N-Heterocyclic Carbene Coinage Metal Complexes of the Germanium-Rich Metalloid Clusters [Ge9R3]− and [Ge9RI2]2− with R = Si(iPr)3 and RI = Si(TMS)3

Abstract

We report on the synthesis of novel coinage metal NHC (N-heterocyclic carbene) compounds of the germanium-rich metalloid clusters [Ge9R3]− and [Ge9RI2]2− with R = Si(iPr)3 and RI = Si(TMS)3. NHCDippCu{η3-Ge9R3} with R = Si(iPr)3 (1) represents a less bulky silyl group-substituted derivative of the known analogous compounds with R = Si(iBu)3 or Si(TMS)3. The coordination of the [NHCDippCu]+ moiety to the cluster unit occurs via one triangular face of the tri-capped trigonal prismatic [Ge9] cluster. Furthermore, a series of novel Zintl cluster coinage metal NHC compounds of the type (NHCM)2{η3-Ge9RI2} (RI = Si(TMS)3 M = Cu, Ag and Au; NHC = NHCDipp or NHCMes) is presented. These novel compounds represent a new class of neutral dinuclear Zintl cluster coinage metal NHC compounds, which are obtained either by the stepwise reaction of a suspension of K12Ge17 with Si(TMS)3Cl and the coinage metal carbene complexes NHCMCl (M = Cu, Ag, Au), or via a homogenous reaction using the preformed bis-silylated cluster K2[Ge9(Si(TMS)3)2] and the corresponding NHCMCl (M = Cu, Ag, Au) complex. The molecular structures of NHCDippCu{η3-Ge9(Si(iPr)3)3} (1) and (NHCDippCu)2{η3-Ge9(Si(TMS)3)2} (2) were determined by single crystal X-ray diffraction methods. In 2, the coordination of the [NHCDippCu]+ moieties to the cluster unit takes place via both open triangular faces of the [Ge9] entity. Furthermore, all compounds were characterized by means of NMR spectroscopy (1H, 13C, 29Si) and ESI-MS.

Synthesis and Reactivity of Multiple Phosphine‐Functionalized Nonagermanide Clusters

“…The two [NHC Dipp Cu] + moieties coordinate to the triangular faces of the [Ge 9 ] core. Cu2 coordinates to Ge7 to Ge9 with nearly similar Cu‐Ge distances between 2.4241(5) Å (Ge1‐Cu1) and 2.5654(5) Å (Ge9‐Cu2), which are in the range of known values,,, whereas Cu1 coordinates the opposite triangular face with significantly shorter and longer distances of 2.3674(5) Å (Ge3‐Cu1) to 2.6873(6) Å (Ge2‐Cu1). As a result the coordination of Cu1 and Cu2 by the NHC ligands and the centres of gravity of the Ge 3 faces significantly deviates from linearity [∡(ctp1‐Cu1‐C1)=166.6(1)° or ∡(ctp2‐Cu2‐C28)=170.4(1)° with ctp1: centre of gravity of Ge1 to Ge3 and ctp2: centre of gravity of Ge7 to Ge9] and the NHC Dipp ligands are tilted toward the Cr(CO) 5 coordinated site of the cluster.…”

Photoexcitation of Ge9− Clusters in THF: New Insights into the Ultrafast Relaxation Dynamics and the Influence of the Cation

“…Most excited inorganic clusters and complexes show intramolecular charge transfer [8,12,18,19] or triplet state dynamics [20][21][22][23][24]. The metalloid cluster [Ge9(Hyp)3] − (Hyp = Si(SiMe3)3) [25] (see Figure 1) with its high-yield synthesis, high stability under inert conditions and good solubility in organic solvents was used for, among others, build up reactions which give access to cluster aggregates and chain compounds with definite compositions [25][26][27][28][29][30][31][32][33]. The Ge9 − entity can be linked, for example, by transition metal ions like Cu + , Ag + , Au + [26] or Zn 2+ , Cd 2+ , Hg 2+ [27] to build up a neutral dimer in the latter case.…”

On the Variable Reactivity of Phosphine‐Functionalized [Ge9] Clusters: Zintl Cluster‐Substituted Phosphines or Phosphine‐Substituted Zintl Clusters

“…The bis-vinylated representative has not yet been introduceda saligand to at ransition-metal complex, whereasa serieso ft ransition-metal complexes bearing [Ge 9 {Si(TMS) 3 } 3 ] À ligandsh as been obtained, including compounds of the type [L x M{Ge 9 R 3 }] nÀ (R:S i(TMS) 3 ; M:C u ÀAu, CrÀW, Zn) [5] or transitionmetal-bridgedd imeric [Ge 9 ]c luster species[ {R 3 Ge 9 }M{Ge 9 R 3 }] nÀ (R:S i(TMS) 3 ; M:C u ÀAu, ZnÀHg, Mn). [9] In addition to the reports on silyl-substituted clusters and their transition-metal complexes,t he synthesis of stannyl-decorated clusters [Ge 9 {SnR 3 } 3 ] À (R: iPr,C y) has been reported, which form large [Ge 18 Pd 3 (SnR) 6 ] 2À aggregates upon reaction with Pd(PPh 3 ) 4 . [5b,d, 7] Furthermore, ar easonable synthesis route for the bis-silylated cluster [Ge 9 {Si(TMS) 3 } 2 ] 2À has been developed,w hich allowedf or the synthesis of mixed-substituted tris-silylated clusterl igands and led to the monomeric unit [Ge 9 {Si(TMS) 3 } 2 {Si(TMS) 2 (SiPh 3 )}] À and to the dimeric species [{Si(TMS) 3 } 2 Ge 9 {SiMe 2 -Ph-SiMe 2 }Ge 9 {Si(TMS) 3 } 2 ] 2À .…”