.36 mL (250 mg,

2.55 rnmol) of trimethylsilyiacetylene. The reaction mixture was allowed to stir

77

ovemight at room temperature, after which time the solvent was evaporated in

vacvo, the residue was suspended in hexane and then filtered through a bed of

celite. The filtrate was concentratad under reduced pressure, chromatographed

using silica gel and hexane as eluent, and then recrystaliized from EtOH/H,O to

give 66 as a white, crystalline solid (53 mg, 29% yield): IR (KBr) 2203, 21 03, 1603,

1509,1299,1249,1172,1108,1048,1014,847,760,694 cm-'; UV-VIS (THF) A,

nm 21 4, 240, 275, 291, 309; 'H-NMR (CDCI,) 6 7.41 (dl J = 8.7 Hz, 2H), 6.83 (d,

J = 8.7 HZ, 2H), 3.59 (s, 2H), 1 -03 (s, 9H), 0.23 (s, 9H); I 3 C - ~ M ~ (CDCI,) 6 1 60.72,

134.49, 114.89, 113.06, 90.03, 88.41, 78.13, 77.48, 73.13, 32.08, 26.77, -0.10; El-

MS &(%) 284 (M+, 65), 214 (65), 199 (100). Anal. calcd. for Cl,H,OSi : C, 76.00;

H, 8-50. Found: C, 76.07; H, 8.20.

Svnthesis of 1 -[~neopento~ohenvl)-1.3-butadivne (67).

The same procedure was used as for the synthesis of 23, using 1.0 g (3.5

mmol) of 66, 2.1 ml (11 mmol) of 5 M NaOH and 50 mL of MeOH. The crude

material was chromatographed through a plug of silica gel using hexane as the

eluent to afford 709 mg of 67 as a white solid which rapidly darkened on exposure

to Iight and air (95% yield). (This material was used immediately in the synthesis

of 68): IR (KBr) 2204, 1896, 1602, 1562, 1509, 1473, 1400, 1364, 1295, 1255,

1 1 70,1109, 1048,101 7, 92?, 834,624 cm"; UV-VIS (THF) A- nm 21 4, 281, 298;

'H-NMR (CDCI,) 6 7.45 (d, J = 8.6 Hz, 2H), 6.85 (d, J = 8.7 Hz, 2H), 3.61 (s, 2H),

2.46 (s, 1 H), 1 -04 (s, 9H); l3C-hJMI3 (CDCI,) 6 1 60.86, 1 34.59, 1 1 4.93, 1 1 2-74,

Synt hesis of 4.5-diW(p-neopentoxy~ henvI)-1.3-butadivnvll~hthalonitrile (68).

The same procedure was used as for the synthesis of 16, using 631 mg (1 -66

mmol) of 1 1, 740 mg (3.49 mmol) of 67, 1 22 mg (0.1 74 mrnol) of Pd(PP h,),C12, 33.2

mg (0.1 74 mmol) of Cul and 40 mL of TEA, except that the entire reaction was

carried out at morn temperature. After 18 h, the soJvent was removed in vacuo and

then the residue was dissolved in CH,C12, washed with H,O and brine, dried over

MgSO, and filtered. The solvent was removed from the filtrate under reduced

pressure and the brown residue was triturated twice with ethyl ether to leave a

golden-yellow solid (683 mg, 75% yield): mp 233OC (ciecomp.); IR (KBr) 2203 (C=N)

cm-'; UV-VIS (THF) A, nm 218,262, 280,294, 308, 386; 'H-NMR (CDCI,) 6 7.86

(s, 2H), 7.52 (dl J = 8.7 Hz, 4H), 6.89 (d, J = 8.7 Hz, 4H), 3.63 (S. 4H), 1 .O5 (s,

1 8H); 13C-NMR (acetone-d,) 6 162.76, 1 38.72, 1 35.69, 1 31.1 9, 1 1 6.38, i 1 6.24,

115.64, 173.14, 88.62, 85.03, 79.13, 77.41, 72.81 , 32.67, 26.96; Anal.calcd.for

CJ-i&i,O,: C, 83.18; H, 5.88; N, 5.1 1. Found: C, 8-1.14; H, 5.64; 4.76. HRMS: in/,

calcd. for C,H,N202: 548.2464. Found: 548.246aL

Svnthesis of dilithium-2.3.9.10.16.17.23,24uctaT4-l~neo~entoxv~henvl~-l.3-

butadivnvll~hthaiocvanine (69b).

To a vigorously stirred suspension containing 25 mg (0.046 mmol) of 68 in

0.4 mL of l-octanol, was added 4 mg (0.58 mmol) of lithium metal (rolled to a foi[

in an argon purged plastic bag). The reacfion mixture was heated to 80°C

ovemight, after which time the colour tumed from bright yellow to dark green. The

reaction mixture was diluted with 10 mL of hexane and then centrifuged. The

supematant liquid was discarded, the cnide pigment was dissolved in anhydrous

THF, reprecipitated into 5 mL of hexane and centrifuged again. This cycle was

repeated 4 times until the octanol was removed and the supematant Iiquid waç

colourless. The remaining crude Pc was dissolved in 2 mL of anhydrous THF and

loaded ont0 a gel permeation wlurnn consisting of SX-2 ~ iobeads~ and anhydrous

THF as the eluting solvent. A single green band was collected in 5, 2 m l fractions,

each of Mich wre analyzed by UV-VIS spectroscopy. The fractions containing the

least intense absorptions in the 200-500 nm reg ion of the spectrum were wmbined

and the solvent rernoved in vacuo to give what is believed to be 69b as a dark

green solid (7 mg, 28% yield): UV-VIS (THF) A- nm 21 4, 304, 408, 660, 738; 'H-

NMR (pyridinezl,, 4.53 x lo4 M, 300 K) 6 9.98 (br, 8H), 7.67 (d, J = 8.4 Hz, 16H),

6.92 (d, J = 8.4 Hz, 16H), 3.60 (s, 16H), f -08 (s, 72H).

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