Synthese und Struktur von AlTaO4

Synthesis and Structure of AlTaO₄ Single crystals of AlTaO₄ were prepared between 1310–1360°C and investigated by X-ray single crystal methods. It crystallizes with tetragonal symmetry (a = 460.6₅; c = 298.5 pm; space group D–P4₂/mnm). AlTaO₄ has got a statistical metal distribution with rutil structure. It shows metastable character in respect to lower temperatures.     

Synthese und Struktur von 1.4-Diborylcyclopentadienen

Bis(trimethylsilyl)cyclopentadiene reacts with two equivalents of boron halides to the bis(dihalogenoboryl)cyclopentadienes I, II and III. Reactions of I, II and III with tetramethyltin and dimethylamine yield the dimethyl- and bis(dimethylamino)-substituted compounds IV and V. The fluoro compound VI is synthesized by the reaction of III with arsenic trifluoride. Addition of pyridine to I and II yields the adducts VII and VIII. Structure and bonding properties of I–VIII are discussed by ¹H-, ¹³C-, ¹¹B- and ¹⁹F.n.m.r- and by i.r. and m.s. data.     

Synthese und Struktur von assoziiertem μ-Phosphinodiboran und von phosphorsubstituierten Derivaten

Associated -phosphinodiborane, (-H₂PB₂H₅) _n , is formed in the reaction of H₂P(BH₃)₂Na with HCl in diethyl ether solution at –96°C. The formation of B–H–B bridges is demonstrated by IR and¹¹B-NMR spectra. (-H₂PB₂H₅) _n decomposes thermally to diborane and polymeric phosphinoborane analogous to -H₂NB₂H₅. Other phosphorus substituted -phosphinodiboranes associated via B–H–B bridges are formed in the reaction of the salts (CH₃)PH(BH₃)₂Li, (CH₃)₂P(BH₃)₂Li, andPhPH(BH₃)₂Li with HCl.

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Herrn Professor Dr.E. Hayek zum 70. Geburtstag gewidmet.     

Synthese und Struktur von Ammin- und Amidokomplexen des Iridiums

Synthesis and Structure of Ammine and Amido Complexes of Iridium The reaction of (NH₄)₂[IrCl₆] with NH₄Cl at 300 °C in a sealed glass ampoule yields the iridium(III) ammine complex (NH₄)₂[Ir(NH₃)Cl₅], which crystallizes isotypically with K₂[Ir(NH₃)Cl₅] in the orthorhombic space group Pnma with Z = 4, and a = 1350.0(2); b = 1028.5(3); c = 689.6(2) pm. The reaction of (NH₄)₂[IrCl₆] with NH₃ at 300 °C, however, gives the already known [Ir(NH₃)₅Cl]Cl₂ beside a small amount of [Ir(NH₃)₄Cl₂]Cl₂. In pure form [Ir(NH₃)₅Cl]Cl₂ is obtained by ammonolysis of (NH₄)₂[Ir(NH₃)Cl₅] at 300 °C with NH₃. [Ir(NH₃)₄Cl₂]Cl₂ crystallizes triclinic (P1, Z = 1, a = 660,2(3); b = 680,4(3); c = 711,1(2) pm; α = 103,85(2)°, β = 114,54(3)°, γ = 112,75(2)°). The structure contains Cl^– anions and [Ir(NH₃)₄Cl₂]²⁺ cations with a trans position of the Cl atoms. Upon reaction of [Ir(NH₃)₅Cl]Cl₂ with Cl₂ one ammine ligand is eliminated yielding [Ir(NH₃)₄Cl₂]Cl, which is transformed to orthorhombic [Ir(NH₃)₄(OH₂)Cl]Cl₂ (Pnma, Z = 4, a = 1335,1(3); b = 1047,9(2); c = 673,4(2) pm) by crystallization from water. In the octahedral complex [Ir(NH₃)₄(OH₂)Cl]²⁺ the four ammine ligands have an equatorial position, whereas the Cl atom and the aqua ligand are arranged axial. Oxidation of (NH₄)₂[Ir(NH₃)Cl₅] with Cl₂ at 330 °C affords the tetragonal Ir^IV complex (NH₄)[Ir(NH₃)Cl₅] (P4nc, Z = 2, a = 702.68(5); c = 912.89(9) pm). Its structure was determined using the powder diagram. Oxidation of (NH₄)₂[Ir(NH₃)Cl₅] with Br₂ in water, on the other hand, gives (NH₄)₂[IrBr₆] crystallizing in the K₂[PtCl₆] type. Oxidation of (PPh₄)₂[Ir(NH₃)Cl₅] with PhI(OAc)₂ in CH₂Cl₂ affords the Ir^V amido complex (PPh₄)[Ir(NH₂)Cl₅].     

Synthese und Struktur von Vinamidinatodiiodalanen [1]

The diiodoalanes (C₅H₇R₂N₂)AlI₂ [ 6 ; R = Me ( a ), Ph ( c )] are obtained from the corresponding alanes (C₅H₇R₂N₂)AlH₂ ( 5 ) and [Me₃NH]I in good yields. (C₅H₇R₂N₂)AlI₂ [ 6 ; R = iso‐Pr ( b )] is alternatively prepared, as well as 6a , from the corresponding vinamidine lithium compound C₅H₇R₂NLi ( 8 ) and AlI₃. (C₅H₇Me₂N₂)AlBr₂ ( 9a ) is formed according to both methods. The X‐ray structures of 6a and 6b are reported.     

Synthese,Struktur und dynamisches Verhalten von Cyclopentadienylboranen

The cyclopentadienylboranes I–XI have been synthesized by the reaction of halogenoboranes with cyclopentadienyl-trimethylsilanes, -trimethylstannanes and -lithium compounds. Substitution reactions at the boron atom in III and VIII with tetramethylstannane and dimethylamine lead to the cyclopentadienylboranes XII–XV. The structures of I–XV have been investigated by ¹H-, ¹³C- and ¹¹B-n.m.r. measurements. The 5-trimethylsilyl-cyclopentadienylboranes show a dynamic behaviour due to sigmatropic rearrangements. The influence of a boryl ligand on the speed of these rearrangements is discussed.     

Zur Synthese und Struktur von K3N

Synthesis and Structure of K₃N Two phases in the binary system K/N have been obtained via co‐deposition of potassium and nitrogen onto polished sapphire at 77 K and subsequent heating to room temperature. The powder diffraction pattern of one of these phases can be satisfactorily interpreted by assuming the composition K₃N, and the anti‐TiI₃ structure‐type, which is also adopted by Cs₃O. The resulting hexagonal lattice constants are: a = 779.8(2), c = 759.2(9) pm, Z = 2, P6₃/mcm. Comparison with possible structures of K₃N generated by computational methods and refined at Hartree‐Fock‐ and DFT level, reveals that the energetically most favoured structure has not formed (presumable Li₃P‐type), but instead one of those with very low density. In this respect, the findings for K₃N are analogous to the results on Na₃N. The thermal evolution of the deposited starting mixture has been investigated. Hexagonal K₃N transforms to another K/N phase at 233 K. Its XRD can be fully indexed resulting in an orthorhombic cell a = 1163, b = 596, c = 718 pm. Decomposition leaving elemental potassium as the only residue occurs at 263 K.     

Synthese und Struktur von Mo2NCl7

Synthesis and Structure of Mo₂NCl₇ The reaction of VN with MoCl₅ at 175 °C in a sealed glass ampoule yields the molybdenum(V) nitride chloride Mo₂NCl₇ in form of air sensitive black crystals with the triclinic space group P1¯ and a = 905.7(8); b = 975.4((6); c = 1283.4(8) pm, α = 103.13(4)°; β = 109.83(5)° und γ = 98.58(5)°. The crystal structure is built up from dinuclear units [Mo₂N₂Cl₇]^3— and [Mo₂Cl₇]³⁺, which are connected by asymmetric nitrido bridges to form endless chains. Within both dinuclear units the Mo atoms are bridged by three Cl atoms resulting in a Mo‐Mo distance of 349.2(3) pm in the unit [Mo₂N₂Cl₇]^3—. In case of [Mo₂Cl₇]³⁺, however, a shorter Mo‐Mo distance of 289.4(3) pm is observed, which can be interpreted by a single bond. Correspondingly a reduced magnetic moment of 0.95 B.M. per Mo atom is observed.     

Synthese,Struktur und Eigenschaften von drei Tetranatrium-tetrametaphosphimat-Hydraten

Synthesis, Structure, and Properties of Three Tetrasodium Tetrametaphosphimate Hydrates Single crystals of three tetrasodium tetrametaphosphimate hydrates Na₄(PO₂NH)₄ · x H₂O with x = 2 and 3, respectively, have been obtained and characterized by single crystal X-ray diffraction. Dimorphous Na₄(PO₂NH)₄ · 3 H₂O is formed at RT. It crystallizes monoclinic ( 1 ) or triclinic ( 2 ) (α-Na₄(PO₂NH)₄ · 3 H₂O ( 1 ): P2₁, a = 1002.7(2), b = 1189.7(2), c=1193.1(2)pm, β=104.93(1)°, Z=4; β-Na₄(PO₂NH)₄ · 3 H₂O ( 2 ): P 1¯, a = 843.64(9), b = 848.54(10), c = 994.7(2) pm, α = 83.07(1), β = 76.31(1), γ = 87.46(1)°, Z = 2). Compound 2 is formed in the presence of NaCl during the crystallization from aqueous solution. Tetrasodium tetrametaphosphimate dihydrate ( 3 ) is formed at 60 °C (Na₄(PO₂NH)₄ · 2 H₂O ( 3 ): C2/c, a = 2225.6(3), b = 513.0(1), c = 1566.7(2) pm, β = 134.21(1)°, Z = 4). In 1 and 2 the P₄N₄ ring of the tetrametaphosphimate ions attains a saddle and in 3 a twistboat conformation. The conformations of the anions have been analysed using torsion angles, displacement asymmetry parameters, and puckering parameters. The (PO₂NH)₄^4– rings of the compounds 1 , 2 , and 3 are linked by N–H · · &mid