1,722,076 research outputs found
Reaction Modes of a Tetragermabutadiene: Cycloadditions versus Ge−Ge Bond Cleavages<sup>1</sup>
No full textTreatment of hexakis(2,4,6-triisopropylphenyl)tetragermabuta-1,3-diene (2) with selenium
in the presence of Et3P furnishes a selenatetragermacyclopentene derivative with an
endocyclic Ge−Ge double bond. With small amounts of water 2 reacts to afford an
oxatetragermacyclopentane, analogous to THF. The reaction of 2 with Et3PTe proceeds by
cleavage of all Ge−Ge bonds to yield a 1,2,4,5-tetratellura-3,6-digermacyclohexane derivative
together with small amounts of the “double-decker” compound R4Ge4Te6, R = 2,4,6-iPr3C6H2,
and a telluradigermirane. In the reaction of 2 with 2-methoxyphenyl isocyanide one Ge−Ge
double bond is cleaved to give the 4(1H)-trigermatimine ring system with an endocyclic Ge−Ge double bond and the known tetrakis(2,4,6-triisopropylphenyl)digermene (10). All new
compounds were characterized by X-ray crystallography. Redetermination of the structure
of 10 revealed two independent molecules with GeGe bond lengths of 2.2894(6) and 2.2635(14) Å, respectively
Reaction Modes of a Tetragermabutadiene: Cycloadditions versus Ge−Ge Bond Cleavages<sup>1</sup>
No full textTreatment of hexakis(2,4,6-triisopropylphenyl)tetragermabuta-1,3-diene (2) with selenium
in the presence of Et3P furnishes a selenatetragermacyclopentene derivative with an
endocyclic Ge−Ge double bond. With small amounts of water 2 reacts to afford an
oxatetragermacyclopentane, analogous to THF. The reaction of 2 with Et3PTe proceeds by
cleavage of all Ge−Ge bonds to yield a 1,2,4,5-tetratellura-3,6-digermacyclohexane derivative
together with small amounts of the “double-decker” compound R4Ge4Te6, R = 2,4,6-iPr3C6H2,
and a telluradigermirane. In the reaction of 2 with 2-methoxyphenyl isocyanide one Ge−Ge
double bond is cleaved to give the 4(1H)-trigermatimine ring system with an endocyclic Ge−Ge double bond and the known tetrakis(2,4,6-triisopropylphenyl)digermene (10). All new
compounds were characterized by X-ray crystallography. Redetermination of the structure
of 10 revealed two independent molecules with GeGe bond lengths of 2.2894(6) and 2.2635(14) Å, respectively
1,2-Bis(ferrocenyl)digermene: A d−π Electron System Containing a GeGe Unit
No full textThe synthesis and structural analysis of the 1,2-bis(ferrocenyl)digermene
(E)-Tip(Fc)GeGe(Fc)Tip (Tip = 2,4,6-triisopropylphenyl,
Fc = ferrocenyl), a stable crystalline compound, is reported. In this
digermene, two ferrocenyl d electron systems are bridged by a GeGe
π spacer. As is evident from X-ray crystallographic, spectroscopic,
and electrochemical analysis, this 1,2-bis(ferrocenyl)digermene shows
effective d−π interaction and the GeGe π
bond is stable in the solid state. The GeGe double bond is
cleaved at elevated temperatures in the presence of butadiene, with
concomitant loss of the π conjugation in the molecule
1,2-Bis(ferrocenyl)digermene: A d−π Electron System Containing a GeGe Unit
No full textThe synthesis and structural analysis of the 1,2-bis(ferrocenyl)digermene
(E)-Tip(Fc)GeGe(Fc)Tip (Tip = 2,4,6-triisopropylphenyl,
Fc = ferrocenyl), a stable crystalline compound, is reported. In this
digermene, two ferrocenyl d electron systems are bridged by a GeGe
π spacer. As is evident from X-ray crystallographic, spectroscopic,
and electrochemical analysis, this 1,2-bis(ferrocenyl)digermene shows
effective d−π interaction and the GeGe π
bond is stable in the solid state. The GeGe double bond is
cleaved at elevated temperatures in the presence of butadiene, with
concomitant loss of the π conjugation in the molecule
Microscopy and Electrical Properties of Ge/Ge Interfaces Bonded by Surface-Activated Wafer Bonding Technology
No full text
We have performed microscopy and electric measurements of the Ge/Ge interfaces bonded by surface-activated wafer bonding (SAB) technology. Similarly to the case of Si wafer bonding, two Ge wafers of 50 mm in diameter, both doped by Ga with a concentration of 2.2×1014 cm-3, were bonded by SAB at room temperature. The SAB process was performed in a high-vacuum chamber (10-4 Pa) at room temperature. The bonding was achieved by attaching and pressing the two wafers, the contact surfaces of which were activated by argon ion beam irradiation. The cross-sectional scanning electron microscopy (SEM) image of the Ge/Ge bonded sample apparently shows an interface that seems to be caused by crystallographic discontinuity. The measurement by transmission electron microscope (TEM) reveals an atomic-disordered layer structure of about 3 nm in thickness at the interface of the bonded Ge/Ge. The resistivity of bonded Ge/Ge samples across the interfaces was measured at 300 and 77 K. As compared with the result of similar measurements for non bonded bulk Ge samples, we find no significant difference in resistivity between the bulk Ge and bonded Ge/Ge samples.
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Near-Infinite-Chain Polymers with Ge=Ge Double Bonds
Full text linkDespite considerable interest in heteroatom-containing conjugated polymers, there are only few examples with heavier p-block elements in the conjugation path. The recently reported heavier acyclic diene metathesis (HADMET) allowed for the synthesis of a polymer containing Ge=Ge double bonds-albeit insoluble and with limited degree of polymerization. By incorporation of long alkyl chains, we now obtained soluble representatives, which exhibit degrees of polymerization near infinity according to diffusion-ordered NMR spectroscopy (DOSY) and dynamic light scattering (DLS). UV/Vis and NMR data confirm the presence of σ,π-conjugation across the silylene-phenylene linkers between the Ge=Ge double bonds. Favorable intermolecular dispersion interactions lead to ladder-like cylindrical assemblies as confirmed by X-ray diffraction (XRD), small angle X-ray scattering (SAXS) and DLS. AFM and TEM images of deposited thin films reveal lamellar ordering of extended polymer bundles
Near-Infinite-Chain Polymers with Ge=Ge Double Bonds
Full text linkDespite considerable interest in heteroatom-containing conjugated polymers, there are only few examples with heavier p-block elements in the conjugation path. The recently reported heavier acyclic diene metathesis (HADMET) allowed for the synthesis of a polymer containing Ge=Ge double bonds—albeit insoluble and with limited degree of polymerization. By incorporation of long alkyl chains, we now obtained soluble representatives, which exhibit degrees of polymerization near infinity according to diffusion-ordered NMR spectroscopy (DOSY) and dynamic light scattering (DLS). UV/Vis and NMR data confirm the presence of σ,π-conjugation across the silylene-phenylene linkers between the Ge=Ge double bonds. Favorable intermolecular dispersion interactions lead to ladder-like cylindrical assemblies as confirmed by X-ray diffraction (XRD), small angle X-ray scattering (SAXS) and DLS. AFM and TEM images of deposited thin films reveal lamellar ordering of extended polymer bundles
Nahezu unendlich lange Polymere mit Ge=Ge-Doppelbindungen
Full text linkTrotz erheblichen Interesses an heteroatomhaltigen konjugierten Polymeren sind Beispiele mit schwereren Elementen des p-Blocks im Konjugationspfad rar. Die kürzlich beschriebene Metathese schwererer acyclischer Diene (HADMET) ermöglichte die Synthese eines Ge=Ge-Doppelbindungen enthaltenden Polymers, wenn auch eines unlöslichen mit begrenztem Polymerisationsgrad. Durch Einführung langer Alkylketten erhielten wir nun lösliche Vertreter mit – nach diffusionsabhängiger NMR-Spektroskopie (DOSY) und dynamischer Lichtstreuung (DLS) – nahezu unendlichen Polymerisationsgraden. UV/Vis und NMR-Daten bestätigen das Vorliegen von σ,π-Konjugation entlang der Silylen-Phenylen-Verknüpfungen zwischen den Ge=Ge-Einheiten. Günstige intermolekulare Dispersionswechselwirkungen führen zu leiterartigen, zylindrischen Aggregaten, wie durch Röntgendiffraktometrie (XRD), Kleinwinkel-Röntgenstreuung (SAXS) und DLS bestätigt. AFM- und TEM-Bilder abgeschiedener dünner Schichten offenbaren eine lamellare Anordnung ausgedehnter Polymerbündel
Tetrakis(trialkylsilyl)digermenes. Salient Effects of Trialkylsilyl Substituents on Planarity around the GeGe Bond and Remarkable Thermochromism
No full textX-ray structural analyses of tetrakis(trialkylsilyl)digermenes have shown that the trialkylsilyl
substituents enforce near-planar geometry around the GeGe
bonds, in accordance with theoretical predictions. A
remarkable temperature dependence of the UV−vis
spectra of tetrakis(triisopropylsilyl)digermene in
solution
was observed, suggesting an equilibrium between two
different structures around the GeGe bond
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