Three double-or triple-stranded chains constructed from different cobalt(II) salts and a flexible bis-triazole ligand

Three coordination compounds, {[Co(btrp)(2)(H2O)(2)]center dot NO3 center dot H2O}(n) (1), {[Co(btrp)(2) (H2O)(2)]center dot H2O center dot 2H(2)btc}(n)(2), and {[Co(btrp)(3)]center dot 2ClO(4)}(n) (3) (btrp = 1,3-bis(1,2,4-triazol-1-yl)propane; H(3)btc = benzene-1,3,5-tricarboxylic acid), have been prepared via solvothermal method and characterized by single-crystal X-ray diffraction and elemental analyses. Compound 1 possesses a 1-D double-stranded chain composed of ribbons of 20-membered cycles. Binuclear water clusters link adjacent nitrate anions to form a 1-D supramolecular helix in the structure. Compound 2 has a 1-D double-stranded chain wherein free H(2)btc ligands constitute 1-D negative chains through classical hydrogen-bonding interactions (O-H center dot center dot center dot O). Compound 3 exhibits a triple-stranded 1-D chain. For 1-3, 3-D supramolecular structures are consolidated by interchain weak hydrogen-bonding interactions as well as electrostatic interactions.