Isomerism in secondary bonded complexes: do structural rules apply?

International audienceThe growing importance of secondary bonded complexes in modern coordination chemistry has given rise to an abundant literature in both experimental and theoretical coordination chemistry. We recently proposed an unified chemical model of secondary interaction enabling to understand the structures in terms of simple chemical rules and concepts. For some complexes the stoichiometry of the electrophilic moiety makes isomerism possible. The problems of isomerism and of the interconversion of isomers are addressed in the present. It is shown, that the reaction mechanisms discussed for pentacoordinated phosphorus derivatives are not suitable for complexes bound by a secondary interaction. The possibility of Berry's pseudo rotations is rejected for this class of systems