Can Contemporary Density Functional Theory Predict Energy Spans in Molecular Catalysis Accurately Enough To Be Applicable for in Silico Catalyst Design? A Computational/Experimental Case Study for the Ruthenium-Catalyzed Hydrogenation of Olefins
Can Contemporary Density Functional Theory Predict Energy Spans in Molecular Catalysis Accurately Enough To Be Applicable for in Silico Catalyst Design? A Computational/Experimental Case Study for the Ruthenium-Catalyzed Hydrogenation of Olefins
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DOI：
10.1021/jacs.5b11997
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发表时间：
2016-01-13
影响因子：
15
通讯作者：
Leitner, Walter
中科院分区：
文献类型：
--
作者：
Rohmann, Kai;Hoelscher, Markus;Leitner, Walter
采用实验和密度泛函理论（DFT）方法研究了新型钌Xantphos（Ph）催化剂对环己烯和1-甲基环己烯的催化加氢反应（4，5-双（二苯基膦基）-9，9-二甲基氧杂蒽）和Xantphos（Cy）（4，5-双-（二环己基膦基）-9，9-二甲基氧杂蒽）预催化剂[Ru（Xantphos Ph）（PhCO_2）（Cl）]（1）和[Ru（Xantphos（Cy））-（PhCO_2）（Cl）]（2）的合成、表征和晶体结构。这项工作的目的是（i）了解微观水平上的反应机制和（ii）比较实验观察到的活化势垒与计算的势垒。吉布斯自由活化能Delta G用预催化剂1从环己烯加氢的Eyring图实验获得了（双匕首）（Δ G（双匕首）= 17.2 + 1.0 kcal/ mol）和1-甲基环己烯（Δ G（双刃）= 18.8 +/- 2.4 kcal/mol），而用预催化剂2氢化环己烯的吉布斯自由活化能Δ G（双匕首）测定为21.1 +/-2.3kcal/mol。在气相（M06-L/def 2-SVP）中计算了合理的活化途径和催化循环。使用各种流行的密度泛函（omega 397 X-D、LC-omega PBE、CAM-B3 LYP、B3 LYP、B 97-D3 BJ、B3 LYP-D3、BP 86-D3、PBEO-D3、M06-L、MN 12-L）来重新优化溶剂相中的转换决定状态（DF/def 2-TZVP：IEF-PCM和/或SMD），以研究实验获得的活化势垒如何通过计算再现。计算了B 97-D3 BJ，MN 12-L，M06-L，B3 LYPD 3，和CAM-B3 LYP再现了实验观察到的两种烯烃的活化势垒非常好，（0.1 kcal/mol）至中度（3.0千卡/摩尔）与实验值的平均偏差表明，对于氢化催化领域，这些官能团中的大多数可用于实验之前的计算机催化剂设计。工作
The catalytic hydrogenation of cyclohexene and 1-methylcydohexene is investigated experimentally and by means of density functional theory (DFT) computations using novel ruthenium Xantphos(Ph) (4,5-bis(diphenylphosphino)-9,9-dimethylxanthene) and Xantphos(Cy) (4,5-bis-(dicydohexylphosphino)-9,9-dimethylxanthene) precatalysts [Ru(XantphosPh)(PhCO2)(Cl)] (1) and [Ru(Xantphos(Cy))-(PhCO2)(Cl)] (2), the synthesis, characterization, and crystal structures of which are reported. The intention of this work is to (i) understand the reaction mechanisms on the microscopic level and (ii) compare experimentally observed activation barriers with computed barriers. The Gibbs free activation energy Delta G(double dagger) was obtained experimentally with precatalyst 1 from Eyring plots for the hydrogenation of cydohexene (Delta G(double dagger) = 17.2 + 1.0 kcal/ mol) and 1-methylcydohexene (Delta G(double dagger) = 18.8 +/- 2.4 kcal/mol), while the Gibbs free activation energy Delta G(double dagger) for the hydrogenation of cyclohexene with precatalyst 2 was determined to be 21.1 +/- 2.3 kcal/mol. Plausible activation pathways and catalytic cycles were computed in the gas phase (M06-L/def2-SVP). A variety of popular density functionals (omega 397X-D, LC-omega PBE, CAM-B3LYP, B3LYP, B97-D3BJ, B3LYP-D3, BP86-D3, PBEO-D3, M06-L, MN12-L) were used to reoptimize the turnover determining states in the solvent phase (DF/def2-TZVP: IEF-PCM and/or SMD) to investigate how well the experimentally obtained activation barriers can be reproduced by the calculations. The density functionals B97-D3BJ, MN12-L, M06-L, B3LYPD3, and CAM-B3LYP reproduce the experimentally observed activation barriers for both olefins very well with very small (0.1 kcal/mol) to moderate (3.0 kcal/mol) mean deviations from the experimental values indicating for the field of hydrogenation catalysis most of these functionals to be useful for in silico catalyst design prior to experimental work.