Raman scattering studies of the high-pressure stability of pentaerythritol tetranitrate, C(CH2ONO2)4

High-pressure Raman scattering studies have been performed on a crystalline energetic material, pentaerythritol tetranitrate C(CH2ONO2)4 (PETN), an important secondary explosive. In situ, ambient-temperature investigations employed diamond anvil cell techniques and nitrogen as a quasi-hydrostatic-pressure-transmitting medium. The pressure-induced alterations in the profiles of the Raman lines, including positions, bandwidths, and intensities, were studied in a compression sequence up to about 31.3 GPa and in a subsequent decompression to ambient conditions. The observed changes of the Raman spectra implied that PETN gradually densified and compressed smoothly up to the highest investigated pressures. Compression below 12 GPa gradually shifted all Raman peaks to higher frequencies without significantly changing their relative intensities or bandwidths. At higher pressures, the peak intensities of the Raman spectra decreased considerably and the bands broadened significantly. The Raman spectrum of the material quenched from 31.3 GPa to ambient conditions indicated that no pressure-driven permanent reconstructive modification or decomposition of the PETN structure occurred. That is, the spectral changes were completely reversible upon compression and subsequent decompression to ambient conditions.     

The sila-explosives Si(CH2N3)4 and Si(CH2ONO2)4: silicon analogues of the common explosives pentaerythrityl tetraazide, C(CH2N3)4, and Pentaerythritol Tetranitrate, C(CH2ONO2)4

The reaction of tetrakis(chloromethyl)silane, Si(CH2Cl)4, with sodium azide afforded tetrakis(azidomethyl)silane (sila-pentaerythrityl tetraazide, Si(CH2N3)4 (1b)). Nitration of tetrakis(hydroxymethyl)silane, Si(CH2OH)4, with nitric acid resulted in the formation of tetrakis(nitratomethyl)silane (sila-pentaerythritol tetranitrate, Si(CH2ONO2)4 (2b)). Compounds 1b and 2b are extremely shock-sensitive materials and very difficult to handle. Spectroscopic data were obtained as good as sensitivity and safety allowed for umambiguous identification. Quantum chemical calculations (DFT) of the C/Si pairs C(CH2OH)4/Si(CH2OH)4, 1a/1b, and 2a/2b regarding the structures and electronic populations were performed.     

Crystallographic report: Bis(norfloxacin)dilead(II) tetranitrate, [Pb2(H‐Norf)2(ONO2)4]

The centrosymmetric binuclear structure of [Pb₂(H‐Norf)₂(ONO₂)₄]shows the geometry around each lead(II) atom to be distorted trigonal bipyramidal with Pb–O distances ranging from 2.357(3) to 2.769(4) Å. Copyright © 2003 John Wiley & Sons, Ltd.     

Zur solvensfreien Darstellung von Tetramethylammoniumsalzen: Synthese und Charakterisierung von [N(CH3)4]2[C2O4], [N(CH3)4][CO3(CH3)], [N(CH3)4][NO2], [N(CH3)4][CO2H] und [N(CH3)4][O2C(CH2)2CO2(CH3)]

Solvent-free Synthesis of Tetramethylammonium Salts: Synthesis and Characterization of [N(CH₃)₄]₂[C₂O₄], [N(CH₃)₄][CO₃CH₃], [N(CH₃)₄][NO₂], [N(CH₃)₄][CO₂H], and [N(CH₃)₄][O₂C(CH₂)₂CO₂CH₃] A general procedure to synthesize tetramethylammonium salts is presented. Several tetramethylammonium salts were prepared in a crystalline state by solvent-free reaction of trimethylamine and different methyl compounds at mild conditions: [N(CH₃)₄]₂[C₂O₄] (cubic; a = 1 114.8(3) pm), [N(CH₃)₄][CO₃CH₃] (P2₁/n; a = 813.64(3), b = 953.36(3), c = 1 131.3(4) pm, β = 90.03(1)°), [N(CH₃)₄][NO₂] (Pmmn; a = 821.2(4), b = 746.5(3), c = 551.5(2) pm), [N(CH₃)₄][CO₂H] (Pmmn; a = 792.8(7), b = 791.7(3), c = 563.3(4) pm) and [N(CH₃)₄][O₂C(CH₂)₂CO₂CH₃] (P2₁; a = 731.1(2), b = 826.4(3), c = 1 025.2(3) pm, β = 110.1(1)°). The tetramethylammonium salts were characterized by IR-spectroscopy and X-ray diffraction. The crystal structures of the methylcarbonate and the nitrite are described.     

[C5H4C(CH3)2CH2CH=CH2]Sm(OH)Cl·2MgCl2·4THF的晶体结构分析

用Ｘ－射线晶体结构衍射法测定了［Ｃ５Ｈ４Ｃ（ＣＨ３）２ＣＨ２ＣＨ＝ＣＨ２］Ｓｍ（ＯＨ）Ｃｌ·２ＭｇＣｌ２·４ＴＨＦ的晶体结构。它属三斜晶系,空间群为Ｐ＾－１,ａ＝１０．７７３（２）,ｂ＝１２．８３６（３）,ｃ＝１５．４７８（３）Ａ,ａ＝１１１．４６（３）,β＝１０７．７１（３）,γ＝９２．５４（３）°,Ｖ＝１８６８（１）Ａ＾３,Ｍｒ＝８２７．９１,Ｄｘ＝１．４７２ｇ／ｃｍ＾３,μ＝２．０００６ｍｍ     

Syntheses,characterizations and crystal structures of two new complexes, [Co2(CH2 =C(CH3)CO2)4(phen)2(H2O)2] and [Pb2(CH2 =C(CH3)CO2)4(phen)2]

Two new complexes, [Co₂(CH₂=C(CH₃)CO₂)₄(phen)₂(H₂O)₂] (1) and [Pb₂(CH₂=C(CH₃)CO₂)₄(phen)₂] (phen = 1,10-phenanthroline) (2), have been synthesized and structurally characterized by single crystal X-ray diffraction methods. There are two cocrystallized conformers of [Co(CH₂=C(CH₃)CO₂)₂(phen)(H₂O)] in the asymmetric unit of 1 with the Co atoms displaying similar coordination modes. In the asymmetric unit of 2, there exist two crystallographically independent [Pb(CH₂=C(CH₃)CO₂)₂(phen)] molecules with the Pb atoms showing completely different coordination geometries. Weak intermolecular interactions such as hydrogen bonding and π–π stacking are responsible for the supramolecular assembly and stabilization of the crystal structures of 1 and 2. The complexes are characterized by elemental analysis, IR spectra, and UV–Vis spectra. The fluorescent properties of 2 are also discussed.     

The nonaqueous microtitration of pentaerythritol tetranitrate (PETN)

Summary PETN has been determined by nonaqueous titration as an acid in pyridine and l, l,3,3-tetramethylguanidine. The titrant was tetrabutylammonium hydroxide. Endpoints were determined potentiometrically by a glass/modified calomel electrode system, or by two polarized platinum electrodes. The method may be applicable to other very weakly acidic compounds for which no other titrimetric methods are currently available.

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Zusammenfassung Pentaeerythrit-Tetranitrat wurde als Säure gelöst in Pyridin und 1,1,3,3-Tetramethylguanidin mit Tetrabutylammoniumhydroxid titriert. Der Endpunkt wurde potentiometrisch mit dem System Glaselektrode/modifizierte Kalomelelektrode oder mit zwei polarisierten Platinelektroden bestimmt. Das Verfahren dürfte sich auch für andere sehr schwache Säuren eignen, für die andere maßanalytische Methoden zur Zeit nicht verfügbar sind.

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Work performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore Laboratory under contract number W-7405-ENG-48.     

(C60)2Ru2Cl4[Ph2P(CH2)4PPh2]配合物的合成

在氮气氛中采用配体取代法合成了C60以σ-π配位方式与Ru形成的稳定η2型富勒烯双核钌金属配合物(C60)2Ru2Cl4[Ph2P(CH2)4PPh2],其结构经UV,IR,XPS,XRD和元素分析表征.     

Synthese und Kristallstruktur des tetrameren Nitridokomplexes [Cu(CH3CN)4]2[W4N4Cl14(CH3CN)2]

Synthesis and Crystal Structure of the Tetrameric Nitrido Complex [Cu(CH₃CN)₄]₂[W₄N₄Cl₁₄(CH₃CN)₂] . The title compound has been prepared by the reaction of CuCl with WNCl₃ in acetonitrile solution, forming red, moisture sensitive crystals. They were characterized by IR spectroscopy and by an X-ray structure determination. Space group I2/a, Z = 4, 2 027 observed unique reflections, R = 0.049. Lattice dimensions at -80°C: a = 2 527.0, b = 971.9, c = 2 137.5 pm, β = 106.01°. The compound consists of [Cu(CH₃CN)₄]⁺ ions, which are arranged to form strands, and of anions [W₄N₄Cl₁₄(CH₃CN)₂]^2?, in which the tungsten atoms were located at the vertices of a square and are linked with one another via linear W?N? W bridges. Two of the four tungsten atoms have four chlorine atoms as terminal ligands, the other two tungsten atoms have three chlorine atoms and an acetonitrile molecule as terminal ligands.     

Strukturen von planaren und tetraedrischen TetrafulminatoMetallkomplexen: [N(C3H7)4]2 [Ni(CNO)4], [N(C3H7)4]2 [Pt(CNO)4] und [N(C3H7)4]2 [Zn(CNO)4]

Pseudohalogeno Metal Compounds. LXXVIII. Structures of Planar and Tetrahedral Tetrafulminato Metal Complexes: [N(C₃H₇)₄]₂ [Ni(CNO)₄], [N(C₃H₇)₄]₂ [Pt(CNO)₄], and [N(C₃H₇)₄]₂ [Zn(CNO)₄] The crystals contain the tetrafulminatometallates of an ideal square planar structure ([Ni(CNO)₄]^2–, [Pt(CNO)₄]^2–) with D_4h symmetry at the nickel and platinum atom and a tetrahedron ([Zn(CNO)₄]^2–) with perfect T_d symmetry at the zinc atom and with linear C≡N–O ligands. The metal carbon bonds (Ni–C: 187 pm, Pt–C: 200 pm, Zn–C: 201 pm) of the metal fulminates are very close to those of the corresponding cyano complexes. In the crystals the anions ([Ni(CNO)₄]^2–, [Pt(CNO)₄]^2–, [Zn(CNO)₄]^2–) are separated by the cations ([N(C₃H₇)₄]⁺) which explains the thermal stability of these compounds.     

Hypercoordinated diorganoantimony(III) compounds of types [2-(Me2NCH2)C6H4]2SbL and [PhCH2N(CH2C6H4)2]SbL (L = Cl,ONO2, OSO2CF3). Synthesis,structure and catalytic behaviour in the Henry reaction

The compounds [2-(Me₂NCH₂)C₆H₄]₂SbL (L = ONO₂ ( 2 ), OSO₂CF₃ ( 3 )) and [PhCH₂N(CH₂C₆H₄)₂]SbL (L = ONO₂ ( 5 ), OSO₂CF₃ ( 6 )) were prepared by reacting [2-(Me₂NCH₂)C₆H₄]₂SbCl ( 1 ) and [PhCH₂N(CH₂C₆H₄)₂]SbCl ( 4 ), respectively, with the appropriate silver(I) salt in a 1:1 molar ratio. The new species 2 – 6 were structurally characterized in solution using multinuclear NMR and in the solid state using infrared spectroscopy. The solid-state structures for compounds 2 , 4 and 6, as well as for the hydrolysis ionic product [{2-(Me₂N⁺HCH₂)C₆H₄}{2-(Me₂NCH₂)C₆H₄}SbOH][CF₃SO₃]⁻ ( 3h ) were determined using single-crystal X-ray diffraction. Medium to strong intramolecular N→ Sb interactions were observed in all these four compounds, thus resulting in hypercoordinated organoantimony(III) species 14-Sb-6 in 2 and 10-Sb-4 in the cation of 3h and in 4 and 6 . Compounds 1 – 6 and the starting amines PhCH₂NMe₂ and PhCH₂N(CH₂C₆H₄Br-2)₂ were investigated as catalysts in the Henry (nitroaldol) addition of nitromethane to benzaldehyde. The activity of compounds 1 – 6 resulted as an effect of the cooperation of the positively charged antimony with the negatively charged nitrogen.     

Wire-like PtC[triple bond]CC[triple bond]CC[triple bond]CC[triple bond]CPt moieties surrounded by double-helical "insulation": new motifs featuring P(CH2)20P and P(CH2)4O(CH2)2O(CH2)4P linkages

Ring-closing alkene metatheses of trans,trans-(C6F5)(Ph2P-Z-CH=CH2)2Pt(C[triple bond]C)4Pt(Ph2P-Z-CH=CH2)2(C6F5) (Z = (CH2)9, (CH2)4O(CH2)2), followed by hydrogenation, give the title compounds; the former exhibits an exceptionally twisted conformation, and the latter establishes that functional groups can be incorporated into the flexible sp3 chain.     

Bis(pyrazolylethyl)thioether ligation to zinc and cadmium: structural characterization of [S(CH2CH2pzMe2)2]ZnCl2, [S(CH2CH2pzMe2)2]CdI2 and [S(CH2CH2pzMe2)2]Cd(NO3)2

Structural characterization of [S(CH₂CH₂pz^Me₂)₂]ZnCl₂ by X-ray diffraction demonstrates that the potentially tridentate [NNS] donor ligand S(CH₂CH₂pz^Me₂)₂ does not coordinate via sulfur, but only binds through the pyrazolyl groups. Furthermore, the ligand does not chelate, but preferentially bridges two zinc centers, thereby resulting in a polymeric, helical, structure. In contrast to the zinc system, the thioether functionality does bind to cadmium in related derivatives, [S(CH₂CH₂pz^Me₂)₂]CdI₂ and [S(CH₂CH₂pz^Me₂)₂]Cd(NO₃)₂.