冠醚—卟啉锰催化剂的制备及其催化性能研究

本文以一类新型的冠醚－卟啉作配体，制备了金属锰配合物，考察了该类配合物对苯乙烯环氧化反应的催化活性，发现具冠醚基团的锰卟啉催化剂在烯烃环氧化的两相溶剂（ＣＨ２Ｃｌ２／Ｈ２Ｏ）体系中，不仅催化活性增强，同时具有相转移能力。本文还探索了反应条件改变对环氧化结果的影响规律，测定了反应的动力学。     

冠醚－卟啉锰催化剂的制备及其催化性能研究

本文以一类新型的冠醚－卟啉作配体，制备了金属锰配合物．考察了该类配合物对苯乙烯环氧化反应的催化活性，发现具冠醚基团的锰卟啉催化剂在烯烃环氧化的两相溶剂（ＣＨ_２Ｃｌ_２／Ｈ_２Ｏ）体系中，不仅催化活性增强，同时具有相转移能力．本文还探索了反应条件改变对环氧化结果的影响规律，测定了反应的动力学．     

N-[4-(2-羟基乙氧基)苯甲酰基]-N-苯基羟胺的合成及其锰配合物对苯乙烯的仿生催化环氧化性能

N-[4-(2-羟基乙氧基)苯甲酰基]-N-苯基羟胺的合成及其锰配合物对苯乙烯的仿生催化环氧化性能;异羟肟酸;苯乙烯环氧化     

巯基乙酸锑配合物的合成与X射线粉末衍射数据指标化

一些锑和铋的配合物可以应用于医药研究[1,2 ] ,已合成了许多锑的有机配体配合物[3～ 7] ,但其中大多数没有生物活性。因此 ,研究锑或铋离子的配合物不仅对主族元素化学、生物无机化学而且对医药都有着非常重要的意义。我们用三氯化锑与巯基乙酸液相反应法合成的二巯基乙酸锑 (Ⅲ)配合物 ,其组成为ＨＳｂ(ＳＣＨ2 ＣＯＯ) 2 ,用Ｘ射线粉末多晶衍射数据指标化来研究配合物晶体结构[8] 。1　实验部分1 1　仪器与试剂ＥＡ - 1 1 0 6型元素分析仪 (意大利卡拉欧巴公司制造 ) ,Ｄ Ｍａｘ -ＹＢ型多晶Ｘ射线粉末衍射仪(日本理学 ,ＣｕＫα射线 ,…     

二氰基二硫纶和邻菲咯啉二酮镍（Ⅱ）,铜（Ⅱ）,锌（Ⅱ）配合物的电子光谱及分子内

各种均一配体的金属二硫纶[1～4]、金属二亚胺[5,6]以及二硫纶和二亚胺混合配体的金属配合物[7,8],因其具有特殊的氧化还原性和光、电、磁功能,近10多年来一直受到科学家们的高度重视.笔者的兴趣在于二氰基二硫纶(mnt2-)的过渡金属配合物,以及二氰基二硫纶和α,α′-二亚胺混合配体过渡金属配合物的合成、性质、结构和电子功能研究[9～12].这些配合物不仅本身具有优异的气敏、光敏、催化等功能性,而且也是合成金属四氮杂卟啉的前驱物[13～14]和自组装有序分子聚集体的功能元件之一[15].……     

二氰基二硫纶和邻菲咯啉二酮镍(Ⅱ)、铜(Ⅱ)、锌(Ⅱ)配合物的电子光谱及分子内荷移跃迁

各种均一配体的金属二硫纶[1～4]、金属二亚胺[5,6]以及二硫纶和二亚胺混合配体的金属配合物[7,8],因其具有特殊的氧化还原性和光、电、磁功能,近10多年来一直受到科学家们的高度重视.笔者的兴趣在于二氰基二硫纶(mnt2-)的过渡金属配合物,以及二氰基二硫纶和α,α′-二亚胺混合配体过渡金属配合物的合成、性质、结构和电子功能研究[9～12].这些配合物不仅本身具有优异的气敏、光敏、催化等功能性,而且也是合成金属四氮杂卟啉的前驱物[13～14]和自组装有序分子聚集体的功能元件之一[15].……     

含NOS配位原子的镍配合物催化苯乙烯氧化反应

合成了含NOS配位原子的三齿西夫碱的镍配合物,并用红外,核磁,元素分析和晶体衍射进行了表征。发现此类配合物在相转移试剂存在下以次氯酸钠为氧源对烯烃的氧化具有较好的催化活性,研究表明配体结构和反应条件对反应结果具有较大影响,在优化条件下,采用该类催化剂催化苯乙烯氧化可得到54％环氧化产率．     

二氰基二硫纶和邻菲咯啉二酮镍(II)、铜(II)、锌(II)配合物的电子光谱及分子内荷移跃迁

各种均一配体的金属二硫纶 [1～ 4 ]、金属二亚胺 [5,6]以及二硫纶和二亚胺混合配体的金属配合物 [7,8] ,因其具有特殊的氧化还原性和光、电、磁功能 ,近 1 0多年来一直受到科学家们的高度重视。笔者的兴趣在于二氰基二硫纶 (mnt2 - )的过渡金属配合物 ,以及二氰基二硫纶和α,α′-二亚胺混合配体过渡金属配合物的合成、性质、结构和电子功能研究 [9～ 12 ] 。这些配合物不仅本身具有优异的气敏、光敏、催化等功能性 ,而且也是合成金属四氮杂卟啉的前驱物 [13～ 14 ]和自组装有序分子聚集体的功能元件之一[15] 。　　最近 ,笔者合成和表征了…     

离子液体体系中离子型锰卟啉对苯乙烯的催化氧化

以单氧给体乙酰碘苯[PhI(OAc)2]为氧源, 在无需轴向配体和有机溶剂的参与下, 离子型锰卟啉[MnⅢ(BF4)T(N-Me-4-Py)P][BF4]4和离子液体 [BMIM]BF4组成的多元离子液体体系, 在温和的反应条件下对苯乙烯的催化氧化表现出较高的活性(87%)和环氧苯乙烷选择性(90％), 并且有较好的底物普适性. 构筑的锰卟啉多元离子液体体系可以一定程度上抑制卟啉聚合和氧化降解等反应.     

单取代色氨酸四苯基卟啉及其配合物的合成、结构表征及催化性质研究

模拟细胞色素 P- 4 5 0的活性中心金属卟啉及周围氨基酸残基的结构 ,研究以其共轭大 π电子体系和中心金属原子价改变为基础的金属卟啉的氧化还原性质 ,以及中心金属对轴向配体的配位能力是当前人们感兴趣的课题[1 ] 。本文报道了 5 - [(对 - N-色氨酸丁氧基 )苯基 ]- 10 -15 - 2 0 -三 (对氯苯基 )卟啉及其铁、钴、锰配合物的合成、结构表征和对芳醛的催化氧化行为。实　验　部　分合成1.色氨酸四苯基卟啉 (H2 L )的合成 :　按文献 [2 ]先合成单对羟基卟啉 (收率 4 .2 % ) ,再与1,4二溴丁烷反应得单对溴丁氧基四苯基卟啉 (收率 6 0 % ) ,…     

Olefin epoxidation by alkyl hydroperoxide with a novel cross-bridged cyclam manganese complex: demonstration of oxygenation by two distinct reactive intermediates

Olefin epoxidation provides an operative protocol to investigate the oxygen transfer process in nature. A novel manganese complex with a cross-bridged cyclam ligand, MnIV(Me2EBC)(OH)2(2+) (Me2EBC = 4,11-dimethyl-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane), was used to study the epoxidation mechanism with biologically important oxidants, alkyl hydroperoxides. Results from direct reaction of the freshly synthesized manganese(IV) complex, [Mn(Me2EBC)(OH)2](PF6)2, with various olefins in neutral or basic solution, and from catalytic epoxidation with oxygen-labeled solvent, H2 18O, eliminate the manganese oxo moiety, Mn(IV)=O, as the reactive intermediate and obviate an oxygen rebound mechanism. Epoxidations of norbornylene under different conditions indicate multiple mechanisms for epoxidation, and cis-stilbene epoxidation under atmospheric 18O2 reveals a product distribution indicating at least two distinctive intermediates serving as the reactive species for epoxidation. In addition to alkyl peroxide radicals as dominant intermediates, an alkyl hydroperoxide adduct of high oxidation state manganese(IV) is suggested as the third kind of active intermediate responsible for epoxidation. This third intermediate functions by the Lewis acid pathway, a process best known for hydrogen peroxide adducts. Furthermore, the tert-butyl peroxide adduct of this manganese(IV) complex was detected by mass spectroscopy under catalytic oxidation conditions.     

Epoxidation of Soybean Oil in the Course of Cooxidation with Hydrogen Peroxide in the Presence of Propanoic Acid and Chlorinated KU-2 × 8 Cation Exchanger

Pattern of soybean oil epoxidation catalyzed by chlorinated KU-2 × 8 cation exchanger in the presence of H₂O₂ and propanoic acid was studied. The epoxidation rate and the selectivity of formation and yield of the epoxidation product were studied as influenced by the concentration of H₂O₂, C₂H₅COOH, and the catalyst. Some kinetic and activation parameters of soybean oil epoxidation were determined.     

Organocatalytic asymmetric epoxidation reactions in water-alcohol solutions

The diastereo- and enantioselective organocatalytic epoxidation of alpha,beta-unsaturated aldehydes in aqueous solutions is presented. By the screening of the reaction conditions for the epoxidation of cinnamic aldehyde applying hydrogen peroxide as the oxidant and 2-[bis-(3,5-bis-trifluoromethyl-phenyl)-trimethylsilanyloxy-methyl]-pyrrolidine as the catalyst, a highly stereoselective reaction has been developed. The scope of the diastereo- and enantioselective organocatalytic epoxidation in aqueous solutions is documented by the asymmetric epoxidation of alpha,beta-unsaturated aldehydes with enantioselectivities up to 96% ee.     

Ti-MWW催化氯丙烯环氧化反应动力学行为

以Ti-MWW分子筛为催化剂,以H2O2为氧化剂,系统研究了氯丙烯环氧化反应的动力学行为.结果表明,该反应速率与Ti-MWW分子筛的用量成正比,是1级反应.当H2O2浓度小于0.67 mol/L时,环氧化反应为1级反应;大于2 mol/L时,为0级反应.随着氯丙烯浓度的增加,环氧化反应级数从1级向0级转变;且只有当其浓...     

Co2+-exchanged faujasite zeolites as efficient heterogeneous catalysts for epoxidation of styrene with molecular oxygen

Co2+-exchanged faujasite zeolites can efficiently catalyze the epoxidation of styrene with molecular oxygen, and the Co2+ ions located in supercages are suggested to account for the activation of O2 for the epoxidation of styrene.     

Olefin epoxidation with hydrogen peroxide catalyzed by lacunary polyoxometalate [gamma-SiW10O34H2O2]4-

The tetra-n-butylammonium (TBA) salt of the divacant Keggin-type polyoxometalate [TBA](4)[gamma-SiW(10)O(34)(H(2)O)(2)] (I) catalyzes the oxygen-transfer reactions of olefins, allylic alcohols, and sulfides with 30 % aqueous hydrogen peroxide. The negative Hammett rho(+) (-0.99) for the competitive oxidation of p-substituted styrenes and the low value of (nucleophilic oxidation)/(total oxidation), X(SO)=0.04, for I-catalyzed oxidation of thianthrene 5-oxide (SSO) reveals that a strongly electrophilic oxidant species is formed on I. The preferential formation of trans-epoxide during epoxidation of 3-methyl-1-cyclohexene demonstrates the steric constraints of the active site of I. The I-catalyzed epoxidation proceeds with an induction period that disappears upon treatment of I with hydrogen peroxide. (29)Si and (183)W NMR spectroscopy and CSI mass spectrometry show that reaction of I with excess hydrogen peroxide leads to fast formation of a diperoxo species, [TBA](4)[gamma-SiW(10)O(32)(O(2))(2)] (II), with retention of a gamma-Keggin type structure. Whereas the isolated compound II is inactive for stoichiometric epoxidation of cyclooctene, epoxidation with II does proceed in the presence of hydrogen peroxide. The reaction of II with hydrogen peroxide would form a reactive species (III), and this step corresponds to the induction period observed in the catalytic epoxidation. The steric and electronic characters of III are the same as those for the catalytic epoxidation by I. Kinetic, spectroscopic, and mechanistic investigations show that the present epoxidation proceeds via III.     

疏水性金属卟啉的合成及催化性能研究

本文合成了一类带疏水性长链的对称卟啉及其金属配合物, 研究了该类金属卟啉在CH2Cl2/H2O两相体系中催化苯乙烯的环氧化反应性能。通过以上研究, 发现催化反应体系中水相PH值对烯烃环氧化反应有很大影响; 改变金属卟啉的疏水性对催化反应影响不大; 具不同中心金属离子的金属卟啉有不同的催化活性, 催化活性顺序为:Mn>Co>Ni>Cu。     

An Overview of Heterogeneous Transition Metal-Based Catalysts for Cyclohexene Epoxidation Reaction

Cyclohexane epoxide, which contains highly active epoxy groups, plays a crucial role as an intermediate in the preparation of fine chemicals. However, controlling the epoxidation pathway of cyclohexene is challenging due to issues such as the allylic oxidation of cyclohexene and the ring opening of cyclohexane epoxide during the cyclohexene epoxidation process to form cyclohexane oxide. This review focuses on the structure-activity relationships and synthesis processes of various heterogeneous transition metal-based catalysts used in cyclohexene epoxidation reactions, including molybdenum(Mo)-based, tungsten(W)-based, vanadium(V)-based, titanium(Ti)-based, cobalt(Co)-based, and other catalysts. Initially, the mechanism of cyclohexene epoxidation by transition metal-based catalysts is examined from the perspective of catalytic active centers. Subsequently, the current research of cyclohexene epoxidation catalysts is summarized based on the perspective of catalyst support. Additionally, the differences between alkyl hydroperoxide, hydrogen peroxide (H₂O₂), and oxygen (O₂) as oxidants are analyzed. Finally, the main factors influencing catalytic performance are summarized, and reasonable suggestions for catalyst design are proposed. This work provides scientific support for the advancement of the olefin epoxidation industry.     

Grafted metallocalixarenes as single-site surface organometallic catalysts

Metallocalixarenes were grafted onto silica using a surface organometallic approach and shown to be active and selective catalysts for epoxidation of alkenes using organic hydroperoxides. Calixarene-Ti(IV) precursors were anchored at surface densities from 0.1 to near-monolayer coverages (0.025-0.25 calixarene nm(-2)). Several spectroscopic methods independently detected calixarene-Ti(IV) connectivity before and after epoxidation catalysis. Kinetic analyses of cyclohexene epoxidation confirmed that the active sites were anchored on the silica surface and were significantly more active than their homogeneous analogues. The steric bulk and multidentate binding of the calixarenes led to structural stability and to single-site behavior during epoxidation catalysis. Rate constants were independent of surface density for cyclohexene epoxidation with tert-butyl hydroperoxide (11.1 +/- 0.3 M(-2) s(-1)) or cumene hydroperoxide (25 +/- 2 M(-2) s(-1)). The materials and methods reported here allow the assembly of robust surface organometallic structures in which the active sites behave as isolated species, even near saturation monolayer coverages. In turn, this makes possible the rational design and synthesis of a class of heterogeneous oxide catalysts with atomic-scale precision at the active site.     

A cyclodextrin-modified ketoester for stereoselective epoxidation of alkenes

A beta-cyclodextrin-modified ketoester 2 was prepared by covalent attachment of a reactive ketone moiety to beta-cyclodextrin. Treatment of 2 with Oxone as terminal oxidant would produce CD-substituted dioxirane, which can effect stereoselective alkene epoxidation. The 2-mediated (S)-alpha-terpineol epoxidations proceeded to give terpineol oxides in high yields, and the stereoselectivities (i.e., cis-/trans-epoxide ratio) decreased from 2.5:1 to 1:1.2 with increasing steric bulkiness of the terpenes. This steric-dependent stereoselectivity can be understood based on different binding geometries of the 2/terpene inclusion complexes according to the (1)H NMR titration and 2D ROESY experiments. Enantioselective epoxidation of styrenes has also been achieved with 2 as catalyst (20-50 mol %) in aqueous acetonitrile solution, and up to 40% ee was obtained in 4-chlorostyrene epoxidation at 0 degrees C. Similar enantioselectivities were also obtained for the 2-mediated epoxidation of 1,2-dihydronaphthalene (37% ee), 4-chlorostyrene (36% ee), and trans-stilbene (31% ee).