Inorg. Chem. zyxwvu 1989, zyxwvut 28, zyxwvu 2187-2189 2187 Contribution from the Department of Chemistry, University of Idaho, Moscow, Idaho 83843 zyxwvutsrqpo Insertion of Tetrafluoroethylene and Trifluorochloroethylene into Nitrogen-Chlorine Bonds. A New Route to Perfluoroazaalkenes Ghulam Sarwar, Robert L. Kirchmeier, and Jean'ne M. Shreeve* Received October zyxwvutsrqponm 12, 1988 Insertion of olefins, CF2=CFX (X = CI, F), into the nitrogen-chlorine bonds of zyxwvu dichloro(perfluoroalkyl)amines, RfNCl2 (Rf = CF,, C2FS), occurs readily, providing an easy, straightforward route to secondary (polyfluoroalky1)- or (perfluoroalkyl)chloroamines and tertiary (polyfluoroalky1)- or (perfluoroa1kyl)amines. At 65-70 "C, insertion into only one of the nitrogen-chlorine bonds occurs to give RfN(CF,CFXCI)Cl, while at 90-100 OC, insertion into both nitrogen-chlorine bonds produces the tertiary amine RfN(CF&FXCI), in good yield. Gas-phase photolysis of RfN(CF2CFXC1)C1 results in essentially quantitative yields of the respective perfluoroazaalkenes,RfN=CF2, and fluorocarbons,CFXCI, (X = F, CI). Introduction While the insertion of olefins into the nitrogen-halogen bond of secondary halo(perfluoroalky1)amines is cited frequently in the literature, e.g., the insertion of hexafluoropropene or ethylene into the nitrogen-halogen bond of bromo- or iodobis(trifluoro- meth~l)arnine,'-~ a survey of the literature indicates that the analogous reaction with dichloro(perfluoroalky1)amines to form secondary or tertiary (polyfluoroalky1)- or (perfluoroalky1)amines has not been reported. In only a single case has mention been made of the potential utility of dichloro(perhaloalky1)amines for the synthesis of tertiary (perhaloalkyl)amines.6 However, no results were given at that time, and no reports have appeared subsequently describing this chemistry for dichloro(perha1o- alky1)amines. The reported chemistry of the dichloroamines is quite limited. The synthesis of diazo compounds is accomplished via pyrolysis7 and of dichloroamines. Dechlorination of ClCF2NC12 by heating at 150 OC for 4 h results in an 80% yield of the chloroimine CF2=NCI.Io Similarly, FN=CFCl is obtained by heating C12CFNFC1 at 53 OC.l1 Reactions of compounds of the type XCC12NF2 (X = C1, F) with mercury generate fluoroimines in good yield,I2 while Cl2NCF2CF2NCI2 is dechlorofluorinated to yield cyanogen quantitatively in 0.5 h at 25 OC.13 Attempts to insert CO or zyxwvutsrqp SO2 into the nitrogen-chlorine bonds of the dichloroamines result primarily in the formation of the corre- sponding azo compound^.'^ The primary amine CF3NH2 is formed by reaction of CF3NC12with hydrochloric acid,15as well as by reaction with trimethylsilane.16 Phosphorus trichloride reacts with R,CF2NCI2 to give good yields of the corresponding phosphazenes, R&F2N=PC13.17 Fluorination of ClCF2NC12 gives a 76% yield of CICF2NClF,l8 while CF3NCIBr is synthesized by the reaction of bromine with CF3NC12.19 The reactions of CF3NC12with SeC1, or Se and S0C12 to give F3CN=SeC12 and Young, J. A,; Tsoukalas, S. N.; Dresdner, R. D. J. Am. Chem. SOC. 1958, 80, 3604. Alexander, E. S.; Haszeldine, R. N.; Newlands, M. J.; Tipping, A. E. J. Chem. SOC. C 1968, 796. EmelCus, H. J.; Tattershall, B. W. zyxwvutsrq 2. Anorg. Allg. Chem. 1964, 327, 147. Haszeldine, R. N.; Tipping, A. E. J. Chem. SOC. 1965, 6141. Barlow, M. G.; Fleming, G. L.; Haszeldine, R. N.; Tipping, A. E. J. Chem. SOC. C 1971,2744. Tullock, C. W. (E. I. du Pont). Br. Pat. 870,328, 1960. Young, D. E.; Anderson, L. R.; Fox, W. B. US. 3685563, 1972. Hynes, J. B.; Bishop, B. C.; Bigelow, L. A. Inorg. Chem. 1967,6,417. Geisel, M.; Waterfeld, A,; Mews, R. Chem. Ber. 1985, 118, 4459. Anderson, L. R.; Fox, W. B.; Young, D. E. Chem. Commun. 1970,395. Abe, T.; Nagase, S.; Kcdaira, K. Bull. Chem. SOC. Jpn. 1970, 43, 957. Swindell, R. F.; Zaborowski, L. M.; Shreeve, J. M. Znorg. Chem. 1971, 10, 1635. DeMarco, R. A.; Shreeve, J. M. J. Fluorine Chem. 1971172, 1, 269. Hynes, J. B.; Bishop, B. C.; Bigelow, L. A. Inorg. Chem. 1966,5, 488. Kloeter, G.; Lutz, W.; Seppelt, K.; Sundermeyer, W. Angew. Chem. 1977, 89, 754. Kumar, R. C.; Shreeve, J. M. J. Am. Chem. SOC. 1980, 102, 4958. Leidinger, W.; Sundermeyer, W. J. Fluorine Chem. 1981, 19, 85. Sekiya, A.; DesMarteau, D. D. Inorg. Chem. 1981, 20, 1. Zheng, Y. Y.,; Mir, Q. C.; OBrian, B. A.; DesMarteau, D. D. Znorg. Chem. 1984, 23, 518. 0020-1669/89/1328-2187$01.50/0 CF3NS0, respectively, have also been reported.20 In addition, the chlorobis(polyfluoroa1kyl)amines are found to be particularly useful precursors in the synthesis of fluorinated azaalkenes. The per- or polyfluoroazaalkenes, RfN=CF2, are a class of compounds whose chemistry remains largely untouched primarily because of the paucity of high-yield routes to the aza compounds from commercially available or easily synthesized precursors. We give here the first documented investigation of the insertion reactions of dichloro(perfluoroalky1)amines with tetrafluoro- ethylene and chlorotrifluoroethylene. We describe a very straightforward route to the synthesis of new chlorobis(per- fluoroalky1)- and bis(polyfluoroalky1)amines as well as new tris(perfluoroalky1) and tris(polyfluoroalky1)amines. Moreover, essentially quantitative yields of the perfluoroazaalkenes RfN= CF2 (Rf = CF3, C2F5), are easily obtained by photolysis of chloroamines of the type RfN(CF2CFXC1)Cl (Rf = CF3, C2F5; X = C1, F). Previously published synthetic routes to the per- fluoroazaalkenes generally require high temperature and/or subsequent fluorination. These include preparation of CF3N=CF2 in 78% yield from fluorination of CC13N=CC12 with excess NaF in sulfolane at 150 to 160 "C over a period of 3 h.21 Pyrolysis of C F 3 N 0 at 160 OC for 1 day gives a 24% yield of CF3N=CF2.22 Photolysis of CF3N=NCF3 results in a 10% yield of CF3N=C- F2.23 Perfluore2-aza- 1-butene was prepared by passing (C2FS)3N through a graphite tube at 745 0C.24 Similarly, pyrolysis of perfluoro-2-ethyl-l,2-oxazetidine) at 550 OC resulted in a nearly quantitative yield of C2F5N=CF2.25q26 Results and Discussion In the case of the secondary haloamines, Haszeldine and co- workers have suggested both free radical and ionic mechanisms for the insertion reaction with 01efins.~ They reported that heat or photolysis favors a radical mechanism, while reactions carried out at low temperatures in the absence of light follow an ionic pathway. The reaction of bromobis(trifluoromethy1)amine with chlorotrifluoroethylene to give (CF3)2NCF2CFC1Br is consistent with a radical mechanism, where the intermediate radical (CF3)2N' initially attacks the difluoromethylene carbon. (CF3)2NBr Q (CF3)2N* + Br' (CF3)2N* + CF,=CFCl - (CF,),NCF2CFCl* (CF3)2NCF2CFCl + (CF3)2NBr - (CFJ2NCF2CFC1Br + (CF3),N' We have found that chlorotrifluoroethylene as well as tetra- fluoroethylene, upon heating, can be readily inserted into one or (20) Thrasher, J. S.; Bauknight, C. W., Jr.; DesMarteau, D. D. Znorg. Chem. 1985, 24, 1598. (21) Petrov, K. A.; Neimysheva, A. A. Zh. Obshch. Khim. 1959,29,2695. (22) Yakubovich, A. Yu.; Ginsburg, V. A,; Makarov, S. P.; Privezentseva, N. F.; Martynova, L. L. Dokl. Akad. Nauk SSSR 1961, 141, 125. (23) Ogden, P. H. J. Chem. SOC. C 1971, 2920. (24) EmelCus, H. .I.; Hurst, G. L. J. Chem. SOC. 1964, 396. (25) Barr, D. A.; Haszeldine, R. N.; Willis, C. J. J. Chem. Soc. 1964, 1351. (26) Klauke, E.; Holtschmidt, H.; Findeisen, K. (Farbenfabriken Bayer A.-G.). Ger. Offen. 210107, 1971/1972. 0 1989 American Chemical Society