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Derivatization of Phosphine Ligands with Bulky Deltahedral Zintl ClustersSynthesis of Charge Neutral Zwitterionic Tetrel Cluster Compounds [(Ge9{Si(TMS)3}2)tBu2P]M(NHCDipp) (M: Cu, Ag, Au)
journal contribution
posted on 2017-07-26, 00:00 authored by Felix
S. Geitner, Jasmin V. Dums, Thomas F. FässlerReactions of silylated clusters [Ge9{Si(TMS)3}3]− or [Ge9{Si(TMS)3}2]2− with
dialkylhalophosphines
R2PCl (Cy, iPr, tBu) at ambient temperature yield the first tetrel Zintl cluster compounds bearing phosphine moieties. Varying
reactivity of the dialkylhalophosphines toward the silylated clusters
is observed depending on the bulkiness of the phosphine’s alkyl
substituents and on the number of hypersilyl groups at the tetrel
cluster. Reactions between phosphines with small cyclohexyl- (Cy)
or isopropyl- (iPr) groups and the tris-silylated
cluster [Ge9{Si(TMS)3}3]− yield the novel neutral cluster compounds [Ge9{Si(TMS)3}3PR2] (R: Cy (1), iPr (2)) with discrete Ge–P exo bonds. By contrast, the bulkier phosphine tBu2PCl does not react with [Ge9{Si(TMS)3}3]− due to steric
crowding. However, the reaction with the bis-silylated cluster [Ge9{Si(TMS)3}2]2− yields the novel cluster compound [Ge9{Si(TMS)3}2PtBu2]− (3). Subsequent reactions of compound 3 with NHCDippMCl (M: Cu, Ag, Au) yield the charge neutral zwitterionic compounds
[(Ge9{Si(TMS)3}2)tBu2P]M(NHCDipp) (M:
Cu, Ag, Au) (4–6), in which compound 3 acts as a phosphine ligand bearing a bulky tetrel Zintl cluster moiety. Compounds 4–6 also represent the first uncharged examples for 3-fold substituted
tetrel Zintl clusters.