Derivatization of Phosphine Ligands with Bulky Deltahedral Zintl Clusters—Synthesis of Charge Neutral Zwitterionic Tetrel Cluster Compounds [(Ge₉{Si(TMS)₃}₂)^tBu₂P]M(NHC^Dipp) (M: Cu, Ag, Au)

Abstract

Reactions of silylated clusters [Ge{Si(TMS)}] or [Ge{Si(TMS)}] with dialkylhalophosphines RPCl (Cy, Pr,Bu) 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- (Pr) groups and the tris-silylated cluster [Ge{Si(TMS)}] yield the novel neutral cluster compounds [Ge{Si(TMS)}PR] (R: Cy (1), Pr (2)) with discrete Ge-P exo bonds. By contrast, the bulkier phosphineBuPCl does not react with [Ge{Si(TMS)}] due to steric crowding. However, the reaction with the bis-silylated cluster [Ge{Si(TMS)}] yields the novel cluster compound [Ge{Si(TMS)}PBu] (3). Subsequent reactions of compound 3 with NHCMCl (M: Cu, Ag, Au) yield the charge neutral zwitterionic compounds [(Ge{Si(TMS)})BuP]M(NHC) (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.

Acylation of Homoatomic Ge9 Cages and Subsequent Decarbonylation

“…Only recently, phosphine‐decorated [Ge 9 {Si(SiMe 3 ) 3 } n ] (4− n )− ( n= 2, 3) cluster compounds have been reported. The neutral species [Ge 9 {Si(SiMe 3 ) 3 } 3 PR 2 ] (R=Cy, i Pr) are of special interest as they carry a free electron pair at the phosphine ligand which allows for further reactions with Lewis acids to form for example the zwitterionic compounds [Ge 9 {Si(SiMe 3 ) 3 } 3 t Bu 2 P] M (NHC Dipp ) ( M =Cu, Ag, Au) …”

“…[14] The functionalization of the Ge 9 cluster unit by silyl ligands has been thoroughly investigated in recent years, with [Ge 9 {Si(SiMe 3 ) 2 (SiPh 3 )} 3 ] À , [15] [Ge 9 (SiHtBu 2 ) 3 ] À [16] and [Ge 9 {Si(SiMe 3 ) 3 } 2 (SiPh 2 pentenyl)] À [17] as the most prominent products.S uch silylated Ge 9 clustere ntities showhigherstability due to the shielding of the clusterc ore and the electronic effect of the ligands, but are still negatively charged and lack a direct organo-functionality.O nly recently,p hosphine-decorated [Ge 9 {Si(SiMe 3 ) 3 } n ] (4Àn)À (n = 2, 3) cluster compounds have been reported.T he neutrals pecies [Ge 9 {Si(SiMe 3 ) 3 } 3 PR 2 ]( R =Cy, iPr) are of speciali nteresta st hey carry af ree electron pair at the phosphine ligand which allows for furtherr eactions with Lewis acids to form for example the zwitterionic compounds [Ge 9 {Si(SiMe 3 ) 3 } 3 tBu 2 P]M(NHC Dipp )( M=Cu, Ag, Au). [18] [Ge 9 {Si(SiMe 3 ) 3 } 3 ] À is still reactive enough to undergo anucleophilic substitution reactionw ith bromoethane in acetonitrile to give the clusters pecies [{Si(SiMe 3 ) 3 } 3 Ge 9 Et]. [19] The latter is obtainedi nh igh yields and presents the first neutral and organo-functionalized Ge 9 cluster species which is soluble in non-polar solvents.…”

The influence of the FeCp(CO)2+moiety on the dynamics of the metalloid [Ge9(Si(SiMe3)3)3]−cluster in thf: synthesis and characterization by time-resolved absorption spectroscopy

“…10) is obtained via this synthetic route by varying the experimental conditions. The latter opened the door to "mixed"-substituted clusters like [Ge 9 (Hyp) 2 (HypPh)] − (HypPh = Si(SiMe 3 ) 2 (SiPh 3 ), 9 [Ge 9 (HypPh) 2 (Hyp)] − , 11 [Ge 9 (Hyp) 2 (PtBu 2 Cu-NHCDipp)] − , 12 [Ge 9 (Hyp) 2 (PtBu 2 )] − , 13 [Ge 9 (Hyp) 2 (SiPh 2 -CHvCH 2 )] − (ref. 14) and connected Ge 9 (Hyp) 2 units in [(Hyp) 2 Ge 9 -Me 2 Si-C 6 H 4 -SiMe 2 -Ge 9 (Hyp) 2 K] − .…”

Enhancing the Variability of [Ge9] Cluster Chemistry through Phosphine Functionalization

“…The phosphine group in 2 is disordered (Figure c) and attached to a further Ge vertex within the open square of the [Ge 9 ] cluster. The two individuals with occurrences of 56.9 % (P1A) and respectively 43.1 % (P1B) show Ge−P distances of 2.362(2) Å (Ge1−P1A) or 2.337(2) Å (Ge1−P1B), which are also in the range of reported Ge−P single bonds (Figure ) . The observed disorder probably results from the pyramidal inversion of the ligands bound to the P atom (P1A: Ge1, C28A, C32A; P1B: Ge1, C28B, C32B).…”