三核钨钼簇合物对苯乙烯氧化反应的催化

关于烯烃的催化氧化,报道较多。Takao等研究了苯乙烯在Ir和Rh络合物存在下的氧化反应;Collman曾报道环己烯在Vaska络合物[IrX(CO)(PPh_3)_2]催化下氧化成环己酮和环已烯氧化物。本文采用Cotton合成的簇合物[W_3O_2(CH_3CO_2)_6(H_2O)_3]Br_2·     

三核钼钨簇合物的电化学性质研究

合成了四种三核钼钨簇合物(［Mo₃L］²⁺, ［Mo₂WL］²⁺, ［MoW₂L］²⁺, ［W₃L］²⁺, 其中L=［(μ₃-O)₂(μ-CH₃COO)₆(H₂O)₃］)。并研究了四种簇合物在铂电极上的电化学特性，结果表明：在0.01 mol/L簇合物的水溶液中，［Mo₃L］²⁺, ［Mo₂WL］²⁺出现两个氧化峰，两个还原峰。［W₃L］²⁺, ［W₂MoL］²⁺则出现三个氧化峰和两个还原峰，四种簇合物的电化学性质不同，主要是由于钼钨的外层电子排布不同造成的。     

新颖四核W-Cu-S簇合物[(η5-C5Me5)WS3Cu3Br(Py)3(dppm)](PF6)的合成和晶体结构

In the presence of NH₄PF₆， reaction of [PPh₄][(η⁵-C₅Me₅)WS₃Cu₃Br(dppm)] with excess pyridine afforded red prismatic crystals， [(η⁵-C₅Me₅)WS₃Cu₃Br(Py)₃(dppm)](PF₆) (1). It was characterized by elemental analy-sis， IR， UV-vis and ¹H NMR spectroscopy and X-ray diffraction. 1 crystallizes in an orthorhombic system with space group Pna2₁ and unit cell parameters a=2.1124(4)nm， b=1.8944(4)nm， c=1.3338(2)nm， V=5.3375(19)nm³， Z=4， D_c=1.807g·cm^-3，M_r=1452.42， F(000)=2864， μ=4.342mm^-1， R₁=0.0487， wR₂=0.1027. The structure of the cluster cation contains an incomplete cubane-like WS₃Cu₃ core where Cu(1) and Cu(2) atoms are bridged by a dppm ligand. Each of the three Cu atoms adopts a distorted tetrahedral coordi-nation geometry. The W-Cu(1)， W-Cu(2) and W-Cu(3) distances are 0.27698(17)nm， 0.2772(17)nm， and 0.27065(9)nm， respectively. CCDC： 199845.     

簇合物[(η5-C5Me5)WS3{Cu(PPh3)}3Cl](PF6)的合成及晶体结构

Reaction of a preformed cluster [{(η⁵-C₅Me₅)WS₃}₃Cu₇(MeCN)₉](PF₆)₄ (1) in MeCN with LiCl and PPh₃ gave rise to a tetranuclear cationic cluster [(η⁵-C₅Me₅)WS₃{Cu(PPh₃)}₃Cl](PF₆) (2). The title compound 2 was characterized by elementary analysis, IR, UV-Vis, ¹H NMR, and its crystal structure was determined by X-ray single crystal diffraction. It belongs to monoclinic, space group P2₁/c with a=1.799 8(4) nm, b=2.083 6(4) nm, c=1.913 5(4) nm, β=113.63(3)°, V=6.574(3) nm³, Z=4. The cluster cation [(η⁵-C₅Me₅)WS₃{Cu(PPh₃)}₃Cl]⁺ of 2 contains a strongly distorted, cubane-like structure [WS₃Cu₃Cl] in which one Cl weakly fills into the void of the nido-like [WS₃Cu₃] fragment with three relatively long Cu-Cl distances. CCDC: 270415.     

一个Yb8簇合物的合成、结构及CO2催化转化性质

使用多齿席夫碱配体H₂L与Yb(acac)₃·2H₂O反应,设计并通过溶剂热法合成了一例结构新颖的八核镱簇合物[Yb₈(acac)₄(HL)₄(L)₂(μ₃-O)₄(C₂H₅O)₄]·2C₂H₅OH·2CH₂Cl₂(1)。单晶X射线衍射分析表明,簇合物呈中心对称的八核结构,中心稀土离子Yb1(Ⅲ)为八配位的双帽三角棱柱几何构型,Yb2、Yb3和Yb4均为七配位,分别为单帽三角棱柱、五角双锥及单帽八面体几何构型。簇合物1具有良好的溶剂稳定性。近红外荧光测试表明：簇合物1在室温下表现出Yb(Ⅲ)特征发射峰。此外,催化性质研究表明：簇合物1可以有效地催化CO₂与环氧化合物的环加成反应,且作为异相催化剂表现出良好的循环性能。     

钴膦簇合物的催化环丙烷化反应

本文首次利用碳基钴簇合物ＰｈＰＣｏ_３（ＣＯ）_９催化剂，在常压和－２０℃－０℃，用苯乙烯和重氮乙酸乙酯进行环丙烷化反应，合成了菊酸酯，重氮乙酸乙酯可全部转化，酯的选择性可达８５％。产物经减压分馏后，由ＩＲ和￣１ＨＮＭＲ分析，确证了产物为菊酸酯，表明了羰基钴簇合物对苯乙烯的环丙烷化反应有良好的催化性能，为四面体异核簇合物用于不对称催化反应打下了基础。     

亚硝酰基钼、钨配合物及其铁杂核簇合物

一氧化氮具有电子给予体和受体的双重性质,在过渡金属配合物中亚硝酰基以线型或弯曲型端基,桥式或面桥式配基配位,很早便引起了结构化学家的注意。这些不同的键合模式影响亚硝酰基的反应能力,它可与亲电试剂如质子酸或路易斯酸反应,也可以与亲核试剂如碳阴离子反应。可以作为氧源与 CO 发生氧化还原反应减少内燃机废气污染,也可以与有机配体发生分子内插入反应,形成新的碳氮     

钼铁钴硫簇合物催化乙炔还原性质的研究

钼铁钴硫簇合物催化乙炔还原性质的研究①南玉明②（大庆石油学院石化系，安达１５１４００）徐吉庆蔡辉（吉林大学化学系，长春１３００２３）关键词簇合物类立方烷结构催化电化学性质在化学模拟生物固氮研究的推动下，人们已合成了上百种Ｍｏ－Ｆｅ－Ｓ簇合物，并研究了...     

双核钨簇合物W2Cl4（OR）4（ROH）2结构的EXAFS研究

我们曾用EXAFS和X射线单晶衍射研究了M_3W_2Cl_9类双钨簇合物的结构,发现簇胳[W_2Cl_9]~(3-)的结构很牢固,改变阳离子M~+的性质和大小,都不会改变其结构。W_2Cl_9(RO)_4(R′OH)_2类簇合物与M_3W_2Cl_9类似,具有一个双钨簇胳。Anderson等曾研究R为甲基或乙基的两个簇合物的单晶结构,正四价的两个钨原子间用双键及两个氧桥键相联接。与M_3W_2Cl_9另一不同处是取代基RO及R′OH与钨原子直接相联,其间还形成氢键,故RO或R′OH对簇胳的影响要大于M_3W_2Cl_9中阳离子M~+。本文合成6种具有不同取代基的W_2Cl_4·(RO)_4(ROH)_2化合物,用EXAFS研究其结构,以期了解不同取代基对簇胳结构的影响。     

RADIATION DEGRADATION OF CHITOSAN IN THE PRESENCE OF H2O2

INTRODUCTIONChitosan, poly-β-(1 -?4)-D-glucosamine, can be obtained from chitin by deacetylation with alkali. It is soluble indilute acidic medium due to the presence of amino groups. The use of chitosan in many areas, such as foodprocessing, biochemistry, Pharmaceuticals, medicine, and agriculture has been developed over the pastdecades[1,2].In recent years, it has been reported that many properties of chitosan depend on the molecular weight[3]. Thechitosan oligomers possess better fun…     

DEEP CATALYTIC OXIDATION OF BENZENE IN THE PRESENCE OF SEVERAL VOLATILE ORGANIC COMPOUNDS ON METAL OXIDES AND Pt/Al2O3 CATALYSTS

Oxidation of benzene into CO₂ in air has been studied in the temperature range of 300-673 K on supported metal oxides and on 0.7% Pt/Al₂O₃, in the absence and in the presence of several Volatile Organic Compounds (VOCs). On the metal oxides, the deep oxidation of benzene is strongly inhibited in presence of VOCs and O-containing VOCs lead to more toxic VOCs (i.e: acetaldehyde).     

CO~2(CO)~8/吡啶络合催化苯乙烯氢羧化反应的研究

在苯乙烯氢羧化反应(Hydrocarboxylation)中,Co_2(CO)_8的催化活性很低,吡啶的加入可显著提高催化活性,Co_2(CO)_8与吡啶的配比不同时,对反应活性、收率和正、异构产物的比例均有影响,而且与反应温度有关。此外,还观察了各种吡啶衍生物对氢羧化反应的影响。     

Electrochromic properties of anodically grown mixed V2O5–TiO2 nanotubes

Mixed V₂O₅–TiO₂ nanotube arrays were fabricated by self-organizing anodization of different Ti–V alloys. The mixed oxide nanotubes show switchable V-oxidation states and strong cathodic coloration. Already a low V content of ≈ 0.2 at.% significantly increases the electrochromic switching properties. Using a sample with 3 at.% V, very high electrochromic contrast can be established and a significantly lower switching onset voltage than for pure TiO₂ nanotubes is observed. At high V contents, although charge storage is increased, the improvement of contrast is diminished due to the strong background color of the sample.     

Lithium-ion intercalation and electrochromism in ordered V2O5 nanoporous layers

Highly ordered V₂O₅ porous layers were fabricated from vanadium metal foils by self-organizing anodization. The defined porous structure of this material provides excellent lithium-ion transportation and intercalation/extraction properties. As a result the highly ordered porous structure shows a very good electrochromic performance with long term switching stability.     

V2O5/赤铁矿催化剂结构及其NH3选择性催化还原NOx性能

以水热合成针铁矿为前驱体浸渍偏钒酸铵,分别于300,400和500℃空气中焙烧,制备了不同活性组分负载量的V₂O₅/赤铁矿（V/H）催化剂,用于氨选择性催化还原（SCR）脱硝。采用X射线衍射、透射电子显微镜、比表面积分析仪、程序升温还原及程序升温脱附等方法对催化剂结构进行了表征,并用标气配制模拟烟气进行了脱硝实验。结果表明,300℃煅烧3%V/H催化剂当烟气温度为250-300℃时NO转化率均可达95%以上;当配气中单独加入水蒸气或低浓度SO₂（0.01%）时,V/H催化脱硝的活性不受影响;当系统加入高浓度的SO₂（0.03%与0.05%）或同时添加H₂O与SO₂时,SCR脱硝效率下降,其机制可能是SO₂在催化剂表面竞争吸附所致,停止添加后,催化活性迅速恢复。     

A cataluminescence gas sensor based on nanosized V2O5 for tert-butyl mercaptan

This work proposed a gas sensor for the determination of tert-butyl mercaptan, one of the highly toxic volatile sulfur compounds, which was based on cataluminescence emission during its catalytic oxidation on the surface of nanosized V₂O₅. The cataluminescence characteristics and the optimum conditions, including the morphology of sensing material, the wavelength of cataluminescence emission, the oxygen flow rate and working temperature were investigated in detail. Under the optimized conditions, the calibration curve of the relative cataluminescence intensity versus the concentration of tert-butyl mercaptan vapor was made, with the linear range of 5.6-196 μg mL⁻¹ and the detection limit of 0.5 μg mL⁻¹ (S/N = 3). The relative standard deviation (R.S.D.) (n = 5) of relative cataluminescence intensity for 84 μg mL⁻¹ tert-butyl mercaptan was 3.6%. There is no or weak response to some common substances, such as formic acid, alcohol (methanol, ethanol, propanol, isopropanol, n-butanol, isoamyl alcohol), o-dichlorobenzene, acetonitrile, ethyl acetate, aldehyde (formaldehyde, acetaldehyde and propanal), 1,2-dichloroethane and ammonia. Furthermore, the proposed sensor was successfully used for determining tert-butyl mercaptan in four artificial samples, with a good recovery. The results demonstrated that the proposed gas sensor had a promising capability for the tert-butyl mercaptan in routine monitoring.     

THE EFEFCT OF MAGNETIC FIELD ON POLYMERIZATION OF STYRENE IN THE PRESENCE OF POLYVINYL NAPHTHALENE AND POLYVINYL BENZOPHENONE

In the process of bulk photopolymerization of styrene initiated by AIBN decomposition polyvinyl benzophenone (PVB) can supply an effective cage for triplet-triplet energy transfer between PVB macromolecules and small molecules of AIBN to influence the molecular weight of polystyrene in weak magnetic field (less than 0.035T), that was different from the case of polyvinyl naphthalene (PVN) which supplied cages for this system only in the stronger magnetic field (more than 0.2 T) studies. It was found that in the same conditions, PVN could exert more tremendous influences on the bulk photopolymerizatiou system of styrene than PVB because in the stronger magnetic field the triplet PVN had much longer life time than PVB.