We demonstrate that the proton dissociation reaction of excited 1-aminopyrene follows a simple structure-reactivity correlation in water-methanol, water-DMSO, water-dioxane, and wateracetonitrile binary mixtures. The role of the proton free energy of transfer from pure water to the binary mixtures, AGtwqS(H+) in determining the rate of transfer is also demonstrated. We have extended our analysi...

Theory and simulation of laser control of single and double proton transfer reactions in hydrogen-bonded molecular systems are reviewed. Different approaches to the construction of potential energy surfaces are introduced as a means to design simple models for unraveling basic mechanistic principles of laser control. Obtaining the control laser field is the central task and various methods such...

Proton-transfer reactions involving the silaformyl anion, HSiO-, and its conjugate acids, HSiOH and H2SiO, have been investigated with ab initio methods. Calculations through fourth-order perturbation theory suggest possible routes for proton transfer. Accurate estimates for the acidity of H2SiO and HSiOH are presented and discussed in light of earlier experimental estimates. Disciplines Chemis...

Excited-state proton transfer has been hypothesized as a mechanism for UV energy dissipation in eumelanin skin pigments. By using time-resolved fluorescence spectroscopy, we show that the previously proposed, but unresolved, excited-state intramolecular proton transfer (ESIPT) of the eumelanin building block 5,6-dihydroxyindole-2-carboxylic acid (DHICA) occurs with a time constant of 300 fs in ...

This letter presents a method for the parametrization of semiempirical models for proton transfer reactions in water clusters. Two new models are developed: AM1-W, which is a reparameterization of the classic AM1 model, and AM1PG-W, which is a modified AM1-like model including a pairwise correction to the core repulsion function. Both models show good performance on hydrogen-bonding energies an...

Proton transfer in pyrazole systems involving interaction with a paramagnetic transition metal complex has been studied with 1H and 13C NMR techniques. Kinetics of the ligand exchange in the pyrazole complex of bis-(acetylacetonato)nickel (II) has been investigated, and hyperfine coupling constants for the interaction of the nickel unpaired electron with the ligand nuclei in the complex have be...

Channelrhodopsins serve as photoreceptors that control the motility behavior of green flagellate algae and act as light-gated ion channels when heterologously expressed in animal cells. Here, we report direct measurements of proton transfer from the retinylidene Schiff base in several channelrhodopsin variants expressed in HEK293 cells. A fast outward-directed current precedes the passive chann...

Catalysis of the hydration of CO2 by human carbonic anhydrase isozyme II (HCA II) is sustained at a maximal catalytic turnover of 1 mus-1 by proton transfer between a zinc-bound solvent and bulk solution. This mechanism of proton transfer is facilitated via the side chain of His64, which is located 7.5 A from the zinc, and mediated via intervening water molecules in the active-site cavity. Thre...

Ab initio molecular dynamics simulations were performed to investigate the effects of nanoscale confinement on the structural and dynamical properties of water and slightly acidic water. Single-walled carbon nanotubes (CNTs) of two different diameters (11.0 and 13.3 Å) were used as confinement vessels, and the inner walls of the CNT were either left bare or fluorinated to explore the influence ...