Ligational Behaviour of the Azetidinone Towards Some Di-, Tri-, Tetra- and Hexavalent Metal Ions

Abstract

A methanolic solution of salicylaldehyde reacts with o-hydroxyphenylurea in methanol to yield Schiff base (1) via nucleophilic addition reaction followed by the elimination of one water molecule. The cycloaddition reaction of 1 with chloroacetyl chloride in presence of Et₃N in dioxane affords the corresponding azetidin-2-one, LH₃ (2). The reaction of 2 with Cu(II), Zn(II), Cd(II), Mn(II), Co(II), Ni(II), Fe(III), MoO₂(VI), UO₂(VI) and Zr(OH)₂(IV) ions in methanol results in the formation of [Cu(OAc)(LH₂)] (3), [M(OAc)(LH₂)] (here M = Zn(II), Cd(II)) (4), [M'(OAc)(LH₂)(MeOH)₂] (here M' = Mn(II), Co(II), Ni(II) (5), [FeCl₂(LH₂)(MeOH)] (6), [MoO₂(acac)(LH₂)(MeOH)] (7), [UO₂(OAc)(LH₂)(MeOH)₂] (8) and [Zr(OH)₂(OAc)(LH₂)] (9). The compounds have been characterized on the basis of elemental analyses, molecular weight, molar conductance, spectral (IR, UV-VIS, ESR) and magnetic susceptibility measurements. 2 acts as a monobasic tridentate ONO donor ligand in these monomeric complexes. A squareplanar structure for 3, a tetrahedral structure for 4 and an octahedral structure for 5, 6 and 9 have been proposed. 7 and 8 afford an eight-coordinate structure.