Coordination Chemistry and Applications of Nitrilotris(N‐Methylenephenoxy)–Metal Complexes

Abstract

Nitrilotris( N ‐methylenephenols), commonly called triphenolamines (TPA), are highly modular, tetradentate molecules that effectively coordinate to transition metals and main group elements with podand topology. They form chiral complexes with intrinsically well‐defined geometries (pentacoordinate trigonal bipyramidal, hexacoordinate octahedral, and, more rarely, trigonal monopyramidal geometries) controlled by the ligand. Nitrilotris( N ‐methylenephenoxy)–metal complexes have been found to be effective and robust catalysts in a series of important processes like polymerizations (titanium(IV), zirconium(VI), hafnium(VI), germanium(VI), and vanadium(V) complexes), oxygen transfer reactions (titanium(VI), vanadium(V), molybdenum(VI), and nickel(II) complexes), carbon–carbon bond formation (aluminium(III), and titanium(VI) complexes), carbon dioxide fixation (iron(III) complexes), and metathesis (Mo(VI) complexes).

Transition Metal Catalysts Bearing Multidentate Ligands for Efficient and Environmental Benign Oxidations by H2O2

“…[4] TPAs easily coordinate to transition metal ions (d 0 ,d 1 ) [5] but examples of complexes of the main group (d 8 ) or late transition metals are also present. [6] The aminotriphenolate metal complexes are generally mononuclear, with a 1 : 1 ligand metal ratio, and they adopt mainly trigonal bipyramidal (TBP, pentacoordinate) or octahedral (OCT, hexa-coordinate) geometries. In Scheme 1 an example of the synthesis of TPA-V(V) complexes exhibiting TBP or OCT geometries is reported.…”