1 H NMR monitoring for in situ irradiation NMR analysis was performed at T = 293K on a Bruker Avance III HD 300MHz spectrometer equipped with a 5mm BBO probe head. All NMR data were processed using TopSpin (Bruker) software. The kinetic analysis was performed by customized "pseudo 2D" experiments synchronized with the LED illumination by the inclusion of TTL commands allowing the NMR spectrometer to trigger the irradiation. The NMR measurements were acquired with a 30° excitation pulse, an accumulation over eight scans, and an interscan delay of 2.74 s.