Copper(II), cobalt(II), nickel(II) and zinc(II) complexes containing the enolate of N-acetyl-3-butanoyltetramic acid (Habta) and its phenylhydrazone derivative analogues. Crystal structure of [Cu(abta)2(py) 2]·2H2O

Abstract

Reaction of N-acetyl-3-butanoyltetramic acid (N-acetyl-3-butanoyl-4- hydroxypyrrolidin-2-one) (Habta) with M(CH3CO2) 2·xH2O (x = 1, 2 or 4; M = CuII, Co II or NiII) in a 1:1 ratio gave M(CH3CO 2)(abta)·yH2O 1, 3, 5 and in 1:2 ratio M(abta) 2·y′H2O 2, 4, 6. A new ligand, the phenylhydrazone of Habta (HPhabta), has been prepared and reacts with M(CH 3CO2)2·xH2O (x = 2 or 4; M = CuII or CoII) in a 1:1 and 1:2 ratio to give the analogous complexes M(CH3CO2)(Phabta)·zH2O 9, 11 and M(Phabta)2·z′H2O 10 respectively. The solid state structure of [Cu(abta)2(py)2]·2H 2O 2a has been determined by single crystal X-ray diffraction. It shows that copper adopts a slightly distorted octahedral co-ordination geometry with the abta enolate ligand adopting an O,O′ mode of co-ordination via the functionalities associated with C4 and the acyl group at C 3 in the pyrrolidine ring. The reaction of Habta with Zn(CH 3CO2)2·2H2O in 1:1 ratio gives a complex 7 with a deacetylated ligand whereas, with 1:2 ratio, Zn(abta)2·2H2O 8 is obtained. In contrast the reaction of HPhabta with Zn(CH3CO2)2· 2H2O, irrespective of the metal to ligand ratio, gives Zn(CH 3CO2)(Phbta)·2H2O 12 containing the deacetylated ligand. © The Royal Society of Chemistry 2001