Syntheses, Characterization, and Biological Activities of Metal Complexes of N-(2-Carbamoylthienyl)-C-(3′-carboxy-2′-hydroxyphenyl) Azetidin-2-one with Some Di-, Tetra-, and Hexavalent Metal Ions

The cyclization of the Schiff base, N-(2-carbamoylthienyl)-3'-carboxy-2'-hydroxybenzylideneimine with ClCH2 COCl in dioxane, in the presence of triethylamine (Et3N) forms N-(2-carbamoylthienyl)-C-(3'-carboxy-2'-hydroxyphenyl) azetidin-2-one, LH3 (I). A methanolic solution of I reacts with Co(II), Cu(II), Zn(II), Zr(OH)(2)(IV), and MoO2(VI) ions and forms the coordination compounds, [Co(LH)(MeOH)](2) (II), [Cu(LH)](2) (III), [Zn(LH)(MeOH)(2)] (IV), [Zr(OH)(2)(LH)(MeOH)] (V), and [MoO2 (LH)(MeOH)(2)] (VI). The compounds have been characterized on the basis of elemental analyses, molar conductance, molecular weight, spectral (IR, NMR, reflectance, and ESR) studies, and magnetic susceptibility measurements. All the coordination compounds are nonelectrolytes (Lambda(M) = 3.1 - 9.2mho cm(2) mol(-1)) in DMF. I behaves as a dibasic tridentate OON donor ligand in V; a dibasic tetradentate OONO donor ligand in II, III, and VI; and a dibasic tetradentate OONS donor ligand in IV. II and III are dimers, while others are monomers in diphenyl. III exhibits subnormal magnetic moment (1.55 B.M.) and is involved in antiferromagnetic exchange, while the other complexes are magnetically dilute. A square-pyramidal structure for III and an octahedral structure for II, IV, and V are suggested. VI exhibits an eight-coordinate structure. The ligand (I) and its compounds show antibacterial activities towards E. coli (gram negative) and S. aureus (gram positive).