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首页> 外文期刊>Chemistry: A European journal >ESIMS Studies and Calculations on Alkali-Metal Adduct Ions of RutheniumOlefin Metathesis Catalysts and Their Catalytic Activity in MetathesisReactions
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ESIMS Studies and Calculations on Alkali-Metal Adduct Ions of RutheniumOlefin Metathesis Catalysts and Their Catalytic Activity in MetathesisReactions

机译：钌-烯烃复分解催化剂的碱金属加合离子的ESIMS研究与计算及其在复分解反应中的催化活性

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摘要

Electrospray ionization massspectrometry (ESIMS) and subsequenttandem mass spectrometry (MS/MS)analyses were used to study some im-portant metathesis reactions with thefirst-generation ruthenium catalyst 1,focusing on the ruthenium complex in-termediates in the catalytic cycle. Insitu cationization with alkali cations(Li~+, Na~+, K~+, and Cs~+) using a mi-croreactor coupled directly to the ESIion source allowed mass spectrometricdetection and characterization of theruthenium species present in solutionand particularly the catalytically activemonophosphine–ruthenium intermedi-ates present in equilibrium with the re-spective bisphosphine–ruthenium spe-cies in solution. Moreover, the intrinsiccatalytic activity of the cationizedmonophosphine–ruthenium complex1a?K~+was directly demonstrated bygas-phase reactions with 1-butene orethene to give the propylidene Ru spe-cies 3 a.K ~+ and the methylidene Ru species 4a?K~+,respectively. Ring-clos-ing metathesis (RCM) reactions of 1,6-heptadiene (5), 1,7-octadiene (6) and1,8-nonadiene (7) were studied in thepresence of KCl and the ruthenium al-kylidene intermediates 8, 9, and 10, re-spectively, were detected as cationizedmonophosphine and bisphosphineruthenium complexes. Acyclic dienemetathesis (ADMET) polymerizationof 1,9-decadiene (14) and ring-openingmetathesis polymerization (ROMP) ofcyclooctene (18) were studied ana-logously, and the expected rutheniumalkylidene intermediates were directlyintercepted from reaction solution andcharacterized unambiguously by theirisotopic patterns and ESIMS/MS.ADMET polymerization was not ob-served for 1,5-hexadiene (22), but the formation of the intramolecularly stabi-lized monophosphine ruthenium com-plex 23a was seen. The ratio of thesignal intensities of the respective withpotassium cationized monophosphineand bisphosphine alkylidene Ru spe-cies varied from [I_(4a)]/[I_4]=0.02 to[I_(23a)]/[I_(23)]=10.2 and proved to be a sen-sitive and quantitative probe for intra-molecular π-complex formation of themonophosphine–ruthenium species andof double bonds in the alkylidenechain. MS/MS spectra revealed the in-trinsic metathesis catalytic activity ofthe potassium adduct ions of the ruthe-nium alkylidene intermediates 8a, 9a,10 a,15 a, and 19 a, but not 23 a by elim-ination of the respective cycloalkene inthe second step of RCM. Computationswere performed to provide informationabout the structures of the alkali metaladduct ions of catalyst 1 and the influ-ence of the alkali metal ions on theenergy profile in the catalytic cycle ofthe metathesis reaction.
机译：电喷雾电离质谱（ESIMS）和随后的串联质谱（MS / MS）分析用于研究第一代钌催化剂1的重要复分解反应，重点是催化循环中的钌络合物。使用直接耦合到ESIion离子源的微型反应器，使用碱阳离子（Li〜+，Na〜+，K〜+和Cs〜+）进行原位阳离子化，可以质谱检测和表征溶液中存在的钌，特别是催化活性的单膦钌中间体与溶液中相应的双膦-钌比平衡存在。此外，阳离子化的单膦-钌配合物1a？K〜+的内在催化活性已通过与1-丁烯或异戊烯的气相反应直接证明，得到了亚丙基Ru物种3 aK〜+和亚甲基Ru物种4a？K〜+，分别。在氯化钾和钌炔基中间体8的存在下，研究了1,6-庚二烯（5），1,7-辛二烯（6）和1,8-壬二烯（7）的开环易位（RCM）反应。分别检测到9、9和10为阳离子化的单膦和双膦钌络合物。对1,9-癸二烯的无环二烯复分解反应（ADMET）（14）和环辛烯的开环复分解聚合反应（ROMP）（18）进行了模拟研究，直接从反应溶液中截取了预期的亚烷基钌中间体，并通过同位素模式和ESIMS /方法对其进行了明确表征。对于1，5-己二烯（22）未观察到MS.ADMET聚合，但是观察到分子内稳定化的单膦钌络合物23a的形成。钾阳离子化的单膦和双膦亚烷基Ru的信号强度比从[I_（4a）] / [I_4] = 0.02变为[I_（23a）] / [I_（23）] = 10.2，证明为是灵敏和定量的探针，用于单膦-钌分子和亚烷基链中双键的分子内π复合物形成。 MS / MS谱图显示了钌烯化亚烷基中间体8a，9a，10a，15a和19a的钾加合离子的内在易位催化活性，但通过在其中环环化了23a则没有。 RCM的第二步。进行了计算以提供关于催化剂1的碱金属加合物离子的结构以及在复分解反应的催化循环中碱金属离子对能量分布的影响的信息。

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