Department of Chemistry, Stanford University , Stanford, California 94305, United States.
J Am Chem Soc. 2017 Jan 18;139(2):738-748. doi: 10.1021/jacs.6b09705. Epub 2017 Jan 4.
Octahedral ruthenium complexes [RuX(CNN)(dppb)] (1, X = Cl; 2, X = H; CNN = 2-aminomethyl-6-tolylpyridine, dppb = 1,4-bis(diphenylphosphino)butane) are highly active for the transfer hydrogenation of ketones with isopropanol under ambient conditions. Turnover frequencies of 0.88 and 0.89 s are achieved at 25 °C using 0.1 mol % of 1 or 2, respectively, in the presence of 20 equiv of potassium t-butoxide relative to catalyst. Electrochemical studies reveal that the Ru-hydride 2 is oxidized at low potential (-0.80 V versus ferrocene/ferrocenium, Fc) via a chemically irreversible process with concomitant formation of dihydrogen. Complexes 1 and 2 are active for the electrooxidation of isopropanol in the presence of strong base (potassium t-butoxide) with an onset potential near -1 V versus Fc. By cyclic voltammetry, fast turnover frequencies of 3.2 and 4.8 s for isopropanol oxidation are achieved with 1 and 2, respectively. Controlled potential electrolysis studies confirm that the product of isopropanol electrooxidation is acetone, generated with a Faradaic efficiency of 94 ± 5%.
八面体钌配合物[RuX(CNN)(dppb)]（1，X = Cl；2，X = H；CNN = 2-氨甲基-6-甲苯吡啶，dppb = 1,4-双（二苯基膦）丁烷）在环境条件下对酮与异丙醇的转移氢化具有很高的活性。在 25°C 下，使用 0.1 mol%的 1 或 2，相对于催化剂，在 20 当量的叔丁醇钾存在下，分别实现了 0.88 和 0.89 s 的转化频率。电化学研究表明，Ru-氢化物 2 通过化学不可逆过程在低电位（相对于 ferrocene/ferrocenium，Fc 为-0.80 V）被氧化，并伴随着氢气的形成。配合物 1 和 2 在强碱（叔丁醇钾）存在下对异丙醇的电氧化具有活性，起始电位接近 Fc 的-1 V。通过循环伏安法，分别用 1 和 2 实现了 3.2 和 4.8 s 的异丙醇氧化的快速转化频率。恒电位电解研究证实异丙醇电氧化的产物是丙酮，法拉第效率为 94±5%。
