Thionyl tetrafluoride, also known as sulfur tetrafluoride oxide, is an inorganic compound with the formulaSOF4. It is a colorless gas.
The shape of the molecule is a distorted trigonal bipyramid, with the oxygen found on the equator. The atoms on the equator have shorter bond lengths than the fluorine atoms on the axis. The sulfur oxygen bond is 1.409Å. A S−F bond on the axis has length 1.596Å and the S−F bond on the equator has length 1.539Å. The angle between the equatorial fluorine atoms is 112.8°. The angle between axial fluorine and oxygen is 97.7°. The angle between oxygen and equatorial fluorine is 123.6° and between axial and equatorial fluorine is 85.7°.[2] The fluorine atoms only produce one NMR line, probably because they exchange positions.[1] It is isoelectronic with phosphorus pentafluoride.
Formation
Thionyl fluoride reacting with fluorine gas can produce thionyl tetrafluoride.[1] This was how the gas was first discovered by Moissan and Lebeau in 1902. They identified the formula by the pressure changes resulting from the reaction. Silver fluoride and platinum are capable of catalyzing the reaction.
Reactions with the strong Lewis acids, such as AsF5 and SbF5, result in the formation SOF3+ cation and the corresponding salts SOF3[AsF6] and SOF3[SbF6], respectively.[5]
Click chemistry
Thionyl tetrafluoride can be used in click chemistry through reactions with primary amines known as sulfur(VI) fluoride exchange (SuFEx).[6] This kind of reaction was the first "click" reaction to generate a three-dimensional core.
References
^ abcdefHarry Julius Emeléus and A.G. Sharpe Advances in Inorganic Chemistry Volume 2 Academic Press 1960 page 117 [1]
^Hedberg, Lise; Hedberg, Kenneth (March 1982). "Thionyl tetrafluoride. Reanalysis of the molecular structure and resolution of the multiple model problem". The Journal of Physical Chemistry. 86 (5): 598–602. doi:10.1021/j100394a004.
^Dudley, F. B. (1956). "Pentafluorosulfur Hypofluorite and Thionyl Tetrafluoride". Journal of the American Chemical Society. 78 (8): 1553–1557. doi:10.1021/ja01589a013.
^Nagase, Shunji; Abe, Takashi; Baba, Hajime (1 July 1969). "Fluorination of Inorganic Sulfur Compounds". Bulletin of the Chemical Society of Japan. 42 (7): 2062–2064. doi:10.1246/bcsj.42.2062.
