Europium Coordination Compound with Highly Improved Luminescent Quantum Yield

The luminescent properties of two Eu~(3+)compounds based on quinoline-2-carboxylic acid(Hqc),[Na_2Eu_2(qc)_6(CH_3COO)_2(H_2O)_4].2DMF(1)and[Eu_2(qc)_6(H_2O)_6].3H_2O(2),as well as their syntheses and structures are reported.Both compounds are formed by slow evaporation at room temperature and exhibit zero dimensional dinuclear structures.It is worth mentioning that a 4.5-fold enhancement in luminescent quantum yield is achieved by reducing the nonradiative deactivation,through which the quantum yield increases remarkably to 67.62%for 1compared with 12.18%for 2.     

A New Two-dimensional Cd（Ⅱ） Coordination Polymer Constructed by Pyridine-2,5-dicarbohydrazide

A new two-dimensional Cd（Ⅱ） coordination polymer, [Cd（2,5-pdch）（H2O）]n·2n（ClO4）·nH2O （2,5-pdch = pyridine-2,5-dicarbohydrazide）, was prepared and characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction analysis. The crystal belongs to monoclinic, space group P21/c with a = 10.905（2）, b = 11.602（1）, c = 15.034（2） A, β = 117.794 （10°, V = 1682.8（4A3, Z = 4, C7H13CdCl2NsO12, Mr = 542.52, Dc = 2.141 g/cm^3,/μ = 1.691 mm^-1, F（000） = 1072, 2（MoKa） = 0.71073A, the final R = 0.0608 and wR = 0.1329 for 2972 observed reflections with I 〉 2σ（I）. Single-crystal X-ray diffraction analysis reveals that the Cd（Ⅱ） atom displays a distorted pentagonal-bipyramidal geometry coordinated by three N atoms and three O atoms from three different 2,5-pdch ligands, and one water molecule. Interestingly, each two Cd（Ⅱ） atoms are bridged by two carbohydrazide groups of the 2,5-pdch ligands to form a dimeric unit, and such dimeric units are further connected by the 2,5-pdch ligand to generate a two-dimensional （4,4）-network.