磷化氢与直链烯烃反应的原位^31PNMR研究

本文应用加压原位核磁共振技术,在反应温度50-70℃、反应压力1.0～2.0MPa,氘代苯为溶剂、偶氮二异丁腈为引发剂的条件下,考察了磷化氢与直链烯烃1,4-戊二烯,1,7-辛二烯及1-十八烯的反应.实验结果表明,磷化氢与1,4-戊二烯可以生成6员膦杂环己烷,与1,7-辛二烯不易生成9员膦杂环壬烷,与1-十八烯主要生成伯膦产物.原位^31PNMR谱的研究也表明,磷化氢与直链烯烃反应为串行机理.     

过渡金属多烯烃配合物的合成与反应

一、在异丙基澳化镁存在下1,5-环辛二烯低价过渡金属氯化物的反应例如,三氯化铑与双烯烃反应可得到双烯烃氯化铑配合物,乙醇既是溶剂,又是还原剂。此外,等双烯烃也都可以与RhCl_3反应生成相应的配合物。1.1,5-环辛二烯氯化铑1与环多烯烃反应1可与环多烯烃反应,生成1,5-环辛二烯铑烯丙基型配合物。由于苯的共振能较高,故1不能与它发生反应。     

含烯烃配体的过渡金属卡宾配合物的研究 Ⅹ.从1,5-环辛二烯三羰基铁配合物合成新奇的η~6-芳烃二羰基铁配合物

1,3-环己二烯三羰基铁和环辛四烯三羰基铁与芳基锂,在低温下反应生成的金属酰羰基锂盐经用Et_3OBF_4烷基化,分别生成一系列新奇的异构化环己二烯二羰基[乙氧基(芳基)卡宾]铁配合物和环辛四烯二羰基[乙氧基(芳基)卡宾]铁配合物的异构化产物和/或8-二氢3,4,5-η-环辛三烯三羰基(芳基)铁配合物.现在,我们以含环状非共轭双烯配体的1,5-环辛二烯三羰基铁(1)为原料,进行类似反应,以进一步研究不同环烯烃配体在卡宾配合物中的异构化行为和对反应产物的影响. 1与约过量20％的芳基锂,LiC_6H_4R(R=H,m-,p-CH_3,p-C_6H_5),在乙醚中于-60—-30℃反应3—4h,从深红色反应溶液中析出橙红色酰羰基锂盐沉淀.当向反应混合物直接滴加过量的(CH_3)_3SiCl乙醚溶液,反应半小时后,所生成的混合物经低温柱层析分离和用石     

单重态氧化物 IV: 6-取代-1,4-环辛二烯的光敏氧化反应

6-取代-1,4-环辛二烯与单重态氧立体有选择地氧化成顺式5,8-和反式5,6-二取代-1,3-环辛二烯的含氧衍生物. 依据产物的分子结构推知, 6-取代-1,4-环辛二烯发生“ene"反应时的优势构象不同于环辛烷, 而是具有角张力的扭曲构象(1), 这为研究环烯的分子构象提供了一种实验方法.用Monroe法测定了6-取代-1,4-环辛二烯对单重态氧反应的β值. 其反应活性顺序为:3>1>4>1, 5-环辛二烯>2>5. 表明推电子取代基增加了同单重态氧反应的能力, 而吸电子取代基则降低了同单重态氧的反应能力, 但是不论取代基性质如何, 都不能改变“ene"反应的本质.     

单重态氧化物 IV: 6-取代-1,4-环辛二烯的光敏氧化反应

6-取代-1,4-环辛二烯与单重态氧立体有选择地氧化成顺式5,8-和反式5,6-二取代-1,3-环辛二烯的含氧衍生物. 依据产物的分子结构推知, 6-取代-1,4-环辛二烯发生“ene"反应时的优势构象不同于环辛烷, 而是具有角张力的扭曲构象(1), 这为研究环烯的分子构象提供了一种实验方法.用Monroe法测定了6-取代-1,4-环辛二烯对单重态氧反应的β值. 其反应活性顺序为:3>1>4>1, 5-环辛二烯>2>5. 表明推电子取代基增加了同单重态氧反应的能力, 而吸电子取代基则降低了同单重态氧的反应能力, 但是不论取代基性质如何, 都不能改变“ene"反应的本质.     

6-取代-l,4-环辛二烯的单重态氧反应——合成顺式-5,8-和反式-5,6-二取代-1,3-环辛二烯含氧衍生物的方便途径

以竹红菌甲素作敏化剂匹配高压钠灯产生单重态氧,在甲醇溶液中,氧化6-取代-1,4-环辛二烯(1),(2),并经亚硫酸钠还原,得到顺-5,8-二取代-1,3-环辛二烯和反-5,6-二取代-1,3-环辛二烯发。化合物(3)是在三氯乙烷溶液中,未经还原得到过氧化氢基取代-1,3-环辛二烯。基态分子的稳定构象决定了反应产物的立体选择性。这类反应为用光氧化方法合成顺-5,8-二取代和反-5,6-二取代-1,3-环辛二烯含氧衍生物提供了方便的途径。     

含烯烃配体的过渡金属卡宾配合物的研究X: 从1,5-环辛二烯三羰基铁配合物合成新奇的η^6-芳烃二羰基铁配合物

研究了以含环状非共轭双烯配体的1,5-环辛二烯三羰基铁为原料,与芳基锂反应,用Et3OBF4烷基化,以进一步研究不同环烯烃配体在卡宾配合物中的异构化行为和对反应产物的影响,用元素分析,红外光谱,核磁共振氢谱,质谱确定了八个新化合物的结构.用X-射线结构测定进一步证实了9-(η^6-芳烃二羰基铁)-9-三甲基硅氧基双环[4.2.1]壬-2-烯的分子结构.     

单重态氧化学——Ⅳ.6-取代-1,4-环辛二烯的光敏氧化反应

6-取代-1,4-环辛二烯与单重态氧立体有选择地氧化成顺式5,8-和反式5,6-二取代-1,3-环辛二烯的含氧衍生物。依据产物的分子结构推知,6-取代-1,4-环辛二烯发生“ene”反应时的优势构象不同于环辛烷,而是具有角张力的扭曲构象(Ⅰ),这为研究环烯的分子构象提供了一种实验方法。用Monroe法测定了6-取代-1,4-环辛二烯对单重态氧反应的β值。其反应活性顺序为:3>1>4>1,5-环辛二烯>2>5。表明推电子取代基增加了同单重态氧反应的能力,而吸电子取代基则降低了同单重态氧的反应能力。但是不论取代基性质如何,都不能改变“ene”反应的本质。     

含烯烃配体的过渡金属卡宾配合物的研究 ⅩⅢ.π-环戊二烯基(二羰基)(芳酰基)铁配合物的新合成法及其晶体结构

不同环多烯配位的羰基铁化合物与亲核试剂芳基锂在低温下反应后再用鎓盐(Et_3OBF_4)烷基化,得到完全不同的产物.例如,环辛四烯-和1,3-环己二烯(三羰基)铁生成一系列异构化的卡宾铁配合物.在这些产物中,环烯烃配体上的一个碳原子键联到“卡宾”碳原子上形成双烯丙基二羰基铁配合物.而环庚三烯(三羰基)铁在相似的条件下则发生开环反应,生成开环的双烯丙基铁配合物.在这个相关的研究中,我们选择环较小的环烯烃配位的羰基金     

均相催化中的结构研究(摘要)

在许多金属催化的有机反应中,能形成金属杂环化合物,举二类反应为例。 1.炔-烯的共齐聚反应炔类的环三聚反应,早已发现。一般用镍催化剂:但是,要使二份炔和一份烯及应而成环己二烯衍生物:则不易达到,因有一竞争反应,所得主要为三份炔的环聚物。有人假设这一反应的中间体是金属杂环化合物(Ⅰ):     

磷化氢与烯烃反应的原位NMR谱研究

本文应用加压原位(in-situ)核磁共振技术, 在反应温度70-75℃, 压力1.0-2.0MPa, 氘代苯为溶剂, 偶氮二异丁腈(AIBN)为引发剂的条件下探索了磷化氢与丙烯腈, 4-乙烯基吡啶, 烯丙基胺, 丙烯酰胺, 氨基吡啉和N-乙烯基咔唑的自由基加成反应, 结果表明除氨基吡啉之外的其它五种含氮化合物均能与磷化氢发生反应, 从而找到合成含氮有机膦的良好路线。     

Hydrochlorination of unsaturated compounds by the action of CH2Cl2 or CHCl3 and rhodium complexes

A new method has been developed for the catalytic hydrochlorination of olefins and acetylenes in the presence of Rh complexes by means of HCl generated in situ from CH₂Cl₂ and CHCl₃ under the reaction conditions. The reaction was studied using the hydrochlorination of propylene, 1-hexene, 1-nonene, vinyl-cyclopropane, 1,1-dicyclopropylethylene, cyclohexene, cyclooctene, norbornene, and 1,5-cyclooctadiene as examples.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1373–1377, June, 1991.     

铑膦配合物的加压原位核磁氢谱研究

在近似工业反应条件下(H2/CO=1:1, 1.0MPa, 70℃), 应用加温加压原位核磁共振技术, 考察了铑膦配合物催化剂HRh(CO)(PPh3)3-PPh3体系的烯烃醛化反应。结果表明,在烯烃醛化反应条件下, 反应液中存在羰基氢化铑中间配合物, 并在^1H NMR获得了该配合物中Rh-H键的质子讯号。     

A computational study of the mechanisms of the photoisomerization reactions of monocyclic and bicyclic olefins

The mechanisms of the photochemical isomerization reactions were investigated theoretically using a model system of cyclohexene (1), cycloheptene (2), norbornene (3), and two bicyclic olefins (4 and 5) using the CASSCF (six-electron/six-orbital active space) and MP2-CAS methods with the 6-311(d,p) basis set. The structures of the conical intersections, which play a decisive role in such photoisomerizations, were obtained. The intermediates and transition structures of the ground state were also calculated to assist in providing a qualitative explanation of the reaction pathways. Two photoreaction pathways were examined in the present work. The first can produce a photoproduct with an extra ring. The other can yield a photoproduct with a smaller ring with an external double bond. Both pathways involve cyclic carbene intermediates. Also, our model investigations suggest that both reaction pathways follow a similar photochemical pattern as follows: reactant → Franck-Condon region → conical intersection → cyclic carbene intermediate → transition state → photoproduct. Moreover, these two reaction pathways can compete with each other since the energetics of their conical intersection points are quite similar. Our present theoretical results agree with the available experimental observations.     

Direct carbonylation at a C-H bond in the benzene ring of 2-phenyloxazolines catalyzed by Ru(3)(CO)(12). Scope, limitations, and mechanistic aspects

The ruthenium-catalyzed carbonylation at a C-H bond in the benzene ring of a 2-phenyloxazoline is described. The reaction of 2-phenyloxazolines with CO and ethylene in toluene in the presence of a catalytic amount of Ru(3)(CO)(12) resulted in propionylation at an ortho C-H bond in the benzene ring. The presence of the oxazoline ring on the benzene ring is essential for the carbonylation to proceed. Other heterocycles, such as oxazine, oxazole, and thiazoline rings, also served as acceptable directing groups as did the oxazoline ring. A wide functional group compatibility was observed. The site selectivity of the carbonylation was examined using meta-substituted phenyloxazolines. It was found that the carbonylation took place exclusively at the less-hindered C-H bond, irrespective of the nature of substituents, indicating that the site selectivity was determined by steric factors. The reaction was also applicable, not only to a benzene ring, but also to naphthyl and thiophenyl rings. Olefins such as propene and trimethylvinylsilane in place of ethylene could also be used in the carbonylation reaction, while other olefins, such as 1-hexene, tert-butylethylene, vinylcyclohexane, isoprene, 1,5-hexadiene, cyclohexene, 1, 5-cyclooctadiene, styrene, methyl acrylate, vinyl acetate, allyltrimethylsilane, and triethoxyvinylsilane did not afford the coupling products. An equilibrium between 2-phenyloxazolines, carbon monoxide, and olefins exists on one hand and the corresponding ketones on the other hand, and product composition is governed by the equilibrium thermodynamics of the system. The results of deuterium labeling experiments suggest that the catalysis involves a reversible C-H bond cleavage and that the rate-determining step is not the cleavage of a C-H bond. The results of kinetic study of the effects of CO pressure show that the reaction rate accelerates with decreasing CO pressure.     

Some aspects of the synthesis and characterization of special polymers and oligomers by olefin metathesis

Homopolymers of 2-norbornene and 2,3-bis(trifluoromethyl)-2,5-norbornadiene and copolymers of these bicyclic olefins with 1,5-cyclooctadiene and cyclopentene were prepared via ring opening metathesis polymerization. The molecular weight distributions of the polymers were estimated by gel permeation chromatography.The polymers were degraded in a cross metathesis reaction with E-4-octene; only poly[2,3-bis(trifluoromethyl)-2,5-norbornadiene] was not degradable.All reactions were carried out with WCl₆/(CH₃)₄Sn as the catalyst system. The low molecular cyclic oligomers in the polymerization mixtures and the degradation products were analyzed by gas chromatography and identified using a gas chromatography/mass spectrometry coupling.The degradation experiments show reactivity differences for the double bonds situated in the polymer backbone. On the basis of these differences and the fact that this is the first time that a metathesis degradation of such polymers has been reported, the consequences on the ring opening metathesis copolymerization of cycloolefins are discussed in general terms, leading to some new aspects in the planning of the synthesis of special copolymers and oligomers.With reference to a lecture presented at the 4th International Symposium on Olefin Metathesis (ISOM 4), Belfast, 1–4 Sept. 1981.     

Ring opening metathesis polymerization (ROMP) of five- to eight-membered cyclic olefins: Computational,thermodynamic, and experimental approach

Ring opening metathesis polymerization (ROMP) of a series of low-strain cyclic olefins and their hydroxyl derivatives using second generation Hoveyda–Grubbs catalyst has been investigated. Additionally, density functional theory (DFT) calculations were performed to evaluate the ring strain energies of the cyclic olefins and their hydroxyl derivatives, coupled with kinetic studies for the ROMP reactions. It was found that among different ring size monomers, Cy8 having a relatively moderate ring strain energy in comparison with the other cyclic olefins, exhibited the highest monomer conversion. The effect of temperature (0, 10, 15, and 25 °C) and monomer concentration (1 M; 2.5 M and 5 M for Cy5 ; and 1 M and 5 M for Cy7 ) for the cyclic olefins Cy5 and Cy7 were investigated. In general, the experimental results for the kinetic ROMP studies obtained using complex HG2 correlate really well with the DFT calculations determined for the ring strain energies of the cyclic olefins. For comparison, DFT calculations predicted the following trend for the ring strain energies Cy8 > Cy5 > Cy7 > Cy6 , and the polymerizations carried out experimentally followed the same trend in terms of monomer conversion, with the exception of Cy5 and Cy7 at lower concentrations, which followed this trend Cy8 > Cy7 > Cy5 > Cy6 . © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3137–3145     

Preparation of cadmium selenide-polyolefin composites from functional phosphine oxides and ruthenium-based metathesis

Cadmium selenide nanoparticles, prepared by known methods, were stabilized with functional phosphine oxide 1, then used to support the polymerization of cyclic olefins radially outward from the surface by ruthenium-catalyzed ring-opening metathesis polymerization (ROMP). The conversion of compound 1 into the new metathesis catalyst 3 by carbene exchange and the subsequent polymerization of cyclic olefins were observed spectroscopically by (1)H NMR to afford for example CdSe-polycyclooctene composite 6. Transmission electron micrographs on thin films of these composites showed good nanoparticle dispersion. This is in stark contrast to the substantial nanoparticle aggregation observed when similar polymerizations were performed in the presence of conventional TOPO-covered nanoparticles. The methods reported here to prepare composite product 6 are applicable to other cyclic olefins, and suggest that this chemistry will be useful for incorporating CdSe nanoparticles into a wide variety of polymer matrices.     

Excitation-energy migration in self-assembled cyclic zinc(II)-porphyrin arrays: a close mimicry of a natural light-harvesting system

The excitation-energy-hopping (EEH) times within two-dimensional cyclic zinc(II)-porphyrin arrays 5 and 6, which were prepared by intermolecular coordination and ring-closing metathesis reaction of olefins, were deduced by modeling the EEH process based on the anisotropy depolarization as well as the exciton-exciton annihilation dynamics. Assuming the number of energy-hopping sites N = 5 and 6, the two different experimental observables, that is, anisotropy depolarization and exciton-excition annihilation times, consistently give the EEH times of 8.0 +/- 0.5 and 5.3 +/- 0.6 ps through the 1,3-phenylene linkages of 5 and 6, respectively. Accordingly, the self-assembled cyclic porphyrin arrays have proven to be well-defined two-dimensional models for natural light-harvesting complexes.     

Activation of olefins with low-valent gallium compounds under ambient conditions

The reactions of Ar'GaGaAr' (Ar' = C(6)H(3)-2,6-(C(6)H(3)-2,6-(i)Pr(2))(2)) with alkenes revealed the addition of two olefins per Ar'GaGaAr' under ambient conditions for ethylene, propene, 1-hexene and styrene but no reactions with more hindered or cyclic olefins.