Reactive quenching studies of Xe (6s,3 P 2) metastable atoms by chlorine containing molecules

Flowing afterglow infrared chemiluminescence studies of vibrational energy disposal in the ion-molecule reactions F−+HBr,DBr→HF,DF+Br− J. Chem. Phys. 83, 3913 (1985); 10.1063/1.449102The temperature dependence of hydrogen abstraction reactions: F+HCl, F+HBr, F+DBr, and F+HI J. Chem. Phys. 72, 5915 (1980); 10.1063/1.439088 HF infrared chemiluminescence: Energy disposal and the role of the radical fragment in the abstraction of hydrogen from polyatomic molecules by F atoms Abstraction fraction in the reaction of deuterium atoms with HBr and HI HF infrared chemiluminescence from the reactions of F atoms with HCI, HBr, and HI was used to assign vibrational-rotational populations of the HF product. Experiments were done in both a cold-wall, arrested vibrational-rotational relaxation apparatus and in a fast-flow. arrested vibrational relaxation apparatus. Since the total HF formation rate constants are known for these reactions, absolute 300 K rate constants for formation of HF.J are established. The mean vibrational energy disposal to HF including estimates for HF (v = 0) is Hel = 0.51, H8, = 0.59 and HI = 0.59. The mean HF rotational energy decreased from 0.18 to 0.12 in the HCI-HI series. The sum is virtually constant for the three reactions, but does increase slightly as the reactions become more exoergic. The HBr reaction yields -10% Br('PI/J, the upper spin-<>rbit state; but I('PI/') is not formed from HI. Independent work by Nip and Clyne on the HCI reaction suggest that CI(,P In> also is formed in -10% yield. The dynamics of these reactions are considered with the aid of information-theoretic analysis. The possibility of two components, direct and complex, for product formation is considered. The HF vibrational distribution from the HBr and HI experiments in the cold-wall apparatus showed an unusual dependence upon reagent flow and the "best" distributions were not found for the lowest flow. The selection of the "best" initial vibrational populations were assisted by the data from the fast-flow apparatus, which included experiments with DCI and DBr as well as HCI, HBr, and HI.

Publication costs assisted by the National Science FoundationInfrared chemiluminescence under arrested relaxation conditions has been used to study the HF and HCl formation channels of the H + C1F reaction at 300 K. From the relative infrared emission intensities the ratio of channels was determined as 4.4 in favor of HC1, the less exoergic channel. The energy disposal is ( / " ) H a = 0.42, (~R ) H C I = 0.14, (~T ) H c~ = 0.44, and (f\-)HF = 0.57, (~R ) H F = 0.10, (fT)HF = 0.33. The rotational distribution for the HF channel is much broader than for the HC1 channel, which is a consequence of two pathways for HF formation. The low J component is attributed to direct reaction and the high J component to migratory collisions in which the H that intially attacked the C1 end of the molecule migrates and forms HF. Since -57% of the HF distribution can be assigned to a high J component, only about one-half of the HF is formed directly.The migratory aspect of the H + ClF reaction is less important than for the H + IC1 or BrCl reactions recently studied by Polanyi and co-workers. The energy disposal and inferred reaction dynamics for H + ClF are compared to that for H + Clz and H + Fz reactions. Using a numerical procedure, improved HC1 and HF transition probabilities were calculated and these values were used to convert the HC1 and HF rotational line intensities to relative populations. These new HCl and HF Einstein coefficients are presented in the Appendix.

A single amino acid-substituted mutant protein, CYP2D6 (G42R) was expressed in Saccharomyces cerevisiae and its enzymatic properties were compared with those of other single (P34S, R296C and S486T) and double amino acid-substituted mutant proteins (P34S/S486T and R296C/S486T) expressed in yeast cells, all of which were known to occur in the CYP2D6 gene as single nucleotide polymorphisms. The protein levels of G42R, P34S and P34S/S486T in microsomal fractions and their oxidation capacities towards debrisoquine as a prototypic substrate and bunitrolol as a chiral substrate were different from those of wild-type CYP2D6, while the R296C, S486T and R296C/S486T behaved similarly to the wild-type in these indices. The CYP contents both in yeast microsomal and in whole cell fractions indicated that some part of G42R protein was localized in the endoplasmic reticulum membrane fraction, whereas most of G42R protein was in some subcellular fractions other than endoplasmic reticulum. In kinetic analysis, the G42R substitution increased apparent Km and decreased Vmax for debrisoquine 4-hydroxylation, while it increased both Km and Vmax for bunitrolol 4-hydroxylation. The P34S substitution did not drastically change Km but decreased Vmax for debrisoquine 4-hydroxylation, whereas Km was increased and Vmax unchanged or decreased for bunitrolol 4-hydroxylation by P34S substitution. These results suggest that the G42R substitution causes a change in the CYP2D6 conformation, which may be different from the change produced by the P34S substitution.

The infrared absorption spectra of eight isotopic ethylamine molecules, i.e., CH3CH2NH2, CD3CH2NH2, CH3CD2NH2, CD3CD2NH2, CH3CH2ND2, CD3CJ2ND2, CH3CD2ND2, and CD3CD2ND2, have been examined in the vapor phase in the 300–100 cm−1 region. Several Q-branch peaks were observed for each isotopic species and assigned to the torsional oscillations of the methyl and amino groups of the trans and gauche isomers. The energy levels were calculated on the basis of a coupled two-top system. The analysis yielded a probable potential function for the internal rotation about the C–N bond of the form V (α) = (316.5/2)(1−cosα)−(11.3/2)(1−cos2α)+(713.7/2)(1−cos3α) −(25.0/2)(1−cos4α)+(25.0/2)(1−cos5α)−(3.7/2)(1−cos6α). The difference between the potential energy minima of the trans and gauche conformations is about 230 cm−1, the trans being the more stable form. It has been concluded that the axis of internal rotation of the amino group does not coincide with the N–C bond but is along a line about 4.5° from the N–C bond and in the plane bisecting the NHH triangle.