Synthesis and Structural Characterization of a New Schiff Base Macrocyclic Ligand Containing a Piperazine Head Unit and Its Metal Complexes. Crystal Structure of the Co(II) Complex

Abstract

A new macrocyclic Schiff base ligand, L, was synthesized by the condensation reaction of 1,4-bis(2-formylphenyl)piperazine and 1,4-diaminobutane in acetonitrile. The Schiff base ligand was characterized by elemental analysis, IR and mass spectroscopy. Three new Co(II), Cu(II) and Zn(II) complexes, [CoL(NO<inf>3</inf>)]ClO<inf>4</inf>, [CuL(NO<inf>3</inf>)]ClO <inf>4</inf> and [ZnL(NO<inf>3</inf>)]ClO<inf>4</inf>, were prepared and characterized by elemental analyses, IR, FAB-MS, conductivity measurements and in the case of [ZnL(NO<inf>3</inf>)]ClO<inf>4</inf> by 1H NMR spectroscopy. The X-ray crystal structure of [CoL(NO<inf>3</inf>)]ClO <inf>4</inf> showed that the complex contains Co(II) in a distorted octahedral geometry with an N<inf>4</inf>O<inf>2</inf> core. Also, theoretical studies on the interaction of the nitrate ion and metal ions were carried out. © 2012 Elsevier Ltd. All rights reserved.