铕与PMBP配合物晶体结构和电子结构的研究

本文测定了 Eu(PMBP) 3 · 2 H2 O的晶体结构 ,该晶体属于单斜晶系 ,空间群 P2 1 / n,a=14 .982 1(1) ,b=14 .75 18(8) ,c=2 4 .4 979(9) ,β=10 1.5 2°,Z=4 ,V=5 30 2 .2 3 ,M=10 0 1.9,Dc=1.2 5 4 g/ cm3 ,μ=12 .315 cm-1 。 Eu与 PMBP及水中的 8个氧原子形成四方反棱柱配位多面体 ,根据选用的模型计算其电子结构 ,分子能量 ,净电荷分布和 Mulliken键级 ,进而讨论了配合物的结构和化学键的特征。实　验　部　分按 Eu(Cl O4) 3 · 2 H2 O中 Eu( )与 HPMBP摩尔比 1∶ 3反应 ,得到配合物固体。置于水与无水乙醇中 ,数周后…     

Chlorine-passivated superatom Al<Subscript>37</Subscript> clusters for nonlinear optics

Utilizing a facile top-down synthetic procedure, here we report the finding of a chlorine-passivated Al₃₇ superatom cluster. It is demonstrated that the presence of electrophilic groups, severing as protecting ligands, alters the valence electron count of the metallic core and stabilize the as-prepared aluminum clusters especially when even-numbered chlorine atoms are located at equilibrium positions. Following the discussion regarding their reasonable stabilities, we illustrate the feasible reaction pathways in forming such chlorine-passivated Al₃₇ superatom clusters which bear delocalized superatomic orbitals with five valence 3P⁵ electrons shifting to the chlorine ligands indicative of a closed electron shell 2F¹⁴ of the metal core. The successful synthesis of such chlorine-protected aluminum clusters evidences the compatibility of general theory of cluster chemistry in both gas phase and wet chemistry. Such simple-ligand-protected aluminum clusters exhibit reverse-saturated-absorption (RSA) nonlinear optical property pertaining to electronic transitions within the discrete energy states of cluster materials.     

铬,硒,镉,锰与心脑血管疾病

通过对５０例心脑血管疾病病人及５０例健康对照组血中微量元素铬、硒、镉、锰的检测分析证实，心脑血管疾病病人血清Ｃｒ、Ｓｅ含量下降，Ｃｄ含量未见明显升高，并进一步探讨了这些微量元素与心脑血管疾病的发生发展的关系及其临床意义。     

Size dependent melting mechanisms of iron nanoclusters

Molecular dynamics simulations were used to study the change in the mechanism of iron cluster melting with increasing cluster size. Melting of smaller clusters (e.g., Fe₅₅ and Fe₁₀₀) occurs over a large temperature interval where the phase of the cluster repeatedly oscillates between liquid and solid. In contrast, larger clusters (e.g., Fe₃₀₀) have sharper melting points with surface melting preceding bulk melting. The importance of the simulation time, the force field and the definition of cluster melting is also discussed.     

新型铽配合物掺杂SiO2荧光纳米粒子的制备

以荧光物质铽的配合物为核，二氧化硅为外壳，制备了大小均匀的新型稀土配合物荧光纳米粒子。实验采用油包水的反相微乳液法，在四乙氧基硅烷和3-氨丙基三乙氧基硅烷（APTEOS）的共水解下进行。通过透射电子显微镜（TEM）观察，所得的纳米粒子呈球形，大小均匀，直径在30nm左右。纳米粒子呈现很强的铽配合物发光，且发光性质十分稳定。可通过表面的氨基方便地与生物分子偶联，可作为一种优秀的时间分辨荧光标记物。     

Synthesis and size control of monodisperse manganese-doped ZnS nanoparticles by methacrylate polymer

A simple route to the fabrication of methacrylate polymer containing Mn-doped ZnS nanoparticles is described. The particles prepared have sizes as small as 1.8-2 nm, capped or modified by methacrylate polymer, and the thermal, mechanical, chemical stability, life and luminescence intensity are greatly improved. The particle sizes can be easily controlled by changing the number-average degrees of polymerization, which can be realized by adjusting the molar ratio of monomer to chain-transfer agent.     

A 1D zinc(II) polymer with W-like pentanuclear secondary building blocks constructed by 2,6-pyridine-diacylhydrazone ligand

A 1D zinc(II) coordination polymer with W-like pentanuclear secondary building blocks constructed by 2,6-bis[(3-methoxysalicylidene)hydrazinocarbonyl]pyridine (H₄Bmshp) ligand, {[Zn₅(Bmshp)(CH₃COO)₅Cl(H₂O)₃]·2H₂O} _n , was synthesized and characterized by elemental analysis, IR, X-ray diffraction, and thermogravimetric analyses. It has the highest nuclear unit constructed by one 2,6-pyridine-diacylhydrazone ligand so far. The luminescent property of the compound was studied. It shows an emission with a maximum at 522 nm upon excitation at 450 nm.     

Effect of SSL and HSC on morphology and properties of PHA based SMPU synthesized by bulk polymerization method

Searching new shape memory polymer and the associating synthesis technology are critical on the development of smart materials. In this paper, a comprehensive study on Poly(hexylene adipate) PHA being the soft segment of shape memory polyurethane (SMPU) was presented. Bulk polymerization method was employed to synthesize the SMPU with different soft segment length (SSL) and hard segment content (HSC). The influences of SSL and HSC on its morphology and thermomechanical property using DSC, DMA, POM, and shape memory behavior were presented here. The results indicate that the thermal properties, dynamic mechanic properties, and crystal morphology of SMPU are influenced significantly by SSL and HSC. And it is found that the shape fixity increases with SSL but decreases with HSC. On the other hand, the shape recovery decreases with both SSL and HSC, and the associated recovery temperature increases either with the increasing SSL or with decreasing HSC. Lastly, it is concluded that in the PHA‐based‐SMPU, the lower limiting value of SSL for polyurethane having shape memory effect is 2000; their response temperature varied with SSL and HSC, changing from 41.0 to 51.9 °C. Stable hard segment crystal are formed at above 30% HSC sample in bulk polymerization, but shape memory behavior can also be observed when its physical crosslink point are formed in the lower HSC PHA‐based‐SMPU. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 444–454, 2007     

Dioxomolybdenum(VI) complex covalently attached to amino‐modified graphene oxide: heterogeneous catalyst for the epoxidation of alkenes

Transition metal salen complex MoO₂–salen was successfully tethered onto amino‐functionalized graphene oxide (designated as MoO₂–salen–GO), which was tested in the epoxidation of various alkenes using tert‐butylhydroperoxide or H₂O₂ as oxidant. Characterization results showed that dioxomolybdenum(VI) complex was successfully grafted onto the amino‐functionalized graphene oxide and the structure of the graphene oxide was well preserved after several stepwise synthesis procedures. Catalytic tests showed that heterogeneous catalyst MoO₂–salen–GO was more active than its homogeneous analogue MoO₂–salen in the epoxidation of cyclooctene due to site isolation. In addition, the MoO₂–salen–GO catalyst could be reused three times without significant loss of activity. Copyright © 2014 John Wiley & Sons, Ltd.     

Small gold clusters catalyzing oxidant-free dehydrogenation of glycerol initiated by methene hydrogen atom transfer

We report a finding of feasible oxidant-free dehydrogenation of glycerol over small Au clusters, with a low-energy barrier of transition state initiated by hydrogen atom transfer from methene, which differs from the general reaction mechanism based on hydroxyl.