Syntheses of heptafluoronitrosocyclobutane and nonafluoronitrosocyclopentane and their reactions with tetrafluoroethene, 1,3-hexafluorobutadiene and tetrafluorohydrazine

Abstract

Hexafluorocyclobutene and octafluorocyclopentene were reacted with nitrosyl chloride or nitrogen dioxide in the presence of KF in acetonitrile to give 80% yields of the blue heptafluoronitrosocyclobutane (I) and nonafluoronitrosocyclopentane (II), respectively. Thermal decomposition of I and II in Pyrex glass resulted in the analogous nitro compounds, CF2C-F2CF2CFN02 and CF2CF2CF2CF2CFN02. Cycloaddition reactions of I and II with tetrafluoroethene gave the oxazetidines CF2CF2CF2CFNOCF2CF2 and CF2CF2CF2CF2CFNOCF2CF2 and with 1,3-hexafluorobutadiene formed the oxazines CF2CF2CF2CFNOCF2CF=CFCF2 and CF2CF2CF2CF2CFNOCF2CF=CFCF2. With tetrafluorohydrazine in metal reaction vessels, either I and II or the cycloolefms gave difluoroamines, CF2CF2CF2CFNF2 and CF2CF2CF2CF2CFNF2. However, in the presence of Pyrex glass, A-(heptafluorocyclobutyl)-A"-fluorodiimide '-oxide and A'-(nonafluorocyclopentyl)-Ar'-fluorodiimide A'-oxide (RfN(0)=NF) resulted from heating I and II with N2F4.

Relation between the potentials where adsorbed and unadsorbed cobalt(III) tetrakis(N-methylpyridinium-4-yl)porphyrin is reduced and those where it catalyzes the electroreduction of dioxygen

“…The peaked response at 0.5 V in Figure 2A matches that obtained at the stationary electrode in Figure 1, as expected if both responses arise from adsorbed reactant. The stable wave obtained in Figure 2B has a half-wave potential of 0.18 V, very close to the solution formal potential of the CoII1/nTMPyP couple measured by Rohrbach et al 2 This wave is therefore assignable to the reduction of ComTMPyP in solution. The steady-state limiting current measured on the plateau of the wave, 25 µ cm"2, is smaller than the value calculated from the Levich equation,8 36 µ cm"2, using the reported diffusion coefficient for ComTMPyP of 2.3 X 10~6 cm2 s"1.9 This may result from the adsorbed porphyrin's acting (8) Bard, A. J.; Faulkner, L. R. "Electrochemical Methods"; Wiley: New York, 1980; p 522.…”

Influence of substituents on bond lengths

“…The second term in eqn. (3) is well known from Raman spectroscopy. The effect of the relaxation on the change of bond length amounts to 0.3 pm for the C-F bond and to 2 pm for the C-CI bond, if the field strength is 0.028 a.u.…”

“…Marsden attempted to explain the "curious striking trends" [3] in (F 3) C-X bond distances, which are shorter than (H 3 ) C-X if X is highly electronegative but longer if X is of moderate or low electro negativity.…”

“…The geometry of the phosphorus compounds was determined in two steps. The geometries of CH 3 , CF 3 and PH 2 , PF 2 were taken from CH 4 , CF 4 and from the completely optimized PH 3 , PF 3 respectively. Then the fragments were put together and the bond length and the rotation around the P-C axis were determined.…”

Structure of a Fluorinated Azoxy Compound: Fluoro(trifluoromethyl)-diazene-2-oxide, CF3N(O)NF

“…However, very few azoxy compounds with halogen or halogenated groups as substituents have been reported, such as hexafluoroazoxymethane CF 3 N(O)NCF 3 . CF 3 N(O)NF is, besides c -C 4 F 7 N(O)NF, the only azoxy compound known in which a halogen atom is bonded directly to one of the nitrogen atoms. Its first synthesis and a short characterization by vibrational and 19 F NMR spectroscopy and mass spectrometry have been reported in 1962 .…”