Laura A. Worl

Photoinduced electron and energy transfer in soluble polymers

Abstract In soluble polystyrene polymers that contain polypyridyl complexes of Ru II or Os II it has been possible to demonstrate the existence of intrastrand photochemical electron and energy transfer.

Photophysical properties of polypyridyl carbonyl complexes of rhenium(I)

The photophysical properties of the metal to ligand charge transfer (m.l.c.t.) excited states of the complexes [Re(4,4′-X2-bipy)(CO)3Cl](X = NH2, NEt2, NHCOCH3, OCH3, CH3, H, Ph, Cl, CO2Et or NO2; bipy = bipyridine) vary systematically as the substituent X is varied. For the cases where m.l.c.t. states are lowest lying a quantitative correlation exists between ln (knr× 1 s)(knr is the rate constant for non-radiative decay) and the Franck–Condon factor calculated from parameters obtained by emission spectral fitting. The solvent reorganizational energy for [Re(bipy)(CO)3Cl] has been determined to be 1100 cm–1 in EtOH–MeOH (4:1 v/v) and 650 cm–1 in 2-methyltetrahydrofuran by a temperature dependent bandwidth study. Based on a comparative analysis of properties with related polypyridyl complexes of RuII and OsII it has been concluded that: (1) the extent of distortion at the 4,4′-X2-bipy acceptor ligand correlates with the energy gap between the excited and ground states; these results are in agreement with an earlier correlation found for polypyridyl complexes of OsII; (2) the unusually large Stokes shift and the broadening of the vibronic components in absorption and emission spectra arise from a combination of increased solvent reorganizational energies and greater distortions in the low-frequency modes between the excited and ground states; and (3) the relatively short lifetimes for the complexes of ReI have as a major contributing factor the participation of a ν(CO) mode at ca. 2020–2040 cm–1 as an energy acceptor in non-radiative decay.

Temperature and pressure effects on charge transfer absorption bands

Abstract The frozen dipole approximation of dielectric continuum theory is shown to apply to the glass-to-fluid transition for charge transfer absorption bands.