A Three-dimensional Tm(Ⅲ)-Zn(Ⅱ) Heteronuclear Metalorganic Framework Based on Imidazole-dicarboxylate Ligand:Synthesis,Crystal Structure and Luminescence Property

A d-f heteronuclear metal-organic framework(MOF),{[Tm_3Zn_6(bipy_2)_2(mimda)_7(H_2O)_3]·(H_2O)_5}_n(1,H3 mimda = 2-methyl-1-H-imidazole-4,5-dicarboxylic acid,and bipy = 4,4?-bipyridine),has been synthesized under solvothermal conditions,and structurally characterized by elemental analysis,IR spectra and X-ray single-crystal diffraction.It crystallizes in orthorhombic system,space group Pnma with a = 16.1102(9),b = 33.5805(19),c = 16.8593(10) ?,β = 97.344(11)°,V = 9120.7(9) ?~3,Z = 4,F(000) = 5184,the final R = 0.0530 and w R = 0.1306.In complex 1,the Tm(Ⅲ) ions adopt two types of coordination fashions.Complex 1 shows onedimensional(1-D) Tm-Zn heteronuclear zigzag chains,and these chains are further linked by H3 mimda ligands into Tm-Zn heteronuclear 2-D lattice-like arrays.The 2-D heteronuclear units were connected through [Zn_6(mimda)_6] rings to give rise to the Tm-Zn heteronuclear cages.Finally,H3 mimda ligands connected the cages into a 3-D heterometallic framework by the combination of [TmO_7]_n and Tm-Zn heteronuclear cages.In addition,the thermal stability and luminescent property have been investigated.     

Molecular Dynamics Simulations of the Elastic Anisotropy of Pd at Extreme Conditions

It is very interesting to discover the elastic properties of engineering material palladium, especially its elastic anisotropy along Hugoniot states. We here investigate the evolution of its high pressure and temperature(PT) elastic ansotropy along Hugoniot using molecular dynamics simulations based on accurate classical interatomic potential. In order to testify the validity of the interatomic potential of Pd in describing the high PT elastic properties, we calculate its isothermal and adiabatic elastic moduli using molecular dynamics method. The obtained data are in good agreement with experimental data. From the isothermal elastic constants, we deduce the Hugoniot acoustic velocities and find that the resulting data are in good agreement with experimental acoustic velocity data. Based on the reliable elastic constants, we further investigate the spacial elastic ansotropy along Hugoniot PT states. It is found that the spacial elastic anisotropy of Pd increases along Hugoniot states.     

A Unique Heteronuclear Metal Organic Framework Based on Amino-acid and N-donor Ancillary Ligand: Synthesis,Structure and Characterization

A novel heteronuclear metal organic framework(MOF) incorporating both transition and alkali metal ions, namely, {(Ni_2K_2L_2·bipy]×6 H_2O]×2 H_2O}n(1, L = N-phosphonomethyl amino diacetic acid, bipy = 4,4?-dipyridine) has been obtained. Its structure was established by single-crystal X-ray diffraction analysis and further characterized by elemental analysis and IR spectroscopy. The complex crystallizes in orthorhombic system, space group Pccn with a = 14.650(11), b = 36.56(3), c = 7.112(5) ? and V = 3809.3(8) ?~3. In this framework, bipy connects adjacent Ni–K heteronuclear coordination units into 1 D railway type chains, which are further propagated into 2 D deck-like array bearing large tunnels through the carboxylic oxygen from N-phosphonomethyl amino diacetic acid. The molar electrical conductivity of heteronuclear complex increases gradually with increasing the temperature. Complex 1 also exhibits strong photoluminescent emission in the visible region.