Stereochemistry of platinum coordination compounds

The coordination chemistry of platinum covers a huge field, as shown by a recent survey covering the crystallographic and structural data of almost two thousand monomeric examples. About 10% of these complexes exist as isomers and are summarised in this review. Included are distortion (65%), cis–trans (30%), mixed isomers and ligand isomerism. These are discussed in terms of the coordination about the platinum atom, and correlations are drawn between donor atom, bond length and interbond angles, with attention to any trans-effect.Distortion isomers, differing only by degree of distortion in Pt–L and L–Pt–L angles, are the most numerous. They are also spread over a wider range of oxidation states of platinum (zero, +2, +3 and +4) than cis–trans isomers (+2 and +4 only), or mixed isomers (+2 only) and ligand isomerism (+2 only).