A theoretical study of the gas-phase reactions of propadiene with NO3: mechanism, kinetics and insights.

In this study, the conversion mechanisms and kinetics of propadiene (CH2[double bond, length as m-dash]C[double bond, length as m-dash]CH2) induced by NO3 were researched using density functional theory (DFT) and transition state theory (TST) measurements. The NO3-addition pathways to generate IM1 (CH2ONO2CCH2) and IM2 (CH2CONO2CH2) play a significant role. P3 (CH2CONOCHO + H) was the dominant addition/elimination product. Moreover, the results manifested that one H atom from the -CH2- group has to be abstracted by NO3 radicals, leading to the final product h-P1 (CH2CCH + HNO3). Due to the high barrier, the H-abstraction pathway is not important for the propadiene + NO3 reaction. In addition, the computed ktot value of propadiene reacting with NO3 at 298 K is 3.34 × 10-15 cm3 per molecule per s, which is in accordance with the experimental value. The computed lifetime of propadiene oxidized by NO3 radicals was assessed to be 130.16-6.08 days at 200-298 K and an altitude of 0-12 km. This study provides insights into the transformation of propadiene in a complex environment.

Computational study on the mechanisms and kinetics of the CH2 = CHCH2F with O(3P) reaction.

The potential energy surface for the reaction of O(3P) with CH2 = CHCH2F has been studied at the CCSD(T)//M06-2X level of theory. Three different reaction entrances were revealed, namely, terminal-C addition, central-C addition, and H(or F)-abstraction, leading to CH2OCHCH2F (IM1), CH2CHOCH2F (IM2) and HO + C3H4I (OF + C3H5), respectively. The corresponding activation barriers are 3.04 (TS1), 3.71 (TS2), 7.06 (h-TS1), 12.68 (h-TS2), 14.04 (h-TS3) and 63.58 kcal/mol (F-TS1) kcal/mol. Several conceivable decomposition and isomerization channels were also examined for IM1 and IM2. The total and individual rate constants were calculated by using Multichannel RRKM and TST theory over a wide range of temperatures (200-3000 K) and pressures(10-14-1014 Torr).The branching ratios indicate that IM1 is the major product at 200-800 K. The production of P1 (CH2FCHCHO + H)via H-elimination from IM1 becomes dominant at high temperatures.

Mechanistic and kinetic study on the reaction of methylperoxy radical with atomic iodine.

Singlet and triplet potential energy surfaces for the CH3O2 with I reaction have been investigated computationally to propose the reaction mechanisms and possible products. Multichannel RRKM theory and transition-state theory have been used to compute the overall and individual rate constants at 200-3000K and 10-14-1014Torr. On the singlet PES, addition-elimination, substitution and H-abstraction mechanisms are located, and the addition-elimination mechanism is dominant. At 70Torr with N2 as bath gas, IM1(CH3OOI) formed by collisional stabilization is dominated at 200-300K, whereas CH2O and HIO are the major products at the temperatures between 350 and 3000K; The title reaction exhibits the typical falloff behavior. The results show that temperature and pressure affect the yield of products. Furthermore, the predicted rate constants at 298K 70Torr of N2 agree well with the available experimental values. On the triplet PES, the most favorable product should be CH3I+O2(3Σ) at atmospheric condition. Other two pathways on the triplet PES will not compete with the pathways on the singlet PES in kinetically and thermodynamically.

Synthesis, structure and photoresponsive properties of 4-(3-fluorobenzylideneamino)antipyrine.

Organic compounds are attracting greater attention largely in the recent years owing to their potential applications in the functional materials. Herein we reported the structural and photophysical properties of 4-(3-fluorobenzylideneamino)antipyrine. The studied molecule adopts a trans configuration about the imine bond, and forms a non-planar molecular device consisted of two effectively conjugated π-electron moieties. The stronger vibrational and nonlinear optical activities are tightly related to the molecular structural characteristics revealed by the analysis on vibrational modes and frontier molecular orbitals. The intramolecular electrons can be separated by the electron-transporting with specified photon-absorbing theoretically. The total molecular dipole moment, mean linear polarizability and first-order hyperpolarizability calculated at B3LYP/6-31G(d) level are 1.5390 Debye, 35.6075 Å(3) and 1.5391×10(-29) cm(5)/esu, respectively. The reported results indicate that the compound is a promising candidate of photoresponsive materials.