Perturbation Theory and Stereoisomerization Modes

It has been shown previously that the ratio of relaxation times is a characteristic of the modes of stereoisomerization for trigonal bipyramidal complexes. This result has been obtained under the assumption that all the rate constants for a given mode are the same. This equality is no longer true when the differences in chemical nature of the ligands are taken into account. In this paper, we describe a method, based on perturbation theory, in which this situation is studied. We show that, in the case where there are two ligands of type 1 and three of type 2, the situation where ligand 1 is more electronegative than 2 preserves the possibility of distinguishing the modes, by comparing the relaxation times.