Synthesis, Structure and Fluorescence Property of New Cd-MOFs Based on a Tetraphenylethylene (TPE) Ligand

A very stable Cd-II-organic framework, {[Cd-3(Tipe)(1.5)(bpodc)(2)Cl-2]center dot(H2O)(2)}(n) (compound 1, Tipe = 1,1,2,2-tetrakis(4-(imidazol-1-yl)phenyl)ethene, bpodc = benzophenone-4,4-dicarboxylic acid), has been successfully synthesized under hydrothermal conditions. Compound 1 crystallizes in the triclinic system, space group P (1) over bar, with a = 12.289(3), b = 15.951(4), c = 20.755(5) angstrom, alpha = 81.248(2)degrees, beta = 83.905(2)degrees, gamma = 89.452(2)degrees, V = 3998.2(17) angstrom(3), Z = 2, M-r = 1839.59, D-c = 1.528 g/cm(3), mu = 0.925 mm(-1), F(000) = 1844, R = 0.0508 and wR = 0.1571 for 13998 observed reflections (I > 2 sigma(I)). Its overall structure is a three-dimensional stacking with a porosity of 10.1% based on a calculation by PLATON. Compound 1 shows a blue fluorescence emission with the peak maximum of 501 nm (lambda(ex) = 397 nm) by ligand-to-ligand charge transfer of TPE chromophore. And it exhibits excellent performance in detecting Fe3+ and Cr2O72- ions in aqueous solutions as a multi-response sensor.