Fig. 6 |. Mechanistic studies.
a, The ultraviolet–visible absorption spectrum of 1a (5 × 10−3 mol l−1), 2d (6 × 10−3 mol l−1) and Ru(dtbbpy)3(PF6)2 (5 × 10−5 mol l−1) in MeCN was collected, respectively. Accordingly, the photocatalyst Ru(dtbbpy)3(PF6)2 and 2d were found to be absorbing species near the excitation wavelength (λmax = 450 nm). b, Infeasibility of direct photosensitization excludes the possibility of an energy transfer pathway. c, Stern–Volmer quenching studies. Stern–Volmer analysis revealed that the luminescence emission of Ru(dtbbpy)3(PF6)2 was quenched efficiently by α-iodonium diazo 2d, whereas no quenching was observed with indene. d, Cyclic voltammetry measurements of indene. e, Cyclic voltammetry measurements of 2d. f, Deuterium labelling experiments. g, Radical capture experiments. h. Deallylation in the carbon insertion of substrate 6g. i, Methyl migration in the carbon insertion of 1,1-dimethylindene 6i. r.t., room temperature. TEMPO, (2,2,6,6-tetramethylpiperidin-1-yl)oxyl; 2,6-DTBP, butylhydroxytoluol.