Four new metal-organic frameworks based on diverse metal clusters: Syntheses, structures, luminescent sensing and dye adsorption properties

Four new complexes, namely {[Cd(L1)(2)]center dot(H2O)-(DMA)}(n)(1),{Z(n)(L1)(2)(HL1)]center dot 3.5H(2)O}(n) (2), {[Ph(L2)(HCOO)]center dot 0.5H(2)O center dot 0.5DMF}(n) (3), and {[Zn(L2)(NO3)(H2O)}-0.5H(2)O center dot 0.5CH(3)CN}(n) (4), were synthesized by two isomeric (2-(pyridin 4 yl) benzimidazole 5 carboxylic acid) (HL1) and (2-(pyridin 2 yl) benzimidazole-5-carboxylic acid) (HL2) under hydro(solvo) thermal conditions. The ligands in the complexes adopt different coordination modes to connect the metal centers and finally form three-dimensional structures with different pore size. The results of fluorescence tests show that complex 3 has high sensitivity and selectivity to both Fe3+ and MnO4- the quenching constants are 8.74 x 10(4)L mol(-1) and 3.88 x 10(4) L mol(-1), and the minimum detection limit are 1.17 x 10(-5) mol L-1 and 4.48 x 10(-5) mol L-1, respectively. In addition, complex 1 has fast and efficient adsorption capacity for Congo red (CR) and Methyl green (MG).