Structural diversities and related properties of four coordination polymers synthesized from original ligand of 3,3',5,5'-azobenzenetetracarboxylic acid.

Abstract

Four new coordination polymers, namely [Co(H2O2abtc)(bibp)]n (), {[Mn1.5(Oabtc)(H2O)2]·(H2bmib)0.5·H2O}n (), {[Cd1.5(O2abtc)]·(H2bmib)0.5·2H2O}n (), and {[Cd(nip)(bibp)]·0.5H2O}n (),were constructed under solvothermal conditions in the presence of two bis(imidazole) bridging linkers (bimb = 1,4-bis(2-methylimidazol-1-ylmethyl)benzene, bibp = 4,4'-bis(imidazol-1-yl)biphenyl). The unstable azo ligand of 3,3',5,5'-azobenzenetetracarboxylic acid (H4abtc) could be oxidized and resulted in three oxidized derivatives of H4Oabtc (one N atom was oxidized), H4O2abtc (two N atoms were oxidized), and H2nip (one H4abtc was oxidized to two 5-nitroisophthalic acids). Their structures were determined by single-crystal X-ray diffraction and further characterized by elemental analyses, IR spectroscopy, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analysis. Complex exhibited an interestingly 2D + 2D → 3D parallel entangled network based on 4-connected (4(4)·6(2))-sql sheets. Complex was found to be a {Mn3(COO)6} trinuclear SBU based 2D (3,6)-connected (4(3))2(4(6)·6(6)·8(3))-kgd sheet. While complex displays a {Cd3(COO)8} trinuclear SBUs based 3D (4,8)-connected (4(6))2(4(12)·6(12)·8(4))-flu network. Complex can be regard as a {Cd2(COO)2} binuclear SBUs based 6-connected (4(4)·6(11))-6T8 framework. In addition, the magnetic property of complexes , and the luminescence properties of complexes , were investigated.