Two Cobalt(II) Coordination Polymers Based on Tetrazylphosphonate and Tetrazylphosphonic Acid Ligands

Two cobalt coordination polymers with the same 2D structure have been hydrothermally synthesized based on two bifunctional ligands with tetrazole and phosphonate (phosphonic acid) groups, namely, diethyl 4-(2H-1,2,3,4-tetrazol-5-yl) benzylphosphonate (C2H5-L1) and 4-(2H-1,2,3,4-tetrazol-5-yl) benzylphosphonic acid (H(2)L2). The structures of the two complexes are characterized by elemental analysis, IR, TGA and X-ray single-crystal/powder diffraction. The pink block crystals of complex [Co(L1)(H2O)]center dot H2O (1) belong to the monoclinic system, space group C2/m with a = 20.8390(11), b = 7.2695(3), c = 10.0156(6) angstrom, beta = 109.773(7)degrees, V = 1427.80(13)angstrom(3), Z = 4, D-c = 1.680 mg/cm(-3), M-r = 361.16, F(000) = 740, R = 0.0316 and wR = 0.0826 for 1702 observed reflections (I > 2 sigma(I)). The purple block crystals of complex [Co(L2)(H2O)]center dot 2H(2)O (2) also belong to the monoclinic system, space group C2/c with a = 25.5382(16), b = 7.3844(3), c = 15.1925(11) angstrom, beta = 124.238(9)degrees, V = 2368.6(2)angstrom(3), Z = 8, D-c = 1.969 mg/cm(-3), M-r = 351.12, F(000) = 1432, R = 0.0475, wR = 0.1617 for 2088 observed reflections (I > 2 sigma(I)). Both the nitrogen atoms of tetrazole group and oxygen atoms of phosphonate (phosphonic acid) groups in the ligands coordinated with the metal cobalt. The magnetic property of complex 1 is also investigated.