The stereodynamics study on the isotopic substitution C + SH(D, T) → H(D, T) + CS reactions on the new HCS(X2A′ ) potential energy surface

The quasi-classical trajectory calculations are carried out to investigate the isotopic substitution effect on title reactions based on the recently developed, accurate potential energy surface of the HCS(X2[Formula: see text]) (Song, Zhang, et al. Sci. Rep. 6, 37734 (2016)). The total integral cross sections (ICSs) and vibrational state resolved ICSs are obtained for C + SH(D, T) → H(D, T) + CS reactions. In addition, differential cross sections and two angle distribution functions P(θr), P([Formula: see text]) at different collision energies are investigated. It is found that the peaks of P(θr) and P([Formula: see text]) become lower with the reagent molecule SH turning into SD and ST.

An experimental study of the influence of hydration on the reactivity of the hydroxide anion in the gas phase at room temperature

Flowing afterglow measurements of rate constants and ionic products are reported which explore the influence of step-wise hydration on the reactivity of the hydroxide anion in the gas phase at 296 ± 2 K. Rate constants have been measured for the reactions of OH−•(H2O)n and/or OD−•(D2O)n with CO2, SO2, CH3OH, C2H5OH, C2H2, CH3COCH3, CH3NO2, and HCN, in most instances for values of n from 0 to 3. The reactions with CO2 and SO2 involve ligand addition or exchange and the results of their study corroborate earlier measurements. The remaining reactions proceed by proton transfer. For these reactions the results establish trends in reactivity as a function of step-wise hydration when relative acidity is preserved and when a reversal occurs in the relative acidity upon hydration. The fast hydrated acid–base reactions were observed to establish interesting hydrated product ions many of which underwent secondary reactions involving the exchange of H2O or D2O for the reagent molecule.

The preparation and some properties of mammalian cytochrome c modified with 2-hydroxy-5-nitrobenzyl bromide

2-Hydroxy-5-nitrobenzyl bromide reacts with horse heart cytochrome c at acid pH to yield a chemically modified protein. Chromatography of the protein on CM-cellulose allows separation of a single chemically modified species. This species is shown by gel chromatography to be monomeric, and isoelectric focusing shows the pI to be lowered from 10.5 to 9.8 on introduction of the reagent molecule. The changes observed in the u.v. region of the spectrum are consistent with the introduction of a single residue of the reagent, and the normal fluorescence of tryptophan is lost. The chemically modified protein exhibits marked changes in its functional properties as compared with native cytochrome c. Unlike the native monomer, the modified cytochrome c has a pH-dependent spectrum which is typical of a high-spin species in the alpha/beta region at low pH, changing to a low-spin species with an apparent pK of 7.5. The modified protein is autoxidizable and the ferrous form binds CO at neutral pH with an affinity constant of 2.6 X 10(5)M-1. The ferrous form of the modified cytochrome c binds CN- at pH 10.0 with an affinity constant of 3.5 X 10(2)M-1. The modified cytochrome c was incapable of restoring the electron-transfer activity to mitochondria depleted of cytochrome c.