胶体离子超级电容器的比容量评价

胶体离子超级电容器作为一种新型的超级电容器,其同时具有能量密度和功率密度高的独特优势。 目前已经发展了包括多种过渡金属阳离子和稀土阳离子,例如Mn²⁺、Fe²⁺、Co²⁺、Ni²⁺、Cu²⁺、Sn²⁺、Sn⁴⁺、La³⁺、Ce³⁺、Er³⁺和Yb³⁺的胶体离子超级电容器体系。 在电化学反应中,识别出电活性物质的存在形式对研究电极反应机理和提高比容量具有重要价值。 本文主要通过对电活性物质比容量的探讨,理解这种新型胶体离子超级电容器的电化学储能机理。 评述了胶体离子超级电容器的比容量核算方式,提出了以阳离子为标准核算比容量的原因,并与传统超级电容器的核算方式进行了比较,表明胶体离子超级电容器在提高能量密度方面具有潜在优势,有望突破现有电化学储能设备的技术瓶颈,实现下一代高能量储能器件的开发。     

New 3D and 2D supramolecular heteroleptic palladium(II) dithiocarbamates as potent anticancer agents

Three new heteroleptic palladium(II) dithiocarbamates with better in vitro anticancer activity than cisplatin were synthesized and characterized by different analytical techniques, elemental analysis, FTIR, NMR, and single crystal X-ray diffraction analysis. The Pd center is chelated by dithiocarbamate ligand {4-benzylpiperazine-1-carbodithioate (1) and (3) or (4-(2-methoxyphenyl)piperazine-1-carbodithioate (2)}, triorganophosphine {tris-(4-flourophenyl)-phosphine (1) and (2) or tris-(4-chlorophenyl)phosphine (3)}, and a chloro-group, resulting in a square planar geometry. The packing diagram reveals a 3D network (1 and 2) and a 2D network (3) composed of various 1D chains in which the molecules are linked via hydrogen bonds (1–3) and halide?π (1, 3) interactions. The anticancer activities of complexes against HeLa cell line varies in the sequence 2 (23.438 μM) > 1 (38.293 μM) > 3 (47.554 μM) > cisplatin (78.075 μM). The cytotoxicity of these complexes is due to their strong induction of oxidative stress and DNA-damage ability leading to apoptosis.     

Theoretical insights into the relative bonding of normal and abnormal N‐heterocyclic carbenes in [PdCl2(NHCR)2] and [PdCl2(NHCR)(aNHCR)] (R = H,Ph, Mes)

Quantum chemical insights into normal Pd‐C2(NHC^R) and abnormal Pd‐C5(aNHC^R) bonding, dominated by dispersion interactions in N‐hetereocyclic carbene complexes [PdCl₂(NHC^R)₂] ( I , R = H; II , R = Ph; III , R = Mes (2,4,6‐trimethyl)phenyl)) and [PdCl₂(NHC^R)(aNHC^R] ( IV , R = H; V , R = Ph; VI , R = Mes) have been investigated at DFT and DFT‐D3(BJ) level of theory with particular emphasis on the effects of the noncovalent interactions on the structures and the nature of Pd‐C2(NHC^R) and Pd‐C5(aNHC^R) bonds. The optimized geometries are good agreement with the experimental values. The Pd‐C bonds are essentially single bond. Hirshfeld charge distributions indicate that the abnormal aNHC^R carbene ligand is relatively better electron donor than the normal NHC^R carbene ligand. The C2 atom has larger %s contribution along Pd‐C2 bond than the C5 atom along Pd‐C5 bond. As a consequence the Pd‐C2(NHC^R) bonds are relative stronger than the Pd‐C5(aNHC^R) bonds. Thus, the results of natural hybrid orbital analysis support the key point of the present study. Calculations predict that for bulky substituent (R = Ph, Mes) at carbene, the Pd‐C2(NHC^R) bond is stronger than Pd‐C5(aNHC^R) bond due to large dispersion energy in [PdCl₂(NHC^R)₂] than in [PdCl₂(NHC^R)(aNHC^R)]. However, in case of non‐bulky substituent with small and almost equal contribution of dispersion energy, the Pd‐C2(NHC^R) bond is relative weaker than Pd‐C5(aNHC^R) bond. The bond dissociation energies are dependent on the R substituent, the DFT functional and the inclusion of dispersion interactions. Major point of this study is that the abnormal aNHCs are not always strongly bonded with metal center than the normal NHCs. Effects of dispersion interaction of substituent at nitrogen atoms of carbene ligand are found to play a crucial role on estimation of relative bonding strengths of the normal and abnormal aNHCs with metal center. © 2016 Wiley Periodicals, Inc.     

Preparation and characterization of palladium immobilized on silica‐coated Fe3O4 and its catalytic performance for Suzuki reaction under microwave irradiation

Supported palladium catalyst (Pd/Fe₃O₄@SiO₂) was easily prepared by supporting PdCl₂ on silica‐coated magnetic nanoparticles Fe₃O₄ in ethylene glycol. The as‐prepared sample was characterized by infrared spectroscopy (IR), X‐ray diffraction (XRD) and X‐ray photoelectron spectrometer (XPS). The formation of active specie Pd(0) was confirmed by XRD and XPS, and the Pd loading for the fresh and recovered catalyst was determined by atomic absorption spectroscopy (AAS). Pd/Fe₃O₄@SiO₂ was employed for the synthesis of biphenyl derivatives via Suzuki reaction. In terms of the yield of biphenyl, the supported catalyst displayed nearly equal catalytic performance to that of homologous PdCl₂ under microwave irradiation for 30 min but higher than that obtained by traditional heating method for 12 h. The catalytic performance of Pd/Fe₃O₄@SiO₂ for Suzuki reactions involving various aryl halides and arylboronic acids were also examined. Impressive yield of biphenyl at 68.2% was obtained even in the presence of unreactive aryl chlorides. Pd/Fe₃O₄@SiO₂ was recovered by a permanent magnet and directly reused in the next run, and no obvious deactivation was observed for up to 6 times. Copyright © 2016 John Wiley & Sons, Ltd.     

含四苯基乙烯的炔酮衍生物的设计合成、聚集诱导发光性质及其对Pd2+的选择性荧光检测

聚集诱导发光（AIE）材料吸引了许多光电器件和生物荧光技术领域的科学家的关注.对聚集诱导发光化合物构效关系的深入理解对于设计新材料至关重要.在本工作中,基于经典的AIE基元四苯基乙烯,设计并合成了一系列具有AIE性质,含不同电子给体/受体取代基的炔酮衍生物.对这一系列化合物的光物理性质进行了系统研究并分别探讨了取代基团对发光波长、发光效率和AIE性质的影响.它们的聚集态最大发射波长位于511～565 nm,在四氢呋喃/水混合溶液中的荧光量子产率可达31%.在末端苯环上的电子给体/受体取代基团会降低聚集态的发光效率,而引入硝基取代基则会在发射波长红移的同时,显著猝灭荧光.最为重要的是,这些化合物结构中的炔酮基元可以在一系列金属离子中选择性地与Pd²⁺配位,猝灭纳米聚集体的发光,并有望作为一个有效的Pd²⁺荧光传感器.     

A Pd4Br4 macrocycle trapped by cocrystallization from a highly dynamic equilibrium of η3‐cycloheptatrienide complexes

In the coordination chemistry of palladium, dimers bridged via halides are a common motif. Higher oligomers, however, are still rare. We report the structure of an alternating eight‐membered [Pd₄Br₄]⁴⁻ ring framed by cycloheptatrienide ligands, which was obtained by cocrystallization of dimers and tetramers of the complex salt bromido{η³‐[3‐(2,6‐diisopropylphenyl)imidazolium‐1‐yl]cycloheptatrienido}palladium(II) tetrafluoroborate, namely bis[di‐μ‐bromido‐bis({η³‐[3‐(2,6‐diisopropylphenyl)imidazolium‐1‐yl]cycloheptatrienido}palladium(II))] cyclo‐tetra‐μ‐bromido‐tetrakis({η³‐[3‐(2,6‐diisopropylphenyl)imidazolium‐1‐yl]cycloheptatrienido}palladium(II)) octakis(tetrafluoroborate) dichloromethane octasolvate, [Pd₄Br₄(C₂₂H₂₆N₂)₄][Pd₂Br₂(C₂₂H₂₆N₂)₂]₂(BF₄)₈·8CH₂Cl₂. These dimers and tetramers form a highly dynamic equilibrium in solution which was studied by low‐temperature NMR spectroscopy. In the light of the presented results, tetrameric Pd^II species can be assumed to co‐exist as a second species in many cases where by current knowledge only a dimeric compound would be expected.     

ChemInform Abstract: A Matrix Isolation and Computational Study of Molecular Palladium Fluorides: Does PdF6 Exist?

Binary palladium fluorides from PdF to PdF₆ are investigated by matrix‐isolation methods using thermal evaporation and laser ablation to generate Pd atoms for reaction with F₂‐doped Ar and Ne matrices as well as neat F₂ matrices.     

聚苯乙烯邻氨基苯甲酸负载钯催化剂的加氢性能研究

含有双配位基的聚苯乙烯邻氨基苯甲酸与钯络合物反应制得螫合的配位高分子钯催化剂。用甲醇-水(pH=12)还原可得晶粒分布均匀的胶态钯催化剂,它们对烯烃的加氢具有良好的催化作用。研究表明,钯络合物上原有配体的给予性常数(E_n)与负载后络合催化剂的加氢活性具有良好的线性关系,金属粒径为40—50A的催化剂对己烯-1的加氢活性最高。本文还研究了溶剂极性,载体孔结构及底物对催化剂活性的影响。     

N,N（二甲庚基）乙酰胺萃钯机理研究

本文研究了N,N二甲庚基乙酰胺(N_(s03))从氯化物体系中萃取钯的机理。应用等摩尔系列法和斜率法确定萃合物组成为:(CH_3CONR_2H)_2PdCl_4。通过紫外-可见光谱法研究,证实N_(503)萃取钯的机理属阴离子交换反应,其萃取方程式为: 2CH_3CONR_2HCl_((o)) PdCl_4~(2-)(a)?(CH_3CONR_2H)_2PdCl_4(o) 2Cl~-(a)