Synthesis, chemistry, and characterization of perfluoroaromatic selenium derivatives

The reaction of perfluoroaryllithium RC6F4Li, where R = F or 4-CF3C6F4O, respectively, with selenium gives the known diselanes (RC6F4Se)(2) (1a, 1b). Redox reactions of 1 with hydrogen peroxide result in the formation of the seleninic acids RC6F4SeOOH which crystallize as hydrates (2a, 2b); with mercury give the bis(arylseleno) mercuries (RC6F4Se)(2)Hg (3a, 3b); with sulfuryl chloride or bromine give the selenenyl chlorides (4a, 4b) or selenenyl bromides (5a, 5b). Selenenyl chlorides (4a, 4b) react with a variety of trimethylsilyl reagents Me3SiX (X = Br, CN, NMe2, NEt2) to form 5a, 5b; selenocyanates RC6F4SeCN (6a, 6b); selenenyl amides RC6F4SeNMe2 (7a, 7b) and RC6F4SeNEt2 (8a, 8b). A new synthetic route to diorgano selanes is developed by reaction of 4a, 4b with perfluoroaryllithium to give the symmetric (RC6F4)(2)Se (9a, 9b). AV derivatives are thoroughly characterized and in addition the molecular structures of 2a, 6a, and 9a are established by X-ray crystallography.