Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA). CSIC and Universidad de Sevilla. Avda. Américo Vespucio 49, 41092, Sevilla, Spain.
Dalton Trans. 2018 Nov 27;47(46):16766-16776. doi: 10.1039/c8dt03951h.
Iridium complexes based on deprotonated lutidine-derived CNP* pincers 2a/2b selectively catalyzed the hydroboration of CO2 under mild conditions (1-2 bar CO2, 30 °C) to methoxyborane using HBcat (TOF up to 56 h-1) and to the formate level with HBpin (TOF up to 1245 h-1). Interestingly, an intriguing, positive water effect on the reaction rates has been observed. NMR spectroscopy and ESI-MS analysis of the hydroboration reactions have shown the formation of ligand-protonated [Ir(CNP)(CO)(BR2)H][B(R2)2] (R2 = catecholate, pinacolate) derivatives under catalytic conditions. Control experiments, however, have demonstrated that these derivatives are not catalytically competent species in the hydroboration of CO2.
基于去质子化的六氢吡啶衍生的 CNP*夹钳 2a/2b 的铱配合物在温和条件下（1-2 巴 CO2，30°C）下选择性地催化 CO2 的硼氢化反应，使用 HBcat（TOF 高达 56 h-1）生成甲氧基硼烷，使用 HBpin（TOF 高达 1245 h-1）生成甲酸盐。有趣的是，观察到反应速率对水有明显的正效应。硼氢化反应的 NMR 光谱和 ESI-MS 分析表明，在催化条件下形成配体质子化的[Ir(CNP)(CO)(BR2)H][B(R2)2]（R2 = 儿茶酚，频哪醇）衍生物。然而，对照实验表明，这些衍生物不是 CO2 硼氢化反应中的催化活性物种。
