Advancement in stereochemical aspects of Schiff base metal complexes

The object of the paper is to look back upon the development of coordination chemistry in the past several decades, during the career of the author, and possibly see how and through what accomplishments the present coordination chemistry has been built up. For the sake of space available, the paper will focus on the stereochemical aspects of Schiff base metal complexes, Those findings which are remarkable from a historical point of view are chosen and discussed. There is other work I would like to include, but must omit for lack of space. The paper is divided for convenience into the two parts dealing with Schiff base ligands of types (A) and (B): (A) Salen and multidentate ligands derived from Salen, and (B) bidentate N-substituted salicylidene-aminates. The main subjects to be discussed include: (A) non-planar Salen in metal complexes, effects of the polymethylene chain between the two imine nitrogen atoms on the structure of metal complexes, the first synthetic sexadentate metal chelates, possibility of trigonal-prismatic configuration for sexadentate chelates, dioxygen adducts of Co(Salen) and analogous complexes. (B) Anomalous solution paramagnetism of Ni(II) complexes, isomerism in the Ni(II) and Cu(II) complexes with Schiff base ligands and 5-coordination of Co(IT) and Ni(II). (C) 1999 Elsevier Science S.A. All rights reserved.