Acylation of Homoatomic Ge9 Cages and Subsequent Decarbonylation. Issue 36 (1st June 2018)

• Record Type: Journal Article
• Authors: Frischhut, Sabine; Klein, Wilhelm; Drees, Markus; Fässler, Thomas F.
• Is Part Of: Chemistry. Volume 24:Issue 36(2018)
• Page Start: 9009
• Page End: 9014
• Publication Date: 2018-06-01
• Subjects: acylation -- functionalization -- germanium clusters -- radical decarbonylation -- Zintl; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201802318
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The direct acylation of Ge9 Zintl clusters by the reaction of K[Ge9 {Si(SiMe3 )3 }3 ] with acyl chlorides in hexane or toluene solutions is presented, leading to the neutral, carbonyl‐derivatized products [{Si(SiMe3 )3 }3 Ge9 (CO)R′] (R′=Me, i Pr, t Bu, Ph, Bz, cyclopropylmethyl, phenethyl, 4‐vinylphenyl). This reaction is applicable to a wide range of acyl chlorides and allows for diverse functionalization of Ge9 Zintl clusters. [{Si(SiMe3 )3 }3 Ge9 (CO) t Bu] readily releases CO at ambient conditions under formation of [{Si(SiMe3 )3 }3 Ge9 t Bu]. This temperature‐dependent decarbonylation most likely proceeds via a radical Norrish‐type I α‐bond cleavage. Except for R′= t Bu and Bz all obtained acyl‐derivatized Ge9 cluster compounds do not release CO even at elevated temperatures. All compounds were characterized by NMR spectroscopy. [{Si(SiMe3 )3 }3 Ge9 (CO)R′] (R′= t Bu, Ph, Me, i Pr) as well as [{Si(SiMe3 )3 }3 Ge9 t Bu] were further structurally characterized by single crystal X‐ray diffraction. Abstract : A new synthetic strategy for specifically functionalized Ge9 Zintl clusters is presented. A variety of neutral acyl‐derivatized Ge9 Zintl clusters were synthesized by reacting [{Si(SiMe3 )3 }3 Ge9 ] − with acyl chlorides in hexane or toluene. In particular, the pivaloyl‐functionalized Ge9 cluster eliminates carbon monoxide in solution at room temperature upon radical α‐bond cleavage.