Comparing Metal–Halide and −Oxygen Adducts in Oxidative C/O–H Activation: Au(III)–Cl versus Au(III)–OH

[Image: see text] High-valent metal–halides have come to prominence as highly effective oxidants. A direct comparison of their efficacy against that of traditional metal–oxygen adducts is needed. [Au(III)(Cl)(terpy)](ClO(4))(2) (1; terpy = 2,2′:6′,2-terpyridine) readily oxidized substrates bearing O–H and C–H bonds via a hydrogen atom transfer mechanism. A direct comparison with [Au(III)(OH)(terpy)](ClO(4))(2) (2) showed that 1 was a kinetically superior oxidant with respect to 2 for all substrates tested. We ascribe this to the greater thermodynamic driving force imbued by the Cl ligand versus the OH ligand.