Theoretical and experimental studies on the novel thiazylfluoroformate, FC(O)SN
Abstract
FC(O)SCl reacts with (CH3)3SiN3 to give a polymeric product with the formula [FC(O)SN]x. Thiazylfluoroformate (nitrilo-λ4-sulfanecarbonyl fluoride) is formed during this reaction and can be trapped by the addition of hexachlorocyclopentadiene (C5Cl6). Before polymerization, FC(O)SN can be trapped by C5Cl6 to give a 1 : 1 adduct. This adduct is hexachloro-3-cyclopentenylideneamino sulfanecarbonyl fluoride, C5Cl6NSC(O)F, as mainly identified by mass spectroscopy. Ab initio calculations at various levels of theory (HF/3-21G*, HF/6-31G*, MP2/6-31G*) are performed for the free molecule FC(O)SN in the gas phase. Thereby, the anti(CO bond in anti position with respect to the SN bond) and syn forms are taken into account. The calculated relative stabilities of FC(O)SN and of the isomeric compound FS(O)CN are discussed. In addition, the ab initio results are compared to density functional theory calculations at the local and non-local level of approximation.