An <i>N</i>,<i>N</i>′-Diamidocarbene: Studies in C−H Insertion, Reversible Carbonylation, and Transition-Metal Coordination Chemistry
作者:Todd W. Hudnall、Christopher W. Bielawski
DOI:10.1021/ja907481w
日期:2009.11.11
degrees = -109.5 J mol(-1) K(-1)). NHC 1 also displayed nucleophilic characteristics. Treatment of 1 with [Ir(COD)Cl](2) (COD = 1,5-cyclooctadiene) afforded 1-[Ir(COD)Cl], a complex with bond lengths and angles that were in accord with known NHC analogues. Treatment of 1-[Ir(COD)Cl] with CO afforded the carbonyl complex 1-[Ir(CO)(2)Cl]. IR studies of this complex revealed a Tolman Electronic Parameter
用 N,N'-双(2,6-二异丙基苯基)-N-三甲基甲硅烷基甲脒和三氟甲磺酸三甲基甲硅烷基酯 (TMS.OTf) 处理二甲基丙二酰二氯,得到嘧啶盐 [1H][OTf],产率 >99%。随后该盐的去质子化导致形成相应的游离 N-杂环卡宾 (NHC) 1。 表现出传统亲电卡宾特有的反应性特征,发现 1 插入叔 CH 键并可逆地固定一氧化碳( CO)在温和条件下提供了第一个二氨基酮的例子。值得注意的是,上述羰基化反应被发现是热可逆的 (K(eq) = 2.62 M(-1) 在 30 摄氏度;DeltaH 度 = -35.33 kJ mol(-1) 和 DeltaS 度 = -109.5 J mol(- 1) K(-1))。NHC 1 也显示出亲核特性。用 [Ir(COD)Cl](2) (COD = 1,5-环辛二烯) 处理 1 得到 1-[Ir(COD)Cl],这是一种具有与已知 NHC 类似物一致的键长和角度的复合物。用