FeCo2(CO)9(μ3-S)簇合物羰基取代衍生物的合成与表征

１９６４ 年Ｓａｍ ｉｒ Ａ．Ｋ．等人合成了第一个既含金属－金属键又含有金属－硫键的簇合物ＦｅＣｏ２（ＣＯ）９（μ３－Ｓ）［１］。该簇合物在空气中相对稳定,其结构中含有一个ＦｅＣｏ２Ｓ构成的四面体骨架。１９６９ 年Ｂｕｒｇｅｒ Ｋ．等人报道了ＰＰｈ３ 对ＦｅＣｏ２Ｓ（ＣＯ）９ 的取代反应［２］,１９７８ 年ＲｏｓｓｅｔｔｉＲ．等人研究了ＦｅＣｏ２Ｓ（ＣＯ）９ 与一系列含磷配体Ｌ（Ｌ＝ ＰＥｔ３, ＰＢｕ３, Ｐ（ＯＰｈ）３, Ｐ（ＯＥｔ）３ 等）之间的取代反应［３］。对该簇合物取代反应规律的研究表明,在ＦｅＣｏ２Ｓ（ＣＯ）９ 簇合物中,三个金属上的配位羰基均可被有机磷配体取代,但取代难易程度不同。钴原子上的配位羰基最容易被取代,即一取代、二取代总是发生在钴原子上,只有发生三取代时,铁原子上的配位羰基才被取代。我们的研究结果也证实了这一反应规律     

含钌异核四面体骨架过渡金属羰基簇合物的合成及表征

含钌异核四面体骨架过渡金属羰基簇合物的合成及表征丁二润李庆山吴树林殷元骐＊（中国科学院兰州化学物理研究所羰基合成与选择氧化国家重点实验室７３００００）关键词过渡金属异核簇合物ＫｅｙｗｏｒｄｓＴｒａｎｓｉｔｉｏｎｍｅｔａｌＨｅｔｅｒｏ－ｎｕｃｌｅａｒＣ...     

Co3（CO）7（μ3—S）（μ,η^2—SCNR2）的合成和晶体结构

Ｃｏ２（ＣＯ）８与４个二硫代双（烷基硫代甲酰胺）类前配体［Ｒ２ＮＣ（Ｓ）Ｓ］２反应,得４个含烷基硫代甲酰胺基的三核钴羰基硫簇合物。通过元素分析、ＩＲ、＾１ＨＮＭＲ和ＭＳ等方法表征了它们的结构,用Ｘ射线衍射法测定了其中一个簇合物Ｃｏ３（ＣＯ）７（μ３－Ｓ）［μ,η＾２－ＳＣＮ（ｉ－Ｐｒ）２］（Ⅲ）的晶体结构。晶体属单斜晶系,Ｐ２１／ｎ空间群,晶胞参数ａ＝１．１４５２（２）ｎｍ,ｂ＝１．５０２８（３）     

Co3（CO）7（μ3—S）[μ,η^2—SCNC（O）C（R1）（R2）N（COR3）]的…

Ｃｏ２（ＣＯ８）分别与４种硫代乙内酰脲Ｓ＝ＣＮＨＣ（Ｏ）Ｃ（Ｒ１）（Ｒ２）Ｎ（ＣＯＲ３）反就，得到４个新的含硫代乙内酰脲桥基双齿配位的三核钴羰基硫族合物。用元素分析、ＩＲ、＾１Ｈ ＮＭＲ和ＭＳ等手段表征了它们的结构，用Ｘ射线衍射测定了其中一个族合物Ｃｏ３（ＣＯ７）７（μ３－Ｓ）［μ，η＾２－ＳＣＮＣ（Ｏ）Ｃ（ＣＨ３）（ＣＨ３）Ｎ（ＣＯＣＨ３）］（Ⅳ）的晶体结构，晶体属三斜晶系，Ｐ１↑－空间群，晶胞     

含μ3—S准平面型四核钴簇合物的化学键性质

具有６４个价电子的含μ３－Ｓ的平面型四核钴簇合物是偏离通常的电子计数规则。为探索其簇骼化学键特性。我们采用量子化学的ＣＮＤＯ／２－ＬＭＯ方法计算其电子结构。结果表明，μ３－Ｓ分别与三个钴原子形成三个双中心键，近似平面型的四个钴原子的Ｐ轨道形成两个Ｐ－π共轭分子轨道，６４个价电子均处于成键轨道上。     

Cu_4簇合物“元件组装”合成及其结构与电催化作用

以元件组装方法合成了Cu4(HL)4·2H2O簇合物(H2L=N-乙氧羰基-N′-o-硝基苯基硫脲)。用X射线单晶衍射技术、核磁共振谱、红外光谱和元素分析等确定了簇合物及其相应组装元件的晶体结构和化学组成,并对簇合物的电催化性质进行了检测。结果表明,该簇合物由4个Cu(I)以M-M键构成簇核,4个硫脲配体分别以硫羰基硫原子和氮原子配位于Cu(I)构成簇合物配位结构,DPV分析显示该簇合物对O2具有较高催化活性。     

51V NMR监测[VS4-Cun](n≤6)簇合物自兜反应过程

采用＾５１Ｖ ＮＭＲ监测在核磁管内模拟（ＮＨ４）３ＶＳ４／Ｅｔ４ＮＢｒ／ＣｕＢｒ／ＰＰｈ３体系在ＣＨ２Ｃｌ２中的反应过程,研究了反应条件如反应物不同配比对生成各种〖ＶＳ４－Ｃｕｎ〗（ｎ≤６）簇合物的影响,提供了该反应体系在ＣＨ２ＣＩ２溶液部成簇过程的一些信息。该方法不仅可用来研究反应机理,而且可用于地一些条件难以确定（溶剂、温度、酸碱度等）的簇合物如低核数及更高核数Ｖ－Ｃｕ－Ｓ簇合物的合成。     

新颖五核Mo/Cu/S簇合物[MoOS3Cu4(α-MePy)6Br2]的合成及晶体结构

杂核金属含硫簇合物具有丰富的结构,在生物化学、催化和非线性光学等方面显示了诱人的应用前景.近年来,我们主要从事用[MS4 ]2 - 和[Cp* MS3]- ( M=Mo,W)和Cu( ) ,Ag( )反应合成Mo( W) /Cu( Ag) /S簇合物并研究其非线性光学性质[1,2 ] .鉴于用硫代金属酸盐作前驱体合成M- Cu- Ag- S杂三核金属簇合物的工作鲜有报道[3] ,我们尝试用( NH4 ) 2 Mo OS3和Cu Br,Ag Br在α- Me Py中反应,希望得到Mo- Cu- Ag- S杂三核金属簇合物.但上述反应却形成了1个仅含Mo和Cu( )的五核簇合物[Mo OS3Cu4 (α- Me Py) 6 Br2 ],其所含的Mo S3…     

氧原子转移试剂促进的异核金属簇合物催化烯烃氢化和异…

氧原子转移试剂（ＯＴＲ）Ｍｅ３ＮＯ．２Ｈ２Ｏ和ＰｈＩＯ可明显地促进异核金属羰基簇合物ＳＲｕＣｏ２（ＣＯ）９和ＳｅＲｕＣｏ２（ＣＯ）９对１－己烯的配位催化氢化和异构化反应，催化剂和四面体簇核骨架在催化过程中保持不变，其反应是一种缔合机理，通过ＯＴＲ的作用经缔合和解离１分子配位羰基，形成配位不饱和簇核骨架，从而促进对其烯烃的催化氢化和异构化反应，在甲醇溶液中，ＳＲｕＣｏ２（ＣＯ）９催化１－己烯氢化最佳     

Mo（W）－Cu（Ag）－S原子簇化合物的研究现状

本文在研究Ｍｏ（Ｗ）－Ｃｕ（Ａｇ）－Ｓ原子簇化合物的低热固态合成化学基础上，详细地对该类簇合物进行了归纳，从中提出：１．（Ｍ＝Ｍｏ，Ｗ；ｎ＝２，３，４）作为配体中心．２．氧原子在簇合物中仅作为端基，不参与同其他金属成键．３．单个ＭＳ４（Ｍ＝Ｍｏ，Ｗ）基团最多只能键合六个Ｃｕ（Ａｇ）原子，即最大核数为七．４．迄今为止所有Ｍｏ（Ｗ）－Ｃｕ－Ｓ原子簇化合物中Ｃｕ均为＋１价．５．预计合低价态Ｍｏ（Ｗ）的这类簇合物将会有很大进展．     

Ab initio studies of the conformations of ethynyl formate, cyano formate and related ethynyl and cyano compounds

The optimized geometries, relative free energies and related thermodynamic properties, harmonic frequencies, and dipole moments have been calculated at the HF and MP2 levels for ethynyl formate (1a), ethynyl acetate (1b), cyano formate, HCO₂CN (1c), cyano acetate (1d), S-ethynyl thioformate (2a), S-ethynyl thioacetate (2b), S-cyano thioformate (2c), S-cyano thioacetate (2d), N-ethynylformamide (3a), N-ethynylacetamide (3b), N-cyanoformamide (3c), and N-cyanoacetamide (3d) with the gaussian 98 program. For ethynyl formate, the calculation for 25 °C at the MP2/6-311++G(df,pd) level predicts that the Z isomer is more stable by 1.23 kcal/mol. For S-ethynyl thioformate, calculations at the MP2/6-311++G(2d,2p) level predict that the E isomer is favored by 0.71 kcal/mol at 25 °C. The E isomers of N-ethynylformamide and N-ethynylacetamide were found at all levels to be more stable than the Z isomers at 25 °C. For cyano formate and cyano acetate, calculations at the MP2/6-311++G(df,pd) level predict that the Z isomers are more stable at 25 °C by 1.50 and 2.72 kcal/mol, respectively. At this level and temperature, the Z isomers of 2c, 2d, 3c, and 3d are predicted to have free energies of 0.46, −0.07, 1.22, and 2.28 kcal/mol, respectively, relative to the E conformations. Z to E free-energy barriers at 25 °C of 8.63, 10.64, 17.63, 7.39, and 14.03 kcal/mol were calculated for 1a, 2a, 3a, 1c, and 3c at the HF/6-311G(d,p) level, and at the HF/6-311+G(d,p) level, the free-energy barrier for 2c was 7.08 kcal/mol.     

Alpha and gamma spectrometry for determination of natural and artificial radionuclides in tea, herbal tea and camomile marketed in Italy

Several kinds of tea, camomile and herbal tea were analysed to determine natural and artificial radioactivity. The radionuclides were determined by alpha (²¹⁰Po) and gamma (²²⁸Ac, ²¹⁴Pb, ²¹⁴Bi, ²¹⁰Pb, ⁴⁰K and ¹³⁷Cs) spectrometry. ²²⁸Ac ranged between 0.6 and 9.0 Bq kg⁻¹_dry; ²¹⁰Po between 1.90 and 36.1 Bq kg⁻¹_dry; ²¹⁴Pb and ²¹⁴Bi between 0.7 and 4.9 Bq kg⁻¹_dry; ²¹⁰Pb between < 10.0 and 58.9 Bq kg⁻¹_dry; ⁴⁰K between 463 and 936 Bq kg⁻¹_dry; ¹³⁷Cs between < 0.3 and 2.6 Bq kg⁻¹_dry. The percentage of ²¹⁰Po extraction in infusion was also determined; the arithmetical mean value of percentage of ²¹⁰Po extraction resulted 20.7 ± 7.50.     

元素医学防治心脑血管病研究和应用

从心脑血管疾病的流行率、心脑血管疾病的元素病因、心脑血管疾病的元素诊断和心脑血管疾病的元素治疗等4个方面讨论了元素医学防治心脑血管疾病的临床意义。     

软硬酸碱规则与体内微量元素

阐述了ＳＨＡＢ规则,分类,酸碱软硬度的定量标度和理论解释。根据ＳＨＡＢ规则把体内微量元素分为Ｌｅｗｉｓ硬酸,软酸与交界酸和硬碱,软碱与交界碱,体内不同体液和器官含有丰富的软硬配体,与各类软硬酸（金属离子）结合成不同稳定性的配合物,发挥其生物活性作用。     

Determination of low level nitrite and nitrate in biological, food and environmental samples by gas chromatography-mass spectrometry and liquid chromatography with fluorescence detection

Gas chromatography-mass spectrometry (GC-MS) and liquid chromatography with fluorescence detection (LC-FL) methods have been proposed for the determination of low level nitrite and nitrate in biological, food and environmental samples. The methods include derivatization of aqueous nitrite with 2,3-diaminonaphthalene (DAN), enzymatic reduction of nitrate to nitrite, extraction with toluene and chromatographic analyses of highly fluorescent 2,3-naphthotriazole (NAT) derivative of nitrite by using GC-MS in selected-ion-monitoring (SIM) mode and LC-FL. Nitrite and nitrate ions in solid samples were extracted with 0.5 M aqueous NaOH by sonication. The recoveries of nitrite and nitrate ions based on GC-MS and LC-FL results were 98.40% and 98.10% and the precision of these methods, as indicated by the relative standard deviations (RSDs) were 1.00% for nitrite and 1.20% for nitrate, respectively. The limits of detection of the GC-MS in SIM mode and LC-FL methods based on S/N = 3 were 0.02 and 0.29 pg/ml for nitrite and 0.03 and 0.30 pg/ml for nitrate, respectively.     

Potentiometric and thermodynamic studies of 2-mercapto-5-(2-hydroxynaphthylideamino)-1,3,4-thiadiazole and its metal complexes

Summary Proton-ligand dissociation constant of 2-mercapto-5-(2-hydroxynaphthylideamino)-1,3,4-thiadiazole (MHT) and the stepwise stability constants of its metal complexes were determined potentiometrically in 40 mass/mass% ethanol-water mixture containing 0.1 M KCl. The stabilities of the complexes follow the order: Cu²⁺>Ni²⁺>Co²⁺>Mn²⁺. The dissociation constant (pK^H) of MHT and the stability constants (logK) of its metal complexes were determined at different temperatures and the corresponding thermodynamic parameters were calculated and discussed. The proton dissociation process is non-spontaneous, endothermic and entropically unfavoured. The formation of the metal complexes was found to be spontaneous, endothermic and entropically favoured.     

Elucidation of activity of copper and copper oxide nanomaterials for electrocatalytic and photoelectrochemical reduction of carbon dioxide

Copper- and copper oxide–based materials are, in principle, promising components (supports, reactive sites, and visible light–absorbing semiconductors) of electrocatalysts and photocathodes for reduction of carbon dioxide. Electrochemical and photoelectrochemical approaches are generally suitable for the low-temperature CO₂-conversion to carbon-based simple organic fuels or utility chemicals.Different concepts of utilization, including nanostructuring, doping, admixing, preconditioning, modification, or functionalization of various copper- and copper oxide–based systems for catalytic electroreduction and photoelectrochemical reduction of CO₂ are elucidated, as well as important strategies to enhance the systems' overall activity and stability are discussed.     

Dynamic mechanical and gas transport properties of blends and random copolymers of bisphenol-A polycarbonate and tetramethyl bisphenol-A polycarbonate

Dynamic mechanical and gas transport properties for homogeneous homopolymer blends and random copolymers of bisphenol-A and tetramethyl bisphenol-A polycarbonates (PC-TMPC) were determined. The gas transport measurements were performed at 35°C for the gases He, H₂, O₂, Ar, N₂, CH₄, and CO₂. The results show that the copolymers have lower permeability, apparent diffusion, and solubility coefficients than the blends. Permeability coefficients for blends follow a semilogarithmic ideal mixing rule while copolymers exhibit negative deviations from this. Specific volume measurements show that the free volume available for gas transport is slightly larger in copolymers than in blends of the same composition. These apparently contradictory results may relate to the differences in local mode chain motions observed for the copolymer and blend series. The γ relaxation processes in PC and TMPC seem to operate independently in the blends (no intermolecular coupling) while there is clear evidence for intramolecular coupling in the copolymers. © 1992 John Wiley & Sons, Inc.     

Synthesis and Structure of 1- and 2-Isomers of (Trimethoxysilylmethyl) and (Silatranylmethyl)benzotriazole

We have synthesized 1- and 2-(trimethylsilylmethyl)- and 1- and 2-(trimethoxysilylmethyl)benzotriazoles by reaction of 1,2,3-benzotriazolylsodium with trimethyl- or trimethoxy(chloromethyl)silane. We obtained 1- and 2-(silatranylmethyl)benzotriazoles by transesterification of the latter with triethanolamine.     

Studies of some monocyclic and bicyclic arylacetonitriles

The high-resolution (1)H, (13)C, (1)H-(1)H COSY and (1)H-(13)C COSY NMR spectra have been recorded in CDCl(3) for arylacetonitriles 1-12 and analyzed. The arylacetonitriles 3-7 exist in two isomeric forms E (methyl group is anti to cyano group) and Z (the methyl group is syn to cyano group) in solution. Normal chair conformation with equatorial orientations of phenyl rings at C-2 and C-6 for monocyclic nitriles 1 and 2, epimeric chair structure EC (axial configuration of methyl group at C-3) for both the E and Z isomers of arylacetonitrile derivatives (3-7) and a distorted boat form, B(3), for the N-acylacetonitrile derivatives (8-10) have been proposed based on NMR data. The bicyclic nitriles 11 and 12 exist in twin chair conformations in solution. DFT calculations and chemical shifts also support these conformations. Geometry optimizations for 1-12 were carried out according to density functional theory using B3LYP/6-31G(d,p) basis set and for 1 and 8 the theoretical geometrical parameters have been compared with those of single crystal measurements.