Two new second sphere complexes of copper(II): Syntheses, characterization, single crystal structure and packing analyses of [trans-Cu(en)2(H2O)2](L1/L2)2 where L1 = 3-methoxybenzoate , L2 = 3,4,5-trimethoxybenzoate

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 = 3-methoxybenzoate, L2 = 3,4,5-trimethoxybenzoate) were obtained by the addition of ethylenediamine to hydrated Cu(II) benzoates, Cu(L1/L2)2·H2O in methanol–water mixture. The newly synthesized complexes have been characterized by elemental analyses, spectroscopic techniques (electronic and FT-IR), magnetic moment determination and molar conductance studies. The complex 1 crystallizes in the triclinic system with space group P-1 and complex 2 crystallizes in the monoclinic system with space group P21/c. X-ray structure determination revealed ionic structures consisting of one complex cation [Cu(en)2(H2O)2]2+ and two respective aryl benzoate anions in 1 and 2. There is a slight difference in the interplanar (plane passing through the Cu centers) distance between two cationic layers of both the complexes due to presence of two more -OCH3 groups on the anionic moiety in 2. A three dimensional hydrogen bonding network formed by N-H...O and O-H...O through second sphere and C-H…π interactions besides electrostatic forces of attraction stabilizes crystal lattice in both the complexes.