The Reactions of Perfluoroalkyl Radicals with Metals

Abstract

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

Spectroscopic and Structural Studies on Polyfluorophenyl Tellurides and Tellurium(IV) Dihalides

“…The chemistry of organo tellurides has been known for more than 150 years, and its progress is demonstrated in the applications for organic syntheses − and utilization in the semiconductor industry. − The first tellurium compound with perfluorinated groups, (CF 3 ) 2 Te 2 , was reported relatively late in the early 1960s . The preparation of (C 6 F 5 ) 2 Te followed, but its characterization is still incomplete.…”

Synthetic Approaches to Fluoroalkyltelluryl‐Substituted Compounds

“…Thus bis(trifluoromethyl)ditelluride was formed, but no yields were provided (Scheme 2). [9] Reactive trifluoromethyl radicals can be generated by using a plasma source. In these conditions, homolytic C-C bond scission of hexafluoroethane produced CF 3…”