Spectra-structure relationship: Syntheses, characterization, single crystal X-ray structural studies and packing analyses of two novel copper(II) complexes: [Cu(pyridine)2(H2O)4](p-toluenesulfonate)2 and [Cu(β-picoline)2(H2O)4]-(p-toluenesulfonate)2

In an attempt to formulate spectra-structural relationship to provide information on coordination around copper(II) ion in aqueous solution, two novel copper(II) complexes were investigated. [Cu(py)(2)(H2O)(4)] (p-toluenesulfonate)(2), 1 and [Cu(beta-pic)(2)(H2O)(4)](p-toluenesulfonate)(2), 2(py = pyridine, beta- were isolated by addition of py and beta-pic respectively to the hydrated Cu(p-toluenesulfonate)(2) suspended in water-methanol (1:4) mixture. The newly isolated complexes have been characterized by elemental analyses, TGA, spectroscopic techniques (EPR, IR and UV/Visible), conductance, magnetic susceptibility studies and single crystal X-ray structure determination. X-ray structural studies revealed the presence of uncoordinated p-toluenesulfonate anions in both of the crystal structures. The copper cations coordinate to two py/beta-pic and four water molecules; the six donor atoms span as a distorted octahedron in both case. The crystal packing in both the complexes 1 and 2 are stabilized by C-H center dot center dot center dot O, C-H center dot center dot center dot pi and pi center dot center dot center dot pi and it it stacking interactions besides electrostatic forces of attraction. (C) 2011 Elsevier B.V. All rights reserved.