Synthesis, structures, luminescent and dielectric properties of lanthanide coordination polymers

Under hydrothermal conditions, four lanthanide coordination polymers were synthesized based on 4-(4,5-dicarboxy-1H-imidazol-2-yl)pyridine1-oxide (H(3)DCImPyO), with the molecular forumulas [Eu(HDCImPyO).(H2O)(2).(CHO2)](n) (1), [Sm(HDCImPyO).(H2O)(2).(HCO2)](n) (2), {[La(HDCImPyO).(H2O).(HCO2)].O-2}(n) (3) and {[Y(HDCImPyO).(C2O4).(H2O)(2)].H2O}(n) (4). With diverse coordination modes, they were further characterized by elemental analysis, infrared spectroscopy, dielectric measurement, and single-crystal X-ray structural analysis. Complexes 1 and 2 were isostructural and had similar structures with {4(4), 6(2)} topology. Complex 1 exhibited strong fluorescent emission in the solid state at room temperature. In 3, HDCImPyO2- adopted mu(4)-kO,O':kO', O'':O''':O'''' coordination to bridge four La(III) ions to form a 3-D framework with {4.5(2)}(2){4(2).5(10).6(12).7.8(3)} topology. In 4, both HDCImPyO(2-) ligands and Y3+ cations were simplified as linkers to form an interpenetrating 3-D framework with {4(13).6(2)}(2){4(22).6(6)} topology.