Steric effects on acetate-assisted cyclometallation ofmeta-substitutedN-phenyl andN-benzyl imidazolium salts at [MCl2Cp*]2(M = Ir, Rh)

Abstract

meta-SubstitutedN-phenyl,N′-methyl andN-benzyl,N′-methyl imidazolium salts undergo acetate-assisted cyclometallation to provide mixtures oforthoandparasubstituted cyclometallated complexes. The effect of the substituents on the isomer ratios is discussed; steric effects are more important in the 6-membered rings derived from theN-benzyl imidazolium salts than 5-membered rings from theN-phenyl salts. Comparisons are made to steric effects with some other common directing groups.