Craig J. Matthews, Sarah L. Heath, Mark R. J. Elsegood, William Clegg, Troy A. Leese and Joyce C. Lockhart
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.