Neutral pentacoordinate silicon complexes with SiO2FC skeleton: Synthesis, structural characterization and stereodynamical behavior

A series of new pentacoordinate intramolecular organosilicon complexes F(Ar)Si(OCH2CH2)2NMe (Ar = 4-MeC6H4 (1), 4-MeOC6H4 (2), 4-ClC6H4 (3), 2-BrC6H4 (4), 3-NO2C6H4 (5)) has been synthesized by transsilylation of aryltrifluorosilanes ArSiF3 by N-methyl-bis(2-trimethylsiloxyethyl)amine. Compounds 1–5 have been fully characterized by 1H, 13C, 19F, 29Si NMR spectroscopy and X-ray diffraction analysis (for compound 3). Variable-temperature 19F NMR studies of 5 indicate stereodynamic process of the ligand exchange with activation barrier Δ G c ≠ of 13.1 kcal mol−1.