Cage effects chlorine atom

The chlorine atom cage effect was used as a highly sensitive probe for studying the effect of viscosity and the possible role of solvent clusters on cage lifetimes and reactivity for reactions carried out in supercritical fluid solvents. The results of these experiments provide no indication of an enhanced cage effect near the critical point in SC-CO2 solvent. The magnitude of the cage effect observed in SC-CO2 at all pressures examined is well within what is anticipated on the basis of extrapolations from conventional solvents (Fletcher et al., 1998). 

Fletcher, B. Suleman, N. K. Tanko, J. M. Free Radical Chlorination of Alkanes in Supercritical Carbon Dioxide The Chlorine Atom Cage Effect as a Probe for Enhanced Cage Effects in Supercritical Fluid Solvents. J. Am. Chem. Soc. 1998, 120, 11839-11844. 

Raner, K. D. Lusztyk, J. Ingold, K. U. Kinetic Analysis of Alkane Polychlorination with Molecular Chlorine. Chlorine Atom/Monochloride Geminate Pairs and the Effect of Reactive Cage Walls on the Competition Between Monochloride Rotation and Chlorine Atom Escape. J. Am. Chem. Soc. 1988, 110, 3519-3524. 

Carbon tetrachloride could be formed by the abstraction of a chlorine atom from a hexachloroacetone molecule by a trichloromethyl radical tetrachloroethylene could then result from the dimerisation of dichlorocarbene radicals produced from the dissociation of pentachloroacetonyl radicals. Haszeldine and Nyman identified trichloroacetyl chloride and octachloropropane as products of the liquid phase photolysis, suggesting a primary step of Type 3 involving rupture of the carbon-halogen bond. Photolysis in the liquid phase was found to be very slow, and this has been attributed to cage effects and recombination of radicals formed in the primary step. 

Dichloro-5-(l-o-carboranylmethyl)-6-methylpyrimidine (674) is said to be a potential synthon for the preparation of 5-(l-o-carboranylmethyl)-6-methylpyrimidines chemoselective nucleophilic substitution of the chlorine atoms can be effected, and the cage can be selectively degraded for the preparation of more water-soluble Wo-undecarborate derivatives. Preparation of the target molecule (674) is effected by the addition of decaborane to an appropriate alkyne (673) as shown in Equation (19) <9lJOC2391>. 

Tanko, et al. utilized the chlorine atom cage effect as a highly sensitive probe for studying the effect of SCF viscosity and the possible role of solvent clusters on cage lifetimes and reactivity [50,51]. These experiments were con-... 

B Fletcher, NK Suleman, JM Tanko. Free radical chlorination of alkanes in supercritical carbon dioxide the chlorine atom cage effect as a probe for enhanced cage effects in supercritical fluid solvents. J Am Chem Soc 120 11839, 1998. 

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