Metal cation-dependent construction of two 3-D interpenetrating networks based on the ligand 1-(4-carboxyphenyl)-1,2,4-triazole

Two d(10) metal-organic frameworks (MOFs) with 1-(4-carboxyphenyl)-1,2,4-triazole (Hcpt), namely [Zn(cpt)(2)](n)(1) and {[Cd(cpt)(2)] center dot 2DMF}(n) (2), have been solvothermally synthesized by fine control over synthetic conditions, and structurally characterized. The results reveal that compound 1, once reported in literature, crystallizes in the acentric Cc space groups, in which the tetrahedral Zn2+ center in 1 coordinates to two triazole nitrogen atoms and two carboxylate oxygen atoms from four mu(2) - eta(1):eta(1) bridging cpt(-) ligands, leading to a noncentrosymmetric 5-fold interpenetrating diamondoid 3-D network. On the other hand, new compound 2 has orthorhombic and space group Pbc2(1), in which distorted octahedral Cd2+ center in 2 coordinates to two triazole nitrogen atoms and two carboxylate oxygen atoms from four mu(2) - eta(1):eta(1):eta(1) bridging cpt(-) ligands, resulting in an interesting 4-fold interpenetrating diamondoid 3-D network structures containing 1-D channels with a cross section of 9.5 x 9.3 angstrom. Considering their different topological structures, the gas adsorption experiments of 2 were carried out, and the results show that 2 presents a selective adsorption of CO2 over N-2/H-2. Moreover, the fluorescent properties of compounds 1 and 2 were also studied. (C) 2013 Elsevier B.V. All rights reserved.