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

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 H-1 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(II) 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. (C) 2009 Elsevier B.V. All rights reserved.