1,1,1-Trichloro-3,3,3-trifluoroacetone

Fluorination and chlorination cause a large decrease in the nonradiative decay rates. The intersystem crossing rate constant drops from 4 x 10 s for acetone to 1.5 x 10 s- - for hexafluoroacetone. For the cyclobutanone/perfluorocyclobutanone pair, the rates are 4.2 x 10 s- - and 1 x 10 s l, respectively. A similar decrease is likely for the glyoxal/oxalyl fluoride pair, where zero-pressure tp values of 2.4 ps and 24 ps, respectively, have been measured (19,25,26). The fluorescence yields of these compounds must be measured before the true extent of this effect is known. Mixed chlorofluoroacetones exhibit nonradiative rates of intermediate value, with k jR increasing at low energy excitation with increasing chlorination from 2.7 x 10 s l for chloropentafluoroacetone to 3.9 x 10 s l and 8.0 x 10 s l for dichlorotetrafluoroacetone and trichloro-trifluoroacetone, respectively (94). 

Propanone, l-chloro-l,l,3,3,3-pentafluoro-] (b.p. 7.8° available from PCR, Inc. or Allied Chemical Corp.) are combined in a flask fitted with a dry ice condenser and a magnetic stirring bar. The refluxing mixture is stirred for 4-0 hours and then allowed to warm gradually to room temperature. The contents of the flask are extracted three times with anhydrous ether, and the combined extracts are distilled at atmospheric pressure. After the ether has been removed, continued distillation gives 22.8-28.5 g. (55-69%) of l,l,l-trichloro-3,3,3-trifluoroacetone, b.p. 83.5-84.5°, infrared (film) 1790 cm. - This compound is stored at room temperature in a tightly stoppered bottle. In the absence of reliable toxicity data, it should be handled with normal precautions. 

A. N-Triflmroacetanilide. In a two-necked, round-bottomed flask fitted with a thermometer, a Drierite tube, and a magnetic stirring bar are placed 4.66 ml. (4.66 g., 0.050 mole) of aniline [Benzenamine] (Note 1) and 15 ml. of dimethyl sulfoxide (Note 2). The resulting solution is stirred and cooled in an ice water bath, and when the internal temperature has dropped to 10-15°, 21.5 g. (0.10 mole) of 1,1,1-tri-chloro-3,3,3-trifluoroacetone [2-Propanone, l,l,l-trichloro-3,3,3-tri-fluoro-] (Note 3) is added in portions through the condenser. A mild exotherm results, and the addition is extended over ca. 5 minutes to... 

Trlchloroethylphosphorodichloridite, 60 Trichloromethylarenes, 240 Trichloromethyl chloroformate, 217 Trichlorosilane-f-Amines, 499 l,l,l-Trichloro-3,3,3-trifluoroacetone,... 

BCl, + 2(CF,),CO ClB[oaCFj,),Cl], BCl, + (CF,),CO — CI,B 0 C(CF,),CI. Attempts to extend these reactions to perchloroacetone and l,I,3-trichloro-l,3,3-trifluoroacetone have met with no success (the latter undergoes the metathetical change BX, + 3 (CF,ClXCFCl,)CO - BF, + 3 (CF,Cl)(CXCl,)CO], like those aimed at achieving insertion of a perhalogenoketone moiety into boron-fluorine bonds. Perfluoroalkyl... 

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