Reaction with antimony halides

Reactions with antimony trifluoride, SbFs in the presence of antimony pen-tachloride, SbCls, form mixed halides of compositions GeClsF, GeCl3F2, GeCl2F2, and GeClFs. 

The first long-lived fluorine-containing carbocation was discovered by Olah and coworkers.32 Thus, the fluorodimethylcarbcnium ion [Me2CF+] was obtained by protonation of 2-fluoropropene and also from 2,2-difluoropropane by reaction with antimony(V) fluoride. In the course of these investigations it was found that a-F stabilizes a cationic state, whereas fi-F is destabilizing. Attempts to prepare the simplest member of this class, the trifluoromethyl carbocation CF3+ failed. The ionization of trifluoromethyl halides with antimony(V) fluoride at — 80 C yielded only carbon tetrafluoride. 

Single crystal X-ray analysis of the ethynyl-l,5-azastibocine 5a showed the presence of intramolecular Sb---N interaction which should be responsible for the reactivity enhancement of the ethynyl-l,5-azastibocines in Pd-catalyzed cross-coupling reactions with organic halides (see Section 14.18.11). The distance between the antimony and nitrogen atoms (2.538(4) A) corresponds to 68% of the sum of the van der Waals radii of both elements (3.74 A). In the crystal central antimony atom exhibited a pseudo-trigonal-bipyramidal structure <2003TL8589>. 

Reaction of phosgene with antimony halides and oxide halides... 

Ene reactions. The antimony pentafluoride—methyl fluoride complex in SO2 undergoes the ene reaction with vinyl halides (1) at -65 to give unsaturated methyl sulfinates (2), isolated after addition of methanol. Yields... 

Interference with the antimony-halogen reaction will affect the flame retardancy of the polymer. For example, metal cations from color pigments or an inert filler such as calcium carbonate or talc may lead to the formation of stable metal halides, rendering the halogen unavailable for reaction with antimony oxide. The result is that neither the halogen nor the antimony is transported into the vapor zone. Silicones have also been shown to interfere with the flame retardant action of halogenated flame retardants. 

Aluminum trichloride and boron trifluoride as additives have a similar effect on the fluorination of (trichloromethyl)benzene by antimony(III) fluoride. With the additives, the reaction starts even at O C but no exchange is observed in the absence of the catalysts.12 The relative exchange reactivity order of the antimony halides is as follows antimony(III) fluoride < anti-mony(III) fluoride + antimony/V) chloride < antimony(V) dichlorotrifluoride, antimony/V) di-bromotrifluoride < antimony/V) fluoride.3... 

Stannoles differ significantly from other group 14 metalloles in their ability to undergo exchange reactions with boron, arsenic or antimony halides. Boroles563,76, arsoles and... 

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