|
Z. Naturforsch. 2014,
69b, 1333 – 1347
doi:10.5560/ZNB.2014-4151
Hydrometallation (M = Al, Ga) of Silicon- and Germanium-centred Oligoalkynes
Institut für Anorganische und Analytische Chemie der Universität Münster, Corrensstraße 30, 48149 Münster, Germany
Reprint requests to Prof. Werner Uhl. E-mail:
uhlw@uni-muenster.de
Received July 11, 2014 / published online December 19, 2014
Dedicated to Professor Hubert Schmidbaur on the occasion of his 80th birthday
Treatment of a variety of alkyl- and arylsilanes, R4−nSi(C≡C-R′)n, and -germanes, R4−nGe(C≡C-R′)n (1–7), with equimolar quantities of the dialkylmetal hydrides HMR′′2 (M = Al, Ga; R′′ = CMe3, CH2CHMe2) yielded by reduction of a single alkynyl group a series of mixed alkenyl-alkynyl compounds R4−nSi(C≡C-R′)n−1{C(MR′′2) =CHR′} (n = 2, 3) and R2Ge(C≡C-R′){C[M(CMe3)2]=CHR′} (8–13). Reactions with two equivalents of the hydrides afforded the dialkenyl compounds R2E{C[(M(CMe3)2]=CHR′}2 (E = Si, Ge, 14–17), Ge(C≡C–CMe3)2{C[Ga(CMe3)2]=CH–CMe3}2 (18) and MeSi(C≡C-p-Tol){C[Ga(CMe3)2]=CH-p-Tol}2 (19) [R = Ph, Mes, Me, C6F5; R′ =
CMe3, Ph). Most of the products were characterised by X-ray crystallography which for the alkenyl-alkynyl derivatives revealed short intramolecular contacts between the coordinatively unsaturated metal atoms and the α-C atoms of unreacted ethynyl groups Cα ≡C-R′.
Key words: Hydroalumination, Hydrogallation, Silicon, Germanium, Alkynes