Two new second sphere coordination 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 P1¯ 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 NH⋯O and OH⋯O through second sphere and CH…π interactions besides electrostatic forces of attraction stabilizes crystal lattice in both the complexes.