Synthesis and Characterization of Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II) Complexes of HeptadentateAsymmetrical Tripodal Schiff Base

Abstract

Bis(2-aminoethyl)(3-aminopropyl)amine, 2-pyridinecarboxalde-hyde and a number of metal ions were used to prepare metal complexes of tripodal Schiff base ligand (L₃₂₂). The resulting complexes, [M(L₃₂₂)](ClO4)2 [M = Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II)];
L₃₂₂N[CH₂CH₂CH₂N═CH(C₅H₄N)][(CH₂CH₂N═CH(C₅H₄N)]₂, were characterized by
microanalysis and IR spectra in all cases and by nothing sup ¹H NMR spectra in the case of
Zn(II) and Cd(II) complexes. In the nothing sup ¹H NMR spectrum of the cadmium complex
the signals of imine protons having two clear satellite peaks (³J = 44.41–47.64 Hz) with
rarely observed intensities in the ratio 1 : 6 : 1 due to coupling with neighbouring ^111/113Cd.
The ab initio studies on [Zn(L₃₂₂)]²⁺ and [Cd(L³²²)]²⁺ complexes were also reported. The
results show that the most bonding interaction between the metal ion and the bridging tertiary
nitrogen atom of ligand occurs in the Cd(II) complex.