Three copper(II) coordination polymers constructed by both rigid and flexible ligands

Three new Copper(II) polymers coordinated by both rigid and flexible ligands, [Cu(bpy)(C5H6O4)](n) (1), [Cu(bpy)(C6H8O4)](n) (2), and [Cu-2(bpy)(2)(C6H8O4)(2)](n) (3) (bpy = 4,4'-bipyridine), have been hydrothermally synthesized and structurally characterized. Complex 1 features a box-like bilayer motif of (4, 4) net. It crystallizes in triclinic space group P1 with cell parameters: a = 8.1395(6) angstrom, b = 9.4312(8) angstrom, c = 10.5473(8) angstrom, alpha, = 112.1830(1)degrees, beta = 92.423(2)degrees, gamma = 104.752(2)degrees, V = 716.31(1) angstrom(3), Z = 2. Complex 2 crystallizes in triclinic space group P1 with a 8.8652(4) angstrom, b = 8.9429(4) angstrom, c = 10.6390(4) angstrom, alpha, = 89.520(2)degrees, beta = 69.123(2)degrees, gamma = for complex 3. To our surprise, two isomeric complexes (2 and 3) were obtained under different pH value. Furthermore, when sodium hydroxide was added to the Cu-glutarate system, an analogous complex of 1, which had been reported by Zaworotko et al. [7], was also obtained. It demonstrated here that pH value played crucial role in the construction of different frameworks.