Catalytic hydration of cyanamides with phosphinous acid-based ruthenium(<scp>ii</scp>) and osmium(<scp>ii</scp>) complexes: scope and mechanistic insights
作者:Rebeca González-Fernández、Daniel Álvarez、Pascale Crochet、Victorio Cadierno、M. Isabel Menéndez、Ramón López
DOI:10.1039/d0cy00523a
日期:——
phosphinous acid-based complexes [MCl2(η6-p-cymene)(PMe2OH)] (M = Ru (1), Os (2)) as catalysts. The reactions proceeded cleanly under mild conditions (40–70 °C), in the absence of any additive, employing low metal loadings (1 mol%) and water as the sole solvent. In almost all the cases, the osmium complex 2 featured a superior reactivity in comparison to that of its ruthenium counterpart 1. In addition
通过使用水合相应的氰胺R 1 R 2 NC N成功地完成了多种脲R 1 R 2 NC(O)NH 2的合成(R 1和R 2 =烷基,芳基或H; 26个实例)的三价膦酸基配合物[的MC1 2(η 6 - p -cymene)(PME 2 OH)](M =茹(1),锇(2))作为催化剂。反应在温和的条件下(40-70°C)干净进行,没有任何添加剂,使用低金属负载量(1 mol%)和水作为唯一溶剂。在几乎所有情况下,complex配合物2的反应活性都比钌配合物1高。另外,对于两种催化剂,氰酰胺底物水合所观察到的反应速率明显快于涉及传统脂族和芳族腈的反应速率。计算研究使我们能够合理化所有这些趋势。因此,计算表明存在直接与碳原子相连的氮原子当与金属中心配位时,N键通过感应效应使腈碳电子减少,从而促进次膦酸配体的OH基团对该碳的分子内亲核攻击。另一方面,Os对Ru的较高反应性似乎与初始金属环上较低的环应