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The precursor 2-chloro-6-fluorotoluene can produce the 2-chloro-6-fluorobenzyl radical in corona discharge, together with the 2-fluorobenzyl radical which could be generated by the displacement of Cl with H of methyl group. In order to identify the reaction mechanism, two precursors, 2-chloro-6-fluorotoluene and 2-chloro-6-fluorobenzyl chloride were employed to observe the vibronic emission spectra from the corona discharge with a large amount of inert carrier gas He. By comparing the spectra observed, we are able to propose the displacement mechanism of Cl, in which methyl group is believed to play an important role in the process, which is discussed in terms of bond dissociation energies. [ABSTRACT FROM AUTHOR]

The vibronically excited but jet-cooled 2,3-dichlorobenzyl radical was generated from the corona discharge of precursor 2,3-dichlorotoluene seeded in a large amount of carrier gas He using a pinhole-type glass nozzle. From an analysis of the visible vibronic emission spectrum observed, we obtained the electronic energy of the D 1 → D 0 transition and vibrational mode frequencies in the D 0 state of the 2,3-dichlorobenzyl radical by comparing the observation with the results of ab initio calculations. In addition, we discussed substituent effect of Cls on electronic transition energy in terms of substituent orientation for the first time. [ABSTRACT FROM AUTHOR]

Highlights: [•] We observe emission spectrum from corona discharge of 2-chloro-5-fluorotoluene precursor. [•] The emission intensity was analyzed to identify the species generated by corona discharge. [•] We propose the possible mechanism for the production of benzyl-type radicals from precursor. [Copyright &y& Elsevier]

We generated vibronically excited but jet-cooled 2-chloro-6-fluorobenzyl radical from precursor 2-chloro-6-fluorotoluene seeded in a large amount of helium carrier gas using a pinhole-type glass nozzle coupled with a technique of corona excited supersonic jet expansion. From an analysis of the visible vibronic emission spectrum observed, we found evidence of the formation of the 2-chloro-6-fluorobenzyl and 2-fluorobenzyl radicals, and determined the electronic energy in the D 1 → D 0 transition and the vibrational mode frequencies of the 2-chloro-6-fluorobenzyl radical in the ground electronic state, for the first time, by comparison with ab initio calculations of the precursor molecule. [ABSTRACT FROM AUTHOR]

We report spectroscopic observations of the α,α-dichlorobenzyl radical obtained by corona excited supersonic jet expansion using a pinhole-type glass nozzle. Vibronically excited but jet-cooled radicals were generated by corona discharge of the precursor benzotrichloride with a large amount of helium carrier gas, from which the visible vibronic emission spectrum was recorded using a long path monochromator. From an analysis of the spectrum observed, the electronic energy of the D 1 → D 0 transition and a few vibrational mode frequencies in the ground electronic state were obtained for the α,α-dichlorobenzyl radical by comparing observed frequencies with those obtained by ab initio calculation. [ABSTRACT FROM AUTHOR]

We report spectroscopic evidence of the jet-cooled p -methyl-α-methylbenzyl radical in corona discharge. The visible vibronic emission spectra were recorded from the corona discharge of three precursors, p -xylene, p -ethyltoluene, and p -isopropyltoluene seeded in a large amount of carrier gas helium using a pinhole-type glass nozzle. From the analysis of the vibronic spectra observed from each precursor and the bond dissociation energies of precursor molecules, we are able to confirm the formation of the jet-cooled p -methyl-α-methylbenzyl radical in corona discharge, and determine the energy of the D 1 → D 0 transition and a few vibrational mode frequencies in the D 0 state. [ABSTRACT FROM AUTHOR]