Synthesis, crystal structures and properties of two novel macrocyclic nickel(II) and copper(II) complexes

Two new 14-membered hexaaza macrocyclic complexes with the formulae [NiL](ClO4)(2)center dot CH3COCH3 (1) and [CuL](ClO4)(2)center dot CH3COCH3 (2), where L = 3,10-bis(2-thiophenemethyl)-1,3,5,8,10,12-hexaazacyclotetradecane, have been synthesized and characterized by elemental analyses, single-crystal X-ray diffraction analyses, electronic spectra, IR and TG-DTA. In 1, the nickel(II) ion is four-co-ordinated with four nitrogen atoms from the macrocycle and forms a square-planar coordination geometry. In 2, the copper(II) ion is six-coordinated with four nitrogen atoms from the macrocyclic ligand in the equatorial plane and two oxygen atoms from the perchlorate anions in the axial position exhibiting an elongated octahedron coordination geometry. The two complexes present two different molecular arrangements in which the [ML](2+) (M = Ni, Cu) cation arrays in the manner of M(1)M(2)M(1)... in sequence. The pendant thiophene groups of the neighboring macrocycles have no pi...pi interactions. All the ClO4- anions and acetone molecules are involved in hydrogen-bonding interactions with the macrocyclic ligand. (c) 2007 Published by Elsevier B.V.