Effect of substituents in the ligand on oxidation of alkanes catalyzed by binuclear oxo-bridged iron complexes

Oxidation of alkanes (methane, ethane, hexane, and cyclohexane) by hydrogen peroxide andtert-butyl hydroperoxide in acetonitrile catalyzed by binuclear -oxo-bridged iron complexes [Fe₂OL₄(H₂O)₂](ClO₄)₄ and [Fe₂OL₂PhCOO)₂(H₂O)₂](ClO₄)₂, where L = bpy, 4,4-Me₂bpy, 4,4-(ClCH₂)₂bpy, phen, and 5-NO₂phen, was studied. It was shown that the nature of the substituent in the ligand affects both the rate of the catalyzed peroxide decomposition and catalytic activity of the complexes studied in the alkane oxidation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2518–2520, December, 1995.This work was financially supported by the Russian Foundation for Basic Research (Project No. 94-03-08529), the International Science Foundation (Grant No. REUOOO), the European Foundation INTAS (Grant No. 93-315), and Amoco Company (USA).     

分子拓扑指数与链烷烃热力学性质的关系

碳原子个数N和路径数P3是表征链烷烃分子的大小、支化度和形状等结构特征的重要参数,引入烷烃所含甲基数的1.5次方M1和3次方M2表征取代基效应,运用多元线性模型研究了链烷烃标准生成焓、标准摩尔熵、标准生成吉布斯自由能等三种热力学性质与N,P3,M1和M2之间的定量关系,相关系数分别达到0.9993,0.9989和0.9972,标准偏差分别是2.2809kJ/mol,5.9093J/(mol·K),2.0585kJ/mol,其计算值与实验值非常接近.     

双(3,5-二甲基-4-苄基吡唑)甲烷ⅥB族羰基化合物的合成及反应

通过 3 ,5 -二甲基 -4-苄基吡唑与二溴甲烷在相转移催化下反应 ,合成了一个新的多吡唑烷配体双 (3 ,5 -二甲基 -4-苄基吡唑 )甲烷 .该配体与 M(CO) 6 (M=Cr,Mo,W)在光照下反应可以得到双 (3 ,5 -二甲基 -4-苄基吡唑 )甲烷四羰基铬 (2 )、钼 (3 )和钨 (4 ) .用 Sn Cl4 处理化合物 3和 4可以高产率地制得含 Mo(W)— Sn键的杂双金属配合物 .用 X射线衍射法测定了化合物 4与 Sn Cl4 反应产物 6的晶体结构 .结果表明 ,该晶体属三斜晶系 ,P1空间群 ,晶胞参数 a=1 .0 92 9(9) nm,b=1 .2 82 (1 ) nm,c=1 .2 82 (1 ) nm,α=1 0 2 .3 5 (1 )°,β=1 0 8.62 (1 )°,γ=97.0 0 (1 )°,V=1 .799(3 ) nm3,Z=2 ,最终结构偏离因子 R=0 .0 5 8,w R=0 .1 0 1 5 ,GOF=0 .90 5 .六元金属杂环 W— N— N— C— N— N为船式构象 ,分子中没有氯桥存在 .     

Analysis of Acidic Properties of Zeolitic and Non-Zeolitic Solid Acid Catalysts Using Temperature-Programmed Desorption of Ammonia

A method of ammonia temperature-programmed desorption (TPD) for analysis of acidic property of a solid was improved by introduction of a water vapor treatment method and development of a theory for calculation of ammonia adsorption heat from the TPD profile. The improved method was applied to various solid acid catalysts to establish relationships between the acidic properties and catalytic performances for various acid-catalyzed reactions. Here, examples of the applications to some important acid catalysts are reviewed. The exact analysis of acidic property of Y zeolite and its change by such modifications as steaming and ethylenediaminetetraacetic acid (EDTA) treatment gave a new interpretation on the generation of alkane (paraffin) cracking activity on an ultra stable Y (USY) zeolite. The surface density and strength of acid sites on WO₃/ZrO₂ and SO₄ ^2–/ZrO₂ catalysts were determined, and their relations with catalytic activities for Friedel–Crafts type alkylation and skeletal isomerization of alkane were found.     

烷烃偏心因子和临界压缩因子的分子拓扑学研究

构建了一种新的拓扑指数ND,可对分子结构实现惟一性表征,具有优良的结构选择性.用ND指数对烷烃的偏心因子ω和临界压缩因子ZC进行研究,结果表明烷烃的偏心因子ω和临界压缩因子ZC可用下述二式来定量描述:ln(2.336 5ω)=0.008 288ND1 0.001 857ND2 0.000 551ND3 0.855 206;ln(ZC0.185)=0.021 496ND1 0.004 385ND2 0.001 235ND32.135 614,用上述二式分别对烷烃的偏心因子和临界压缩因子进行计算,计算值与实验值吻合良好.     

Selective alkane C-H-bond functionalizations utilizing oxidative single-electron transfer and organocatalysis

Alkane C-H-bond functionalization methods not utilizing metal-catalysis are discussed based on experimental and computational data, beginning with molecule-induced homolysis (reactions of alkanes with dioxiranes). Electrophilic reactions are elaborated next with an emphasis on mechanistic details that reveal that many so-called electrophilic C-H or C-C-bond insertions can be rationalized by electron-transfer reactions (inner sphere, H-coupled, and outer sphere). Finally, radical functionalizations utilizing carbon-centered (relatively stable) radicals generated under organocatalytic (phase-transfer catalysis, PTC) conditions are presented as valuable alternatives to other radical-chain alkane functionalizations. The remarkable chemo- and regioselectivities of these PTC radical reactions and the tolerance of high strain in certain aliphatic hydrocarbons make them particularly useful for laboratory-scale halogenations, in particular, iodinations of unactivated alkane C-H-bonds.     

甲硫醇制烯烃的催化反应机理研究进展

从碳硫污染物(CO_2、 H_2S)出发合成甲硫醇(CH_3SH),再经由甲硫醇资源化催化制低碳烯烃(methyl mercaptan to olefins,M_2TO)的工艺技术,不仅实现污染物CO_2和H_2S协同资源化利用,还为低碳烯烃的多元化来源拓展了新路径.因此甲硫醇资源化催化制低碳烯烃具有重要的研究意义和应用前景.我们介绍了甲硫醇资源化催化制低碳烯烃反应的发展历程及研究现状,对比了甲醇制烯烃(MTO)与甲硫醇制烯烃(M_2TO)反应机理,分析了M_2TO反应较难实现的原因,也探讨了反应温度、酸性位密度、分子筛结构和甲硫醇甲基化能力对M_2TO反应的影响,并提出了一些解决方法 .     

不对称取代双(吡唑)甲烷VIB羰基金属化合物的合成及表征

3-苯基吡唑与二溴甲烷在相转移催化下反应,得到(3-苯基吡唑-5'-苯基吡唑)甲烷(1)和双(3-苯基吡唑)甲烷(2)的混合物.当该混合配体与M(CO)₆(M=Cr,Mo,W)在光照下反应时,分离得到了不对称取代的(3-苯基吡唑-5'-苯基吡唑)甲烷四羰基铬(3),钼⑷和钨(5).用X-射线衍射测定了化合物5的晶体结构.结果表明,该晶体属于单斜晶系,P2(1)/n空间群,a=1.7976(7) rnn,b=1.3210(5) nm, c=1.8681(7) nm;β=98.293(8)°, V=4.390(3) nm³, Z=8,最终结构偏离因子[I>2σ(I)]=0.0516, Rw=0.0898, GOF=0.879.两个苯基分别处于两个吡唑的3位及5'位.     

一个新的分子电性距离矢量(MEDV)

有机化合物通常由电性各异的碳、氢、氧、氮、硫等元素以共价键相互连接而成。我们提出了一个称为分子电性距离矢量(简称MEDV)的新描述来表征有机分子结构。以含有环、饱和与不饱和键及碳氧氮等元素的色氨酸分子为例,说明构建MEDV的基本方法。开发设计了计算有机MEDV分子的TrueBASIC语言程序。不借用其他任何描述子,仅用MEDV建立了烷、醇、多环芳烃等多种有机化合物包括沸点、密度、保留指数等多种性质的定量结构-性质相关(QSPR)模型,相关系数均达0.98以上。     

VPO催化剂前驱体的溶液法合成和结构研究

用丁烷代替苯为原料生产马来酸酐 ,是低碳烷烃选择氧化成功实现工业化的极少数例子之一 [1] ,其中 VPO复氧化物是唯一能高活性且高选择性地催化这一过程的催化剂 .因而 ,这一领域的研究备受关注 [2 ,3] .以 VPO铵盐单晶结构的研究为例 ,迄今已对α- NH4 V ( HPO4 ) [4 ] ,β- NH4 V ( HPO4 ) [5] ,NH4 VOPO4 [6 ] ,NH4 VOPO4 · H2 O[7] 和 α- NH4 VO2 HPO4 [8] 等进行了结构研究 .作为催化剂活性物质( VO) 2 P2 O7的前驱体 ,β- NH4 ( VO2 ) ( HPO4 )也曾被 Pulvin等 [9,10 ] 由粉末衍射数据推测分子组成为NH4 ( VO…