Ropp Anthony, André Rémi F, Carenco Sophie
Sorbonne Université, CNRS, Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), 4 place Jussieu, 75005, Paris, France.
Chempluschem. 2023 Nov;88(11):e202300469. doi: 10.1002/cplu.202300469. Epub 2023 Oct 5.
Transition metal phosphides are promising, selective, and air-stable nanocatalysts for hydrogenation reactions. However, they often require fairly high temperatures and H pressures to provide quantitative conversions. This work reports the positive effect of phosphine additives on the activity of cobalt phosphide nano-urchins for the semi-hydrogenation of phenylacetylene. While the nanocatalyst's activity was low under mild conditions (7 bar of H , 100 °C), the addition of a catalytic amount of phosphine remarkably increased the conversion, e. g., from 13 % to 98 % in the case of P Bu . The heterogeneous nature of the catalyst was confirmed by negative supernatant activity tests. The catalyst integrity was carefully verified by post-mortem analyses (TEM, XPS, and liquid P NMR). A stereo-electronic map was proposed to rationalize the activity enhancement provided over a selection of nine phosphines: the strongest effect was observed for low to moderately hindered phosphines, associated with strong electron donor abilities. A threshold in phosphine stoichiometry was revealed for the enhancement of activity to occur, which was related to the ratio of phosphine to surface cobalt atoms.
过渡金属磷化物是用于氢化反应的有前景、具有选择性且对空气稳定的纳米催化剂。然而，它们通常需要相当高的温度和氢气压力才能实现定量转化。这项工作报道了膦添加剂对磷化钴纳米海胆用于苯乙炔半氢化反应活性的积极影响。虽然在温和条件下（7巴氢气，100°C）纳米催化剂的活性较低，但添加催化量的膦显著提高了转化率，例如，对于三丁基膦，转化率从13%提高到了98%。通过阴性上清液活性测试证实了催化剂的多相性质。通过事后分析（透射电子显微镜、X射线光电子能谱和液体³¹P核磁共振）仔细验证了催化剂的完整性。提出了一个立体电子图，以合理化在九种膦的选择中活性增强的原因：对于低至中度受阻的膦观察到最强的效果，这与强电子供体能力有关。揭示了膦化学计量比的一个阈值，以实现活性增强，这与膦与表面钴原子的比例有关。
