Very recently it was shown that the metalloid cluster compound {Ge(9)[Si(SiMe(3))(3)](3)}(-) can be used for subsequent reactions as the shielding of the cluster core is rather incomplete. Here further reactions of with M(+) sources of group 11 metals are described, leading to metalloid cluster compounds of the formula {MGe(18)[Si(SiMe(3))(3)](6)}(-) (M = Ag, Cu). These reactions can be seen as first steps into a supramolecular chemistry with metalloid cluster compounds. Beside this feature, the structural properties as well as the bonding situations in these cluster compounds are discussed.

Very recently it was shown that the metalloid cluster compound {Ge(9)[Si(SiMe(3))(3)](3)}(-) can be used for subsequent reactions as the shielding of the cluster core is rather incomplete. So the reaction of with M(+) sources of group 11 metals gives metalloid cluster compounds of the formulae {MGe(18)[Si(SiMe(3))(3)](6)}(-) (M = Au, Ag, Cu). These reactions can be seen as first steps into a supramolecular chemistry with metalloid cluster compounds. However, further build-up reactions lead to insoluble products, thus better soluble starting materials are needed for further build-up reactions. Here the first neutral MGe(18)[Si(SiMe(3))(3)](6) (M = Hg, Cd, Zn) compounds are described, exhibiting a strongly enhanced solubility in inert solvents. Beside the synthesis, the structural properties as well as the bonding situations in these cluster compounds are discussed.

Very recently it was shown that the metalloid cluster compound {Ge(9)[Si(SiMe(3))(3)](3)}(-)1 can be used for subsequent reactions as the shielding of the cluster core is rather incomplete. So the reaction of 1 with Cr(CO)(3)(CH(3)CN)(3) leads to a cluster enlargement where the chromium atom is incorporated into the cluster core. Here further applications of 1 as a flexible ligand in coordination chemistry are presented where the reaction of 1 with Mo(CO)(3)(EtCN)(3) and W(CO)(3)(CH(3)CN)(3) leads to [(CO)(3)MoGe(9)R(3)](-)4 and [(CO)(3)WGe(9)R(3)](-)5 respectively (R = Si(SiMe(3))(3)), showing that 1 can indeed be used as a flexible ligand in coordination chemistry. Structural and electronic properties of the Ge(9)M clusters 4 and 5 are discussed as well as mechanistic aspects of their formation.

Femtosecond pump-probe absorption spectroscopy in tetrahydrofuran solution has been used to investigate the dynamics of a metalloid cluster compound {Ge9[Si(SiMe3)3]3}(-). Upon UV photoexcitation, the transients in the near-infrared spectral region showed signatures reminiscent of excess electrons in THF (bound or quasi-free) whereas in the visible part excited state dynamics of the cluster complex dominates.

Metalloid cluster compounds [1] of the general formula M n R m (n > m; R = ligand such as Si(SiMe 3 ) 3 or N(SiMe 3 ) 2 ) are ideal model compounds for molecular entities in the gray area between molecules and the solid state. [2] This borderland is of particular interest especially for metals or semi-metals, as drastic changes in the physical properties take place during the reduction from salt-like oxidized compounds (e.g. oxides, halides: non-conducting) to the elemental bulk phase (metal: conducting; semi-metal: semiconducting).[3] As the dimensions of metalloid clusters are in the nanometer range, the synthesis of metalloid clusters also opens the possibility of obtaining structural information on small nanoparticles, an important prerequisite for structure-property relations in this expanding area. [4] In the case of germanium, several different synthetic routes have been introduced in recent years, leading to a number of metalloid clusters, which exhibit new and unusual structures as well as exceptional bonding properties. Hence, by a reductive elimination reaction [Ge 10 (SitBu 3 ) 6 I]+ is obtained, [5] whereas the metalloid clusters [Ge 5 {CH-(SiMe 3 ) 2 } 4 ][6] and [Ge 6 (C 6 H 3 Dipp 2 ) 2 ] (Dipp = 2,6-iPr 2 C 6 H 3 ) [7] have been synthesized by reductive coupling reactions. The most fruitful route to metalloid germanium clusters to date uses the disproportionation reaction of dissolved metastable Ge I halides, which thus allows the synthesis of clusters with eight [Ge 8 {N(SiMe 3 ) 2 } 6 ], [8] [Ge 8 {(OtBu) 2 C 6 H 3 } 6 ], [9] nine [Ge 9 {Si(SiMe 3 ) 3 } 3 ]À , [10] ten [Ge 10 Si{Si(SiMe 3 ) 3 } 4 -(SiMe 3 ) 2 Me] À , [11] [Ge 10 {Fe(CO) 4 } 8 {Na(thf) 3 } 6 ], [12] and up to fourteen [Ge 14 {E(SiMe 3 ) 3 } 5 {Li(thf) 2 } 3 ] (E = Si, Ge) [13,14] germanium atoms in the cluster core.Among metalloid main-group clusters in general [Ge 10 {Fe(CO) 4 } 8 {Na(thf) 3 } 6 ] is an exceptional example as it is the only metalloid cluster which is exclusively stabilized by transition-metal-based ligands. This shows that the influence of transition-metal ligands on metalloid clusters is nearly unexplored. Furthermore, such metalloid clusters stabilized with transition-metal-based ligands might open an access to new metastable binary materials.[15] However, transitionmetal reagents have already been used in the chemistry of germanium clusters; either as ligands in direct synthesis to gain fully substituted clusters, such as [Ge 6 {Cr(CO) 5 X compounds (X = À1: M = Cu, Ag, Au;[23, 24] X = 0: M = Zn, Cd, Hg [25] ). We now present a second example of a metalloid maingroup cluster exclusively stabilized by transition-metal-based ligands, showing a unique arrangement of the tetrel atoms in the cluster core. After work up of a reaction mixture of a metastable GeBr solution (CH 3 CN, THF, nBu 3 N (2:2:1); 0.28 m) with solid K[FeCp(CO) 2 ] (Cp = cyclopentadienyl) we obtained black crystals of the metalloid germanium cluster [Ge 12 {FeCp(CO) 2 } 8 {FeCp(CO)} 2 ] (1). The molecular structure of 1, as shown in Figure ...

It caused a sensation eight years ago, when the first room temperature stable molecular compound with a Mg–Mg bond (LMgMgL, L = chelating ligand) containing magnesium in the oxidation state +1 was prepared.

The cluster anion {Ge 9 [Si(SiMe 3 ) 3 ] 3 } -(1) is transferred intact into the gas phase via the electro spray method. Subsequently the fragmentation of 1 after resonant excitation as well as the oxidation reaction with O 2 and Cl 2 are investigated in an FT-ICR mass spectrometer (Fourier Transform Ion Cyclotron Resonance). Unlike former results with off-resonant excitation the fragmentation leads mainly to the end-product Ge 9 -. Moreover, applying an on-resonant excitation the dissociation experiment can be quantified; 2.0 ± 0.15 eV (193 ± 15 kJ·mol -1 ) for the elimination of the first two ligands and 2.7 ± 0.15 eV (261 ± 15 kJ·mol -1 ) for all ligands, respectively. Particular attention is turned on the first step, where sterically encumbered Si 2 (SiMe 3 ) 6 molecules are formed in a concerted reaction. This result, which is also important for elemental reactions on metal surfaces in catalyses, is based on experi-

Metalloide Cluster [1] der allgemeinen Summenformel M n R m (n > m; R= Ligand, beispielsweise Si(SiMe 3 ) 3 oder N(SiMe 3 ) 2 ) sind ideale Modellverbindungen für den unbekannten Grenzbereich zwischen Molekülen und Festkçrperphase. [2] Dieses Grenzgebiet ist besonders für Metalle und Halbmetalle von Interesse, da drastische Veränderungen der physikalischen Eigenschaften während der Reduktion von salzartigen, oxidierten Verbindungen (z. B. Oxide, Halogenverbindungen: Isolatoren) zur entsprechenden Festkçrperphase (Metall: Leiter; Halbmetall: Halbleiter) stattfinden. [3] Da sich die Abmessungen metalloider Cluster bis in den Nanometerbereich erstrecken, erçffnet die Synthese solcher Clusterverbindungen auch einen Zugang zu strukturellen Informationen kleiner Nanopartikel, eine wichtige Grundvoraussetzung für das Verständnis von Struktur-Eigenschafts-Beziehungen in diesem schnell wachsenden Gebiet. [4] Im Fall von Germanium wurden in den letzten Jahren mehrere verschiedene Syntheserouten für metalloide Cluster vorgestellt, wobei gezeigt werden konnte, dass innerhalb dieser Klasse an Clusterverbindungen neue Strukturmotive und außergewçhnliche Bindungssituationen realisiert werden. So wurde [Ge 10 (SitBu 3 ) 6 I] + über eine reduktive Eliminierung erhalten, [5] während [Ge 5 {CH(SiMe 3 ) 2 } 4 ] [6] und Ge 6 (C 6 H 3 Dipp 2 ) 2 (Dipp = 2,6-iPr 2 C 6 H 3 ) [7] mithilfe einer reduktiven Kupplung synthetisiert wurden. Die bisher fruchtbarste Syntheseroute zu metalloiden Germaniumclustern nutzt die Disproportionierung von metastabilen Germanium(I)-Halogeniden. Auf diesem Weg konnten metalloide Cluster mit acht ([Ge 8 {N(SiMe 3 ) 2 } 6 ], [8] [Ge 8 {(OtBu) 2 -C 6 H 3 } 6 ]), [9] neun ([Ge 9 {Si(SiMe 3 ) 3 } 3 ] À ), [10] zehn ([Ge 10 Si-{Si(SiMe 3 ) 3 } 4 (SiMe 3 ) 2 Me] À , [11] [Ge 10 {Fe(CO) 4 } 8 {Na(thf) 3 } 6 ]) [12] und vierzehn ([Ge 14 {E(SiMe 3 ) 3 } 5 {Li(thf) 2 } 3 ] (E = Si, Ge)) [13,14] Germaniumatomen im Clusterkern hergestellt werden.Im Bereich metalloider Hauptgruppenmetallcluster nimmt [Ge 10 {Fe(CO) 4 } 8 {Na(thf) 3 } 6 ] eine außergewçhnliche Stellung ein, da es sich dabei um den einzigen metalloiden Cluster handelt, der ausschließlich von Übergangsmetallliganden stabilisiert wird; folglich ist der Einfluss von Übergangsmetallliganden auf metalloide Cluster nahezu unerforscht. Weiterhin kçnnten übergangsmetallstabilisierte metalloide Cluster einen Zugang zu neuen binären Materialien erçffnen. [15] Übergangsmetallverbindungen wurden jedoch in der Vergangenheit bereits in der Synthese von Germaniumclustern eingesetzt; entweder als Liganden, um vollständig substituierte Cluster wie [Ge 6 {Cr(CO) 5 } 6 ] 2À [16] zu erhalten, oder in verschiedenen Folgereaktionen mit Zintl-Ionen, [17] die zu grçßeren Clustern wie [Pt@Pb 12 ] 2À , [18] [Au 3 Ge 45 ] 9À[19] oder [Ni 3 Ge 18 ] 4À führten. [20] Solche Folgereaktionen mit Übergangsmetallverbindungen wurden kürzlich auch für den metalloiden Germaniumcluster [Ge 9 {Si(SiMe 3 ) 3 } 3 ] À beschrieben. Über diese Reaktionen sind die Clusterverbindungen[M(CO) 3 Ge 9 {S...