Application of spin-orbit-coupling induced magnetic field effects for probing the dynamics of photoinduced charge separation and recombination

Abstract

In this paper we present two examples demonstrating how magnetic field effects can be utilized for a quantitative exploration of mechanistic details of the behaviour of short-lived redox intermediates in photoelectron transfer reactions with excited triplet states. This magnetokinetic approach takes advantage of the spin memory present in the intermediates (exciplexes, correlated radical pairs) which controls the competition between spin-allowed formation of free redox products and spin-forbidden backward electron transfer regenerating the ground state reactants. In particular we demonstrate that the strong spin-orbit coupling exhibited by a heavy atom substituent or by heavy transition metal centers can be very useful for inducing and exploiting such diagnostic magnetic field effects.