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）;（OX）;（H;O）;DMF]·DMF};（1） and {[Dy（L）;（OX）;（H;O）;DMF]·DMF};（2）,have been prepared under solvothermal conditions based on l,4-bis（3,5-dicarboxylicpyrazol-1-ylmethyl） benzene（H;L）,oxalis acid（H;OX） and lanthanide ions.Compound 1 crystallizes in monoclinic system,space group P2;/c with a=9.418（15）,b=15.23（2）,c=14.47（2） ?,β=100.07（3）°,V=2044（5） ?;,Z=4,M;=590.3 g/mol,D;=1.919 g/cm;,μ=3.524 mm;,F（000）=1168,R=0.0893 and wR=0.1902 for 3486 observed reflections(I>2σ（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 [Tb;（OX）(L);] unit.Each [Tb;（OX）(L);] 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.