Differential binding of a facultative tridentate ligand 4-(benzimidazol-2-yl)-3-thiabutanoic acid to CuII and NiII

Abstract

The crystal structure of a new tridentate ligand 4-(benzimidazol-2-yl)-3-thiabutanoic acid (HL), which provides a benzimidazole, a thioether and a carboxyl donor group that can be regarded as mimics of His, Met and Asp/Glu side chains in proteins, has been determined, together with those of its octahedral [CuL₂] (brilliant blue) and [NiL₂] (bright turquoise) complexes and the ligand field spectra of the chelates, for which the ligands provide an S₂N₂O₂ donor set, in each case, but different positional isomers for the copper (t,c,c) and the nickel (c,c,c) chelates.