Studies of the Chemical Intermediate Diphenylcarbene: Intersystem Crossing, Solvent Effects on Dynamics, Spin State Selective Chemistry, Photochemistry of the Excited Triplet State

Abstract

This paper describes the recent results from our laboratory concerning kinetic studies on diphenylcarbene (DPC). A combination of picosecond and nanosecond laser spectroscopy measurements, chemical quenching experiments and triplet sensitization experiments has allowed the determination of the rapid singlet to triplet and slower triplet to singlet intersystem crossing rates for diphenylcarbene in fluid solution at room temperature. It is shown that under the conditions of the kinetic measurements, singlet and triplet diphenylcarbene (1DPC and 3DPC, respectively) are in rapid equilibrium relative to reactions, so that knowledge of the values of kST and kTS allows determination of the equilibrium constant and change in energy gap for the 1DPC ⇄ 3DPC process. It is found that there is a significant solvent effect on the intersystem crossing rates and energy gaps.KeywordsTriplet StateMethanol ConcentrationExcited Triplet StateExcited TripletChemical IntermediateThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.