Second sphere coordination complexes: Synthesis, characterization, single crystal structure and packing analyses of [trans-Cu(en)2(H2O)2](L1/L2)2 where L1 = p-toluenesulphonate, L2 = 5-bromo-2-methoxybenzenesulphonate

Two new copper(II) complexes of composition [trans-Cu(en)2(H2O)2](L1)2, 1 and [trans-Cu(en)2(H2O)2](L2)2, 2 (L1 = p-toluenesulphonate, L2 = 5-bromo-2-methoxybenzenesulphonate) were obtained by the addition of ethylenediamine to hydrated Cu(II) sulphonates, Cu(L1/L2)2·nH2O in methanol–water solution. The newly synthesized complex salts have been characterized by elemental analyses, TGA, spectroscopic techniques (electronic and FT-IR), magnetic moment determination and conductance measurements. The complex salt 1 crystallizes in the monoclinic system with space group P21/c and complex salt 2 crystallizes in the triclinic system with space group P. X-ray structure determination revealed ionic structures consisting of one complex cation [Cu(en)2(H2O)2]2+ and two respective sulphonate anions in 1 and 2. A three dimensional hydrogen bonding network formed by N–H…O, C–H…O and O–H…O through second sphere interactions besides electrostatic forces of attraction stabilize crystal lattice in both complex salts.