Arsenic trifluoromethyl compounds

Methylarsine, trifluoromethylarsine, and bis(trifluoromethyl)arsine [371-74-4] C2HAsF, are gases at room temperature all other primary and secondary arsines are liquids or solids. These compounds are extremely sensitive to oxygen, and ia some cases are spontaneously inflammable ia air (45). They readily undergo addition reactions with alkenes (51), alkynes (52), aldehydes (qv) (53), ketones (qv) (54), isocyanates (55), and a2o compounds (56). They also react with diborane (43) and a variety of other Lewis acids. Alkyl haUdes react with primary and secondary arsiaes to yield quaternary arsenic compounds (57). 

Cyclic and Polymeric Substances Containing Arsenic—Arsenic Bonds. A number of organoarsenic compounds containing rings of four, five, or six arsenic atoms have been prepared (cycHc polyarsines). The first such four-membered ring compound to be adequately characterized, tetrakis (trifluoromethyl) tetrarsetane [7547-15-17, was obtained by the interaction of a diiodoarsine and mercury (107,108) ... 

Salts of the bis[trifluoromethyl]fluorotelluronium cation with tetrafluoroborate, hexafluoro-arsenate, or hexafluoroantimonate are the only known compounds of this type. 

The method is applicable for triorganoarsenic compounds bearing aryl or vinyl substituents (equations 76 , 77 and 78 ), while for the preparation of alkylarsenic halides this method has not been useful since only adduct formation and redox reactions have been reported between R3AS and AsXj (equations 79a and b) . Reaction of tris(trifluoromethyl) arsine with arsenic iodide, however, has been reported to afford a mixture of halides (equation 80) . In the reaction of unsymmetrically substituted compounds such as 4, cleavage of the aryl-arsenic bond is preferred to that of the alkyl-arsenic bond (equation 78 ). The cleavage of 4 by this method is in contrast to that of 3 in thermolysis (equation 75). 

Action of Alkyl, Aryl, or Fluoroalkyl Halides on Arsenic Compounds a. With R As to Produce Arsonium Derivatives. The reaction of alkyl halides with trialkylarsines to produce tetraalkylarsonium halides has been known for over 100 years (J). In general, alkyl bromides or iodides interact easily with trialkylarsines, although as more negative groups such as phenyl or trifluoromethyl are substituted for the alkyl groups on the arsine, ease of reaction decreases. There have been only a few attempts made to evaluate the factors affecting arsonium salt formation 157,158). 

Nearly all trifluoromethyl arsenicals are hydrolyzed quantitatively by base affording fluoroform. This reaction has been of value in the analysis of these compounds. Exceptions are the compounds (CF3)2AsH, CF3ASH2, and (CF3)2As— As(CF3)2 which give fluoride and carbonate as well as fluoroform. Hydrolysis of the diarsine is believed to involve hydrolytic fission of the As— As bond (30). 

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