Synthesis of beta-Imino Carbonyl Enolato Complexes by Reaction of Nickel(II), Palladium(II), and Copper(II) Acetates with the Enaminodiones (MeOCO)(RCO)CC(R')NH(2) (R = Me, OMe; R' = Et, EtOCO).

Nickel(II), palladium(II), and copper(II) acetates undertake exchange reaction with the beta-enaminodiones (MeOCO)(RCO)CC(R')NH(2) (R = Me, OMe; R' = Et, EtOCO) in ethanol to give the neutral complexes [M((MeOCO)(RCO)CC(R')NH)(2)] (1-8) [R = Me, R' = Et: M = Ni (1), Pd (2a,b), Cu (3); R = Me, R' = EtOCO: M = Ni (4), Pd (5), Cu (6); R = MeO, R' = Et, M = Pd (7a,b); R = MeO, R' = EtOCO, M = Pd (8a,b)]. The trifunctional N,O,O ligands act in all cases as bidentate through the imino and one carbonyl group. Complexes 1-8 are all monomers with a square planar geometry. Nickel and palladium complexes show more than one form in the solid state. For example the palladium complex 2 has been synthesized in two forms a and b, which differ in the conformation of the methoxy carbonyl substituent of the chelate ring, while the third isomer or conformer is obtained by thermal treatment at 120 degrees C. Complexes 7 and 8 also exhibit two forms which differ in the degree of intermolecular hydrogen bonding. Both 7b and 8b crystallize in monoclinic unit cells [7b: space group P2(1)/n, a = 11.963(2), b = 8.438(1), c = 19.637(2) Å, beta = 94.2(1) degrees. 8b: P2(1)/c, a = 10.698(2), b = 14.902(2), c = 13.918(2) Å, beta = 95.2(1) degrees ] containing four molecules linked by intermolecular hydrogen bonding [N-H.O=C, 2.14-2.36 Å]. All complexes are thermally stable and volatile. Their mass spectra exhibit intense molecular ion peaks under EI mass conditions.