Air and Moisture Tolerant Synthesis of a Chelated bis(NHC) Methylpalladium(ii) Complex Relevant to Alkyl Migration Processes in Catalysis
Michael G. Gardiner A , Curtis C. Ho
A B , David S. McGuinness A and Yi Ling Liu A
+ Author Affiliations
- Author Affiliations
A School of Natural Sciences – Chemistry, Private Bag 75, University of Tasmania, Hobart, Tas. 7001, Australia.
B Corresponding author. Email: Curtis.Ho@utas.edu.au
Australian Journal of Chemistry 73(12) 1158-1164 https://doi.org/10.1071/CH20194
Submitted: 12 June 2020 Accepted: 1 July 2020 Published: 28 July 2020
Abstract
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.
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