Z. Naturforsch. 2014, 69b, 1333 – 1347
Hydrometallation (M = Al, Ga) of Silicon- and Germanium-centred Oligoalkynes
Werner Uhl, Jörg Bohnemann, Benedikt Kappelt, Kira Malessa, Martina Rohling, Jens Tannert, Marcus Layh, and Alexander Hepp
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 (17), 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′} (813). Reactions with two equivalents of the hydrides afforded the dialkenyl compounds R2E{C[(M(CMe3)2]=CHR′}2 (E = Si, Ge, 1417), 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
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