Following the Solvent Directly during Ultrafast Excited State Proton Transfer

Abstract

Excited state intramolecular proton transfer in 1-chloroacetylaminoanthraquinone is investigated from the perspective of the solvent. Using a new two-dimensional nonlinear optical spectroscopy the solvent response is probed directly as the proton transfer takes place. The measurements indicate that solvent reorganization controls the proton transfer in acetonitrile by dynamically shifting the position of equilibrium in the excited state, even on subpicosecond time scales.

Dynamical Study of Guest-Host Orientational Interaction in LiquidCrystalline Materials

“…In the past, solvation was often studied through observation on reporter chromophores that reflect the solvent effects on the reporter molecule. Only recently have there been studies that looked at the response of the solvent, which provides complementary information on solvation [31,32,33]. Seen in this light, our study can be considered a comprehensive study of the orientational solvation dynamics of a guest-host system.…”

“…This approach of looking at the host response is similar in spirit to recent studies of solvation dynamics in Refs. [31,32,33]. Our study, with picosecond excitation pulses, focuses exclusively on the diffusional reorientational dynamics, while the other studies, with femtosecond excitation pulses, could probe the faster diffusion, libration, and interaction-induced responses [33].…”

The Relation between Hydrogen Atom Transfer and Proton‐coupled Electron Transfer in Model Systems

“…Blank and coworkers have successfully applied this technique to probe the role of the solvent in excited state intramolecular PT reactions and ultrafast solvation dynamics [244][245][246][247]. Prior to this work, inferences regarding the solvent response were made by comparing the observed kinetics to known timescales of solvent response, and by interpreting solvent-induced spectral shifts in the solute (reporter) molecules [248][249][250][251].…”

“…Prior to this work, inferences regarding the solvent response were made by comparing the observed kinetics to known timescales of solvent response, and by interpreting solvent-induced spectral shifts in the solute (reporter) molecules [248][249][250][251]. The more direct experiments of Blank revealed a nonequilibrium solvent response in the excited state PT reaction [245,246]. The solvent response lagged behind progress along the PT reaction coordinate, leading to the breakdown of linear response and inducing time-dependent evolution of the reaction free energy surface.…”

The Claisen Rearrangement – Part 2: Impact Factor Analysis of the Claisen Rearrangement, in Batch and in Flow

“…Ultra-short pulse laser spectroscopy gives very detailed and individual information about all major species on the reaction trajectory, including the transition state, through vibration analysis of many groups within a molecule [5,[7][8][9][10][11][12][13][14][15][16][17][18]. This equals the comprehensive functional-group analysis known from Raman spectra of molecules in their ground state; yet now on a femto-second time scale allowing to catch even the most-short lived species.…”