Bolaño Tamara, Castarlenas Ricardo, Esteruelas Miguel A, Oñate Enrique
Departamento de Química InorgAnica, Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain.
J Am Chem Soc. 2007 Jul 18;129(28):8850-9. doi: 10.1021/ja071972a. Epub 2007 Jun 20.
Complex [OsH(=C=C=CPh2)(CH3CN)2(PiPr3)2]BF4 (1) reacts with primary and secondary alcohols to give the corresponding dehydrogenated alcohols and the hydride-carbene derivative [OsH(=CHCH=CPh2)(CH3CN)2(PiPr3)2]BF4 (2), as a result of hydrogen transfer reactions from the alcohols to the Calpha-Cbeta double bond of the allenylidene ligand of 1. The reactions with phenol and t-butanol, which do not contain any beta-hydrogen, afford the alkoxy-hydride-carbyne complexes [OsH(OR)(CCH=CPh2)(CH3CN)(PiPr3)2]BF4 (R = Ph (3), tBu (4)), as a consequence of the 1,3-addition of the O-H bond of the alcohols to the metallic center and the Cbeta atom of the allenylidene of 1. On the basis of the reactions of 1 with these tertiary alcohols, deuterium labeling experiments, and DFT calculations, the mechanism of the hydrogenation is proposed. In acetonitrile under reflux, the Os-C double bond of 2 undergoes hydrogenation to give 1,1-diphenylpropene and [Os{CH2CH(CH3)PiPr2(CH3CN)3(PiPr3)]BF4 (11), containing a metalated phosphine ligand. This reaction is a first-order process with activation parameters of DeltaH = 89.0 +/- 6.3 kJ mol-1 and DeltaS = -43.5 +/- 9.6 J mol-1 K-1. The X-ray structures of 2 and 3 are also reported.
配合物[OsH(=C=C=CPh2)(CH3CN)2(PiPr3)2]BF4（1）与伯醇和仲醇反应，生成相应的脱氢醇以及氢化物-卡宾衍生物[OsH(=CHCH=CPh2)(CH3CN)2(PiPr3)2]BF4（2），这是由于醇中的氢原子转移至1的亚丙二烯基配体的α-碳-β-碳双键上。与不含β-氢的苯酚和叔丁醇反应，会生成烷氧基-氢化物-卡宾配合物[OsH(OR)(CCH=CPh2)(CH3CN)(PiPr3)2]BF4（R = Ph（3），tBu（4）），这是因为醇的O-H键对金属中心以及1的亚丙二烯基的β-碳原子进行了1,3-加成。基于1与这些叔醇的反应、氘标记实验以及密度泛函理论计算，提出了氢化反应的机理。在乙腈中回流时，2的Os-C双键发生氢化反应，生成1,1-二苯基丙烯和[Os{CH2CH(CH3)PiPr2(CH3CN)3(PiPr3)]BF4（11），后者含有一个金属化的膦配体。该反应是一级反应，活化参数为ΔH = 89.0 ± 6.3 kJ mol-1和ΔS = -43.5 ± 9.6 J mol-1 K-1。还报道了2和3的X射线结构。
