A novel sodium holmium carboxylate compound,namely Na 4 Ho 4 （μ 3-OH） 4 （1,4BDC） 6 ·6.25H 2 O （1,1,4-BDC=1,4-benzenedicarboxylate）,has been solvothermally synthesized and structurally characterized.The structure features a two-fold interpenetrated three-dimensional open-framework constructed by the [Ho 4 （μ 3-OH） 4 ] 8＋ clusters bridged by 1,4-BDC ligands.The Na ＋ ions and lattice water molecules are located in the channels.The structure is further stabilized by hydrogen-bonding and π-π stacking interactions.The thermal stability of the compound has been investigated via thermogravimetric analysis.
Two isostructural inorganic-organic hybrid M（II）–Nb（V） oxyfluorides, namely, M（H2O）2（pyz）NbOF5 （M=Co 1, Cu 2; pyz=pyrazine） have been hydrothermally synthesized and structurally characterized. Both compounds possess two-dimensional layer structure constructed by neutral M（H2O）2NbOF5 chains inter-connected via bridging pyrazine ligands. The structure is further extended into three-dimensional supramolecular architecture through inter-layer H-bonding interactions between the coordinated water molecules and fluorine ions. The luminescent properties and thermal stability of both compounds have been investigated.
A magnesium metal organic framework, [N-H2（CH3）2][-N（CH3）4][Mgs（bpdc）3（O2CH）6]· 3H2O （1, bpdcH2 = 4,4＇-biphenyldicarboxylic acid）, has been solvothermally synthesized and structurally characterized. 1 crystallizes in the trigonal system, space group R-3, with a = 11.3427（3）, c = 41.5662（18） A, V = 4631.3（3） A^3, Z = 3 and the final R = 0.0457. Its structure features a pillared-layered three-dimensional network with 8.21 A cavities, in which cationic [NH2（CH3）2]^＋ or [N（CH3）4]^＋ and lattice water molecules are located. Thermal stability of the title compound has also been investigated.
Two new gallium antimony sulfides,[enH2][Ga2Sb2S7]·en（1） and [puH]2[Ga2Sb2S7]（2）（en = ethylenediamine,pu = propyleneurea）,have been solvothermally synthesized.In the pre-paration of compound 2,the protonated propyleneurea cation as counterion and template was in situ synthesized by the reaction of 1,3-diaminopropane with CO2 in pyridine.Both structures contain a two-dimensional network composed of novel heterometallic clusters of {Ga2Sb2S9} as the second-dary building unit.The thermal and optical properties of compounds 1 and 2 were characterized by TGA and UV-Vis,respectively.
The nuclear fuel cycle inevitably generates a large amount of radioactive waste liquid,which will pose a serious threat to the ecological environment and human health.Ion exchange method has received wide attention for its easy operation,low cost and no secondary pollution.However,the effective removal of radioactive ions from complex solutions still remains a serious challenge due to their environmental mobility and radiotoxicity.We have developed an efficient strategy to construct crystalline ion-exchange materials by inducing layered or three-dimensional microporous anionic frameworks by organic cations that can be effectively exchanged by radioactive metal ions.This type of materials can be applied effectively to the removal of radioactive ions from complex solutions and the removal mechanism has been deeply clarified by means of single crystal structure analyses,theoretical calculations,etc.This review summarizes our recent progress in the study of synthesis,structures and properties of radioactive ion removals for such type of crystalline ion-exchange materials.
