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., RuII, IrIII, or RhIII, induces spontaneous and
chemoselective cyclometalation involving C–H bond activation
of the N-bound phenyl group exclusively. Less electrophilic metals
such as IrI, RhI, and PtII yield
a monodentate triazolylidene complex, while cyclometalation with borderline
cases (PdII) or the activation of the C-bound phenyl ring
requires acetate as a promoter.