AMBIDENTATE LIGANDS, THE SCHIZOPHRENICS OF COORDINATION CHEMISTRY

Representative examples of ambidentate ligand chemistry, drawn primarily from studies published during the past decade, are presented. An overview of the physical methods used for structural elucidation is included, with major emphasis being placed on structures emanating from single crystal X-ray diffraction studies. A great variety of ambidentate ligands are covered, although the bulk of the review deals with the schizophrenic behaviour of the classic ambidentate ligands NO2-CN- NCO-, NCS- NCSe- and NCTe-. As usual, the thiocyanate ion is accorded the most extensive coverage. Other ambidentate ligands discussed include CNO-, CNS-, azaphospholes, aminobenzonitriles, 4,4'-bipyrimidine, cyanoborohydrides, CCO, ClC(CN)3, chloranilate ion, isonitroso(β-ketoimine), nicotinate ion, nitramines, nitrosobenzenes and -anilines, Ph2PC(S)NHR, phosphine/arsine, phosphine sulfide/methine, and phosphinethioamide hybrid ligands, pyridine-2-thione, N-(2-pyridyl)imidazole, 4,6-dimethylpyrimidine, saccharinate ion, H2NSO3-, SO32-, Me2SO, SO2, SO2-, SNO-, NSO-, S2O32-, S2CO2-, SeO32-, SC(O)NHR-, OSNH-, dithioimidodiphosphinate ion, dithiosquarate ion, triphosphate ion, and ureas. Transition metal complexes of ambidentate ligands are emphasized throughout the review. © 1990.