Yields of Br* (42P12) as a function of wavelength in the photodissociation of Br2 and IBr

Photofragment Dynamics

“…Photodissociation processes in the halogens have been extensively reviewed.' 82 The ratio of magnitudes of the Br* yields from IBr and Br, was 0.9 at 503 nm. Br* from IBr, C1* from ICl, C1* from BrCl).…”

“…82 Morse, Freed, and Band have considered the further possibilities of bent excited-state geometries and the effect that this has on rotational state distributions through the final-state interactions. There are two major considerations: (1) the initial Franck-Condon excitation, where changes in the geometry of the photoexcited state are taken into account (sometimes called intrafragment) and (2) the final-state interactions, where the impulsive recoil of the separating fragments causes an alteration of the final translational, vibrational, and rotational states (sometimes called interfragment).…”

Direct bromination of hydrocarbons catalyzed by Li2MnO3 under oxygen and photo-irradiation conditions

“…Fluorescent room light was selected as a light source for the investigation and cyclohexane (1a) was 15 consequently converted into bromocyclohexane (2a) in 70% yield using a lower reaction temperature and a shorter reaction time (Table 1, entry 1). When a strong light source was used, such as a high pressure mercury-vapor lamp (Ushio, UM-452, 450 W) or a xenon lamp (Asahi Spectra, MAX-302, 300 W), complex 20 polybrominated products derived from the photoinduced formation of free bromine radicals were obtained. In the absence of light, 2a was not formed at 80 °C following a 10 min reaction period (Table 1, entry 2).…”

“…20 It was envisaged that the rate of the reaction could be accelerated in the presence of a catalytic amount of Li 2 MnO 3 and under irradiation with weak light. Fluorescent room light was selected as a light source for the investigation and cyclohexane (1a) was 15 consequently converted into bromocyclohexane (2a) in 70% yield using a lower reaction temperature and a shorter reaction time (Table 1, entry 1).…”

“…3 They can also be synthesized from the corresponding alkanes by reaction with brominating reagents, 20 such as NBS, 4 CBr 4 5 and Et 4 NBr. 6 Although alkyl bromides can be synthesized from the corresponding alkanes by reaction with Br 2 under photolysis or high temperature conditions without any catalyst, the reactions do not exhibit any selectivity, 7 because the bromine radicals present in the reaction mixtures indiscriminately 25 attack the C-H bonds of the starting material and the products (alkyl bromides).…”