Fig. 4: Photoredox reactions performed with Ru and Cr catalysts.
From: Cage escape governs photoredox reaction rates and quantum yields
a,d,g, Aerobic hydroxylation of 4-methoxyphenylboronic acid (a), reductive debromination of 2-bromoacetophenone (d) and aza-Henry reaction (g). The concentrations of [Ru(bpz)3]2+ and [Cr(dqp)2]3+ were adjusted to ensure equal absorbance at the irradiation wavelength of 415 nm. b,e,h, The product yields (η) of 4-methoxyphenol (b), acetophenone (e) and THIQ-MeNO2 (h) as a function of irradiation time for [Ru(bpz)3]2+ (green circles) and [Cr(dqp)2]3+ (blue triangles). Linear regression fits (orange lines) to the data points over the initial irradiation period provide the initial product formation rates ν(RuII) and ν(CrIII). c,f,i, Cage escape quantum yields (ФCE) obtained with the [Ru(bpy)3]2+ reference (dark-grey traces), [Ru(bpz)3]2+ (green traces) and [Cr(dqp)2]3+ (dark-blue traces) and the electron donors DIPEA (10 mM) (c), DMT (10 mM) (f) and THIQ (2 mM) (i), used in the photoredox reactions in a, d and g, respectively. For donor THIQ, only an upper limit could be determined for ФCE with [Cr(dqp)2]3+ (Supplementary Section 7.10). j, Experimentally determined ratios of the cage escape quantum yield (ФCE), the initial product formation rate (ν) and the initial product formation quantum yield (ФP) for [Ru(bpz)3]2+ and [Cr(dqp)2]3+ in the three photochemical reactions in a, d and g using DIPEA, DMT and THIQ, respectively, as electron donors.
