Synthese und Kristallstrukturen der Phosphaniminato-Komplexe [AlCl2(NPEt3)]2, [GaI2(NPEt3)]2 und [GaI2(NPPh3)]2

Synthesis and Crystal Structures of the Phosphoraneiminato Complexes [AlCl₂(NPEt₃)]₂, [GaI₂(NPEt₃)]₂, and [GaI₂(NPPh₃)]₂ [AlCl₂(NPEt₃)]₂ ( 1 ) is made according to the known method by reaction of aluminium trichloride with the silylated phosphaneimine Me₃SiNPEt₃ in acetonitrile; it is isolated as colourless, moisture sensitive crystals. The phosphoraneiminato complexes [GaI₂(NPEt₃)]₂ ( 2 ) and [GaI₂(NPPh₃)]₂ ( 3 ), on the other hand, are obtained by redox reactions as pale yellow crystals; ( 2 ) of “gallium(I) iodide” with Me₃SiNPEt₃ in toluene and ( 3 ) of gallium with N-iodine triphenylphosphaneimine, INPPh₃, in tetrahydrofuran. 1 and 3 are characterized spectroscopically and by crystal structure determinations; 2 is characterized only crystallographically. 1 : Space group Pbca, Z = 4; lattice dimensions at –70 °C: a = 1232.6(2), b = 1341.1(2), c = 1393.4(3) pm, R₁ = 0.0315. 1 forms centrosymmetric molecules in which the Al atoms are linked via Al–N bonds of the two (NPEt₃^–) groups; with 185.0 and 184.4 pm these bonds are of almost the same lengths. 2 : Space group Pbca, Z = 4; lattice dimensions at –80 °C: a = 1380.0(1), b = 1311.0(1), c = 1429.1(1) pm, R₁ = 0.0273. 2 crystallizes isotypically with 1 . The gallium atoms of the centrosymmetric Ga₂N₂ four-membered ring are connected with Ga–N distances of equal length (190.9 pm). 3 · THF: Space group P2₁2₁2₁, Z = 2; lattice dimensions at –140 °C: a = 1494.6(1), b = 1536.3(1), c = 974.6(1) pm, R₁ = 0.0382. 3 forms dimeric molecules in which the gallium atoms are linked via the N atoms of the (NPPh₃^–) groups to form a non-planar Ga₂N₂ four-membered ring of C₂ symmetry with Ga–N bonds of equal lengths – within standard deviations – of 194.7 pm. The phosphoraneiminato groups are arranged in a synperiplanar way.     

Synthese und Kristallstruktur von [(PhCH2)2GaF(tBuNH2)]2 · 2 THF

Synthesis and Crystal Structure of [(PhCH₂)₂GaF(^tBuNH₂)]₂ · 2 THF (PhCH₂)₂GaF reacts with ^tBuNH₂ to the adduct [(PhCH₂)₂GaF(^tBuNH₂)] ( 1 ). 1 was characterized by NMR, IR and MS techniques. 1 can be recrystallized from THF forming crystals of [ 1 ]₂ · 2 THF. According to an X-ray structure analysis [ 1 ]₂ · 2 THF consists of dimers of 1 formed by hydrogen bridges. The THF molecules are coordinated to [ 1 ]₂ by hydrogen bridges, too.     

[PtIn6][GaO4]2 – das erste Oxid mit [PtIn6]‐Oktaedern. Darstellung,Charakterisierung und Rietveldverfeinerung – mit einer Bemerkung zur Mischkristallreihe [PtIn6][GaO4]2–x[InO4]x (0 < x ≤ 1)

[PtIn₆][GaO₄]₂ – The First Oxide Containing [PtIn₆] Octahedra. Preparation, Characterisation, and Rietveld Refinement – With a Remark to the Solid Solution Series [PtIn₆][GaO₄]_2‐x[InO₄]_x (0 < x ≤ 1) The novel oxides [PtIn₆][GaO₄]_2–x[InO₄]_x (0 < x ≤ 1) are formed by heating intimate mixtures of Pt, In, In₂O₃, and Ga₂O₃ in the corresponding stoichiometric ratio in corundum crucibles under an atmosphere of argon (1220 K, 70 h). The compounds are black, stable in air at room temperature, reveal a semiconducting behaviour, and decompose only in oxidizing acids. X‐ray powder diffraction patterns can be indexed by assuming a face centered cubic unit cell with lattice parameters ranging from a = 1001.3(1) pm (x = 0) to a = 1009.3(1) pm (x = 1). According to a Rietveld refinement [PtIn₆][GaO₄]₂ crystallizes isotypic to the mineral Pentlandite (Fm3m, Z = 4, R(profile) = 6.11%, R(intensity) = 3.95%). The characteristic building units are isolated [PtIn₆]¹⁰⁺ octahedra which are linked via [GaO₄]^5– tetrahedra to a three dimensional framework. Starting from [PtIn₆][GaO₄]₂ the substitution of Ga³⁺ ions by larger In³⁺ ions leads to the formation of a solid solution series according to the general formula [PtIn₆][GaO₄]_2–x[InO₄]_x and becomes apparent in an increase of the lattice parameter.     

Das unterschiedliche Reaktionsverhalten von basefreiem Tris(trimethylsilyl)methyl‐Lithium gegenüber den Trihalogeniden der Erdmetalle und des Eisens

The Variable Reaction Behaviour of Base‐free Tris(trimethylsilyl)methyl Lithium with Trihalogenides of Earth‐Metals and Iron Base‐free tris(trimethylsilyl)methyl Lithium, Tsi–Li, reacts with the earth‐metal trihalogenides (MHal₃ with M = Al, Ga, In and Hal = Cl, Br, I) primarily to give the metallates [Tsi–MHal₃]Li. Simultaneous to this simple metathesis a methylation also takes place, mainly with heavier halogenides of Ga and In with excess Tsi–Li, forming the mono and dimethyl compounds Tsi–M(Me)Hal (M = Ga, In; Hal = I), Tsi–MMe₂ (M = Ga), and the bis(trisyl)derivative (Tsi)₂InMe, respectively and the main by‐product 1,3‐disilacyclobutane. Representatives of each type of compound have been isolated by fractionating crystallizations or sublimations and characterized by spectroscopic methods (¹H, ¹³C, ²⁹Si NMR, IR, Raman) and X‐ray elucidations. Reduction takes place, when FeCl₃ reacts with Tsi–Li (1 : 3 ratio) in toluene at 55–60 °C, yielding red‐violet Fe(Tsi)₂, 1,1,1‐tris(trimethylsilyl)‐2‐phenyl ethane and low amounts of Tsi–Cl. Fe(Tsi)₂ is monomeric, crystallizes in the monoclinic space group C2/c and consists of a linear C–Fe–C skeleton with d(Fe–C) of 204,5(4) pm.     

Coordination modes of 2-mercapto-1,3-benzothiazolate in gallium and indium complexes

2-Mercapto-1,3-benzothiazole (mbztH) may act as a chelating or bridging ligand. In this study, reactions of mbztH with Me₃Ga and Me₃In were examined. The products were characterized by NMR spectroscopy, elemental analyses, melting point, and molecular weight determinations. Formation of mononuclear chelating complexes Me₂M(mbzt) (M = Ga, In) was observed in solutions. Crystallization of Me₂M(mbzt) yielded uncommon non-symmetrical dinuclear complexes Me₄M₂(mbzt)₂, in which one metal is bonded to two sulfurs and the other to two nitrogens.     

Synthesis and Structures of Gallium‐β‐Diketiminate Complexes: Isolation of a Dinuclear Gallium(II) Complex

The sterically demanding β‐diketiminate ligand L^dmp [L^dmp = HC{(CMe)N(dmp)}₂, dmp = C₆H₃‐2,6‐Me₂] was used to stabilize various gallium complexes in the formal oxidation states +II and +III. The reaction of in situ generated [L^dmpLi] with gallium chloride affords [L^dmpGaCl₂] ( 1 ), which was used as starting complex to synthesize a variety of gallium(III) compounds [L^dmpGaX₂] [X = F ( 2 ), I ( 3 ), H ( 4 ), and Me ( 5 )]. Synthesis of the dinuclear complex [L^dmpGaI]₂ ( 6 ), with gallium in the formal oxidation state +II was accomplished by converting “GaI” with in situ generated [L^dmpLi] in toluene. All compounds were characterized by elemental analyses, NMR spectroscopy, LIFDI‐TOF‐MS, and single‐crystal X‐ray diffraction. Additionally DFT calculations were performed for analysis of the bonding in 6 .     

Temperature dependence of GaSb and AlGaSb solar cells

Sb-based alloys offer great potential for photovoltaic and thermophotovoltaic applications. In this paper, we study the performance of Al_xGa_1-xSb (x = 0, 0.15, and 0.50) single-junction solar cells over a temperature range of 25–250 °C. The dark current-voltage, one-sun current-voltage, and external quantum efficiency measurements were acquired at different temperatures. Correlations between experimental and numerical results are made to draw conclusions about the thermal behavior of the cells. It is shown that, while the bandgaps decrease linearly with temperature leading to the reduction of open-circuit voltages, the short-circuit current densities decrease with non-linear trends. The temperature-dependent dark current densities were extracted by fitting the dark current-voltage curves to single- and double-diode models to give an insight into the effect of intrinsic carrier concentration (n_i) on the cell performance. We find that the n_i has a significant impact on temperature-dependent cell performance. These findings could lay a groundwork for the future Sb-based photovoltaic systems that operate at high temperatures.     

Invention,development, and status of the blue light-emitting diode,the enabler of solid-state lighting

The realization of the first high-brightness blue-light-emitting diodes (LEDs) in 1993 sparked a more than twenty-year period of intensive research to improve their efficiency. Solutions to critical challenges related to material quality, light extraction, and internal quantum efficiency have now enabled highly efficient blue LEDs that are used to generate white light in solid-state lighting systems that surpass the efficiency of conventional incandescent lighting by 15–20×. Here we discuss the initial invention of blue LEDs, historical developments that led to their current state-of-the-art performance, and potential future directions for blue LEDs and solid-state lighting.