Synthesis and spectroscopic properties of N-acetyl-DL-phenyl-glycinato complexes of cobalt(II), nickel(II) and copper(II). Crystal structures of bis(N-acetyl-DL-phenyl-glycinato)diaquobis-(N-methylimidazole)cobalt(II), bis(N-acetyl-DL-phenylglycinato)diaquobis (imidazole)cobalt(II) and nickel(II)

A series of complexes of N-acetyl-DL-phenylglycine and CoII, NiII and CuII containing heterocyclic bases as imidazoles, phen, bipy and terpy were prepared and characterized by conventional methods, IR spectra and, for [Co(OH2)2(mimi)2(Ac-phgly)2] (1), [Co(OH2)2(imi)2(Ac-phgly)2] (2) and [Ni(OH2)2(imi)2(Ac-phgly)2 (3), by X-ray crystal structure. The structure of these complexes consists of discrete [M(OH2)2(mimi/imi)2(Acphgly)2] units in which the metal shows nearly ideal centrosymmetrical trans-octahedral geometry bonding two imidazole nitrogens, two carboxylic oxygens and two water molecules. In all cases the amino acid behaves as monodentate via carboxylic oxygen, the second carboxylic oxygen; the NH and CO peptide groups are involved in hydrogen bonds which are responsible for the packing in the crystal.