The Radiation Chemistry of Organized Systems...2017/04/25 · The Radiation Chemistry of Organized Systems: Basic Studies and Implications Vladimir Feldman Department of Chemistry,

The Radiation Chemistry of Organized Systems:

Basic Studies and Implications

Vladimir Feldman

Department of Chemistry,

Lomonosov Moscow State University, Moscow, Russian Federation

ICARST 2017, Vienna, Austria, April 24-28, 2017

Outline

• Background and motivation: concept of molecular organization

• Experimental approaches and methods

• Intermolecular complexes: modeling the first step

• Polymers: effect of molecular packing

• Crown ethers: effect of steric configuration and host-guest interactions

• Interpolyelectrolyte complexes: controlled assembling of metal nanoparticles

• Conclusions and outlook


Background and motivation:

molecular organization and radiation chemistry

• Ionizing radiation is rather a scalpel than a bludgeon

• Common reasons for selectivity:

• - inhomogeneous energy deposition

• - selective localization of primary events

• - selectivity of secondary radical reactions

Knowing molecular structure and chemical composition is not

enough to predict the effect – molecular organization is

important

• Self-organization and forced organization (e.g., orientation,

application of high pressure, etc.)

• Driving forces for self-organization at molecular level:

• - “weak” non-covalent interactions

• - ionic interactions

• - guest-host interactions

• Organized systems: from simplest binary complexes to micelles and

biopolymers ICARST 2017, Vienna, Austria, April 24-28, 2017

Experimental approaches and methods

• Modeling the first step: matrix isolation at low and

ultra-low temperatures (down to 5 K)

• Characterization of weak interactions: FTIR spectroscopy

• Irradiation: X-rays, gamma-rays and e-beam in various

experimental configurations (low-temperature matrices,

films and solutions at room temperature)

• Identification of the radiation-induced intermediates: EPR

and optical spectroscopy

• Characterization of the radiation-induced structural changes: XRD, TEM and other methods


The role of weak intermolecular interactions: H2O/CO2/Ng system

Spectroscopic evidence

for intermolecular

complexes in matrices

Formation of HOCO radicals

correlates with the concentration of

CO2…H2O complexes

• S.V. Ryazantsev and V.I. Feldman, J. Phys. Chem. A, 2015, 119, 2578

Other recent works on radiation-chemistry of weak complexes in matrices: S.V. Kameneva et al.,

J. Chem. Phys., 2016, 145, 214309; V.I. Feldman et al., Rad. Phys. Chem., 2016, 124, 7


Effect of molecular packing in polymers: polystyrene

Isotactic polysyrene

Pre-existing benzene ring

dimers act as hole traps due to

lower IP

Formation of dimeric radical

cations is an important factor

of the radiation resistance of

polystyrene

Particularly high yield of dimeric radical cations is observed in isotactic

polystyrene (A.A. Zezin, V.I. Feldman, Dokl. Chem., 2004, 394, 26)

R

R

( ).+ no damage



Effect of stereoisomerism, ionic and guest-host interactions: crown ether complexes with metal

cations “Free” dicyclohexano-18-crown-6

(DCH18C6)

is most suitable host-ligand

for radioactive 90Sr binding

Cis-syn-cis-DCH18C6

Tm = 61-62 ° С

Cis-anti-cis-DCH18C6

Tm = 69-70 ° С

Complex formation leads to

O

O

O

O

O

O

O

O

O O

O

O

O

O

O

O

O

O

Macrocycle

conformation changes

C-O bonds elongation

Me2+ coordination by both

O-atoms of CE and anion

Does the nature of cation and anion in CE complexes

affect the radiation stability?

Cl-

Cl-

O

Me2+

O

O

OO

O

A-

A-

O

O

O

O

OMe2+

O

Cl-

Cl-

A-

A-

Effect of stereoisomerism

on radiolysis?


Crown ethers: effect of stereoisomerism

Radiolysis of complexes

O

O

O

O

OMe2+

O

Cl-

Cl-Cl-

Cl-

O

Me2+

O

O

OO

O

Cis-syn-cis-DCH18C6 · МеCl2 Cis-anti-cis-DCH18C6 · МеCl2

Cis-syn-cis-isomer has a higher radiation resistance to macrocycle

cleavage at early and post-irradiation stages of radiolysis. O.A. Zakurdaeva, S.V. Nesterov, V.I. Feldman. Rad. Phys. Chem., 2017, 130, 379–384.

Radiolysis of “free” DCH18C6

Macrocycle destruction occurs in

reactions of primary radical cations

Macrocycle destruction occurs in

reactions of primary radical cations

and in post-irradiation processes

–CH–C(H)=O

Ratio of macrocycle cleavage yields:

Ganti/Gsyn = 1.4

Ratio of macrocycle cleavage yields:

Ganti/Gsyn = 2

O

O

H

.–CH–C(H)=O +


Crown ethers: effect of metal cation inclusion

CE CE+ + e–

I. “Free” crown ether

II. Macrocyclic complex with metal chloride

Inclusion of metal ion into macrocyclic cavity initiate a new

channel of macrocycle cleavage at post-irradiation stage

–CH2–ĊH–O– + RH2+

–CH–C(H)=O + CH3CH2–O– CE+ + CE

RH2+ + e– CE + H

CE + H –CH2–ĊH–O– + H2

CE+ H –O–(C6H9)–O– + H2

H H

H

H

O

O

O

CH 2 CH 2

CH 2 CH 2

Ba 2+

CH 2 CH 2

CH 3 CH 2

O

O

H

. .

A

B

H

O

H H

H

H

H H

H

H

H H

H

O

O

Ba 2+ +

Cis-syn-cis-DCH18C6 · МеCl2

O. A. Zakurdaeva, S.V. Nesterov, V. I. Feldman. Rad. Phys. Chem., 2013, 87, 40-45.

Me2+ = Ca2+, Sr2+, Ba2+

Cl-

Cl-

O

Me2+

O

O

OO

O


Crown ethers: effect of anion

Basic Intermediates –CH–CH–O– (90%) + –CH–C(H)=O (10%)

O

O

O

OO

O

Me2+

A-

A-

Me2+ = Sr2+, Ba2+

A- = BF4-, PF6

- and NO3-

Basic intermediates

NO32- (>85%) + –CH–CH2–O– (<15%)

Direct action on CE:

CE CE+ + e–

CE+ + CE –CH2–ĊH–O– + RH2+

CE+ + CE –CH–C(H)=O + C2H5–O–

RH2+ + e– CE+ H

CE + H –CH2–ĊH–O– + H2

Direct action on anion:

XFn- /\/\/\ XFn

+ e–

XFn- + e– XFn-1

- + F-

XFn XFn-1 + F

Indirect Action on CE: F + CE –CH–CH2–O– + HF

Direct action on anion:

NO3– NO3 + e–

NO3– + e– NO3

2–

Direct action on CE:

CE CE+ + e–

CE+ + CE –CH2–ĊH–O– +

RH2+

While nitrate anions protect the crown ether up to 40 kGy, radiolytic

products of halogenous anions promote additional destruction channels

Crown ether (CE) 18C6

O.A. Zakurdaeva, et al. Rad. Phys. Chem, 2015, 115,183–188.


Interpolymer and interpolyelectrolyte complexes:

films, ultrathin coatings and suspensions

interpolymer

PAA - PVT

interpolyelectrolyte

PAA - PEI

- Triple interpolyelectrolyte -metal complexes (TIMC) - stable, swellable

films with readily adjustable content of metal ions (up to 20 - 25 wt %) [see A.B. Zezin, V. B. Rogacheva, V.I. Feldman, P. Afanasiev, A.A. Zezin, Adv. Colloid Interface

Sci., 2010, 158, 84-93 for more details]

OOC OOC OOC OOC

NH2 NH2 NH2 NH2 Cu2+

NH NH NH NH

COO OOCCOO OOC

Cu2+

H_

Cu2+

+


The radiation-induced preparation of metal

nanoparticles: a mechanistic overview

Specific features of the radiation-induced reduction of metal ions in

polyelectrolytes:

- inhomogeneous dose distribution (particularly, for X-rays)

- involvement of additional reaction channels

- diffusion restrictions and size selection

H2O e- aq,

.OH, H3O

+, H2, H.

.OH + CH3CH2OH CH3

.CHOH + H2O

Меn+ + e- aq Ме(n-1)+ ... Me0

Меn+ + R. Ме(n-1)+ + R+

Me0 + Men+ Me2n+ …Mek

p+ (p<k) … nanoparticles

For review: Belloni, J.: Catal. Today ,113 (2006)141; Ershov, B.G.: Russ. Chem. Rev., 66 (1997)

103

General scheme for aqueous solutions


Tuning the size and spatial distribution of nanoparticles in a polymer matrix

due to variations of system composition, radiation type and dose rate

Nanocomposites prepared by radiation-

chemical method from organized systems

Polymer films with NPs Cotton fibers with NP-filled coatings

Zezin A.B., Rogacheva V.B., Feldman V.I., Afanasiev P., Zezin A.A.: Adv. Colloid. Interface Sci. 158

(2010) 84; Feldman V.I., Zezin A. A., Abramchuk S. S., Zezina E. A.: J. Phys. Chem. C 117

(2013) 7286


Formation of copper nanoparticles in irradiated

suspensions: self-organization and generation of

spatially ordered structures

0.05 М PAA 0.05 М PVIM

0.02 М Cu2+ pH=2.9

2 3 4 5 6 7

0

5

10

15

20

nan

opar

ticl

e fr

acti

on,

%

Nanoparticle diameter, nm

PAA-PVIM

0.05 М PAA 0.05 М PVIM

0.01 М Cu2+ pH=2.4

PAA-PAAm

Bakar A. , De V. V. , Zezin A. A. , Abramchuk S. S., Guven O., Feldman V. I. :Mendeleev Communs.

2012, 22,. 211.; Bakar A., Guven O., Zezin A. A. , Feldman V. I. : Rad. Phys.Chem., 2014, 94, 62

D. Dagas et al., manuscript in preparation

Conclusions and outlook

• Molecular organization controlled by relatively weak interactions is crucial for the radiation chemistry of a wide variety of different systems

• Implications: novel approaches to radiation stability and radiation modification may be based on the molecular organization concept

• Prospective applications: • - development of radiation-resistant sorbents and extraction systems • - stabilization and sensitization of polymers without chemical

modification • - fabrication of different-type metal-polymer nanohybrides for various

purposes (sensors, bactericide films, catalysts…) • - nanolithography • - and more… • Outlook: we still need to learn more, but we can start developing

technologies now


Research team (major contributions) • Dr. A.A. Zezin • Dr. S.V. Nesterov • Dr. O.A. Zakurdaeva • Dr. E. V. Saenko • Dr. E.S. Shiryaeva • Dr. D. A. Tyurin PhD students: • S. V. Ryazantsev • S. V. Kameneva Collaborations: Institute of Synthetic Polymeric Materials of RAS, Moscow, Russia Prof. Olgun Güven (Hacettepe University, Ankara, Turkey) Support from: Russian Foundation for Basic Research Russian Science Foundation


Acknowledgements

13th International Symposium on

Ionizing Radiation and Polymers

(IRaP 2018)

Conference chair: Prof. Vladimir Feldman ([email protected])

Detailed information is coming soon

Welcome to Moscow in 2018 (and at any other time) !


IRaP 2018 is to be held in Moscow region, Russia

on August 26-31, 2018

(exact location to be confirmed before September 1, 2017)

mailto:[email protected]

The Radiation Chemistry of Organized Systems...2017/04/25 · The Radiation Chemistry of Organized Systems: Basic Studies and Implications Vladimir Feldman Department of Chemistry,

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