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1 Lesson 7 Case Studies A. Monitoring synthetic procedure in situ B. Electrochemistry C. Spectroelectrochemistry As well as data treatment and presentation You Will Learn Instrumentation for:
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Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

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Page 1: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

1

Lesson 7Case Studies

• A. Monitoring synthetic procedure in situ• B. Electrochemistry• C. Spectroelectrochemistry

• As well as data treatment and presentation

You Will Learn Instrumentation for:

Page 2: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

2

A. Monitoring synthetic procedure in situIt is known that the smaller the size of the nanoparticle, the shorter the wavelength theyabsorb. ---Quantum Confinement (http://pubs.acs.org/cgi-bin/archive.cgi/jacsat/1993/115/i19/pdf/ja00072a025.pdf)

C. B. Murray, D. J. Norris, M. G.Bawendi, "Synthesis andcharacterization of nearly monodisperseCdE (E = sulfur, selenium, tellurium)semiconductor nanocrystallites", Journalof the American Chemical Society 115(1993) 8706-8715.

Page 3: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

3

Preparation of monodispersed CdSe nanoparticles is desirable.Peng et al reported that these nancrystals can be made in abenign way:

2 /TOPOTOPCdAc Se CdSe∆+ →

L. Qu, X. Peng, "Control of PhotoluminescenceProperties of CdSe Nanocrystals in Growth",Journal of the American Chemical Society124 (2002) 2049-2055.

L. Qu, W. W. Yu, X. Peng, "In Situ Observationof the Nucleation and Growth of CdSeNanocrystals", Nano Letters 4 (2004) 465-469.

(http://pubs.acs.org/cgi-bin/asap.cgi/nalefd/asap/html/nl035211r.html)

Page 4: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

4

Post-measurements by Peng et al in 2002

In-situ control and measurements by Peng et al in 2004

Page 5: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

5

A dip probe immersed in the reaction solution can be connected with a cost-effectivehand-held spectrometer (From Ocean Optics Inc or Aventes ), to monitor the UV-VISabsorption spectrum with LabVIEW and to watch absorption peak wavelength shiftingfrom shorter wavelength to longer wavelength, i.e. the particle size becomes larger andlarger.

Instrumentation:

Probe with SMA connector

Containerwith solution

Light in(from source)

Emission(to spectrometer)

Bifurcated fiber

A lamp and a spectrometer interfaced by LabVEW can be connected.

At desired wavelength (i.e. desired size), the reaction can be stopped.

The same principle can be applied for a dip probe in situ infrared spectrometer.

Page 6: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

6

B. Electrochemistry at liquid/liquid interfaces

Polarised interface

UV-VIS Detection

water

DCE

Fluorescence Detection

Xn+/- =MO -, EO -, Ru(bpy) 32+ ...

O1 (Fe(CN)64-) R1 (Fe(CN)63-)

Polarised interface

UV-VIS Detection

O2 (TCNQ.-) R2 (TCNQ)

α (water)

β (DCE)

Vacuum

Gibbs Energy of Hydration

Water

Gibbs Energy of Solvation

OilGibbs Energy of Transfer

Gibbs Energy of Transfer

Thermodynamics of Ion Transfer

∆G io w o

io

iw

tr,, ~ ~→ = −µ µ

Organic Phase

Aqueous Phase

RE2

light from Xenon arc lamp

reflected light to monochromator

CE1CE2

Organic Reference Electrolyte

RE1

Page 7: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

7

The absorbance of species in solution measured by reflection can be estimated by integration of

the Beer-Lambert expression over the distance (x) from the reflecting surface,

∫∞

=0

TIRcos

)(2 dxxcAθ

ε

where θ is the angle of incidence of the light beam at the interface, ε is the molar absorption

coefficient of the transferring ion in the phase of higher refractive index and c(x) its concentration

at a distance x from the interface.

C. Spectroelectrochemistry

Organic Phase

Aqueous Phase

RE2

light from Xenon arc lamp

reflected light tomonochromator

CE1CE2

Organic Reference Electrolyte

RE1

Theory of in-situ UV-VIS and Fluorescence Spectroscopies

∫= t dIzFS

A 0TIR )(

cos2 ττ

θε

)(cos

2TIRtI

zFSdtdA

θε

=

∫Φ

=to )dI(

zFSIF

0

incidcos

2 ττθ

ε

IzFS

Idt

dF o

cos2 incid

θεΦ

=

∫=∫∞ t dI

zFSdxtxc 00 )(1),( ττ

1. Introduction

Page 8: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

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XenonLamp

M

M

M

MDCE

H 2 O

TIR : 75°NeutralDensity Filter Monochromator

Lock-inAmplifier

Focussing Lens

Potentiostat

Input

Modulated Potential

PM

E

t

E

t

WaveformGenerator

DC in

AC in

dc Inac In

∆R/R

2. Instrumentation:Instruments: waveform generator+potentiostat+Lamp+spectrometer

or monochromatorPMT

LabVIEW for data acquisition

Page 9: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

9

(http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TG0-3VGV20K-2&_coverDate=09%2F01%2F1998&_alid=152032082&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5240&_sort=d&view=c&_acct=C000048763&_version=1&_urlVersion=0&_userid=940030&md5=eae917920b982fc9a0f06cb8880fa607)

3. Voltabsorptommetry on transfer of methyl and ethyl orangesZ. Ding, F. Reymond, P. Baumgartner, D. J. Fermin, P.-F. Brevet, P.-A. Carrupt, H. H. Girault,"Mechanism and dynamics of methyl and ethyl orange transfer across the water/1,2-dichloroethaneinterface", Electrochimica Acta 44 (1998) 3-13.

NN+

SO3-

H

N+H3C

CH3

H

NN

SO3-

N+H3C

CH3

H

NN

SO3-

NH3C

CH3

K a1 K a2

Page 10: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

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Let’s examine SM_SP_EO.vi

Page 11: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

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Digestion of the VI(1). Read From Spreadsheet.vi

(3). Concatenated string.vi

(2) How do data flow in LabVIEW----Index Array, Subarray

Page 12: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

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For single wavelength (monochromator+PMT):

Page 13: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

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1. Find the VI from Help»Find Examples...»Search2. Type in “lowpass” and search3. Choose EquiRipple Filter Design.vi

(1) How to read a spreadsheet file into LabVIEW

(3) How to filter out noise in LabVIEW

(2) How do data flow in LabVIEW

Page 14: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

14

At (http://pubs.rsc.org/ej/CC/1997/E9705156.PDF)

4. Voltabsorptommetry of electron transfer at liquid/liquid interfacesZ. Ding, P. F. Brevet, "Heterogeneous electron transfer at the polarized water/1,2-dichloroethane

interface studied by in situ UV-VIS spectroscopy and differential cyclic voltabsorptometry",Chemical Communications (Cambridge) (1997) 2059-2060.

O1 (Fe(CN)64-) R1 (Fe(CN)63-)

Polarised interface

UV-VIS Detection

O2 (TCNQ.-) R2 (TCNQ)

α (water)

β (DCE)

Organic Phase

Aqueous Phase

RE2

light from Xenon arc lamp

reflected light tomonochromator

CE1CE2

Organic Reference Electrolyte

RE1

2.0

1.5

1.0

0.5

0.0

Abs

orpt

ion

1000900800700600wavelength /nm

Let’s examine SM_SP_TCNQ.vi

Page 15: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

15

References

1. C. B. Murray, D. J. Norris, M. G. Bawendi, "Synthesis and characterization of nearlymonodisperse CdE (E = sulfur, selenium, tellurium) semiconductor nanocrystallites",Journal of the American Chemical Society 115 (1993) 8706-8715.

2. L. Qu, X. Peng, "Control of Photoluminescence Properties of CdSe Nanocrystals inGrowth", Journal of the American Chemical Society 124 (2002) 2049-2055.

3. L. Qu, W. W. Yu, X. Peng, "In Situ Observation of the Nucleation and Growth ofCdSe Nanocrystals", Nano Letters 4 (2004) 465-469.

4. Z. Ding, F. Reymond, P. Baumgartner, D. J. Fermin, P.-F. Brevet, P.-A. Carrupt, H.H. Girault, "Mechanism and dynamics of methyl and ethyl orange transfer across thewater/1,2-dichloroethane interface", Electrochimica Acta 44 (1998) 3-13.

5. Z. Ding, P. F. Brevet, H. H. Girault, "Heterogeneous electron transfer at the polarizedwater/1,2-dichloroethane interface studied by in situ UV-VIS spectroscopy anddifferential cyclic voltabsorptometry", Chemical Communications (Cambridge)(1997) 2059-2060.

6. Z. Ding, D. J. Fermin, P.-F. Brevet, H. H. Girault, "Spectroelectrochemicalapproaches to heterogeneous electron transfer reactions at the polarized water/1,2-dichloroethane interfaces", Journal of Electroanalytical Chemistry 458 (1998) 139-148.

Page 16: Lesson 7 Case Studies - Instructinstruct.uwo.ca/chemistry/532/lecture7.pdf · Lesson 7 Case Studies ... CdAc Se CdSe ∆ + → L ...

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Summary

• Acquire• Anywh

ere

• Analyze• Anywh

ere

• Present• Anywh

ere

In-situ reaction monitoring, electrochemistry, spectroelectrochemistrycan easily be done.