Synthesis, Structure, Spectroscopic and Electrochemical Properties of Bis(histamine-Saccharinate) Copper(II) Complex

Abstract

Crystal structure of [Cu(hsm)<inf>2</inf>(sac)<inf>2</inf>] (hsm is histamine and sac is saccharinate) complex has been determined by X-ray diffraction analyses and its magnetic environment has been identified by electron paramagnetic resonance (EPR) technique. The title complex crystallizes in the monoclinic system, space group P 21/c with a = 7.4282(4), b = 22.5034(16), c = 8.3300(5) Å, β = 106.227(4)°, V = 1336.98(14) Å3, and Z = 2. The structure consist of discrete [Cu(hsm)<inf>2</inf>(sac)<inf>2</inf>] molecules in which the copper ion is centrosymmetrically coordinated by two histamine ligands forming an equatorial plane [Cu-N<inf>hsm</inf> = 2.024(2) and Cu-N<inf>hsm</inf> = 2.0338(18) Å]. Two N atoms from the saccharinate ligands coordinate on the elongated axial positions with Cu-N<inf>sac</inf> being 2.609(5) Å. The complex is also characterized by spectroscopic (IR, UV/Vis) and thermal (TG, and TDA) methods. The cyclic voltammogram of the title complex investigated in DMSO (dimethylsulfoxide) solution exhibits only metal centred electroactivity in the potential range - 1.25-1.5 V versus Ag/AgCl reference electrode. The molecular orbital bond coefficients of Cu(II) ion in d9 state is also calculated by using EPR and optical absorption parameters. © 2006 Elsevier B.V. All rights reserved.