Synthese,Kristallstruktur und Festkörper‐NMR‐spektroskopische Untersuchung des Oxonitridosilicates BaSi6N8O

Synthesis, Crystal Structure and Solid‐State NMR Spectroscopic Investigation of the Oxonitridosilicate BaSi₆N₈O The phase‐pure oxonitridosilicate BaSi₆N₈O has been synthesized starting from BaCO₃ and silicon diimide Si(NH)₂ in a radiofrequency furnace at temperatures below 1630 °C as a coarsely crystalline colorless material. The structure has been determined by single‐crystal X‐ray diffraction analysis (BaSi₆N₈O, space group Imm2 (no. 44), a = 810.5(2), b = 967.8(2), c = 483.7(1) pm, V = 379.4(2)·10⁶ pm³, Z = 2, R1 = 0.014, 618 independent reflections, 44 parameters). The oxonitridosilicate comprises a three‐dimensional network structure of corner sharing SiN₄ and SiON₃ tetrahedra with Ba²⁺ located in the resulting voids. BaSi₆N₈O is isostructural with the oxonitridoalumosilicate (sialon) Sr₂Al_xSi_12?xN_16?xO_2+x (x ≈ 2) that previously has been described in the literature. Furthermore, the anionic network of BaSi₆N₈O derives from that of the homeotypic reduced nitridosilicate SrSi₆N₈ by a topotactic insertion of oxygen into the Si–Si single bonds. In the ²⁹Si MAS‐NMR spectrum two sharp isotropic signals have been observed at ?54.0 and ?56.3 ppm, respectively. With respect to their observed intensity ratio of 1 : 2.1(1) these two signals have to be attributed to the central atoms of SiON₃ and SiN₄ tetrahedra, respectively, which is in accordance with the X‐ray crystal structure determination (Si at Wyckoff positions 4d (SiON₃) and 8e (SiN₄)).     

Die neuen Schichtsilicate Ba3Si6O9N4 und Eu3Si6O9N4

The New Layer‐Silicates Ba₃Si₆O₉N₄ and Eu₃Si₆O₉N₄ The new oxonitridosilicate Ba₃Si₆O₉N₄ has been synthesized in a radiofrequency furnace starting from BaCO₃, amorphous SiO₂ and Si₃N₄. The reaction temperature was at about 1370 °C. The structure of the colorless compound has been determined by single‐crystal X‐ray diffraction analysis (Ba₃Si₆O₉N₄, space group P3 (no. 143), a = 724.9(1) pm, c = 678.4(2) pm, V = 308.69(9)· 10⁶ pm³, Z = 1, R1 = 0.0309, 1312 independent reflections, 68 refined parameters). The compound is built up of corner sharing SiO₂N₂ tetrahedra forming corrugated layers between which the Ba²⁺ ions are located. Substitution of barium by europium leads to the isotypic compound Eu₃Si₆O₉N₄. Because no single‐crystals could be obtained, a Rietveld refinement of the powder diffractogram was conducted for the structure refinement (Eu₃Si₆O₉N₄, space group P3 (no. 143), a = 711.49(1) pm, c = 656.64(2) pm, V = 287.866(8) ·10⁶ pm³, R_p = 0.0379, R_F² = 0.0638). The ²⁹Si MAS‐NMR spectrum of Ba₃Si₆O₉N₄ shows two resonances at ?64.1 and ?66.0 ppm confirming two different crystallographic Si sites.     

Synthese,Röntgenstrukturanalyse und Multikern‐NMR‐spektroskopische Untersuchung einiger intramolekular stickstoffstabilisierter Bor‐, Aluminium‐ und Galliumorganyle

Synthesis, X‐Ray Structure, and Multinuclear NMR Investigation of some intramolecularly Nitrogen stabilized Organoboron, ‐aluminum, and ‐gallium Compounds The intramolecularly nitrogen stabilized organoaluminum‐ and organoboron compounds Me₂Al(CH₂)₃NMe₂ ( 1 ), Me₂AlC₁₀H₆‐8‐NMe₂ ( 2 ), ⁱPr₂Al(CH₂)₃NEt₂ ( 3 ), (CH₂)₅Al(CH₂)₃NMe₂ ( 4 ), and (CH₂)₅B(CH₂)₃NMe₂ ( 5 ) are synthesized from Me₂AlCl and the corresponding organolithium compounds and from AlCl₃ or BCl₃, the lithium alkyl and ⁱPrMgCl or BrMg(CH₂)₅MgBr, respectively. AlCl₃ and GaCl₃ react with Li(CH₂)₃NMe₂ or LiCH₂CHMeCH₂NMe₂ forming Cl₂AlCH₂CHMeCH₂NMe₂ ( 6 ), Cl₂Al(CH₂)₃NMe₂ ( 8 ), and Cl₂Ga(CH₂)₃NMe₂ ( 9 ). The reaction of 6 and of 8 or 9 with BrMg(CH₂)₅MgBr and BrMg(CH₂)₆MgBr, respectively, yields (CH₂)₅AlCH₂CHMeCH₂NMe₂ ( 7 ), (CH₂)₆Al(CH₂)₃NMe₂ ( 10 ), and (CH₂)₆Ga(CH₂)₃NMe₂ ( 11 ). MeAlCl₂, made by the redistribution reaction of AlCl₃ with Me₂AlCl, reacts with 2 equivalents of Li(CH₂)₃NMe₂ yielding MeAl[(CH₂)₃NMe₂]₂ ( 12 ) and with MeN[(CH₂)₃MgCl]₂ under formation of MeAl[(CH₂)₃]₂NMe ( 13 ). MeAlCl₂, MeGaCl₂, or GaCl₃ accordingly react with one equivalent of organolithium reagent to give the intramolecularly nitrogen stabilized organoaluminum and organogallium chlorides MeClAl(CH₂)₃NMe₂ ( 14 ), MeClGa(CH₂)₃NMe₂ ( 15 ), MeClGaC₆H₄‐2‐CH₂NMe₂ ( 16 ) as well as Cl₂GaC₆H₄‐2‐CHMeNMe₂ ( 17 ). The compounds were characterized by elemental analyses, mass spectroscopy, ¹H, ¹¹B, ¹³C and ²⁷Al NMR investigations. Single crystal X‐ray structure analyses of 1 , 2 , 4 , 5 and 17 reveal the monomeric molecular structures with intramolecular nitrogen coordination.     

Synthese,Strukturen, NMR‐ und EPR‐spektroskopische Untersuchungen an Übergangsmetallkomplexen monofluorsubstituierter Acylselenoharnstoffliganden

Synthesis, Structures, NMR and EPR Investigations on Transition Metal Complexes of monofluorosubstituted Acylselenourea Ligands The syntheses and the structures of the ligand N, N‐diethyl‐N′‐(2‐fluoro)benzoylselenourea HEt₂mfbsu and the complexes [Ni(Et₂mfbsu)₂] and [Zn(Et₂mfbsu)₂] as well as of the ligand N, N‐diisobutyl‐N′‐(2‐fluoro)benzoylselenourea HBuⁱ₂mfbsu and the complexes [Ni^II(Buⁱ₂mfbsu)₂] and [Pd^II(Buⁱ₂mfbsu)₂] are reported. The ligands coordinate bidendately forming bischelates. The Pd^II and Ni^II complexes are cis coordinated; in [Zn^II(Et₂mfbsu)₂] the ligands are tetrahedrally arranged. The structure of the also obtained bis[diisobutylamino‐(2‐fluorobenzoylimino)methyl]diselenide is reported. The Cu^II complexes of both selenourea ligands could not be isolated. They were obtained as oils. Their EPR spectra, however, confirm the presence of Cu^II bischelates unambiguously. Detailed NMR investigations ‐ ¹H‐, ¹³C‐ and ¹⁹F‐COSY, HMBC and HMQC ‐ on [M^II(Et₂mfbsu)₂] (M = Ni^II, Zn^II) allow an exact assignment of all signals to the magnetically active nuclei of the complexes.     

Sm2Si3O3N4 und Ln2Si2,5Al0,5O3,5N3,5 (Ln = Ce,Pr, Nd,Sm, Gd) – neuer synthetischer Zugang zu N‐haltigen Melilith‐Phasen und deren Einkristall‐Röntgenstrukturanalyse

Sm₂Si₃O₃N₄ and Ln₂Si_2.5Al_0.5O_3.5N_3.5 (Ln = Ce, Pr, Nd, Sm, Gd) – A Novel Synthetic Approach for the Preparation of N‐containing Melilites and X‐Ray Single‐Crystal Structure Determination The high‐temperature synthesis of nitridosilicates using an especially developed rf furnace was now transferred to the preparation of single‐crystalline oxonitridosilicates and oxonitridoaluminosilicates (sialons). Sm₂Si₃O₃N₄ was obtained by the reaction of SrCO₃, Si(NH)₂, and the respective lanthanoides, for Ln₂Si_2.5Al_0.5O_3.5N_3.5 (Ln = Ce, Pr, Nd, Sm, Gd) additionally AlN was used. The compounds were obtained as coarsely crystalline products. Their crystal structures were refined on the basis of single‐crystal X‐ray diffraction data. Sm₂Si₃O₃N₄ (a = 768.89(4), c = 499.60(4) pm) and the isotypic sialons Ce₂Si_2.5Al_0.5O_3.5N_3.5 (a = 779.20(3), c = 506.94(4) pm), Pr₂Si_2.5Al_0.5O_3.5N_3.5 (a = 778.26(4), c = 508.56(5) pm), Nd₂Si_2.5Al_0.5O_3.5N_3.5 (a = 776.15(4), c = 506.7(3) pm), Sm₂Si_2.5Al_0.5O_3.5N_3.5 (a = 772.63(13), c = 502.80(9) pm), and Gd₂Si_2.5Al_0.5O_3.5N_3.5 (a = 774.15(5), c = 506.46(4) pm) are new representatives of the N‐containing melilite structure type (space group P 4 2₁m (no. 113), Z = 2). For the structure analysis specific models were applied, which have been developed by Werner et al. on the basis of powder diffraction data.     

Beiträge zur Kristallchemie und zum thermischen Verhalten von wasserfreien Phosphaten. XXXVI [1] Synthese,Kristallstruktur und spektroskopische Charakterisierung von Palladium(II)‐diphosphat Pd2P2O7

Synthesis, Crystal Structure and Spectroscopical Characterization of Palladium(II)‐Diphosphate Pd₂P₂O₇ Pd₂P₂O₇ is synthesized by heating (T_max = 500 °C) stoichiometric amounts of PdO and phosphoric acid. Using chemical vapour transport experiments (850 °C → 750 °C, addition of PdCl₂) Pd₂P₂O₇ was crystallized. Pd₂P₂O₇ adopts its own structure type (C 2/c (No. 15), Z = 4, a = 13,151(2) Å, b = 5,172(1) Å, c = 8,139(1) Å, β = 97,52(1)°, 1160 independent reflections, 55 variables, R1 = 0,021 and wR2 = 0,050). Square‐planar [PdO₄]‐units are linked by diphosphate‐groups generating a 3D framework. Within this framework ribbons may be distinguished. Thus Pd₂P₂O₇ might be described as palladium(II)‐[diphosphatopalladate(II)]. The results of various spectroscopic measurements (IR, Raman, UV/VIS, ³¹P‐MAS‐NMR) are reported and discussed within the context of the crystal structure.     

Synthese,Kristallstruktur und spektroskopische Charakterisierung von Tetraphosphorhexaoxiddiselenid P4O6Se2

Synthesis, Crystal Structure, and Spectroscopic Characterization of Tetraphosphorus Hexaoxide Diselenide P₄O₆Se₂ P₄O₆Se₂ has been prepared by photochemical selenation of P₄O₆ with red selenium in CS₂ in presence of catalytical amounts of iodine. Isolation and single crystal growth were performed by fractional crystallization and subsequent sublimation. The compound crystallizes in the monoclinic space group P2₁/c (Nr. 14) with a = 11.473(2); b = 6.536(1); c = 11.796(2) Å; β = 90.06(1)°; Z = 4; R₁ = 0.030; wR² = 0.073. Within the limits of experimental error, the P₄O₆Se₂ molecules exhibit C_2v symmetry in the crystal. Bond lengths and angles within the molecule as well as the arrangement of the molecules within the crystal are discussed; IR-, Raman-, and ³¹P solution NMR data are reported.     

Das Indid‐Hydrid Ba9[In]4[H]: Synthese,Kristallstruktur, NMR‐Spektroskopie,Chemische Bindung

The new indide hydride Ba₉[In]₄[H] was synthesized from the elements in stoichiometric proportions using the inherent hydrogen content of commercial elemental barium as hydrogen source. Its structure, constituting a new type, was determined using single‐crystal X‐ray data (tetragonal, space group I4/m, a = 1397.3(2), c = 591.8(1) pm, Z = 2) in sufficient quality (R1 = 0.0261) to allow identification and location of the hydride ion as well as the refinement of its thermal parameter. The crystal structure of Ba₉[In]₄[H] exhibits isolated indium atoms, which are coordinated by 10 barium cations in a cubicosahedral arrangement. The hydride anions are octahedrally surrounded by six Ba²⁺ cations. According to [HBa₄Ba_2/2] these octahedra are connected by opposite corners to form chains running along the c axis. The presence of the hydride ion was determined by solid state NMR spectroscopy, where the chemical shift of the ¹H‐MAS‐NMR signal of–9.0 ppm nicely corresponds to the values in BaH₂ and other metallid hydrides. Like in other binary alkaline‐earth indides, the band structure calculated in the frame of the FP‐LAPW methods shows a pseudo band gap slightly above the Fermi level, associated with the electron precise valence electron count after Zintl (isolated In^5–). The title compound was compared to other hydrides and indides both according to the structural as well as the bonding features.     

Indenylvanadium(V)‐Verbindungen. Darstellung,Struktur und NMR‐spektroskopische Untersuchungen

Indenylvanadium(V) Compounds Synthesis, Structure, and NMR Spectroscopic Studies Syntheses of the indenylvanadium(V)compounds are described: ^tC₄H₉N = V(η⁵‐C₉H₇)Cl₂ ( 1 ), ^tC₄H₉N = V(η⁵‐C₉H₇)Br₂ ( 2 ), ^tC₄H₉N = V(η⁵‐C₉H₇)(O^tC₄H₉)Cl ( 3 ), ^tC₄H₉N = V(η¹‐C₉H₇)(O^tC₄H₉)₂ ( 4 ), ^tC₄H₉N = V(η¹‐C₉H₇)₂(O^tC₄H₉) ( 5 ), ^tC₄H₉N = V(η¹‐C₉H₇)(η⁵‐C₅H₅) · (O^tC₄H₉) ( 6 ), ^tC₄H₉N = V(η¹‐C₉H₇)(η⁵‐C₅H₅)(NH^tC₄H₉) ( 7 ). All compounds were totally characterized by spectroscopic methods (MS; ¹H, ¹³C, ⁵¹V NMR), 3 by single crystal X‐ray diffraction. For 6 the presence of the diastereomeres RR/SS and RS/SR was shown by NMR spectroscopy. The chlorovanadate (IV) complex [NHC₄H₉]₂⁺[(^tC₄H₉N)₇V₇ · (μ‐Cl)₁₄Cl₂]^2– has been obtained by decomposition of 1 in solution; the crystal structure indicates a wheel structure with hydrogen bonds between the tert‐butylammonium cations and the complex anion.     

Synthese und Kristallstruktur von [(n‐Bu)4N][W6Cl18]

Synthesis and Crystal Structure of [(n‐Bu)₄N][W₆Cl₁₈] Single‐crystals of [(n‐Bu)₄N][W₆Cl₁₈] were obtained as thin needles by adding methanol to a solution of W₆Cl₁₈ and [(n‐Bu)₄N]Cl in tetrahydrofuran. The structure was determined by single‐crystal X‐ray diffraction at 210 K. [(n‐Bu)₄N][W₆Cl₁₈] crystallizes in the monoclinic space group C 2/c with Z = 8 and the lattice parameters a = 2175.6(1) pm, b = 1738.0(1) pm, c = 2160.36(9) pm, and β = 91.680(5) °. The crystal structure contains isolated [(W₆Cl₁₂ⁱ)Cl₆^a]^— clusters and [(n‐Bu)₄N]⁺ ions.     

Nd3Si5AlON10 – Synthese,Kristallstruktur und Eigenschaften eines Sialons im La3Si6N11‐Strukturtyp

Nd₃Si₅AlON₁₀ – Synthesis, Crystal Structure, and Properties of a Sialon Isotypic with La₃Si₆N₁₁ Nd₃Si₅AlON₁₀ was synthesized by the reaction of silicon diimide, aluminium nitride, aluminium oxide, and neodymium in a pure nitrogen atmosphere at 1650 °C using a radiofrequency furnace. The compound was obtained as a coarsely crystalline solid. According to the single‐crystal structure determination the title compound is isotypic with Ln₃Si₆N₁₁ (Ln = La, Ce, Pr, Nd, Sm). Nd₃Si₅AlON₁₀ (P4bm, a = 1007.8(1), c = 486.3(1) pm, Z = 2, R₁ = 0.016, wR₂ = 0.031) is built up by a three‐dimensional network structure of corner sharing SiON₃ and (Si/Al)N₄ tetrahedra (molar ratio Si : Al = 3 : 1). According to lattice energetic calculations using the MAPLE concept a differentiation of O and N seems to be reasonable. One of the two different sites for the tetrahedral centres is probably occupied by Si (distances: Si–O: 168.4(1), Si–N: 173.6(3)–176.0(4) pm) the second site by Si and Al with the molar ratio 3 : 1 (distances: (Si/Al)–N: 172.0(3)–176.6(2) pm). The Nd³⁺ ions are located in the voids of the (Si₅AlON₁₀)^9– framework (distances: Nd–O: 261.07(8), Nd–N: 246.1(2)–286.6(2) pm).     

Zur Kenntnis von Tripraseodym‐hexanitridotriborat Pr3B3N6: Neue Synthese und Verfeinerung der Kristallstruktur

On Tripraseodymium Hexanitridotriborate Pr₃B₃N₆: New Synthesis and Crystal Structure Refinement Single‐crystalline Pr₃B₃N₆ was obtained by the reaction of praseodymium and BN_x(NH)_y(NH₂)_z in a NaCl melt under N₂ atmosphere in a high‐frequency furnace at 1250 °C. Contrary to literature data, Pr₃B₃N₆ crystallizes in the centrosymmetric space group R 3 c as revealed by single‐crystal X‐ray diffraction (a = 1211.95(9), c = 701.53(7) pm, Z = 6, R1 = 0.0258, wR2 = 0.0658). In the solid, Pr₃B₃N₆ contains Pr³⁺ and planar cyclotrinitridoborate units B₃N₆^9–. The anions represent motifs from the structure of hexagonal boron nitride (h‐BN) and they are stacked analogously along [001]. Both the bond lengths B–N (average value 147.8 pm) and the interionic distances between the anions (350.8 pm) are comparable with the values in h‐BN.     

LiLa5Si4N10O and LiPr5Si4N10O – Chain‐Type Oxonitridosilicates

The isotypic lithium rare‐earth oxonitridosilicates LiLn₅Si₄N₁₀O (Ln = La, Pr) were synthesized at temperatures of 1200 °C in weld shut tantalum ampoules employing liquid lithium as flux. Thereby, a silicate substructure with a low degree of condensation was obtained. LiLa₅Si₄N₁₀O crystallizes in space group P$\bar{1}$ [Z = 1, LiLa₅Si₄N₁₀O: a = 5.7462(11), b = 6.5620(13), c = 8.3732(17) Å, α = 103.54(3), β = 107.77(3), γ = 94.30(3), wR₂ = 0.0405, 1315 data, 96 parameters]. The nitridosilicate substructure consists of loop branched dreier single‐chains of vertex sharing SiN₄ tetrahedra. Lattice energy calculations (MAPLE) and EDX measurements confirmed the electrostatic bonding interactions and the chemical compositions. The ⁷Li solid‐state MAS NMR investigation is reported.     

Über die Synthese und spektroskopische Charakterisierung von Strontium‐ und Bariumtetrabromoferrat(III) und die Kristallstruktur von Ba(FeBr4)2

Preparation and Spectroscopic Characterization of Strontium and Barium Tetrabromoferrate(III) and the Crystal Structure of Ba(FeBr₄)₂ The synthesis of the hitherto unknown bromoferrates(III) of alkaline‐earth metals was carried out by heating mixtures of the metals or the binary bromides together with bromine at temperatures of 450 °C and pressures of up to 1500 bar in closed quartz ampoules. The attempts have been successful only with the larger cations of Sr and Ba. In the case of Be, Mg, and Ca only mixtures of the binary bromides with FeBr₃ could be received. By analysis of the Raman and electronic spectra the dark red compounds of Sr and Ba have been characterized as ternary tetrabromoferrates(III) containing tetrahedral FeBr₄ anions. The composition M(FeBr₄)₂ (M = Sr, Ba) has been determined by potentiometric and titrimetric analysis and thermal degradation by thermogravimetry. A single crystal structure determination of Ba(FeBr₄)₂ confirmed the spectroscopic assignments. The orthorhombic crystal structure (space group Pbca; a = 13.054(3) Å; b = 11.093(2) Å; c = 21.764(4) Å; Z = 8) consists of FeBr₄ and BaBr₉ polyhedra.     

Synthese und Kristallstruktur von Terbium(III)‐meta‐Oxoborat Tb(BO2)3 (≡ TbB3O6)

Synthesis and Crystal Structure of Terbium(III) meta‐Oxoborate Tb(BO₂)₃ (≡ TbB₃O₆) The terbium meta‐oxoborate Tb(BO₂)₃ (≡ TbB₃O₆) is obtained as single crystals by the reaction of terbium, Tb₄O₇ and TbCl₃ with an excess of B₂O₃ in gastight sealed platinum ampoules at 950 °C after three weeks. The compound appears to be air‐ and water‐resistant and crystallizes as long, thin, colourless needles which tend to growth‐twinning due to their marked fibrous habit. The crystal structure of Tb(BO₂)₃ (orthorhombic, Pnma; a = 1598.97(9), b = 741.39(4), c = 1229.58(7) pm; Z = 16) contains strongly corrugated oxoborate layers {(BO₂)^‐} built of vertex‐linked [BO₄]^5‐ tetrahedra (d(B‐O) = 143 ‐ 154 pm, ?(O‐B‐O) = 102‐115°) which spread out parallel (100). The four crystallographically different Tb³⁺ cations all exhibit coordination numbers of eight towards the oxygen atoms (d(Tb‐O) = 228‐287 pm). The corresponding metal cation polyhedra [TbO₈]¹³⁺ too convene to layers (composition: {(Tb₂O₁₁)^16‐}) which are likewise oriented parallel to the (100) plane.     

Synthese,Kristallstruktur und Eigenschaften von Phosphor(V)-nitridimid HP4N7

Synthesis, Crystal Structure, and Properties of Phosphorus(V) Nitride Imide HP₄N₇ Pure HP₄N₇ was obtained as a fine crystalline solid which is resistant to hydrolysis. The compound was synthesized by thermal condensation at 750 °C in sealed quartz ampoules starting from the molecular precursor compound (NH₂)₂P(S)NP(NH₂)₃. The crystal structure was solved by direct methods and refined by a Rietveld algorithm on the basis of synchrotron X-ray powder diffraction data which have been collected at the NSLS Brookhaven, beamline X7A (HP₄N₇, P2₁/a, a = 1507.95(2), b = 480.304(6) c = 710.722(8)pm, β = 92.191(1)°, Z = 4, 1689 reflections, wR_p = 0.082, R_p = 0.063, R_F = 0.038). In HP₄N₇ there are PN₄-tetrahedra as characteristic structural motifs which are connected through common edges and corners resulting in a three-dimensional network structure. Two out of seven nitrogen each are bridging two and the remaining N are bridging three neighbouring P atoms. Solid state IR spectroscopy of HP₄N₇ reveals a strong N–H stretching vibration at 3089 cm^–1. The ³¹P MAS NMR spectrum shows one signal at –26 ppm. In a nonoxidizing atmosphere HP₄N₇ is stable up to 800 °C. Above that temperature NH₃ eliminates and P₃N₅ is formed.