Chemical Physics Letters, Vol.445, No.4-6, 167-172, 2007
Femtosecond time-resolved photo-absorption studies on the excitation dynamics of chromium(III) porphyrin complexes in solution
The electronic relaxation dynamics of the excited states of the chromiurn(III) tetraphenylporphyrin complexes, [Cr(TPP)(Cl)(L)] (L = H2O, pyridine, 1-methylimidazole), in toluene were studied by using femtosecond time-resolved absorption spectroscopy. The excited state (T-4(1)) of 1-methylimidazole and pyridine complexes given by a very rapid intersystem crossing from S-4(1) to T-4(1) decays to establish the T-4(1); = T-6(1) equilibrium in several hundred picoseconds. The T-4(1) state of [Cr(TPP)(Cl)(H2O)] exhibits a biexponential decay composed of the photodissociation process of the axial H2O ligand and the decay of the photolyzed intermediate to the ground state of [Cr(TPP)(Cl)]. (C) 2007 Elsevier B.V. All rights reserved.