10551-67-4Relevant academic research and scientific papers
Surface Photochemistry: Evidence for Rotational and Translational Movement of Cyanopropyl Radicals on a Silica Gel Surface
Johnston, Linda J.,Mayo, Paul de,Wong, S. King
, p. 1106 - 1108 (1982)
The photolysis of azoisobutyronitrile is shown to generate radicals which, contrary to an earlier report, undergo rotational and translational movement on a silica gel surface.
Surface Photochemistry: Decomposition of Azobis(isobutyronitrile) on Dry Silica Gel
Johnston, Linda J.,Mayo, Paul de,Wong, S. King
, p. 20 - 26 (1984)
The generation of cyanopropyl radical pairs by the photolysis of azobis(isobutyronitrile) (AIBN) adsorbed on dry silica gel-benzene slurries has been investigated.The results require revision of an earlier observation that restrictions on the rotational motion of cyanopropyl radicals at a silica gel-benzene interface prevented the formation of the unsymmetrical coupling product dimethyl-N-(2-cyano-2-propyl)ketenimine.Both tetramethylsuccinodinitrile and the ketenimine were formed on the silica gel surface, even when dry, although the latter was partially hydrolyzed to the corresponding amide.Measurements of geminate recombination of radicals produced by direct photolysis of mixtures of deuterated and nondeuterated AIBN indicated that some radicals could escape, by translational motion, from their original geminate partners.The amount of translational motion was increased for the same cyanopropyl radical pair generated by triplet-sensitized AIBN decomposition.This latter observation supports the view that the triplet-sensitized decomposition of AIBN occurs directly from an exited state rather than by isomerization to a thermally labile cis isomer.
The Effect of Viscosity on the Diffusion and Termination Reaction of Organic Radical Pairs
Li, Xiaopei,Ogihara, Tasuku,Abe, Manabu,Nakamura, Yasuyuki,Yamago, Shigeru
, p. 9846 - 9850 (2019/07/10)
The effect of viscosity on the diffusion efficiency (Fdif) of an organic radical pair in a solvent cage and the termination mechanism, that is, the selectivity of disproportionation (Disp) and combination (Comb) of the geminated caged radical pair and the diffused radicals encountered, were investigated quantitatively by following the photolysis of dimethyl 2,2′-azobis(2-methylpropionate) (V-601) in the absence and presence of PhSD. Fdif and Disp/Comb selectivity outside the cage [Disp(dif)/Comb(dif)] are highly sensitive to the viscosity. In contrast, the Disp/Comb selectivity inside the cage [Disp(cage)/Comb(cage)] is rather insensitive. The difference in viscosity dependence between Disp(cage)/Comb(cage) and Disp(dif)/Comb(dif) is explained by the spin state of the radical pair inside and outside the cage and the spin state dependent configurational changes of the radical pair upon their collision. Given that the configurational change of the radicals associates the displacement and reorganization of solvents around the radicals, the termination outside the cage, which requires larger change than that inside the cage, is highly viscosity dependent. Furthermore, while the bulk viscosity of each solvent shows good correlation with Fdif and Disp/Comb selectivity, microviscosity is the better parameter predicting Fdif and Disp(dif)/Comb(dif) selectivity regardless of the solvents.
