Four cluster-containing highly connected coordination networks: syntheses, structures, and properties

Abstract

Four three-dimensional highly connected coordination polymers, [Zn₄(μ₄-O)(L)₂(btbp)_1.5] (1), [Zn₈(μ₃-OH)₄(L)₄(btb)(H₂O)₂] (2), [Cd₈(μ₃-OH)₄(L)₄(4,4′-bipy)(H₂O)₄]·H₂O (3) and [Cd₅(L)₂(ipt)₄(H₂O)₂]·6H₂O (4), where H₃L = (3,5-dicarboxyl-phenyl)-(4-(2′-carboxyl-phenyl)-benzyl) ether, btbp = 4,4′-bis(1,2,4-triazol-1-ylmethyl)biphenyl, btb = 1,4-bis(1,2,4-triazol-1-yl)butane, 4,4′-bipy = 4,4′-bipyridine and Hipt = 5-(4-imidazol-1-yl-phenyl)-2H-tetrazole, have been synthesized under hydrothermal conditions. In complex 1, 9-connected tetranuclear [Zn₄(μ₄-O)(COO)₆] clusters are bridged by L anions and btbp ligands to form a (3,3,9)-connected network. Complexes 2 and 3 possess (3,3,14)-connected nets based upon octanuclear [Zn₈(μ₃-OH)₄(COO)₁₂] and [Cd₈(μ₃-OH)₄(COO)₁₂(H₂O)₄] clusters, respectively. Complex 4 reveals a tetranodal (3,4,8)-connected network based on trinuclear [Cd₃(COO)₂(H₂O)₂] units. Additionally, the fluorescence properties of complexes 1–4 were investigated.