Formation of Di- and Tricarbonylruthenium(O) Species from [RuH<sub>2</sub>(CO)(PPh<sub>3</sub>)<sub>3</sub>] via Decarbonylation of Methyl Benzoates: X-Ray Crystal Structures of [Ru(CO)<sub>2</sub>(PPh<sub>3</sub>)<sub>3</sub>] and [Ru(O<sub>2</sub>)(CO)<sub>2</sub>(PPh<sub>3</sub>)<sub>2</sub>]
作者:Katsuma Hiraki、Shu-ichi Kira、Hiroyuki Kawano
DOI:10.1246/bcsj.70.1583
日期:1997.7
Dihydridoruthenium(II) complex [RuH2(CO)(PPh3)3] (1) reacts with methyl benzoate in the presence of an olefin at 110 °C to afford some dicarbonylruthenium(O) species [Ru(CO)2(PPh3)3] (2) and “Ru(CO)2(PPh3)2L” (L = the olefin or the ester). A tricarbonylruthenium(O) complex [Ru(CO)3(PPh3)2] (3) is formed at higher reaction temperature. The experiment using 13C-enriched methyl benzoate reveals that the
二氢化钌 (II) 络合物 [RuH2(CO)(PPh3)3] (1) 在烯烃存在下于 110 °C 与苯甲酸甲酯反应,得到一些二羰基钌 (O) 物种 [Ru(CO)2(PPh3)3 ] (2) 和“Ru(CO)2(PPh3)2L”(L = 烯烃或酯)。三羰基钌(O)配合物[Ru(CO)3(PPh3)2](3)在较高反应温度下形成。使用富含 13C 的苯甲酸甲酯的实验表明,第二个和第三个羰基配体主要是通过从酯中减去羰基而衍生的。当反应在三乙氧基乙烯基硅烷存在下进行时,部分第二和第三羰基衍生自硅烷的乙氧基,因为 1 在没有酯的情况下在 110 °C 与硅烷反应得到2和3。2和3的形成比例受所用烯烃类型的影响;
Experimental and Theoretical Studies on Gas-Phase Fragmentation Reactions of Protonated Methyl Benzoate: Concomitant Neutral Eliminations of Benzene, Carbon Dioxide, and Methanol
作者:Hanxue Xia、Yong Zhang、Athula B. Attygalle
DOI:10.1007/s13361-018-1997-8
日期:2018.8.1
a methanol molecule after a protonation on the methoxy group. The incipient proton migrates to the ring and randomizes to a certain degree before a subsequent transfer of one of the ring protons to the alkoxy group for the concomitant methanol elimination. The spectrum recorded from deuteronated methyl benzoate showed two peaks at m/z 105 and 106 for the benzoyl cation at a ratio of 2:1, confirming
活化后,质子化的苯甲酸甲酯通过三个不同的途径断裂。对通过氦等离子体电离(HePI)生成的质子化物质的m / z 137离子进行了质量选择,并进行了碰撞活化。在一个断裂途径中,质子化的分子通过消除苯分子产生了m / z 59的产物离子(途径I)。该M / Z以这种方式产生的59离子(通常被认为是甲氧羰基阳离子),然后通过脱羧原位形成甲基碳正离子,然后通过分子过程在苯环上引发亲电芳族加成反应,生成甲苯阳离子(途径II)。此外,质子化的苯甲酸甲酯也经历甲醇损失(途径III)。然而,在甲氧基上质子化之后,不是简单地除去甲醇分子。初始质子迁移至环并随机化至一定程度,然后环质子之一随后转移至烷氧基以伴随甲醇消除。氘化苯甲酸甲酯记录的光谱在m / z处显示两个峰苯甲酰基阳离子的比率为105和106,比率为2:1,这证明赋予电荷的质子是可移动的。然而,在达到完全加扰状态之前,发生了从苯中间体中间质子转移至甲氧基的甲醇损失。
Isomerization of Trimethyl α-Keto Trithioorthocarboxylates into α,α-Bis(methylthio) Thiolcarboxylates. A New Rearrangement of Synthetic Interest
A study was made of the isomerization reaction of a great variety of trimethyl alpha-keto trithioorthocarboxylates to alpha,alpha-bis(methylthio) thiolcarboxylates, intermediates of high synthetic value for the synthesis of alpha-arylpropionic acids. The reaction was carried out In methylene chloride in the presence of catalytic amounts of trityl perchlorate or methanesulfonic acid and was complete in 2 h at rt. In most of the investigated cases the result was positive, the yields usually being greater than 90%. Also the reaction mechanism was subjected to an experimental study.
Porphyrin Dimer Carbocations with Strong Near Infrared Absorption and Third-Order Optical Nonlinearity
作者:Karl J. Thorley、Joel M. Hales、Harry L. Anderson、Joseph W. Perry
DOI:10.1002/anie.200802687
日期:2008.9.1
Studies in negative ion mass spectrometry: XIV—Electron attachment reactions of a series of η6-arenetricarbonylchromium(O) complexes
作者:M. R. Blake、J. L. Garnett、I. K. Gregor、S. B. Wild
DOI:10.1002/oms.1210150711
日期:1980.7
AbstractElectron attachment reactions of a series of (η6‐arene)tricarbonylchromium(O) complexes have been examined in the gas phase. The electron capture process has been shown to be influenced by the structure of the η6‐arene ligand and its substituents. Whereas (η6‐benzene)‐ and (η6‐mesitylene)tricarbonylchromium(O) undergo dissocative electron capture, or reductive decarbonylation, yielding [MCO]−˙ ions of highest abundance in their negative ion mass spectra, [η6‐(2,2‐dimethylindan‐1,3‐dione)]tricarbonylchromium(O) forms a molecular negative ion which undergoes sequential CO eliminations and finally a demetallation to give the arene radical ion. A localization of charge on the coordinated arene ligand is proposed for the formation of [M]−˙ in this case. (η6‐Methylbenzoate)tricarbonylchromium(O) also forms a molecular negative ion by secondary electron attachment which decomposes by simultaneous and consecutive eliminations of up to four CO molecules. The elucidation of a mechanism and sequence for these CO eliminations has been achieved by synthesizing and examining the negative ion mass spectrum of [η6‐(C6H5·13CO2Me)]Cr(CO)3. The first CO loss in the principal fragmentation pathway occurs solely from the –Cr(CO)3 group of [M]−˙. The effect of para substituent groups on the stabilities of molecular negative ions and their fragmentations has been ascertained using a series of para‐substituted (η6‐methylbenzoate)tricarbonylchromium(O) compounds containing the groups NH2, OH, OCH3, CL and COOMe. The stabilities of the [M]−˙ ions have been rationalized in terms of the Hammett and Taft parameters σP, σI, σRP, σPO and σRO. The overall electronic substituent effect transmitted to the carbonyl groups of the –Cr(CO)3 unit involves both resonance and inductive components. In this series of compounds the stability of [M]−˙ decreases as the electron withdrawing capacities of the para substituents increase.