Synthesis and Crystal Structure of a Heteronuclear Fe–Ru Silyl Complex*

The reaction of the iron metalate [Fe{Si(OMe)₃}(CO)₃(dppm-P)]⁻ (1b) with [Ru(CO)₃Cl(μ-Cl)]₂ afforded the heterodinuclear complex [(OC)₃{(MeO)₃Si}Fe(μ-dppm)Ru(CO)₃Cl)] (Fe–Ru) (3) in which a long Fe–Ru separation of 2.956(1) ? has been crystallographically evidenced. It was shown by density functional theory (DFT) calculations to correspond to the minimum-energy structure. Upon treatment of the corresponding hydrido complex [HFe{Si(OMe)₃}(CO)₃(dppm-P)] (1a) with [Ru(CO)₃Cl(μ-Cl)]₂, the chloride-bridged tetranuclear hydrido complex [(OC)₃{(MeO)₃Si}Fe(H)(μ-dppm)Ru(CO)₂Cl(μ-Cl)]₂ (4) was formed in which the Fe and Ru centers are only linked via bridging dppm ligands. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

Zr粉粒径对Zr/KClO4烟火剂燃烧特性的影响

 研究了烟火药激光器泵浦源传统配方Zr/KClO₄中Zr粉粒径对该配方燃烧特性的影响。结果表明：Zr粉从61.375 μm减小到18.675 μm,Zr/KClO₄混合物的点火温度从506.40 ℃降低到492.42 ℃,燃烧辐射脉宽由60 ms缩短到25 ms,峰值辐射强度增加1倍;在 200～1 100 nm波段内,随着Zr粉粒径的减小,可见光区内的辐射能所占的比例增强;针对掺钕激光介质的泵浦而言,Zr粉粒径为800目时,分布在激光介质的3个主要泵浦带内的辐射能最高,而且闪光脉宽最短。因此,在其它条件相同时,选择颗粒尺寸小的Zr粉有利于获得高的激光输出。     

Density functional study of structural, electronic, and optical properties of small bimetallic ruthenium-copper clusters

The structural, electronic, bonding, magnetic, and optical properties of bimetallic [Cu(n)Ru(m)](+/0/-) (n + m ≤ 3; n, m = 0-3) clusters were computed in the framework of the density functional theory (DFT) and time-dependent DFT (TD-DFT) using the full-range PBE0 nonlocal hybrid GGA functional combined with the Def2-QZVPP basis sets. Several low-lying states have been investigated and the stability of the ground state spinomers was estimated with respect to all possible fragmentation schemes. Molecular orbital and population analysis schemes along with computed electronic parameters illustrated the details of the bonding mechanisms in the [Cu(n Ru(m)](+/0/-) clusters. The TD-DFT computed UV-visible absorption spectra of the bimetallic clusters have been fully analyzed and assignments of all principal electronic transitions were made and interpreted in terms of contribution from specific molecular orbital excitations.     

Deprotonative metalation of aromatic compounds by using an amino-based lithium cuprate

Deprotonative cupration of aromatic compounds by using amino‐based lithium cuprates was optimized with 2,4‐dimethoxypyrimidine and 2‐methoxypyridine as the substrates and benzoyl chloride as the electrophile. [(tmp)₂CuLi] (+2 LiCl) (tmp=2,2,6,6‐tetramethylpiperidino) was identified as the best reagent and its use was extended to anisole, 1,4‐dimethoxybenzene, other substituted pyridines, furan, thiophene and derivatives, and N‐Boc‐indole (Boc=tert‐butyloxycarbonyl). Of the electrophiles employed to attempt the interception of the generated aryl cuprates, aroyl chlorides, iodomethane, and diphenyl disulfide efficiently reacted. In addition, different oxidative agents were identified to afford symmetrical biaryls. Finally, palladium‐catalyzed coupling with aryl halides was optimized and allowed the synthesis of different aryl derivatives in medium to good yields.     

Influence of particle size on the electromagnetic and microwave absorption properties of FeSi/paraffin composites

The electromagnetic and microwave absorption properties of the composites employing FeSi alloy powders with different particle sizes as absorbent and paraffin as matrix were investigated. The results showed that the particle size had significant influence on the electromagnetic and microwave absorption properties of the composites in the 2-7 GHz frequency range. By decreasing the particle size of FeSi alloy powders, both the complex permittivity and permeability of the composites increased to a certain extent. In addition, the microwave absorption properties were improved, and the frequency of absorption peak shifted towards lower frequency range. In other words, the micron-grade FeSi alloy powders with smaller particle size were more suitable to be used as absorbent in measured frequency region.     

Synthesis of mono and diesters using eco-friendly solid acid catalyst – zirconium titanium phosphate

Abstract

Amorphous zirconium titanium phosphate (ZTPA), an advanced inorganic ion exchanger of the class of tetravalent bimetallic acid (TBMA) salt, has been synthesized by sol gel route. ZTPA has been characterized by inductively coupled plasma atomic emission spectrometer (ICP-AES), Thermal analysis, Fourier transform infrared spectrometer (FTIR), and X-ray diffraction (XRD). The acid sites present in ZTPA indicate good potential to be explored as solid acid catalyst. The catalytic characteristics of ZTPA have been evaluated by determining surface area and surface acidity. The catalytic performance of ZTPA as a solid acid catalyst has been explored by studying esterification as a model reaction wherein mono and diesters have been synthesized. Crystalline zirconium titanium phosphate as well as amorphous and crystalline phases of zirconium phosphate and titanium phosphate have also been synthesized, characterized, and their catalytic performance investigated for comparative studies. TBMA salt exhibits enhanced catalytic activity compared to its single salt counterparts and amorphous phases exhibit higher catalytic activity compared to their crystalline phases.     

Cu含量对Pd-Cu/铝土矿CO氧化催化剂结构和性能的影响

利用资源丰富的天然铝土矿经NaOH溶液水热处理后焙烧,获得比表面积达174 m²·g^-1铝土矿载体,制备了双金属Pd-Cu为活性组分的催化剂,金属Pd负载量为0.5%（质量百分数）,以CO氧化反应为探针反应,详细考察了Cu含量的变化对催化剂物化性能的影响。研究发现,Cu的引入有利于提高金属Pd的分散度,同时随着Cu含量的变化,金属Pd与Cu之间以及金属与铝土矿载体之间的相互作用随之改变。催化剂的CO氧化反应性能评价结果表明,Pd和Cu负载量分别为0.5%和4%的样品（PdCu₄/MB）催化反应性能最佳。结合表征结果认为,PdCu₄/MB的高活性归因于良好的Pd和Cu分散度,金属Pd、Cu以及金属与载体之间较强的相互作用。此外,CO-TPD表征结果说明较强的CO吸附能力和从载体中获取氧的能力也有利于提高PdCu₄/MB样品的CO氧化反应性能。     

超细磁性钴粉的制备及磁性能

在室温条件下,水溶液中以聚乙烯吡咯烷酮K30(PVP)作为分散剂,水合联氨为还原剂,制备超细磁性钴粉。用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、能谱仪(EDS)和振动样品磁强计(VSM)对其进行表征。结果显示:超细磁性钴粉为蠕虫状微球,粒径约为0.8μm,晶型为面心立方(FCC)和六方密堆积(HCP)结构,饱和磁化强度为25.6 emu·g^-1,矫顽力为499.2 Oe(1 Oe=79.5775 A·m^-1,测试温度为298.15 K)。