New Aspects of Hydrogallation Reactions with Alkynes: Simple Addition versus Formation of Cyclophanes

Treatment of 1,4-bis(3,3-dimethyl-1-butynyl)benzene C6H4(C⋮C−CMe3)2 with 2 equiv of diethylgallium hydride resulted in addition of one Ga−H bond to each triple bond of the starting compound. Whereas in that case products of secondary reactions could not be isolated, dineopentylgallium hydride afforded a [3,3]-cyclophane derivative with two bridging Ga−CH2−CMe3 groups, which may be derived from the simple addition product by condensation and release of trineopentylgallium. A cis-arrangement of Ga and H was observed in all cases

New Insight into Hydrogallation Reactions: Facile Synthesis of a Gallium-Bridged [3,3,3]-Cyclophane

Treatment of 1,3,5-tris(3,3-dimethyl-1-butynyl)benzene, C6H3(C⋮C−CMe3)3, with di(neopentyl)gallium hydride, HGa(CH2CMe3)2, resulted in the addition of one Ga−H bond to each C⋮C triple bond (hydrogallation). Spontaneous condensation by the release of tri(neopentyl)gallium yielded a [3,3,3]-cyclophane derivative (1) with three tricoordinated Ga atoms in bridging positions

Hydrogallation of Trimethylsilylethynylbenzenes: Generation of Potential Di- and Tripodal Chelating Lewis Acids

Hydrogallation of 1,4-bis(trimethylsilylethynyl)benzene and 1,3,5-tris(trimethylsilylethynyl)benzene with dialkylgallium hydrides R2GaH (R = Et, nPr, iPr, neopentyl, tBu) afforded the corresponding addition products with intact GaR2 groups and two or three alkenyl substituents. In all products the gallium atoms attacked those carbon atoms that are attached to the trimethylsilyl groups. The expected cis arrangement of gallium and hydrogen atoms at the CC double bonds was detected only with di(tert-butyl)gallium residues. Smaller alkyl groups gave the spontaneous formation of the trans-addition products. Cis/trans isomerization is an inevitable step for the formation of effective chelating Lewis acids, and in particular the trisalkene derivatives form interesting chalice-like hollows containing three Lewis-acidic centers at their inner surfaces

Hydrogallation of Trimethylsilylethynylbenzenes: Generation of Potential Di- and Tripodal Chelating Lewis Acids

Hydrogallation of 1,4-bis(trimethylsilylethynyl)benzene and 1,3,5-tris(trimethylsilylethynyl)benzene with dialkylgallium hydrides R2GaH (R = Et, nPr, iPr, neopentyl, tBu) afforded the corresponding addition products with intact GaR2 groups and two or three alkenyl substituents. In all products the gallium atoms attacked those carbon atoms that are attached to the trimethylsilyl groups. The expected cis arrangement of gallium and hydrogen atoms at the CC double bonds was detected only with di(tert-butyl)gallium residues. Smaller alkyl groups gave the spontaneous formation of the trans-addition products. Cis/trans isomerization is an inevitable step for the formation of effective chelating Lewis acids, and in particular the trisalkene derivatives form interesting chalice-like hollows containing three Lewis-acidic centers at their inner surfaces

Inorganic Frameworks from Selenidotetrelate Anions [T₂Se₆]⁴⁻ (T = Ge, Sn): Synthesis, Structures, and Ionic Conductivity of [K₂(H₂O)₃][MnGe₄Se₁₀] and (NMe₄)₂[MSn₄Se₁₀] (M = Mn, Fe)

Syntheses, structures, and physical properties of three inorganic framework compounds [K2(H2O)3][MnGe4Se10] (1), (NMe4)2[MnSn4Se10] (2), and (NMe4)2[FeSn4Se10] (3) are presented. The title compounds are based on a prominent open framework anionic structure; in these cases, however, they contain K+, the smallest type of counterion to be included so far (1), or represent Sn analogues (2, 3). Both changes with respect to related compounds are reflected in peculiar physical properties, such as ion conductivity or relatively small band gaps

Hydrogallation of Trimethylsilylethynylbenzenes: Generation of Potential Di- and Tripodal Chelating Lewis Acids

Hydrogallation of 1,4-bis(trimethylsilylethynyl)benzene and 1,3,5-tris(trimethylsilylethynyl)benzene with dialkylgallium hydrides R2GaH (R = Et, nPr, iPr, neopentyl, tBu) afforded the corresponding addition products with intact GaR2 groups and two or three alkenyl substituents. In all products the gallium atoms attacked those carbon atoms that are attached to the trimethylsilyl groups. The expected cis arrangement of gallium and hydrogen atoms at the CC double bonds was detected only with di(tert-butyl)gallium residues. Smaller alkyl groups gave the spontaneous formation of the trans-addition products. Cis/trans isomerization is an inevitable step for the formation of effective chelating Lewis acids, and in particular the trisalkene derivatives form interesting chalice-like hollows containing three Lewis-acidic centers at their inner surfaces

New Lithium Chalcogenidotetrelates, LiChT: Synthesis and Characterization of the Li⁺-Conducting Tetralithium <i>ortho-</i>Sulfidostannate Li₄SnS₄

A new lithium chalcogenidotetrelate, denoted as LiChT phase, with the elemental combination Li/Sn/S was synthesized as solvent-free and solvent-containing salts. We present and discuss syntheses, crystal structures, spectroscopic and thermal properties of the phases, as well as the Li⁺ ion conductivity of Li₄SnS₄, which is formally related to the thio-LISICON parent system Li₄GeS₄, and thus represents the first member of a new thiostannate-LISICON family. The solvent-free title compound shows a very promising Li⁺ ion conductivity of 7 × 10^–5 S·cm^–1 at 20 °C and 3 × 10^–3 S·cm^–1 at 100 °C, which is exceptionally high for a ternary compound. Activation energies for the lithium ion transport measured via impedance spectroscopy (0.41 eV) correlate reasonably well with the values (0.29 to 0.33 eV) deduced from ionic mobility studies by ⁷Li solid-state NMR spectroscopy. NMR two-time correlation functions suggest the occurrence of an additional, geometrically more restricted, ultra-slow-motional process down to 121 K

Lithium Chalcogenidotetrelates: LiChTSynthesis and Characterization of New Li⁺ Ion Conducting Li/Sn/Se Compounds

Five new lithium chalcogenidotetrelates, so-called “LiChT” phases, with the elemental combination Li/Sn/Se, Li4[SnSe4] (1), 1∞{Li2[SnSe3]} (2), and the respective solvates Li4[SnSe4]·13H2O (3), Li4[Sn2Se6]·14H2O (4), and Li4[SnSe4]·16MeOH (5) were generated in single-crystalline form. We present and discuss syntheses, crystal structures, spectroscopic and thermal behavior, as well as Li+ ion conducting properties of the phases that represent uncommon Li+ ion conducting materials with a maximum conductivity found for 1 (σ20°C = 2 × 10–5 S·cm–1, σ100°C = 9 × 10–4 S·cm–1). The latter was elucidated via impedance spectroscopy and further studied by electronic structure calculations, revealing vacancy migration as the dominant Li+ transport mechanism. Thus, studies on a selenido-LISICON family were found to be a very interesting starting point for an extension of the LISICON-related solid state lithium ion conductors (SSLIC)

Lithium Chalcogenidotetrelates: LiChTSynthesis and Characterization of New Li⁺ Ion Conducting Li/Sn/Se Compounds

Five new lithium chalcogenidotetrelates, so-called “LiChT” phases, with the elemental combination Li/Sn/Se, Li₄[SnSe₄] (<b>1</b>), ¹_∞{Li₂[SnSe₃]} (<b>2</b>), and the respective solvates Li₄[SnSe₄]·13H₂O (<b>3</b>), Li₄[Sn₂Se₆]·14H₂O (<b>4</b>), and Li₄[SnSe₄]·16MeOH (<b>5</b>) were generated in single-crystalline form. We present and discuss syntheses, crystal structures, spectroscopic and thermal behavior, as well as Li⁺ ion conducting properties of the phases that represent uncommon Li⁺ ion conducting materials with a maximum conductivity found for <b>1</b> (σ_20°C = 2 × 10^–5 S·cm^–1, σ_100°C = 9 × 10^–4 S·cm^–1). The latter was elucidated via impedance spectroscopy and further studied by electronic structure calculations, revealing vacancy migration as the dominant Li⁺ transport mechanism. Thus, studies on a selenido-LISICON family were found to be a very interesting starting point for an extension of the LISICON-related solid state lithium ion conductors (SSLIC)