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首页> 外文期刊>Catalysis science & technology >H/D exchange in N-heterocycles catalysed by an NHC-supported ruthenium complex
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H/D exchange in N-heterocycles catalysed by an NHC-supported ruthenium complex

机译：H / D交易所N-heterocycles促成的NHC-supported钌复杂

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摘要

NHC-supported trihydrides Cp(NHC)RuH3 show excellent catalytic activity in the H/D exchange of pyridine and some other N-heterocycles under mild conditions and low catalyst loading. Of the catalysts screened, Cp(IMes)RuH3 showed the highest activity. H/D exchange in other aromatic systems also occurs with good to excellent conversions, whereas aliphatic, olefinic and acetylenic positions are much less active. This result is complementary to the significant aliphatic H/D exchange mediated by the related complex Cp((Pr3P)-Pr-i)RuH3 (1). Mechanistic studies, supported by DFT calculations, suggest that the reaction proceeds via elimination of dihydrogen from Cp(NHC)RuH3 to give the monohydride Cp(NHC)RuH amenable to oxidative addition of C-H for aromatic (benzene and pyridine) and aliphatic (methane and ethane) substrates. Different reaction paths were revealed: a two-step route with an intermediate, a single step with a pre-reactive complex, and a reaction path branching with a bifurcation point. For pyridine, DFT calculations show that the catalyst off-loop state Cp(L)RuH(py) is less stable relative to Cp(L)RuH in the case of L = NHC than for L = (Pr3P)-Pr-i, Delta(r)G(50 degrees C) = 2.6 kcal mol(-1)vs. -9.41 kcal mol(-1), respectively, which may account for the difference in reactivity of these two catalytic systems. The DFT results for the B3LYP, M06L, and SCAN functionals were benchmarked against each other and the DLPNO-CCSD(T) and DLPNO-MP2 data and discussed with respect to the determined catalytic activity and the catalyst inhibition.
机译：NHC-supported trihydrides Cp (NHC) RuH3显示优秀的催化活性的H / D交换吡啶和一些其他N-heterocycles下轻微的加载条件和较低的催化剂。催化剂的筛选,Cp (ime) RuH3显示最高的活动。系统也会发生好优秀转换,而脂肪族、烯和乙炔的位置不太活跃。结果是重要的补充脂肪族H / D交换由相关复杂的Cp ((Pr3P) -Pr-i) RuH3(1)机械研究,由DFT计算,建议通过消除反应所得从二氢Cp (NHC) RuH3给monohydride Cp (NHC) RuH适合氧化除了对芳烃(苯和碳氢键吡啶)和脂肪族(甲烷和乙烷)基板。透露:一个中间的两步路线,一个单步pre-reactive复杂,反应路径分支与分支点。表明,吡啶,DFT计算催化剂off-loop状态Cp (L) RuH (py)更少相对稳定的Cp (L) RuH L =美国小妞NHC煤L = (Pr3P) -Pr-i, d组(r) G (50度)= 2.6千卡摩尔(1)vs。摩尔(1),分别,这也许可以解释区别这两个催化的反应系统。对每个基准测试扫描其他和DLPNO-CCSD (T)和DLPNO-MP2数据并讨论了关于确定催化活性和抑制催化剂。

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