A radical exchange reaction occurs when CF, radicals react with some main-group organometallic compounds; for the system CF, + SnMe, kexch = lo7 ml m-1 s-1.REBBERT and AUSLOOS~ reported the exchange of methyl radicals in the system CH, + Hg(CH,),. We have found that methane, ethane, and 1 , 1 , 1-trifluoroethane are formed in the reaction of CF, radicals with the methyls of B, Si, Ge, and Sn; this suggests that methyl radicals may be produced. If methyl radicals are formed, then the combination reactions (l), (2), and (3) would be expected to occur.

Trifluoromethyl radicals generated from the photolysis of hexafluoroacetone abstract hydrogen atoms from trichlorosilane; the competitive abstraction of chlorine atoms does not occur under the experimental conditions. The rate of the abstraction ������� �����������������CF3 + SiHCl3 → CF3N + SiCl3 has been measured in comparison with the known rate for the recombination of trifluoromethyl radicals, to yield a rate constant, ������������������ k = 1012.13exp(-6850/RT) ml mole-1 sec-1 Methyl radicals similarly abstract hydrogen to yield methane. A quantitative study of this reaction proved impractical, due to complications using acetone as a radical source.

Accurate binary diffusion coefficients measured over the temperature range 275-323 K, together with some excellent virial coefficients in the literature, have been used to derive (m,6,8) potential parameters for the systems He-CH4, He-CF4, He-O2, Ar-O2, CH4-C2H6, CH4-C3H8 and CH4-C4H10. These parameters predict quite well the viscosities reported for these systems by Kestin and coworkers. The results indicate that binary diffusion coefficients can be used to predict viscosities more accurately than binary viscosities can be used to predict diffusion coefficients.

Perfluoroalkyl iodides react directly with trialkylbismuth compounds at 100�C to form dialkylperfluoroalkyl- and alkylbisperfluoroalkylbismuthines. These previously unknown compounds decompose below their boiling points. They are readily oxidized and may be hydrolysed by aqueous alkali, liberating the appropriate fluorocarbon. Halogens rapidly split off both alkyl and perfluoroalkyl groups. Whereas interconversion of the mixed alkylperfluoroalkyl compounds readily occurs, attempts to form the fully perfluoroalkylated bismuth compounds have been unsuccessful. Vapour pressure-temperature and infrared spectral data are presented and discussed.

A new, potentially general method for the synthesis of trifluoromethylated derivatives of metals has been used to prepare bistrifluoromethylditelluride. The procedure is derived from the classical one used by Panethl to prepare metal alkyls by the action of alkyl radicals on metal mirrors. It has now been found that trifluoromethyl radicals react similarly with some metals.Trifluoromethyl radicals, generated by pyrolysis of hexafluoroacetone,2 were passed over a tellurium mirror and yielded the red liquid bistrifluoromethylditelluride (CF3TeTeCF3). This is the first reported perfluoroalkyltellurium compound and, apart from dimethylditelluride, the only ditelluride not containing aryl groups. Rioe and Glasebrook3 prepared dimethylditelluride by the similar reaction of methyl radicals on tellurium. The thermal stability of the perfluoroalkyltellurium compound is less than that of dimethylditelluride. The perfluoroalkyl groups are readily split off by alkaline hydrolysis to yield fluoroform quantitatively. This reaction is similar to those found with the perfluoroalkyl derivatives of Group VB elements but differs from those with perfluoroalkyl derivatives of other Group VI elements which yield fluoride ions when treated with alkali.4The infrared spectrum of bistrifluoromethylditelluride has the following bands : 1367w, 1321m, 1219s, 1150s, 1088s, 1043s, 917m, 722s.Both lead and bismuth mirrors are removed, but very slowly by trifluoromethyl radicals under conditions similar to those used for the reaction with tellurium. The quantities of the lead and bismuth compounds formed so far have been too small to permit full chemical analyses to be performed. However, the infrared spectra of these compounds suggest the presence of trifluoromethyl groups, the compounds decompose on heating to give metal mirrors and yield fluoroform on treatment with alkali. In view of the known instability of dilead5 and dibismuthl alkyl compounds and the fact that the temperature of the reaction zone is greater than 100°C, it is considered that the reaction products are tetrakistrifluoromethyl-lead and tristrifluoromethylbismuth.Further work, designed to improve the yields of these products, is in progress.* Manuscript