N-heterocyclic carbene tethered amido complexes of palladium and platinum
作者:Warren B. Cross、Christopher G. Daly、Rachel L. Ackerman、Ian R. George、Kuldip Singh
DOI:10.1039/c0dt01149e
日期:——
With a view to applications in bifunctional catalysis, a modular cross-coupling strategy has been used to prepare amine bis(imidazolium) salts (3a and 3b) and an amine mono(imidazolium) salt (6) as precursors to chelating amido-NHC ligands. Treating the pro-ligands 3 with 3 equivalents of the bulky base KHMDS and Pd(OAc)2 or PtCl2(COD) gave the four amido bis(N-heterocyclic carbene) pincer complexes
考虑到在双功能催化中的应用,模块化交叉偶联策略已用于制备胺双(咪唑鎓)盐(3a和3b)和胺单(咪唑鎓)盐(6)作为螯合氨基-NHC配体的前体。用3当量的笨重碱KHMDS和Pd(OAc)2或PtCl 2(COD)处理前配体3得到四个酰胺基双(N-杂环卡宾)夹杂物[CNC-R] MI [M = Pd(7)或Pt(8);R = i -Pr(a)或n -Bu(b)],包括CNC配体的铂络合物的第一个实例。7a与AgOTf的反应吡啶得到阳离子络合物[CNC - i -Pr] Pd-py} OTf(9a)。加热胺单(咪唑鎓)盐6与PdCl 2或K 2 PtCl 4,K 2 CO 3和KI的混合物吡啶在100°C下得到的络合物[C,NH] MI 2 py [M = Pd(10)或Pt(11)],其中NHC配体的胺臂未去质子化且不与金属配位。对于10 in的解决方案1,4-二恶烷,胺的去质子化发生在与水溶液的双相反应中