Preparation of FC(S)SF, FC(S)SeF and FC(Se)SeF through matrix photochemical reactions of F₂ with CS₂, SCSe, and CSe₂

The reactions of F₂ with CS₂, SCSe, and CSe₂, respectively, were analyzed under matrix conditions by co-deposition of the halogen with the triatomic molecules trapped in argon matrices at cryogenic temperatures. In all cases, after co-deposition, the formation of the respective van der Waals complexes is observed. When each mixture is subsequently irradiated by means of broad-band UV-visible light (200 ≤ λ ≤ 800 nm), FC(S)SF, fluorothiocarbonylsulfenyl fluoride, FC(S)SeF, fluorothiocarbonylselenyl fluoride and FC(Se)SeF, fluoroselenocarbonylselenyl fluoride are produced, respectively. All these species exist as two stable planar syn- and anti-conformers (syn- and anti- of the CZ double bond, Y = S, Se, with respect to the S-F or Se-F single bond, respectively). For FC(S)SF, syn- is the rotamer with the lowest energy, while for both FC(S)SeF and FC(Se)SeF the anti-form is the lowest energy conformer. In all cases, other products due to alternative or subsequent photochannels are observed during the photochemical processes carried out in argon matrices at cryogenic temperatures.