Hexafluorothioacetone is an organic perfluoro thione compound with formula CF₃CSCF₃. At standard conditions it is a blue gas.

Production

Hexafluorothioacetone was first produced by Middleton in 1961 by boiling ''bis''-(perfluoroisopropyl)mercury with

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

Properties

Hexafluorothioacetone boils at 8 °C. Below this it is a blue liquid.

Colour

The blue colour is due to absorption in the visible light range with bands at 800–675 nm and 725–400 nm. These bands are due to T₁–S₀ and S₁–S₀ transitions. There is also a strong absorption in ultraviolet around 230-190 nm.

Reactions

Hexafluorothioacetone acts more like a true thiocarbonyl (C=S) than many other thiocarbonyl compounds, because it is not able to form thioenol compounds (=C-S-H), and the sulfur is not in a negative ionized state (C-S⁻). Hexafluorothioacetone is not attacked by water or oxygen at standard conditions as are many other thiocarbonyls. Bases trigger the formation of a dimer 2,2,4,4-tetrakis-(trifluoromethyl)-1,3-dithietane. Bases includes

amine In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of elec ...

s. The dimer can be heated to regenerate the hexafluorothioacetone monomer. The dimer is also produced in a reaction with hexafluoropropene and sulfur with some

potassium fluoride Potassium fluoride is the chemical compound with the formula KF. After hydrogen fluoride, KF is the primary source of the fluoride ion for applications in manufacturing and in chemistry. It is an alkali halide salt and occurs naturally as the ...

. Hexafluorothioacetone reacts with bisulfite to form a

Bunte salt In organosulfur chemistry, a Bunte salt is an archaic name for salts with the formula . They are also called ''S''-alkylthiosulfates or ''S''-arylthiosulfates. These compounds are typically derived from alkylation on the pendant sulfur of sodium t ...

CH(CF₃)₂SSO₂⁻.

Thiol In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl grou ...

s reacting with hexafluorothioacetone yield

disulfide In chemistry, a disulfide (or disulphide in British English) is a compound containing a functional group or the anion. The linkage is also called an SS-bond or sometimes a disulfide bridge and usually derived from two thiol groups. In inorg ...

s or a dithiohemiketal: :R-SH + C(CF₃)₂S → R-S-S-CH(CF₃)₂. :R-SH + C(CF₃)₂S → RSC(CF₃)₂SH (for example in

methanethiol Methanethiol (also known as methyl mercaptan) is an organosulfur compound with the chemical formula . It is a colorless gas with a distinctive putrid smell. In small amounts, it is pervasive in nature and found in certain foods, such as some n ...

ethanethiol Ethanethiol, commonly known as ethyl mercaptan, is an organosulfur compound with the formula CH3CH2SH. It is a colorless liquid with a distinct odor. Abbreviated EtSH, it consists of an ethyl group (Et), CH3CH2, attached to a thiol group, SH. It ...

). With mercaptoacetic acid, instead of a thiohemiketal, water elimination yields a ring shaped molecule called a dithiolanone -CH₂C(O)SC(CF₃)₂S- (2,2-di(trifluoromethyl)-1,3-dithiolan-4-one). Aqueous

hydrogen chloride The Chemical compound, compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hyd ...

results in the formation of a dimeric disulfide CH(CF₃)₂SSC(CF₃)₂Cl.

Hydrogen bromide Hydrogen bromide is the inorganic compound with the formula . It is a hydrogen halide consisting of hydrogen and bromine. A colorless gas, it dissolves in water, forming hydrobromic acid, which is saturated at 68.85% HBr by weight at room temper ...

with water yields the similar CH(CF₃)₂SSC(CF₃)₂Br. Dry

hydrogen iodide Hydrogen iodide (HI) is a diatomic molecule and hydrogen halide. Aqueous solutions of HI are known as hydroiodic acid or hydriodic acid, a strong acid. Hydrogen iodide and hydroiodic acid are, however, different in that the former is a gas und ...

does something different and reduces the sulfur making CH(CF₃)₂SH. Wet hydrogen iodide only reduces to a disulfide CH(CF₃)₂SSC(CF₃)₂H. Strong organic acids add water to yield a disulfide compound CH(CF₃)₂SSC(CF₃)₂OH. Chlorine and bromine add to hexafluorothioacetone to make CCl(CF₃)₂SCl and CBr(CF₃)₂SBr. With

diazomethane Diazomethane is an organic chemical compound with the formula CH2N2, discovered by German chemist Hans von Pechmann in 1894. It is the simplest diazo compound. In the pure form at room temperature, it is an extremely sensitive explosive yellow ga ...

hexafluorothioacetone produces 2,2,5,5-tetrakis(trifluoromethyl)-l,3-dithiolane, another substituted dithiolane. Diphenyldiazoniethane reacts to form a three membered ring called a thiirane (di-2,2-trifluoromethyl-di-3,3-phenyl-thiirane) Trialkylphosphites (P(OR)₃) react to make a trialkoxybis(trifluoromethyl)methylenephosphorane (RO)₃P=C(CF₃)₂ and a

thiophosphate Thiophosphates (or phosphorothioates, PS) are chemical compounds and anions with the general chemical formula (''x'' = 0, 1, 2, or 3) and related derivatives where organic groups are attached to one or more O or S. Thiophosphates feature tetrahedr ...

(RO)₃PS. Hexafluorothioacetone can act as a ligand on nickel. Hexafluorothioacetone is highly reactive to

alkene In organic chemistry, an alkene, or olefin, is a hydrocarbon containing a carbon–carbon double bond. The double bond may be internal or at the terminal position. Terminal alkenes are also known as Alpha-olefin, α-olefins. The Internationa ...

s and

diene In organic chemistry, a diene ( ); also diolefin, ) or alkadiene) is a covalent compound that contains two double bonds, usually among carbon atoms. They thus contain two alk''ene'' units, with the standard prefix ''di'' of systematic nome ...

s combining via addition reactions. With

butadiene 1,3-Butadiene () is the organic compound with the formula CH2=CH-CH=CH2. It is a colorless gas that is easily condensed to a liquid. It is important industrially as a precursor to synthetic rubber. The molecule can be viewed as the union of two ...

it reacts even as low as -78 °C to yield 2,2-bis-(trifluoromethyl)-3,6-dihydro-2H-l-thiapyran.

References

External links