Regioselective Electrophilic C-H Bond Activation in Triazolylidene Metal Complexes Containing a N-Bound Phenyl Substituent

Transmetalation of a 1,4-diphenyl-substituted 1,2,3-triazolylidene silver complex with an electrophilic metal center, e.g., Ru-II, Ir-III Rh-III, induces spontaneous and chemoselective cyclometalation involving C-H bond activation of the N-bound phenyl group exclusively. Less electrophilic metals such as Ir-I, Rh-I, and Pt-II yield a monodentate triazolylidene complex, while cyclometalation with borderline cases (Pd-II) or the activation of the C-bound phenyl ring requires acetate as a promoter.