Charge-transfer emission of compact porphyrin-fullerene dyad analyzed by Marcus theory of electron-transfer

Spectrochim Acta A Mol Biomol Spectrosc. 2001 Sep 14;57(11):2229-44. doi: 10.1016/s1386-1425(01)00496-6.

Abstract

A porphyrin-fullerene dyad, which is characterized by a close proximity of the porphyrin donor and the fullerene acceptor, was found to undergo a photoinduced electron transfer both in solutions and in solid films. Near-infrared charge-transfer (CT) emission was observed and analyzed in frame of the semi-classical Marcus electron-transfer theory yielding values for the reaction free energy, -deltaG degrees = 1.75 eV, the internal reorganization energy, lambdav = 0.05 eV, and the donor-acceptor vibrational energy, hv(v) = 0.14 eV, both in solution and in solid film. The influence of the environment on the CT properties of the dyad is described by a single parameter, the outer-sphere reorganization energy, lambdas, which varies from 0.05 eV in non-polar solvents and films to 0.13 eV in solvents of moderate polarity. At low temperatures (T< 200 K), the CT emission consists of distinct bands shifted from each other by value hv(v). This is the first direct observation of the vibrational frequencies of a porphyrin-fullerene donor-acceptor system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biophysical Phenomena
  • Biophysics
  • Carbon / chemistry*
  • Electron Transport*
  • Electrons
  • Fullerenes*
  • Models, Chemical
  • Photosensitizing Agents / chemistry*
  • Porphyrins / chemistry*
  • Spectrometry, Fluorescence
  • Spectrophotometry / methods*
  • Temperature
  • Thermodynamics
  • Time Factors

Substances

  • Fullerenes
  • Photosensitizing Agents
  • Porphyrins
  • Carbon
  • fullerene C60