Supramolecular networks in copper(II) malonate complexes

Six new copper(II)-malonate containing complexes [Cu(dpydiol)(mal)(H2O) center dot 2H(2)O (1) (dpydiol = bis(2-pyridyl)-methanediol), [Cu(dpa)(mal)(H2O)] center dot H2O (2) (dpa = 2,2'-dipyridylamine), [Cu(pyim)(mal)(H2O) center dot H2O (3) (pyim = 2-(2-pyridyl)imidazole), [Cu(dpp)(mal)(H2O)] center dot 3/2H(2)O (4) (dpp = 2,3-bis(2-pyridyl)pyrazine), [Cu(phen)(mal) (H2O)] center dot H2O (5), and [Cu-2(phen)(2)(mal)(H2O)(3)](NO3)(2) center dot 2H(2)O (6) (phen = 1,10-phenanthroline) were prepared and their structures were determined by single-crystal X-ray diffraction analysis. 1-5 are mononuclear complexes, whereas 6 is a dinuclear species. The neutral mono- and dinuclear units and the crystallization water molecules are linked together by hydrogen bonds to afford three-dimensional networks. In addition, pi center dot center dot center dot pi stacking (2, 5 and 6) and hydrophobic (4 and 6) interactions contribute to the stabilization of the structures. The analysis of the magnetic data of 6 in the temperature range 1.9-300 K shows the occurrence of a significant ferromagnetic interaction between the copper(II) ions through the carboxylate-malonate bridge [J = +6.22(1) cm(-1), the isotropic spin Hamiltonian being defined as (H) over cap = -J (S) over cap (A) center dot (S) over cap (B)].