Using Me 3 Si–F–Al(O R F ) 3 and Me 3 Si–Cl as Methylating Agents – Synthesis and Characterization of SeMeCl 2 [F{Al(O R F ) 3 } 2 ]

Upon reacting SeCl 4 with Me 3 Si–F–Al(OR F ) 3 , the selenonium salt SeMeCl 2 [ al‐f‐al ] ( 1 ) {[ al‐f‐al ] – = [F[Al(OC(CF 3 ) 3 ) 3 ] 2 ] – } was obtained and characterized by NMR, IR, and Raman spectroscopy as well as single crystal XRD experiments. Despite the [Se X 3 ] + ( X = F, Cl, Br, I) and [Se R 3 ] + salts ( R = aliphatic organic residue) being well known and thoroughly studied, the mixed cations are scarce. The only previous example of a salt with the [SeMeCl 2 ] + cation is SeMeCl 2 [SbCl 6 ], which was never structurally characterized and is unstable in solution over hours. Only 1 H‐NMR studies and IR spectra of this compound are known. The unexpected use of Me 3 Si–F–Al(OR F ) 3 as a methylating agent was investigated via DFT calculations and NMR experiments of the reaction solution. The reaction of SeCl 3 [ al‐f‐al ] with Me 3 Si‐Cl at room temperature in CH 2 Cl 2 proved to yield the same product with Me 3 Si–Cl acting as a methylating agent.