Syntheses, Crystal Structures, and Magnetic Properties of Two Cobalt(II) and Nickel(II) Coordination Polymers Constructed from Biphenyl-Type Tricarboxylic Acids

Two 1D cobalt(II) and 2D nickel(II) coordination polymers, namely [Co(mu(2)-H(2)btc)(2)(4,4'-bipy)(2)](n) (1) and 1[Ni-3(mu(4)-dPPa)(2)(H2O)(6)]center dot 2H(2)O}(n) (2), have been constructed hydrothermally using H(3)btc (H(3)btc=bipheny1-2,4,4'-tricarboxylic acid), H(3)dppa (H(3)dppa =5-(3,4-dicarboxylphenyl)picolinic acid), 4,4'-bipy(4,4'-bipy=4,4'-bipyridine), and cobalt or nickel chlorides. Single-crystal X-ray diffraction analyses reveal that both compounds crystallize in the triclinic system, space group P1. Compound 1 has a 1D double-helix chain structure, which is assembled to a 3D supramolecular framework through O-H center dot center dot center dot O/N hydrogen bond. Compound 2 shows a 2D sheet based on 1D chain units. Moreover, 4,4'-bipy can tune the structures of both coordination polymers by its coordination or template effect. Magnetic studies for compound 1 demonstrate a ferromagnetic coupling between the adjacent Co (II) centers. CCDC: 1889686, 1; 1889687, 2.