Stereodynamics and degenerate ligand exchange in solutions of tetracoordinate chelate complexes of nontransition metals

Nontransition metal (d⁰ , d¹⁰ ) chelate complexes possessing a tetrahedral configuration at the metal centre undergo fast intramolecular stereoisomerisation and intermolecular ligand exchange reactions in solution. Inversion of the stereochemical configuration is governed by two types of intramolecular reactions: (1) polytopal rearrangement (digonal twist) and (2) dissociation-recombination reaction due to the cleavage-formation of one of the metal-ligand bonds. The energetically preferred mechanism for the inversion is chiefly determined by the nature of the metal, but it also depends on the type of ligating atoms and their environment. The energy barriers to the inversion of the tetrahedral configuration vary in the range of 10-30 kcal mol^-1. The bibliography includes 175 references.