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 ClCH2COCl 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 ofIreacts 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 (ΛM=3.1-9.2 mho cm2mol−1) in DMF.Ibehaves as a dibasic tridentate OON donor ligand inV; a dibasic tetradentate OONO donor ligand inII,III, andVI; and a dibasic tetradentate OONS donor ligand inIV.IIandIIIare dimers, while others are monomers in diphenyl.IIIexhibits subnormal magnetic moment (1.55 B.M.) and is involved in antiferromagnetic exchange, while the other complexes are magnetically dilute. A square-pyramidal structure forIIIand an octahedral structure forII,IV, andVare suggested.VIexhibits an eight-coordinate structure. The ligand (I) and its compounds show antibacterial activities towardsE. coli(gram negative) andS. aureus(gram positive).