Abstract
A new potentially tetradentate (N(4)) Schiff base ligand (L),
1,9,12,20-tetraazatetracyclo18.2.2.02,7.014,19tetracosa-2(7),3,5,8,1
2,14(19),15,17-octaene containing a piperazine moiety is described.
Macrocyclic Schiff base complexes, NiL(ClO(4))(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'(ClO(4))(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 N(6) donor set. The
spectroscopic characterization of all complexes is consistent with their
crystal structures. (C) 2010 Elsevier B.V. All rights reserved.
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