We study the mechanism of proton transfer (PT) between the photoacid 8-hydroxy-1,3, 6-pyrenetrisulfonic acid (HPTS) and the base chloroacetate in aqueous solution. We investigate both proton and deuteron transfer reactions in solutions with base concentrations ranging from 0.25 M to 4 M. Using femtosecond midinfrared spectroscopy, we probe the vibrational responses of HPTS, its conjugate photob...

bacteriorhodopsin operates as a light/proton transfer pump which converts the light energy into a proton gradient. energy stored in the proton gradient can be used in a variety of ways. bacteriorhodopsin producing sources are some halobacterium species such as halobacterium sodomense and halobacterium salinarum which continue to grow in harsh and salt-saturated conditions. two types of red pigm...

We have found that photo-excited indigo carmine causes stepwise proton transfer to generate monoalcohol intermediate, which immediately returns to the parent molecule [I. Iwakura, A. Yabushita, T. Kobayashi, Chem. Lett. 38 (2009) 1020]. The kinetic isotope effect in the proton transfer of this system has been studied by direct observation of the real-time molecular vibrational amplitude during ...

DFT B3LYP/6-31G(d,p) calculations were performed to describe the proton transfer reaction pathway in the 2,6-dichlorophenolate of pyridine. The aim of these calculations was to establish the character of the dependence of the structure parameters on the proton transfer and comparing the results with known structures, e.g. the 2,6-dichloro-4-nitro- and pentachlorophenolates of pyridines. To make...

This Account presents a theoretical formulation for proton-coupled electron transfer reactions. The active electrons and transferring protons are treated quantum mechanically, and the free energy surfaces are obtained as functions of collective solvent coordinates corresponding to the proton and electron transfer reactions. Rate expressions have been derived in the relevant limits, and methodol...

The rate constant of the reaction catalyzed by the enzyme carbonic anhydrase II, which removes carbon dioxide from body fluids, is calculated for a model of the active site. The rate-determining step is proton transfer from a zinc-bound water molecule to a histidine residue via a bridge of two or more water molecules. The structure of the active site is known from X-ray studies except for the n...

Using noninvasive magnetic resonance imaging techniques to accurately evaluate the grading and cellularity of gliomas is beneficial for improving the patient outcomes. Amide proton transfer imaging is a noninvasive molecular magnetic resonance imaging technique based on chemical exchange saturation transfer mechanism that detects endogenous mobile proteins and peptides in biological tissues. Be...

PURPOSE In this article, we evaluate a plastic scintillation detector system for quality assurance in proton therapy using a BC-408 plastic scintillator, a commercial camera, and a computer. METHODS The basic characteristics of the system were assessed in a series of proton irradiations. The reproducibility and response to changes of dose, dose-rate, and proton energy were determined. Photogr...

A new proton transfer compound, formulated as (Hamp-6-pic)(Hpyzd) ∙H2O (1), has been synthesized from the reaction of pyrazine-2,3-dicarboxylic acid (H2pyzd)  and 2-amino-6-methyl pyridine (amp-6-pic), in 1:1 molar ratio. Extensive O−H×××O, N−H×××N and O−H×××O hydrogen bonds involving (Hamp-6-pic)+ cation, (Hpyzd)- anion and co-crystal water molecule٫ static electronic٫ and π…π stacking interac...

A new method for the determination of the real part of the elastic scattering amplitude is examined for high energy proton-proton and proton-nuclei elastic scattering at small momentum transfer. This method allows us to decrease the number of model assumptions, to obtain the real part in a narrow region of momentum transfer and to test different models for hadron-nuclei scattering. ∗Unité de Re...