Dunne John P, Blazina Damir, Aiken Stuart, Carteret Hilary A, Duckett Simon B, Jones Jonathan A, Poli Rinaldo, Whitwood Adrian C
Department of Chemistry, University of York, UK.
Dalton Trans. 2004 Nov 7(21):3616-28. doi: 10.1039/B410912K. Epub 2004 Sep 16.
The photochemical reaction of Ru(CO)(3)(L)(2), where L = PPh(3), PMe(3), PCy(3) and P(p-tolyl)(3) with parahydrogen (p-H(2)) has been studied by in-situ NMR spectroscopy and shown to result in two competing processes. The first of these involves loss of CO and results in the formation of the cis-cis-trans-L isomer of Ru(CO)(2)(L)(2)(H)(2), while in the second, a single photon induces loss of both CO and L and leads to the formation of cis-cis-cis Ru(CO)(2)(L)(2)(H)(2) and Ru(CO)(2)(L)(solvent)(H)(2) where solvent = toluene, THF and pyridine (py). In the case of L = PPh(3), cis-cis-trans-L Ru(CO)(2)(L)(2)(H)(2) is shown to be an effective hydrogenation catalyst with rate limiting phosphine dissociation proceeding at a rate of 2.2 s(-1) in pyridine at 355 K. Theoretical calculations and experimental observations show that H(2) addition to the Ru(CO)(2)(L)(2) proceeds to form cis-cis-trans-L Ru(CO)(2)(L)(2)(H)(2) as the major product via addition over the pi-accepting OC-Ru-CO axis.
对Ru(CO)(3)(L)(2)（其中L = PPh(3)、PMe(3)、PCy(3)和P(p - 甲苯基)(3)）与仲氢（p - H(2)）的光化学反应进行了原位核磁共振光谱研究，结果表明存在两个相互竞争的过程。其中第一个过程涉及CO的损失，导致形成Ru(CO)(2)(L)(2)(H)(2)的顺 - 顺 - 反 - L异构体，而在第二个过程中，单个光子会诱导CO和L同时损失，从而导致形成顺 - 顺 - 顺Ru(CO)(2)(L)(2)(H)(2)以及Ru(CO)(2)(L)(溶剂)(H)(2)，其中溶剂 = 甲苯、四氢呋喃和吡啶（py）。在L = PPh(3)的情况下，顺 - 顺 - 反 - L Ru(CO)(2)(L)(2)(H)(2)被证明是一种有效的氢化催化剂，在355 K的吡啶中，限速膦解离的速率为2.2 s(-1)。理论计算和实验观察表明，H(2)加成到Ru(CO)(2)(L)(2)上主要通过在π - 接受的OC - Ru - CO轴上加成形成顺 - 顺 - 反 - L Ru(CO)(2)(L)(2)(H)(2)。
