Classification of P,N-binucleating ligands for hetero- and homobimetallic complexes

This review focuses on P,N-ligands capable of establishing binucleating interactions and on the resulting bimetallic complexes. The work is grouped by the type of P,N-binucleating ligand backbones which are closely responsible for the chemistry of their correspondent bimetallic complexes. The P,N-binucleating ligands are classified according to their length (the number of atoms between the N- and P-donor), their backbone structure (the relative disposition of the N- and P-donor), and the presence or not of additional donor atoms. Similarities between the structures of the bimetallic complexes obtained with P,N-ligands inside each group are highlighted. Based on the analysis of the different groups, the structure of new metallo/P,N-ligand complexes not yet synthesized can be hypothesized. A summary of the few examples of P,N-binucleating ligand based bimetallic complexes that have catalytic activity is given.