Cu(II) complexes of selenium bearing Se2N4O2 macrocyclic Schiff bases: Synthesis and electrochemical studies

Abstract

In this paper we report an effortless, convenient and less hazardous route for the synthesis of two Cu(II) complexes of phenol based 24- and 28-membered macrocyclic Schiff bases, [Se2{(CH2)nN = C PhC6H2(OH)(4-CH3)PhC = N(CH2)n}2] (where n = 2, LaH2; n = 3, LbH2) of Se2N4O2 type. These ligands on coordination with Cu(CH3COO)2·H2O in 1:2 M ratio in methanol gave mononuclear complexes [Se{(CH2)nN = CPhC6H2(O)(4-CH3)PhC = O}2Cu] (n = 2, 1; n = 3, 2) with the loss of bis(aminoalkyl)selenide and acetic acid. In both of these complexes, two imine (C = N) bonds of the ligand molecule undergo hydrolysis, and links with Cu(II) in tetradentate (N2O2) fashion. The selenium atom does not form part of the copper(II) coordination sphere. The complexes (1 and 2) have been characterized by elemental analyses, conductivity measurements, mass spectrometry, IR, electronic, 1H, 13C{1H} and 77Se{1H} NMR spectroscopy and cyclic voltammetry.