solvatochromism and photo induced intramolecular electron transfer l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Solvatochromism and Photo-Induced Intramolecular Electron Transfer PowerPoint Presentation
Download Presentation
Solvatochromism and Photo-Induced Intramolecular Electron Transfer

Loading in 2 Seconds...

play fullscreen
1 / 8

Solvatochromism and Photo-Induced Intramolecular Electron Transfer - PowerPoint PPT Presentation


  • 271 Views
  • Uploaded on

Solvatochromism and Photo-Induced Intramolecular Electron Transfer. Katelyn Billings, Dr. Bret Findley Saint Michael’s College. Abstract. Develop a laboratory exercise for a physical chemistry course Major topics covered Solvatochromism Intramolecular photo-induced electron transfer

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Solvatochromism and Photo-Induced Intramolecular Electron Transfer' - ocean


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
solvatochromism and photo induced intramolecular electron transfer

Solvatochromism and Photo-Induced Intramolecular Electron Transfer

Katelyn Billings, Dr. Bret Findley

Saint Michael’s College

abstract
Abstract
  • Develop a laboratory exercise for a physical chemistry course
    • Major topics covered
      • Solvatochromism
      • Intramolecular photo-induced electron transfer
    • Method
      • Steady state absorption
      • Steady state fluorescence
    • Goal
      • Determine the change in dipole moment between ground and excited electronic states
    • Compounds used
      • Coumarin 153
      • 4-amino-N-methylphthalimide
      • 2,6-diphenyl-4-(2,4,6-triphenyl-1-pyridinio)phenolate
reaction pathway
ReactionPathway

Background

A - D + heat

k-ET, non-rad

kET

hυ1

A- - D+

A* - D

A - D

A* —D

k-ET, rad

Electron

Transfer

A- —D+

hυ2

A-D +

Solvent Relaxation

A- —D+

hυ1

E

hυ2

A—D

A—D

Energy Diagram

Key Terms

  • Solvatochromism Bathochromic Shift Hypsochromic Shift
experimental method
Experimental Method
  • Take fluorescence measurements for Coumarin 153 in a variety of solvents (with different polarities).
  • Plot , the maximum emission frequency in cm-1, versus Δf, a solvent polarity parameter.
  • Slope of this line yields Δμ, the difference in excited and ground state dipole moment of the solute.
  • We plan to make similar measurements with other compounds.
relevant equations 1

~

~

Relevant Equations1

~

~

Where:

  • Δf = the solvent factor (change in the reaction field)
  • ε = the solvent dielectric constant
  • n = the refractive index
  • h = Planck’s constant
  • c = speed of light
  • vct = frequency of maximum emission in cm-1
  • vct (0)= frequency of maximum emission in the gaseous phase in cm-1
  • Δμ = difference in excited and ground state dipole moment
  • ρ = the radius of the solute cavity
  • 4πε0 = gas permittivity constant

(1) Hermant, R. M.; Bakker, N. A. C.; Scherer, T.; Krijnen, B.; Verhoeven, J. W.; J. Am. Chem. Soc, 1990, 112, 1214-1221.

solutes studied

3

Solutes Studied

N

Coumarin 153

O

Reichardt’s Dye

4-amino-N-methylphthalimide

sample results for coumarin 153

Fluorescence Spectra for

Coumarin 153

Sample Results for Coumarin 153

Maroncelli value2:

Theoretical Δμ = 3.9D

Empirical Δμ = 6.0D (assuming ρ=3.9A)

**Note the Bathochromic Shift

Our Experimental Δμ : 7.05D

(2) Maroncelli, Fleming. "Picosecond solvation dynamics of coumarin

153: The importance of molecular aspects of solvation." J. Chem.

Phys. 86 (11)(1987): 6221-6239.

a quick review of the lab

Future Plans

A Quick Review of the Lab
  • Run spectra for the Reichardt’s Dye and for Coumarin 153 or 4-amino-N-methylphthalimide
  • Solvents
    • Chlorobenzene
    • Dichloromethane
    • Dimethyl Sulfoxide
    • Acetonitrile
  • Calculate the change in dipole moment for Reichardt’s Dye
  • Reevaluate our data—Check Fluorimeter Calibration/Correction of max values
  • Test lab and submit for publishing