2669-89-8Relevant articles and documents
The vinyl radical investigated by infrared diode laser kinetic spectroscopy
Kanamori, Hideto,Endo, Yasuki,Hirota, Eizi
, p. 197 - 205 (1990)
A c-type band was observed at around 895 cm-1 by infrared diode laser kinetic spectroscopy combined with the excimer laser photolysis of vinyl halides at 193 nm and was assigned to the CH2 wagging mode of the vinyl radical.The band was found to consist of two component bands separated by 0.0541(11) cm-1.Both component bands showed clearly the statistical weight in an alternative way, that is, of one shows the weight 1:3 for even:odd Ka levels, the other exhibits 3:1, indicating that the radical is of C2υ effective symmetry, executing a double-minimum motion probably associated with the C-H in-plane rocking vibration.The upper states of the two bands were found to be perturbed weakly, possibly by a Coriolis interaction with the first overtone state of the C-H rocking mode.
193 nm photolysis of vinyl bromide: Nascent product distribution of the C2H3Br→C2H2 (vinylidene)+HBr channel
Liu,Letendre,Dai
, p. 1734 - 1741 (2007/10/03)
The internal energy content of fragment HBr and C2H2 following photolysis of the precursor, vinyl bromide, at 193 nm was determined using time-resolved Fourier transform spectroscopy (TR FTS). Data taken 1 μs after the laser photolys
A combined crossed beam and ab initio investigation on the reaction of carbon species with C4H6 isomers. I. The 1,3-butadiene molecule, H2CCHCHCH2(X1A')
Hahndorf, I.,Lee, H. Y.,Mebel, A. M.,Lin, S. H.,Lee, Y. T.,Kaiser, R. I.
, p. 9622 - 9636 (2007/10/03)
The reaction between ground state carbon atoms, C(3Pj), and 1,3-butadiene, H2CCHCHCH2, was studied at three averaged collision energies between 19.3 and. 38.8 kJmol-1 using the crossed molecular beam technique. Our experimental data combined with electronic structure calculations show that the carbon atom adds barrierlessly to the ?-orbital of the butadiene molecule via a loose, reactantlike transition state located at the centrifugal barrier. This process forms vinylcyclopropylidene which rotates in a plane almost perpendicular to the total angular momentum vector J around its C-axis. The initial collision complex undergoes ring opening to a long-lived vinyl-substituted triplet allene molecule. This complex shows three reaction pathways. Two distinct H atom loss channels form 1- and 3-vinylpropargyl radicals, HCCCHC2H3(X2A ) and H2CCCC2H3(X2A ), through tight exit transition states located about 20 kJmol-1 above the products; the branching ratio of 1- versus 3-vinylpropargyl radical is about 8:1. A minor channel of less than 10 percent is the formation of a vinyl, C2H3(X2A'), and propargyl radical C3H3(X2B2). The unambiguous identification of two C5H5 chain isomers under single collision has important implications to combustion processes and interstellar chemistry. Here, in denser media such as fuel flames and in circumstellar shells of carbon stars, the linear structures can undergo a collision-induced ring closure followed by a hydrogen migration to cyclic C5H5 isomers such as the cyclopentadienyl radical-a postulated intermediate in the formation of polycyclic aromatic hydrocarbons (PAHs).
