A new series of trivalent lanthanide (Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy) coordination polymers with a 1,2-cyclohexanedicarboxylate ligand: synthesis, crystal structure, luminescence and catalytic properties

Eight lanthanide coordination polymers (Ln(1,2-chdc)(form)(H 2 O)) have been solvothermally synthesized from the reaction of 1,2-cyclohexane dicarboxylic acid (denoted as 1,2-chdcH 2 ) with trivalent metallic cations (Ce 3+ ( 1 ), Pr 3+ ( 2 ), Nd 3+ ( 3 ), Sm 3+ ( 4 ), Eu 3+ ( 5 ), Gd 3+ ( 6 ), Tb 3+ ( 7 ) and Dy 3+ ( 8 ); from a nitrate or chloride source) in a mixed H 2 O/ N , N -dimethylformamide solvent (DMF) at T = 100-150 °C (form = formate ligand). Their crystal structures are similar and built up from nine-fold coordinated lanthanide cations (LnO 9 - tricapped trigonal prism), linked to each other through three Ln-O-Ln bonds (face sharing connection mode of LnO 9 polyhedra) in order to generate infinite ribbons. The coordination sphere of the lanthanide center is ensured by oxygen atoms from the 1,2-chdcH 2 ligand and formate groups. The latter come from the partial solvothermal decomposition of DMF solvent. The resulting compounds exhibit a layered structure with infinite chains of LnO 9 , connected to each other via the ditopic 1,2-chdc linker. Luminescence studies (steady-state excitation, emission and time-resolved decay measurements) have been performed on the compounds bearing Ce 3+ , Nd 3+ , Sm 3+ , Eu 3+ , Tb 3+ , and Dy 3+ cations. The Nd compound ( 3 ) was found to be efficient for isoprene (methyl-2-butadiene, CH 2 &z.dbd;CH-C(Me)&z.dbd;CH 2 ) polymerization despite the presence of water in its molecular structure, affording a highly cis stereo-regular polymer. The lanthanide coordination complexes containing aliphatic cyclic dicarboxylate linker have been characterized for their luminescence and catalytic properties.