No abstract available

[en] Two pathways for N-hydroxyphthalimide (NHPI)-mediated electrocatalytic oxidation using phenylacetate derivatives as template substrates were first reported for benzylic CH oxidation to oxygenated and non-oxygenated products. DFT calculation indicates that the hydrogen-atom transfer (HAT) process between phthalimido-N-oxyl (PINO) and substrate is a rate-determined step. Aromatic α-keto esters and 2-((1,3-dioxoisoindolin-2-yl)oxy)-2-aryl acetate obtained by cross-coupling between benzylic radical and PINO can be selectively synthesized through controlling the concentration of PINO radical. This method provides a deep understanding for selective weak CH oxidation using NHPI as redox mediator.

[en] Searching for new molecular radicals which are believed to play an important role as reaction intermediates in aromatic chain reactions, we have applied the technique of corona excited supersonic expansion employing a pinhole-type glass nozzle to obtain the vibronic spectrum from the corona discharge of precursor 3,5-difluorotoluene with a large amount of inert carrier gas helium. An analysis of the observed spectrum revealed that many vibronic bands are from other isomeric difluorobenzyl radicals generated in the jet by migration of the fluorine atom or methylene group to the adjacent position in the 3,5-difluorobenzyl radical. A possible mechanism was proposed for the formation of other isomers by using a bridged cyclic intermediate structure

[en] Published in summary form only

No abstract available

No abstract available

[en] C₆₀ fullerene was radiolyzed in toluene solution both in presence of air and in vacuum at four different radiation doses 12, 24, 36, 48 and 96 kGy. Clear evidences of the addition of benzyl radicals to the fullerene cage derive from FT-IR and C¹³-NMR spectra of the reaction product. In presence of air the interference of oxygen is evident in the FT-IR spectra and from the elemental analysis. A detailed analysis of the kinetics of the multiple addition of benzyl radicals to the fullerene cage was made spectrophotometrically with the determination of the addition rate constants at the each addition step and the average number of benzyl groups added to the fullerene cage as function of the radiation dose. (author)

[en] Highlights: We study the substituent effect on the electronic transition energy. We analyze the red-shifts of the origin bands of dichlorobenzyl radicals. We propose a model for delocalized Ͽ electronic structure. The model describes well the observed red-shifts of dichlorobenzyl radicals. Ring-substituted benzyl radicals exhibit electronic energies of the D₁ - D₀ transition being shifted to red region with respect to the benzyl radical. The red-shifts of disubstituted benzyl radicals are highly dependent on the substitution positions irrespective of substituents. By analyzing the red-shifts of dichlorobenzyl radicals observed, we found that the substituent effect on electronic transition energy is attributed to the molecular plane shape of delocalized Ͽ electrons. We will discuss the influences of locations of Cl substituents on the D₁ - D₀ transition energies of dichlorobenzyl radicals using Hückel's molecular orbital theory.

[en] Nowadays, contamination of copper (Cu(II)) has become one of the worst environmental problems. Due to its environmental resistance and persistence, the treatment of Cu(II) is crucial. Poly(vinylbenzyl chloride) (PVBC) was synthesised through reversible addition-fragmentation chain transfer (RAFT) polymerisation technique utilising monomer vinylbenzyl chloride (VBC), 4-cyanopentanoic acid dithiobenzoate (CPADB) as RAFT agent and 4,4'-Azobis (4-cyanopentanoic acid) (ACPA) as initiator. This study aims to synthesise PVBC and to test the ability of PVBC to remove Cu(II) ions from aqueous solution. In this study, PVBC was successfully synthesised when reacted for 24 h at 80 °C, and the ability of the PVBC to adsorb and remove Cu(II) ions was investigated. Important adsorption parameters such as adsorbate concentration, adsorption dosage, and contact time were studied. The maximum Cu(II) adsorption capacity (qmax) of PVBC was 263.15 mg/g with a copper removal rate of 95% under optimum initial concentration (160 mg/L), adsorbent dosage (14 mg), and contact time (180 min). The experimental results better fit into the Langmuir adsorption isotherm model than the Freundlich model, and the kinetics experiments were compared with the pseudo-second-order kinetic model. Polymer adsorption efficiency was above 90% after five cycles of adsorption and desorption, but the overall adsorption capability of PVBC for Cu(II) ions began to decrease after another five cycles from 80% to 54%. Given the outcomes acquired, it can be concluded that PVBC can be an efficient and potential adsorbent for the removal of Cu(II) ions from aqueous solution. The adsorption study showed that PVBC has an affinity to Cu(II) ions. The prepared PVBC is potentially useful for wastewater treatment applications. (author)

[en] The 1 ²B₂ → 3 ²B₂ transition in the absorption spectrum of the benzyl radical has been recorded in the gas phase together with a new band at shorter wavelengths, probably the first Rydberg band of the radical. The radicals formed in the flash photolysis of benzyl chloride and benzyl bromide and subsequent reactions have been investigated. It was possible to follow the kinetics of the radicals' decay which occurred predominantly by bimolecular recombination. The absolute extinction coefficients are calculated. (orig.)