Vereinfachte Synthese und Reaktionen von Selenocarbonyldifluorid / A Simplified Synthesis and Reactions of Selenocarbonyldifluorid

Abstract

<jats:title>Abstract</jats:title><jats:p>SeCF<jats:sub>2</jats:sub> is prepared on a preparative scale reacting AII<jats:sub>3</jats:sub> with Hg(SeCF<jats:sub>3</jats:sub>)<jats:sub>2</jats:sub> in octamethyl-cyclotetrasiloxane. It adds MF [M = Cs, Tl, [(CH<jats:sub>3</jats:sub>)<jats:sub>4</jats:sub>N] and Ag] to form MSeCF<jats:sub>3</jats:sub>. AgSeCF<jats:sub>3</jats:sub> was also synthesized from AgF and B(SeCF<jats:sub>3</jats:sub>)<jats:sub>3</jats:sub>. Under the influence of sunlight SeCF<jats:sub>2</jats:sub> dissolved in CFCI<jats:sub>3</jats:sub> dimerizes quantitatively to 2,2,4,4-tetrafluoro-1,3-diselenetane, which above 360 °C pyrolyses to the monomer. The cyclic dimer reacts with B(SeCF<jats:sub>3</jats:sub>)<jats:sub>3</jats:sub> to give (CF<jats:sub>3</jats:sub>Se)<jats:sub>2</jats:sub>CSe. The reaction of AgSeCF<jats:sub>3</jats:sub> with CF<jats:sub>n</jats:sub>Cl<jats:sub>3-n</jats:sub>SCl leads to CF<jats:sub>3</jats:sub>SeSCF<jats:sub>n</jats:sub>Cl<jats:sub>3-n</jats:sub> (n = 1, 2, 3). IR, NMR and mass spectra of the newly prepared compounds were presented.</jats:p>

Preparation, characterisation and reactions of tellurocarbonyl difluoride and trifluoromethanetellurenyl iodide

“…The only minor impurities observed were elemental tellurium (indicated by a Te, + peak) and C2F4 both formed through the decomposition of 1 en route to the spectrometer. Additionally peaks associated with 02+ and N, + appeared, caused by a working pressure during pyrolysis (1 O4 Torr) higher than that in the ionisation chamber of the mass spectrometer (lo-' Torr); m/z 256 (2,Te2+) -In line with methods described earlier, a sample of 1 was obtained in a glass ampoule cooled to -196 "C. If the liquid-nitrogen Dewar was removed, after ca. 5 s a spontaneous change in the colour of the deposit from violet to red could be observed, corresponding to the quantitative formation of 2.…”

“…The reactivity of 1 greatly exceeds those of the selenocarbonyls. It is not transferable in vucuo and warming to temperatures slightly above 77 K results in its rapid dimerisation [equation (2)] to the intensely coloured Te2C2F4, which was characterised structurally by X-ray crystallography.…”

“…In the search for a larger-scale preparation we tried to synthesise Me,SnTeCF, with the intention of pyrolysing it following the precedent set by the corresponding selenium compound.' 2,21 The stannyl telluride can be produced in yields of 90-95% by the reaction of CF,TeTeCF, with Me,SnH according to equation (3). Using this synthetic route, 3 CF,TeTeCF, + 2Me,SnH ---2Me,SnTeCF, + H, (3) 3 can be prepared on a 10 g scale and therefore appeared to be a promising starting material for the synthesis of 1 on a useful scale [equation (4)].…”

Recent Advances in the Development of Direct Trifluoromethylselenolation Reagents and Methods

“…AgSeCF 3 was first synthesized through the reaction of B(SeCF 3 ) 3 and AgF in 1980 [12] . Two decades later, Tyrra reported an alternative route to get AgSeCF 3 from the reaction of AgCF 3 and red selenium powder [13] .…”

“…AgSeCF 3 was first synthesized through the reaction of B(SeCF 3 ) 3 and AgF in 1980. [12] Two decades later, Tyrra reported an alternative route to get AgSeCF 3 from the reaction of AgCF 3 and red selenium powder. [13] However, until very recently, it was first applied in the Csp 3 À H trifluoromethylselenolation by Cook and co-workers (Scheme 3).…”