Data for Unravelling solvent-independent excited state proton transfer dynamics in sterically substituted photoactive systems

Here, we investigate the excited state photodynamics of two structurally complex triazine- and benzotriazole-based molecules that bear sterically bulky substituents around the proton transfer unit: bis-ethylhexyloxyphenol methoxyphenyl triazine (BEMT) and methylene bis-benzotriazolyl tetramethylbutylphenol (MBBT).

Using femtosecond transient electronic absorption spectroscopy in solvents of contrasting polarity and hydrogen-bonding character, supported by mixed reference spin-flip time-dependent density functional theory calculations, we show that ultrafast relaxation in both systems is governed by a largely solvent insensitive intramolecular ESPT. We demonstrate that the solvent-independent behavior primarily arises from intrinsic, electronic, properties of BEMT and MBBT rather than steric substitution.