Metal-ion directed synthesis of N2O2 type chelate complexes of Ni(II), Cu(II) and Zn(II): Spectral, thermal and single crystal studies

Abstract

A set of Ni(II), Cu(II) and Zn(II) complexes of Schiff base have been synthesized by one pot condensation reaction of 2-hydroxy-4-methoxybenzophenone with 1,3-diaminopropane in 1:2:1 molar ratio. They have been characterized by elemental analysis, conductance measurement, thermal analysis (TGA/DTA), FT-IR, 1H-NMR, EPR spectra, ESI–MS and electronic spectral studies. In order to establish the geometry, a single crystal X-ray structure for [Ni(L)] complex was determined. It crystallizes in monoclinic system having unit cell parameters a=14.015(5)Å, b=13.391(5)Å, c=14.931(5)Å and α=90.000(5)o, β=112.237(5)o, γ=90.000(5)o with P 21/c space group. No π–π stacking interaction was obtained in molecular packing diagram. A square-planar geometry has been confirmed for Ni(II) complex. Furthermore, on the basis of elemental analysis, IR, UV–visible and EPR data a square-planar geometry for Cu(II) and a distorted octahedral geometry for the Zn(II) complex has been established. In case of Zn(II) complex NO3- group was found to be coordinated in monodentate fashion. The low molar conductivity values of the complexes measured in chloroform and DMSO suggest their non-ionic nature.