Synthesis, spectral, electrochemical and catalytic properties of Cu(II), Ni(II) and Co(II) complexes containing N, O donors

Abstract

Metal(II) chelates of Schiff bases derived from the condensation of multi-substituted aniline with mono- and di-substituted salicylaldehyde have been prepared and characterized by 1H NMR, IR, electronic, EPR, magnetic and cyclic voltammetry measurements. The complexes are of the type M(X-DPMP) 2 [(M = Cu(II), Ni(II) or Co(II)), DPMP = 2-[(2,6-diisopropylphenylimino)methyl]phenol, X = Br, Cl, I, BrCl]. The Schiff bases behave as monobasic bidentate ligand in their complexes. The spectral data indicate that the ligand coordinates through the phenolic oxygen and the azomethine nitrogen atoms. The observed A || values in the Cu(II) complexes indicate a tetrahedrally distorted square planar structure. The cyclic voltammetric redox potential of copper(II) and nickel(II) complexes suggest the existence of irreversible pairs in acetonitrile. Cu(Br-DPMP) 2 was found to be an efficient catalyst for cyanosilylation of aldehydes under mild conditions.