In this work, cluster expansion of nine-atomic germanium clusters with nickel and platinum atoms is reported. The compounds [(Me3Si)3­Si]3­Et­[Ge9Ni]­(PPh3) and [(Me3Si)3­Si]3­Et­[Ge9Pt]­(PPh3) are characterized by NMR spectroscopy, elemental analysis, and single crystal X-ray structure analysis. The latter represents the first intermetalloid Ge-Pt cluster with a platinum atom as part of a deltahedron. So far, only one compound of this type has been reported for the homologous Pd. Hence, with these new compounds, metal-coordinated deltahedral Ge9 clusters are now known for the whole triad of group 10 elements. The cluster compounds are accessible by treating [(Me3Si)3­Si]3­EtGe9 with η2-ethylene-bis-(triphenyl­phos­phine)-nickel­(0) and η2-ethylene-bis-(triphenyl­phos­phine)-platinum­(0), respectively, in toluene. The crystal structure determination reveals ten-vertex-closo-[Ge9 M]-cluster cores (M = Ni, Pt) bearing five exo-bonded ligands. Unlike the nine-vertex-cluster [(Me3Si)3­Si]3­EtGe9, the penta-functionalized platinum containing cluster compound [(Me3Si)3­Si]3­Et­[Ge9Pt]­(PPh3) does not show fluctuating behavior in solution over a wide temperature range on the NMR time scale, whereas the [(Me3Si)3­Si]3­Et­[Ge9Ni]­(PPh3) shows highly dynamic processes in solution at ambient temperature.

The first alkenyl-functionalized, uncharged deltahedral germanium clusters [{Si(SiMe)}Ge(CH)CH[double bond, length as m-dash]CH] (n = 1 or 3) comprising five Ge atoms are presented. All compounds were NMR-spectroscopically and mass-spectrometrically characterized. [{Si(SiMe)}Ge(CH)CH[double bond, length as m-dash]CH] was further characterized by X-ray structure analysis and Raman spectroscopy. Temperature-dependent NMR studies reveal dynamic behavior for both compounds in solution at room temperature. The propenyl derivative [{Si(SiMe)}GeCHCH[double bond, length as m-dash]CH] undergoes fast decomposition in solution. The possibility of the comparatively stable pentenyl-substituted Ge cluster as a candidate for follow-up reactions is highlighted.

The direct acylation of Ge Zintl clusters by the reaction of K[Ge {Si(SiMe ) } ] with acyl chlorides in hexane or toluene solutions is presented, leading to the neutral, carbonyl-derivatized products [{Si(SiMe ) } Ge (CO)R'] (R'=Me, iPr, tBu, Ph, Bz, cyclopropylmethyl, phenethyl, 4-vinylphenyl). This reaction is applicable to a wide range of acyl chlorides and allows for diverse functionalization of Ge Zintl clusters. [{Si(SiMe ) } Ge (CO)tBu] readily releases CO at ambient conditions under formation of [{Si(SiMe ) } Ge tBu]. This temperature-dependent decarbonylation most likely proceeds via a radical Norrish-type I α-bond cleavage. Except for R'=tBu and Bz all obtained acyl-derivatized Ge cluster compounds do not release CO even at elevated temperatures. All compounds were characterized by NMR spectroscopy. [{Si(SiMe ) } Ge (CO)R'] (R'=tBu, Ph, Me, iPr) as well as [{Si(SiMe ) } Ge tBu] were further structurally characterized by single crystal X-ray diffraction.

The close relationship of C60 and deltahedral tetrel element cluster anions has been pointed out before. We report herein on UV/Vis spectra of the Zintl anions and compounds [Ge9]2–, [(CH2=CH)2Ge9]2–, [{(Me3Si)3Si}3Ge9]–, {(Me3Si)3Si}3Ge9CH2CH3, {(Me3Si)3Si}3Ge9(CH2)2CH3, {(Me3Si)3Si}3Ge9(CH2)3CH=CH2, and [{(Me3Si)3Si}3Ge9CH2CH3]Pt(PPh3). The spectra are compared to those of the C60 fullerene, which were recorded under the same conditions. The UV/Vis spectrum of pristine [Ge9]2– resembles that of C60 and at higher concentration hint at the known trimeric [(Ge9)3]6–. The influence of ligand substitution at the Ge9 cluster‐core is highlighted. For this, the synthesis of the specifically functionalized deltahedral Ge9 clusters {(Me3Si)3Si}3Ge9(CH2)2CH3, {(Me3Si)3Si}3Ge9(CH2)2CH=CH2, and {(Me3Si)3Si}3Ge9(CH2)3C6H5 are reported for the first time and is achieved by the reaction of K[{(Me3Si)3Si}3Ge9] with the respective alkyl halides in acetonitrile. The newly synthesized products were characterized by NMR spectroscopy.

Triads with extended conjugated π-electronic systems between polyhedral cage molecules possess promising electronic properties. In contrast to the known fullerene-bridge-fullerene triads, fewer synthetic procedures are known for the related homoatomic deltahedral cage molecules of the heavier homologues of carbon. The synthesis of the organo-Zintl triads [RGe-CH═CH-CH═CH-GeR] with R = -CH═CH (R), -C(CH)═CH-CH═N(CH)NH ((2Z,4E)-7-amino-5-azahepta-2,4-dien-2-yl) (R) is reported, in which the deltahedral Ge cages carry an additional functional group, allowing for further connections. Both anionic cage entities bear a butadiene-1,4-diyl bridge which is formed by reacting the Zintl ion [Ge] with 1,4-bis(trimethylsilyl)butadiyne in ethylenediamine. The organic tethers can be attached by nucleophilic attack of the Ge clusters at the bis(trimethylsilyl)acetylene and (3Z/3E)-7-amino-1-(trimethylsilyl)-5-azahepta-3-en-1-yne, respectively, in ethylenediamine, and the products cis/trans-[RGe-CH═CH-CH═CH-GeR] and cis/cis-[RGe-CH═CH-CH═CH-GeR] have been isolated as [A(2,2,2-crypt)] salts with A = K, Rb, respectively. Crystals containing the novel anions [RGe-CH═CH-CH═CH-GeR] have been structurally characterized by X-ray diffraction methods, and the compounds have been investigated by H andC NMR as well as by Raman spectroscopy. The cis/cis configurational isomer of [RGe-CH═CH-CH═CH-GeR] was characterized by means of NMR spectroscopy. Via in situ NMR measurements, we shed some light on the formation of the Zintl triads [RGe-CH═CH-CH═CH-GeR] bearing supplemental organic tethers.