Coordination chemistry of two new tetraaza Ni(II) and Cu(II) macrocyclic and two new Co(II) and Zn(II) macroacyclic Schiff base complexes containing piperazine moiety: X-ray crystal structures of Ni(II) and Zn(II) complexes

Keypour H., Arzhangi P., Rahpeyma N., Rezaeivala M., Elerman Y., Khavasi H. R.

Inorganica Chimica Acta, vol.367, no.1, pp.9-14, 2011 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 367 Issue: 1
  • Publication Date: 2011
  • Doi Number: 10.1016/j.ica.2010.11.033
  • Journal Name: Inorganica Chimica Acta
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.9-14
  • Keywords: Macroacyclic Schiff base complex, Piperazine moiety, Tetraaza macrocycle, X-ray crystal structure
  • Ankara University Affiliated: Yes

Abstract

A new potentially tetradentate (N4) Schiff base ligand (L), 1,9,12,20-tetraazatetracyclo[18.2.2.02,7.014,19]tetracosa-2(7),3,5,8,12,14(19), 15,17-octaene containing a piperazine moiety is described. Macrocyclic Schiff base complexes, [NiL](ClO4)2 (1) and [CuL](ClO 4)2 (2) have been obtained from equimolar amounts of ligand (L) with nickel(II) and copper(II) metal ions. While the equilibrium reaction in the presence of cobalt(II) and zinc(II) metal ions with ligand L in a 1:1 molar ratio yielded the open-chain Schiff base complexes, [CoL′](ClO4)2 (3) and [ZnL′](ClO 4)2 (4) containing two terminal primary amino groups. The ligand L′ is 1,4-bis(2-(2-aminoethyliminomethyl)phenyl)piperazine. The crystal structures of (1) and (4) have been also determined by X-ray diffraction. It was shown that the Ni(II) is coordinated to the ligand L by two nitrogen atoms of piperazine group and two nitrogen atoms of the imine groups, in a slightly distorted square-planar geometry. Also single crystal X-ray analysis of (4) confirmed a distorted octahedral arrangement in the vicinity of Zn atom with N6 donor set. The spectroscopic characterization of all complexes is consistent with their crystal structures. © 2010 Elsevier B.V. All rights reserved.