Über Silikone, CVIII. Fluorierungen mit Organopentafluorosilicaten

Abstract

Organopentafluorosilicate wirken gegenüber Organochlorsilanen und Benzotrichlorid als Fluorierungsmittel, wobei zwei von den zur Verfügung stehenden fünf Fluoratomen ausgetauscht werden; Natriumfluorid, das mit Chlorsilanen allein nicht reagiert, wird durch Anlagerung an Organotrifluorsilane und Bildung der Organopentafluorosilicate aktiviert. Durch deren geeignete Auswahl lassen sich die Fluorierungsprodukte von den aus den Komplexen gleichzeitig wieder frei werdenden Organotrifluorsilanen durch Destillation leicht trennen. Das Verfahren kann mit Vorteil zur Darstellung von Methylhydrogendifluorsilan verwendet werden.

Efficient synthesis of p-bis-(chlorodifluoromethyl)benzene

“…The selectivity observed for this process appears to be unique to the preparation of bis-(chlorodifluoromethyl)benzenes, since no similar selectivity was exhibited in the analogous reaction with (trichloromethyl)benzene [10][11][12]. Thus, the selectivity must derive from the effect of the second trihalomethyl group upon the relative ease of formation of the various carbocation intermediates involved in the specific chlorine/fluorine exchange processes.…”

Hypervalent diorganoantimony(iii) fluorides via diorganoantimony(iii) cations – a general method of synthesis

“…S1 and S2 (see ESI †). The crystals were attached with Krytox™ to a glass ber (1$2CH 2 Cl 2 , 3$2CHCl 3 ) or mounted on cryoloops (5)(6)(7)(8). For 3$2CHCl 3 , 5-8 data were collected at room temperature, while for 1$2CH 2 Cl 2 the crystal was cooled under a nitrogen stream at low temperature.…”

“…Synthesis of [2-(Me 2 NCH 2 )C 6 H 4 ] 2 SbF (7). A solution of [Bu 4 N]F$3H 2 O (0.131 g, 0.42 mmol) in acetonitrile (15 mL) was added to a solution of [{2-(Me 2 NCH 2 )C 6 H 4 } 2 Sb] + [SbF 6 ] À (4) (0.260 g, 0.42 mmol) in acetonitrile (15 mL).…”

“…In earlier works [NH 4 ] 2 [PhSiF 5 ] was used for phenylation of SbF 3 in aqueous solution to give Ph 2 SbF. 7,8 This is, so far, the only R 2 SbF species investigated by single-crystal X-ray diffraction; its solid state structure consisting of innite chains of Ph 2 SbF units connected by strong intermolecular uorine bridges. 8 It should be noted here that organotin(IV) uorinating agents such as Me 3 SnF or [2-(Me 2 NCH 2 )C 6 H 4 ]Sn( n Bu) 2 F were used successfully in halogen exchange reactions to prepare organoantimony(III) diuorides of the type [2,6-(YCH 2 ) 2 C 6 H 3 ]SbF 2 (Y ¼ MeO, t BuO, Me 2 N) from the corresponding dichlorides containing (O,C,O)or (N,C,N)-pincer ligands.…”

“…In earlier works [NH 4 ] 2 [PhSiF 5 ] was used for phenylation of SbF 3 in aqueous solution to give Ph 2 SbF. 7,8 This is, so far, the only R 2 SbF species investigated by single-crystal X-ray diffraction; its solid state structure consisting of innite chains of Ph 2 SbF units connected by strong intermolecular uorine bridges. 8 It should be noted here that organotin(IV) uorinating agents such as Me 3 14 Several other methods failed to produce the desired Ph 2 SbF derivative.…”