Fig. 5: Decay of 0.2 mM *[Ru-LH]2+ (photoexcitation at 387 nm in water/acetonitrile with 50 mM phosphate buffer at pH 6.7, 25 °C and 5 MPa) at variable MQ+ concentrations and kinetics of ET. | Nature Chemistry

Fig. 5: Decay of 0.2 mM *[Ru-LH]2+ (photoexcitation at 387 nm in water/acetonitrile with 50 mM phosphate buffer at pH 6.7, 25 °C and 5 MPa) at variable MQ+ concentrations and kinetics of ET.

From: High-pressure pump–probe experiments reveal the mechanism of excited-state proton-coupled electron transfer and a shift from stepwise to concerted pathways

Fig. 5: Decay of 0.2 mM *[Ru-LH]2+ (photoexcitation at 387 nm in water/acetonitrile with 50 mM phosphate buffer at pH 6.7, 25 °C and 5 MPa) at variable MQ+ concentrations and kinetics of ET.

a, ns-TAS spectra with 10 mM MQ+. b, SAS obtained for the reaction in a from the target analysis for *[Ru-LH]2+ (black), *[Ru-L]+ (orange), [Ru-L]+ + [Ru-L]2+ + MQ• (blue), [Ru-L]2+ + HMQ•+ (pink) and residual [Ru-LH]2+ ground-state bleach (green). The green SAS in b and e was necessary for target analysis owing to the non-quantitative recovery of the [Ru-LH]2+ ground state at the end of the time scale. c, The time-resolved population profile of the corresponding SAS, obtained from target analysis of a. The green profile in c and f, though required in target analysis, reflects only incomplete [Ru-LH]2+ ground-state recovery and provides no kinetic information. d, The ns-TAS spectra with 100 mM MQ+. e, The SAS obtained for the reaction in d from the target analysis of *[Ru-LH]2+ (black), [Ru-L]+ + [Ru-L]2+ + MQ• (blue), [Ru-L]2+ + HMQ•+ (pink) and residual [Ru-LH]2+ ground-state bleach as a result of incomplete thermal reverse PCET between [Ru-L]2+ and HMQ•+ (green). f, The time-resolved population profile of the corresponding SAS, obtained from target analysis of d. g, The kinetic traces recorded at 550 nm for the reaction in a and d in the presence of various concentrations of MQ+. h, A linear plot of kobs-MQ versus the concentration of MQ+ to determine the second-order rate constant for ET. The parameters for the linear fit are summarized in Supplementary Table 3.1. i,j, The residual trace (i) and two-dimensional (2D) differential residual map (j) of the ns-TAS spectra shown in a after fitting by target analysis. k,l, The residual trace (k) and 2D differential residual map (l) of the ns-TAS spectra shown in d after fitting by target analysis. The scaling parameters of the individual reaction steps were adjusted to ensure that the intensity of the SAS at λ = 420 nm remained constant. The jump in the residual traces at 80 µs noted in i and k is a result of an instrument artefact caused by light scattering.

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