The First Structure of a Vicinal (E)-Fluoroselenoolefin: (E)-(5-Fluoro-4-octen-4-yl)dimethylselenonium Picrate

The structure of the title compound, C₁₀H₂₀FSe⁺.C₆H₂N₃O₇^-, synthesized from (E)-4-methylseleno-5-fluoro-4-octene with trimethyloxonium tetrafluoroborate, followed by anion exchange with natrium picrate, proves the trans addition of RSeF equivalents in the fluoroselenenylation of acetylenes with XeF₂-R₂Se₂ and XeF₂-PhSeSiR₃ reagents [dihedral angle Se-C4-C5-F -178.7 (1)°].