Squarato-metal(II) complexes: Part 6(1). Synthesis, structure and magnetic characterization of an usual squarate-based 1D copper(II) coordination polymer composed of hexanuclear entities and a trinucleating ligand scaffold

Abstract

The reaction of the polynucleating ligand 1,3,5-tris[bis(2-pyridylmethyl)aminomethyl]benzene (L-TDPA) with Cu(ClO4)(2)center dot 6H(2)O afforded the trinuclear complex Cu-3(T-TDPA)(H2O)(7)(6)center dot 5H(2)O (I). When the reaction was performed in the presence of the squarate dianion, C4O42-, the compound {Cu-6(L-TDPA)(2)(mu(1,3)-C4O4)(3)(6)center dot 12H(2)O}(n) (2) was obtained. Both compounds have been characterized by X-ray crystallography, showing a trinuclear and a 1D polymeric structures for 1 and 2, respectively. Complex 2 is composed of unusual hexametallic building blocks. Magnetic susceptibility measurements (SQUID) reveal essentially uncoupled copper(II) ions in complex 1, whereas complex 2 shows weak antiferromagnetic coupling via the squarato bridges within magnetically isolated dicopper(II) subunits of the 1D chain. (C) 2013 Elsevier B.V. All rights reserved.