Supramolecular assemblies of copper(II)-pyridine-2,3-dicarboxylate complexes with N-donor ligands and clustered water molecules

Four new dinuclear and polynuclear Cu(II)-pyridine-2,3-dicarboxylate complexes with N-donor ligands, [Cu-2(mu-pydc)(2)(dmim)(4)]center dot 6H(2)O (1), {(4-mimH)(2)[Cu(mu-pydc)(2)]center dot 2H(2)O}(n) (2), {[Cu(mu-pydc)(eten)]center dot 2H(2)O}(n) (3) and {[Cu(pen)(2)Cu(mu(3)-pydc)(2)]center dot H2O}(n) (4) (pydcH(2) = pyridine-2,3-dicarboylic acid, dmim = 1,2-dimethylimidazole, 4-mim = 4-methylimidazole, eten = N,N-diethylethylenediamine and pen = 1,3-diaminopropane) have been prepared by utilizing metalloligand approach in a two-stage synthesis and characterized by elemental analysis, FT-IR spectroscopy, thermal analysis and X-ray diffraction techniques. In 1, the dinuclear units are connected each other by cyclic discrete water tetramers to form a 2D hydrogen bonded supramolecular compound, which are extended into a three-dimensional network by C-H . . . pi interactions. In 2, the adjacent 1D chains are connected by the water cluster to form a 2D layer structure. The 2D layers of 4 are further extended into 3D supramolecular network by only weak C-H . . . pi interaction. (C) 2013 Elsevier B.V. All rights reserved.