Reactions of bis(beta-alaninato) metal(II) complexes with formaldehyde and benzamide: The crystal structure of bis[N-methyl-N-(N '-methyl-benzamido)-beta-alaninato]copper(II) monohydrate and characterization of bis[N,N-di(N '-methylbenzamido)-beta-alaninato]metal(II) complexes

The bis[N-methyl-N-(N'-methylbenzamido)-beta-alaninato]copper(II), Cu(II)[Me-MeBA](2), is synthesized by reacting bis(O-alaninato)copper(II) with formaldehyde and benzamide in the presence of a base (NaOH) over the pH range 5.5-8.5. However, the bis[N,N-di(N'-methylbenzamido)-beta-alaninato]metal(II) complexes, M(II)[DMeBA](2) (M = Zn, Ni, Co), are obtained when the respective bis(beta-alaninato)metal(II) reacts with formaldehyde and benzamide in the presence of the base in similar pH ranges. Nevertheless, Cu(II)[DMeBA](2) can be synthesized if the reaction is carried out in the absence of base. The M(II)[DMeBA](2) complexes are characterized by elemental analysis, IR and UV-Visible spectroscopy and magnetic susceptibility measurements. X-ray crystal structure analysis of Cu(II)[Me-MeBA](2) suggests that the N'-methylbenzamido substituent of the beta-alanine moiety is formed through Mannich aminomethylation, and that the other N-methyl substituent is formed via a Canizzaro-type methylation