Synthesis, crystal structure and forming mechanism of two novel copper (II) α-methacrylate complexes with benzimidazole

Two copper (II) a-methacrylate complexes with benzimidazole, Cu[CH2 = C(CH3)-COO](2)(C7H6N2)(2)(1) and Cu-2[CH2 = C(CH3)-COO](4)(C7H6N2)(2)(2), have been prepared and characterized by elemental analyses, IR and electronic reflectance spectroscopies. The single crystal X-ray diffraction study of the two complexes shows that complex 1 has a square planar configuration, while complex 2 has a binuclear cage structure. The crystal structural analyses show that both complexes 1 and 2 are monoclinic, with space group P2(1)/c, a = 0.924 16(8) nm, b = 1.233 02(13) nm, c = 0.989 1(3) nm, beta = 91.912(13)degrees, D-c 1.386 g/cm(3), Z = 2, R = 0.033 9 for the former; and a = 0.905 7(2) nm, b = 2.252 1(5) nm, c = 1.623 5(4) nm, beta = 90.11(2)degrees D-c = 1.411 g/cm(3), Z = 4, R = 0.056 8, Cu-Cu = 0.266 21 Nn for the latter. Different structural types of complexes 1 and 2 were produced simultaneously in the reaction of copper (II) alpha-methacrylate with benzimidazole in methanol solution. The forming mechanism of the complexes has been summarized.