Extension of the Alkane Bridge in BisNHC−Palladium−Chloride Complexes. Synthesis, Structure, and Catalytic Activity

Abstract

A series of bisNHC chelate ligands with alkyl bridges of different chain lengths and their palladium complexes have been prepared. The influence of the different bridges on the solid-state structure and reactivity of the complexes has been studied. The catalytic activity of the palladium complexes was successfully tested in the Mizoroki−Heck reaction and the catalytic CH activation of methane. The ethylene-bridged palladium complex showed the highest catalytic activity in the CH activation of methane and the Mizoroki−Heck coupling of bromoarenes, while for unreactive chloroarenes bisNHC complexes with longer bridges give better results.