Australian Journal of Chemistry ( IF 1.0 ) Pub Date : 2020-07-28 , DOI: 10.1071/ch20194 Michael G. Gardiner , Curtis C. Ho , David S. McGuinness , Yi Ling Liu
An air- and moisture-tolerant alternate synthetic pathway to the preparation of a cationic chelated bis(NHC) methylpalladium(ii) complex, [{(MesIm)2CH2}Pd(Me)(NCMe)][PF6], is described. The pathway involves the isolation of a bis(NHC) AgI complex, [{(MesIm)2CH2}2Ag2][PF6]2, via metallation of the corresponding diimidazolium salt with Ag2O followed by carbene transfer to [(COD)PdBrMe]. This new method avoids a previously reported unstable intermediate that displayed rapid decomposition at room temperature, attaining the targeted cationic methylpalladium(ii) complex in high yield. CO/ethylene copolymerisation catalysis trials are reported showing solvent dependent catalyst lifetime and copolymer yields. Preliminary ethylene insertion studies are also outlined revealing possible pathways leading towards catalyst deactivation.
中文翻译:
与烷基迁移过程有关的螯合双(NHC)甲基钯(II)配合物的耐空气和湿气合成
制备阳离子螯合的双(NHC)甲基钯(ii)配合物[{(MesIm)2 CH 2 } Pd(Me)(NCMe)] [PF 6 ]的耐空气和湿气的替代合成途径是描述。该途径包括通过相应的二咪唑鎓盐与Ag 2的金属化分离双(NHC)Ag I络合物[{(MesIm)2 CH 2 } 2 Ag 2 ] [PF 6 ] 2。O,然后将卡宾转移到[(COD)PdBrMe]中。该新方法避免了先前报道的不稳定中间体,该中间体在室温下显示出快速分解,从而以高收率获得了目标阳离子甲基钯(ii)络合物。据报道,CO /乙烯共聚催化试验显示出取决于溶剂的催化剂寿命和共聚物产率。还概述了初步的乙烯插入研究,揭示了导致催化剂失活的可能途径。