A series of new tetramethylcyclopentadienyl-functionalised N-heterocyclic carbene ligands with different wingtip substituents have been prepared and characterised. These ligands have been successfully coordinated to nickel affording complexes of the general type (Cp*-NHCR)NiX (X = Cl, I). These well-defined nickel complexes selectively catalysed the coupling of aromatic thiols with Et3SiH to give the corresponding silylthioethers (RSSiEt3). The nickel complexes bearing ethyl, iso-butyl, and n-butyl wingtips displayed comparable catalytic efficiency, while the nickel complex bearing a methyl substituent on the wingtip was the worst performing catalyst.
一系列新的四
甲基环戊二烯基功能化的N-杂环卡宾
配体,配有不同的翼端取代基,已被合成并表征。这些
配体成功地与
镍配位,形成一般类型为(Cp*-NHCR)NiX(X = Cl, I)的络合物。这些结构明确的
镍络合物选择性催化芳香
硫醇与Et3SiH的偶联反应,生成相应的
硅基
硫醚(RSSiEt3)。带有乙基、异丁基和正丁基翼端的
镍络合物显示出相似的催化效率,而在翼端有甲基取代基的
镍络合物则表现出最差的催化活性。