PNN Ruthenium Pincer Complexes Based on Phosphinated 2,2′-Dipyridinemethane and 2,2′-Oxobispyridine. Metal–Ligand Cooperation in Cyclometalation and Catalysis
作者:Rigoberto Barrios-Francisco、Ekambaram Balaraman、Yael Diskin-Posner、Gregory Leitus、Linda J. W. Shimon、David Milstein
DOI:10.1021/om400194w
日期:2013.5.24
however it was possible to isolate and characterize a stable dicarbonyl-dearomatized ruthenium(II) complex, 9c, when the deprotonation was performed under a CO atmosphere. Dearomatization of 6a under CO also led to dicarbonyl-dearomatized ruthenium(II) complex 9a, which slowly rearranged into the dicarbonyl-aromatized ruthenium(0) complex 10a. These complexes were tested in catalytic alcohol–amine coupling
描述了基于2,2'-二吡啶甲烷膦衍生物和2,2'-氧代双吡啶膦膦配体的新型PNN钌钳配合物的合成,以及它们对脱芳香化和环金属化的反应性。脱芳族化合物7a,b进行环金属化以产生配合物8a,b。为了进行环金属化,必须重新布置Ru中心周围的配位球,这取决于系统的灵活性,这表明,在二甲基衍生物7a的情况下,环金属化的质量比在螺环戊基的情况下环化的速度更快。导数7b。环金属化非对映选择性地发生并且仅导致环金属化化合物中的一种非对映异构体。在2,2'-氧代双吡啶复合物6c的情况下,脱芳香化的复合物太不稳定而无法分离。但是,当在CO气氛中进行去质子化时,可以分离并表征稳定的二羰基-脱芳构钌(II)络合物9c。在CO下6a的脱芳香化作用还导致二羰基-脱芳香化的钌(II)络合物9a缓慢重新排列成二羰基-芳香化的钌(0)络合物10a。这些配合物在催化的醇-胺偶联,伯醇的酯化和仲酰胺的氢化中进行了测试。在酰胺加