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研究了溶剂分别为THF,H2O/THF,CH3CN/THF以及ROH/THF(R=Me,Et,iso-Pr,tert-Bu)条件下TpRuH(PPh3)-(CH3CN)[Tp=hydrotris(pyrazolyl)borate]催化氢化苯乙烯生成乙基苯的反应,发现向干燥THF体系中添加微量H2O,CH3CN或ROH对催化反应都具有显著的促进作用.催化机理研究表明,小分子添加物首先取代TpRuH(PPh3)(CH3CN)中的PPh3配体形成中间体TpRuH(CH3CN)L(L=H2O,CH3CN或ROH),降低空间位阻,CH3CN配体随后被苯乙烯取代生成中间体TpRuH(H2C=CHPh)L;η2-苯乙烯插入Ru—H键后形成的Ru-烷基中间物与H2反应生成η2-H2配合物TpRu(CH2CH2Ph)(H2)L或TpRu[CH(CH3)Ph](H2)L,进而发生σ-复分解反应生成乙基苯完成催化循环.
The effects of TpRuH (PPh3) - (CH3CN) [Tp = hydrotris (pyrazolyl)] on the conditions of THF, H2O / THF, CH3CN / THF and ROH / THF with R = Me, Et, borate] catalyzed hydrogenation of styrene to ethylbenzene and found that the addition of trace amounts of H2O, CH3CN or ROH to the dry THF system significantly promoted the catalytic reaction.Research on the catalytic mechanism showed that the small molecule additive firstly replaced TpRuH (PPh3 (CH3CN) (L = H2O, CH3CN or ROH) to reduce the steric hindrance. The CH3CN ligand is subsequently substituted with styrene to form the intermediate TpRuH (H2C = CHPh) L ; η-2-styrene intercalation Ru-H bond formed Ru-alkyl intermediate and H2 reaction η2-H2 complex TpRu (CH2CH2Ph) (H2) L or TpRu [CH (CH3) Ph] And then occur σ-metathesis reaction of ethylbenzene to complete the catalytic cycle.