Wavelength dependent mechanism of phenolate photooxidation in aqueous solution.
Kate RobertsonWilliam G FortuneJulia A DaviesAnton N BoichenkoMichael S ScholzOmri TauAnastasia V BochenkovaHelen H FieldingPublished in: Chemical science (2023)
Phenolate photooxidation is integral to a range of biological processes, yet the mechanism of electron ejection has been disputed. Here, we combine femtosecond transient absorption spectroscopy, liquid-microjet photoelectron spectroscopy and high-level quantum chemistry calculations to investigate the photooxidation dynamics of aqueous phenolate following excitation at a range of wavelengths, from the onset of the S 0 -S 1 absorption band to the peak of the S 0 -S 2 band. We find that for λ ≥ 266 nm, electron ejection occurs from the S 1 state into the continuum associated with the contact pair in which the PhO˙ radical is in its ground electronic state. In contrast, we find that for λ ≤ 257 nm, electron ejection also occurs into continua associated with contact pairs containing electronically excited PhO˙ radicals and that these contact pairs have faster recombination times than those containing PhO˙ radicals in their ground electronic state.
Keyphrases
- aqueous solution
- high resolution
- molecular dynamics
- single molecule
- photodynamic therapy
- energy transfer
- solar cells
- magnetic resonance
- electron transfer
- ionic liquid
- dna damage
- density functional theory
- molecular dynamics simulations
- electron microscopy
- dna repair
- magnetic resonance imaging
- oxidative stress
- cerebral ischemia
- subarachnoid hemorrhage
- brain injury