Synthesis, characterization of cationic half-sandwich scandium mono(silylamide) complexes and their unexpected reactivity toward C–Cl σ bond activation of chlorobenzene

• Cationic half-sandwich scandium mono(silylamide) complexes were synthesized.
• Cationic half-sandwich scandium amide complexes were able to activate C–Cl σ-bond of PhCl.
• Cationic half-sandwich scandium chloride complex was prepared.

Treatment of the half-sandwich scandium bis(silylamide) complex (η5-C5Me5)Sc[N(SiMe3)2]2 with 1 equiv. of [PhNMe2H][B(C6F5)4] in THF and toluene gave the cationic half-sandwich scandium mono(silylamide) complexes [(η5-C5Me5)Sc{N(SiMe3)2}(THF)2][B(C6F5)4] (1) and [(η5-C5Me5)Sc{N(SiMe3)2}(PhNMe2)][B(C6F5)4] (2), respectively. 2 could be transformed into 1 by introducing of a small amount of THF. 2 was capable of activating kinetically inert C–Cl σ-bond of chlorobenzene to afford the cationic half-sandwich scandium chloride complex [{(η5-C5Me5)Sc(μ-Cl)(THF)2}2][B(C6F5)4]2 (3). 1–3 were characterization by elemental analysis and NMR spectroscopy. 1 and 3 were further structurally authenticated by X-ray crystallography.

The cationic half-sandwich scandium mono(silylamide) complex [(η5-C5Me5)Sc{N(SiMe3)2}(PhNMe2)][B(C6F5)4] is generated directly from its corresponding bis(silylamide) precursor (η5-C5Me5)Sc[N(SiMe3)2]2 with [PhNMe2H][B(C6F5)4], and can activate C–Cl σ-bond of chlorobenzene to give the cationic scandium chloride complex [{(η5-C5Me5)Sc(μ-Cl)(THF)2}2][B(C6F5)4]2.Figure optionsDownload as PowerPoint slide