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首页> 外文期刊>Chemistry: A European journal >Reactivity of rhodium-triflate complexes with diphenylsilane: Evidence for silylene intermediacy in stoichiometric and catalytic reactions
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Reactivity of rhodium-triflate complexes with diphenylsilane: Evidence for silylene intermediacy in stoichiometric and catalytic reactions

机译：三氟甲基磺酸铑配合物与二苯基硅烷的反应性：化学计量和催化反应中甲硅烷基中间体的证据

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Addition of Ph2SiH2 to [Rh(iPr(3)P)(2)(OTf)] (1) yielded the thermally unstable Rh-III adduct [Rh(iPr(3)P)(2)-(OTf)(H)(SiPh2H)] (2), which decomposed to [Rh(iPr(3)P)(2)(H)(2)(OTf)] (3), liberating (unobserved) silylene. The silylene was trapped by 1, resulting in the Rh-I-silyl complex [Rh(iPr(3)P)(2)-(SiPh2OTf)]. Complex 3 was converted to 2 by addition of diphenylsilane, providing a basis for a possible catalytic cycle. The last reaction did not involve a Rh-I intermediate, as shown by a labeling study. Complex 1 catalyzed the dehydrogenative coupling of Ph2SiH2 to Ph2HSi-SiHPh2. A mechanism involving a silylene intermediate in this catalytic cycle is proposed. The mechanism is supported by complete lack of catalysis in the case of the tertiary silanes Ph2MeSiH and PhMe2SiH, and by a study of individual steps of the catalytic cycle. The outcome of the reaction of Ph2SiH2 with styrene in the presence of 1 depends on the complex/substrate ratio; under stoichiometric conditions olefin hydrogenation prevailed over hydrosilylation, whereas with excess of substrates hydrosilylation prevailed. Catalytic hydrosilylation resulted in double addition giving Ph2Si(CH2CH2Ph)(2). Mechanistic aspects of the reported processes are discussed, and a new hydrosilylation mechanism based on silylene intermediacy is proposed.
机译：在[Rh（iPr（3）P）（2）（OTf）]（1）中添加Ph2SiH2产生热不稳定的Rh-III加合物[Rh（iPr（3）P）（2）-（OTf）（H） （SiPh2H）]（2）分解为[Rh（iPr（3）P）（2）（H）（2）（OTf）]（3），从而释放（未观察到）亚甲硅烷基。甲硅烷基被1捕获，生成Rh-I-甲硅烷基络合物[Rh（iPr（3）P）（2）-（SiPh2OTf）]。通过加入二苯基硅烷将络合物3转化为2，为可能的催化循环提供了基础。如标记研究所示，最后的反应不涉及Rh-1中间体。配合物1催化了Ph2SiH2与Ph2HSi-SiHPh2的脱氢偶联。提出了在该催化循环中涉及甲硅烷基中间体的机理。在叔硅烷Ph2MeSiH和PhMe2SiH的情况下，完全缺乏催化作用以及对催化循环各个步骤的研究为该机理提供了支持。在1存在下，Ph2SiH2与苯乙烯反应的结果取决于配合物/底物比;在化学计量条件下，烯烃氢化胜于氢化硅烷化，而底物过量则氢化硅烷化占优势。催化氢化硅烷化导致两次加成，得到Ph2Si（CH2CH2Ph）（2）。讨论了所报道方法的机理，并提出了一种新的基于甲硅烷基中间体的氢化硅烷化机理。

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