Syntheses, Structures and Photoluminescence of Novel Lanthanide-organic Frameworks Based on 1, 4-Bis(3,5-dicarboxylic pyrazol-1-ylmethyl) Benzene

Two isomorphic 3D lanthanide metal-organic frameworks, {[Tb(L)(0.5)(OX)(0.5)(H2O)(2)DMF]center dot DMF}(n) (1) and {[Dy(1)(0.5)(OX)(0.5)(H2O)(2)DMF]center dot DMF}ll (2), have been prepared under solvothermal conditions based on 1,4-bis(3,5-dicarboxylicpyrazol-1-ylmethyl) benzene (H4L), oxalis acid (H2OX) and lanthanide ions. Compound 1 crystallizes in monoclinic system, space group P211c with a = 9.418(15), b = 15.23(2), c = 14.47(2) A, = 100.07(3), V = 2044(5) A3, Z = 4, Mr = 590.3 g/mol, D, = 1.919 g/cm3, p = 3.524 mm-1, F(000) = 1168, R = 0.0893 and wR = 0.1902 for 3486 observed reflections (I > 2o(I)). In compound 1, the central terbium(III) ions are coordinated with eight atoms, and two neighboring terbium(III) ions are linked together by one bridging oxalic acid group to give rise to a [Tb2(OX)(L)41 unit. Each [Tb2(0X)(L)41 unit connects to the surrounding six identical ones by the oxygen atoms bridging to lead to a 3D framework. Compound 1 exhibits strong luminescent emissions at the solid state owing to the antenna effect of the ligand.