Hexafluorothioacetone is an organic perfluoro thione compound with formula CF<sub>3</sub>CSCF<sub>3</sub>. At standard conditions it is a blue gas.
Hexafluorothioacetone was first produced by Middleton in 1961 by boiling bis-(perfluoroisopropyl)mercury with sulfur.
Hexafluorothioacetone boils at 8 ðC. Below this it is a blue liquid.
The blue colour is due to absorption in the visible light range with bands at 800âÂÂ675 nm and 725âÂÂ400 nm. These bands are due to T<sub>1</sub>âÂÂS<sub>0</sub> and S<sub>1</sub>âÂÂS<sub>0</sub> transitions. There is also a strong absorption in ultraviolet around 230-190 nm.
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<sup>âÂÂ</sup>). 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 amines.
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.
Hexafluorothioacetone reacts with bisulfite to form a Bunte salt CH(CF<sub>3</sub>)<sub>2</sub>SSO<sub>2</sub><sup>âÂÂ</sup>.
Thiols reacting with hexafluorothioacetone yield disulfides or a dithiohemiketal:
With mercaptoacetic acid, instead of a thiohemiketal, water elimination yields a ring shaped molecule called a dithiolanone -CH<sub>2</sub>C(O)SC(CF<sub>3</sub>)<sub>2</sub>S- (2,2-di(trifluoromethyl)-1,3-dithiolan-4-one). Aqueous hydrogen chloride results in the formation of a dimeric disulfide CH(CF<sub>3</sub>)<sub>2</sub>SSC(CF<sub>3</sub>)<sub>2</sub>Cl. Hydrogen bromide with water yields the similar CH(CF<sub>3</sub>)<sub>2</sub>SSC(CF<sub>3</sub>)<sub>2</sub>Br. Dry hydrogen iodide does something different and reduces the sulfur making CH(CF<sub>3</sub>)<sub>2</sub>SH. Wet hydrogen iodide only reduces to a disulfide CH(CF<sub>3</sub>)<sub>2</sub>SSC(CF<sub>3</sub>)<sub>2</sub>H. Strong organic acids add water to yield a disulfide compound CH(CF<sub>3</sub>)<sub>2</sub>SSC(CF<sub>3</sub>)<sub>2</sub>OH.
Chlorine and bromine add to hexafluorothioacetone to make CCl(CF<sub>3</sub>)<sub>2</sub>SCl and CBr(CF<sub>3</sub>)<sub>2</sub>SBr.
With diazomethane 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)<sub>3</sub>) react to make a trialkoxybis(trifluoromethyl)methylenephosphorane (RO)<sub>3</sub>P=C(CF<sub>3</sub>)<sub>2</sub> and a thiophosphate (RO)<sub>3</sub>PS.
Hexafluorothioacetone can act as a ligand on nickel.
Hexafluorothioacetone is highly reactive to alkenes and dienes combining via addition reactions. With butadiene it reacts even as low as -78 ðC to yield 2,2-bis-(trifluoromethyl)-3,6-dihydro-2H-l-thiapyran.