Concomitant formation of differently coordinated copper(II) complexes in the same reaction: Structural studies of [trans-Cu(γ-picoline)2(H2O)4](p-toluene sulfonate)2·2H2O and [trans-Cu(γ-picoline)4](p-toluenesulfonate)2·2H2O

Two new copper(II) complexes comprising of coordinated and non-coordinated p-toluenesulfonate, [trans-Cu(γ-pic)2(H2O)4](pts)2·2H2O, 1 and [trans-Cu(γ-pic)4(pts)2]·2H2O, 2 (where p-toluenesulfonate = pts and γ-picoline = γ-pic) have been isolated from the same reaction mixture. These complexes have been characterized by spectroscopic techniques, molar conductance, TGA, magnetic susceptibility studies, and single crystal X-ray structure determination. Both complexes crystallize in the monoclinic crystal system with P21/c space group having cell dimensions of a = 8.0203(2) Å, b = 19.4471(4) Å, c = 10.3000(3) Å, β = 93.4420(9)°, V = 1603.61(7) Å3, (Z = 2) in 1 and a = 10.1473(2) Å, b = 10.9948(2) Å, c = 18.0952(5) Å, β = 93.0340(9)°, V = 2015.96(8) Å3, (Z = 2) in 2. Single -crystal X-ray structure determinations revealed the presence of ionic complex, viz: one complex cation [trans-Cu(γ-pic)2(H2O)4], two pts anions and two water molecules of crystallization in the complex 1 and neutral [trans-Cu(γ-pic)4(pts)2] and two water molecules of crystallization in 2. The crystal packing in both complexes is stabilized by OH⋯O, CH⋯O hydrogen bonds and CH⋯π interactions.

► Two new copper(II) complexes have been synthesized from same reaction mixture. ► Non-covalent interactions are playing crucial role in crystal lattice stabilization. ►p-Toluenesulfonate in the presence of base γ-picoline exhibit diverse coordination modes.