Synthesis and Structures of Simple (Silylmethyl)(methyl)ethers

2003 ◽  
Vol 58 (8) ◽  
pp. 759-763 ◽  
Author(s):  
Norbert W. Mitzel
Keyword(s):  
Crystal Structures ◽  
Structural Parameters ◽  
Structural Basis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Donor Acceptor

The compound Cl3SiCH2OCH3 was prepared by reacting ClCH2OCH3 with the Cl3SiH/NEt3 reagent. H3SiCH2OCH3 and F3SiCH2OCH3 were synthesized from Cl3SiCH2OCH3 by reduction with LiAlH4 and by fluorination with SbF3, respectively. The crystal structures of the low-melting compounds H3SiCH2OCH3 and F3SiCH2OCH3 were determined by X-ray diffraction of in situ grown crystals. Both compounds do not show any observable β -donor-acceptor interactions, but behave structurally like usual dialkylethers or silanes, as is obvious from the structural parameters in H3SiCH2OCH3 (<SiCO 108.4(3)-109.4(3)°, <COC 111.0(4)-111.6(4)°) and in F3SiCH2OCH3 (<SiCO 107.1(1), <COC 111.2(2)°). Earlier postulates of Si· · ·O interactions in compounds with SiCO units could thus not be confirmed on a structural basis.

The Crystal Structures of Chlorodimethyl( dimethylamino)silane and Dimethyl-bis-(dimethylamino)silane

2003 ◽  
Vol 58 (7) ◽  
pp. 708-710 ◽  
Author(s):  
Norbert W. Mitzel ◽  
Krunoslav Vojinović
Keyword(s):  
Single Crystals ◽  
Crystal Structures ◽  
Low Temperatures ◽  
Structural Parameters ◽  
X Ray Diffraction ◽  
X Ray

Single crystals of chlorodimethyl(dimethylamino)silane, Me2NSiMe2Cl, and dimethyl-bis-(dimethylamino)silane, (Me2N)2SiMe2, have been grown in situ from the melt at low temperatures and their structures determined by X-ray diffraction. Important structural parameters (Å / °): Me2NSiMe2Cl (C2/m) Si-N 1.686(2), Si-C 1.851(1), Si- Cl 2.109(1), N-Si-Cl 111.7(1), C-Si-Cl 105.1(1), C-N-C 112.8(2), Si-N-C 123.4(1); (Me2N)2SiMe2 (P21/c) Si-N(1) 1.725(1), Si-C(1) 1.868(1), N(1)-Si-N(2) 105.7(1), C(3)- N(1)-C(4) 111.6(1), Si-N(1)-C(3) 122.4(1), Si-N(1)-C(4) 120.0(1).

Synthese und Kristallstrukturen einiger Tetramethylstibonium-Hydrogendicarboxylate / Synthesis and Crystal Structures of Some Tetramethylstibonium Hydrogendicarboxylates

1982 ◽  
Vol 37 (11) ◽  
pp. 1393-1401 ◽  
Author(s):  
Beatrix Milewski-Mahrla ◽  
Hubert Schmidbaur
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Spectroscopic Data ◽  
Molar Ratio ◽  
Ionic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carboxylate Oxygen ◽  
Donor Acceptor ◽  
New Compounds

Reactions of pentamethylantimony (CH3)5Sb with carboxylic acids in the molar ratio 1:2 afford one equivalent of methane and essentially quantitative yields of crystalline tetramothylstibonium hydrogendicarboxylates. Six new compounds of this series have been synthesized using benzoic, o-phthalic, salicylic, 4-ethoxy-salicylic, oxalic, and malic acid, and characterized by analytical and spectroscopic data. An ionic structure with strong hydrogen bonds in the anionic components is proposed.The crystal structures of the hydrogen-dibenzoato (1), hydrogen-ortho-plithalato (2) and 4-ethoxy-hydrogen-salicylate (3) were determined by single crystal X-ray diffraction. The compounds can be described as having ionic lattices with some donor-acceptor inter­actions between the stibonium centers and the carboxylate oxygen atoms. The anions are characterized by strong hydrogen bonds O...H...O. Thus, the (CH3)4Sb-tetrahedron in 1 is distorted by two benzoate oxygon atoms (at 304(2) and 340(2) pin). The cation in 2 is largely undistorted and the anion has a hydrogenphthalate hydrogen bond of d(O...H...O) = 232 pm. The cation-anion contact in 3 is as short as d(Sb-O) = 289 pm rendering the Sb atom pentacoordinate.

Dimethyl-, Disilyl- and Digermylsulfide: Different Intermolecular Contacts in the Solid State

2004 ◽  
Vol 59 (6) ◽  
pp. 635-638 ◽  
Author(s):  
Norbert W. Mitzel ◽  
Udo Losehand
Keyword(s):  
Solid State ◽  
Low Temperature ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intermolecular Contacts

The compounds (H3C)2S, (H3Si)2S and (H3Ge)2S have been crystallised in situ on a diffractometer and their crystal structures determined by low-temperature X-ray diffraction. The molecules are present as monomers in the crystals. The aggregation of the molecules through secondary intermolecular contacts in the crystal is different: (H3C)2S is weakly associated into dimers by S···S contacts, whereas (H3Si)2S and (H3Ge)2S form Si···S and Ge···S contacts in an ice-analogous aggregation motif. Important geometry parameters are (H3C)2S: C-S 1.794(av) Å , C-S-C 99.2(1)°; (H3Si)2S: Si- S 2.143(1) Å , Si-S-Si 98.4°; (H3Ge)2S Ge-S 2.223(2) and 2.230(2) Å , Ge-S-Ge 98.2(1)◦.

Copper Phosphonatoethanesulfonates: Temperature Dependent in Situ Energy Dispersive X-ray Diffraction Study and Influence of the pH on the Crystal Structures

2012 ◽  
Vol 51 (22) ◽  
pp. 12540-12547 ◽  
Author(s):  
Mark Feyand ◽  
Annika Hübner ◽  
André Rothkirch ◽  
David S. Wragg ◽  
Norbert Stock
Keyword(s):  
Diffraction Study ◽  
Crystal Structures ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray

Die Kristallstrukturen der Cyclothiazenokomplexe [MoCl3(N3S2)(Pyridin)] und [MoCl3(N3S2)(Tetrahydrofuran)] / The Crystal Structures of the Cyclothiazeno-Complexes [MoCl3(N3S2)(Pyridine)] and [MoCl3(N3S2)(Tetrahydrofurane)]

1986 ◽  
Vol 41 (10) ◽  
pp. 1196-1200 ◽  
Author(s):  
Karin Völp ◽  
Wolfgang Willing ◽  
Ulrich Müller ◽  
Kurt Dehnicke
Keyword(s):  
Crystal Structures ◽  
Dihedral Angles ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Donor Acceptor ◽  
Molybdenum Pentachloride ◽  
In Trans ◽  
Moisture Sensitive

An improved method of synthesis for MoCl3(N3S2) from molybdenum pentachloride and trithiazylchloride is given. Its reaction with pyridine and tetrahydrofuran in a CH2Cl2 suspension yields the donor-acceptor complexes [MoCl3(N3S2)(C5H5N)] and [MoCl3(N3S2)(C4H8O)], respectively. Both are soluble in CH2Cl2 and can be obtained in form of black, moisture sensitive crystals. Their IR spectra are reported and their crystal structures were determined by X-ray diffraction. Both compounds have nearly the same structure (monoclinic, space group P21/c, Z = 4). Lattice constants: [MoCl3(N3S2)(C5H5N)], a = 1102.2, b = 997.7, c = 1134.9 pm, α = 94.19° (1582 observed, independent reflexions, R = 0.023); [MoCl3(N3S2)(C4H8O)], a = 1069.7, b = 1002.5, c = 1122.0 pm, β = 93.77° (1440 reflexions, R = 0.024). In the molecules, the Mo atoms are members of nearly planar MoN3S2 rings with MoN bond distances between 178 and 185 pm , which correspond to double bonds. The sixfold coordination of the Mo atoms is completed by three chlorine atoms and the N or O atom of the pyridine or tetrahydrofuran ligand, respectively. The solvate molecules are in trans positions to one of the N atoms and form dihedral angles of 34.0° and 41.4° with the M oN3S2 rings, respectively.

MBE Growth and Characterization of Zns/Gan Heterostructures

1996 ◽  
Vol 449 ◽  
Author(s):  
E. C. Piquette ◽  
Z. Z. Bandić ◽  
J. O. McCaldin ◽  
T. C. McGill
Keyword(s):  
Nitrogen Plasma ◽  
Carbon Surface ◽  
X Ray Diffraction ◽  
Lower Growth ◽  
Mbe Growth ◽  
X Ray ◽  
Donor Acceptor ◽  
Free Films

ABSTRACTHeterostructures involving ZnS/GaN show promise for the injection of holes from p-GaN into n-ZnS. This combination could result in multi-color electroluminescent displays. We have grown single crystal ZnS on GaN and sapphire (0001) by MBE using elemental sources. The ZnS was grown at temperatures from 150°C–400°C, with beam flux equivalent pressures of (0.3 – 2.0) × 10−7 torr. Growth rates of up to 0.4 μm per hour were observed for the lower growth temperatures, with rapidly diminishing rates for temperatures above 350μC. The GaN substrate consisted of a 3 μm epilayer grown on sapphire by MOCVD. XPS analysis revealed the presence of carbon surface contamination on the GaN, which was removed by in situ exposure to an RF nitrogen plasma. RHEED observations indicate that the zincblende ZnS layers commonly contain (111) twins, although twin free films may be grown at a high substrate temperature. The samples were characterized using photoluminescence and X-ray diffraction. X-ray peaks typically had FWHM of 400 arcsec for ω/2θ scans, and somewhat worse for ω scans. Photoluminescence spectra of the ZnS films doped with Ag and Al demonstrated the well known blue donor acceptor transition at 440 nm.

Coexistence of structure I and II hydrates formed from a mixture of methane and ethane gases

2003 ◽  
Vol 81 (1-2) ◽  
pp. 479-484 ◽  
Author(s):  
S Takeya ◽  
Y Kamata ◽  
T Uchida ◽  
J Nagao ◽  
T Ebinuma ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Gas Hydrates ◽  
X Ray Diffraction ◽  
Mixed Gas ◽  
Growth Processes ◽  
X Ray ◽  
Gas Concentration ◽  
In Situ Observations

X-ray diffraction measurements were conducted to determine the hydrate structures formed from a mixture of CH4 and C2H6 gases at 263 K. With increasing initial fractions of C2H6 in the gas, the crystal structures of the hydrate were structure I, structure I + structure II, structure II, structure I + structure II, and structure I. In situ observations of the growth processes of the mixed gas hydrates under constant gas concentration suggest that the coexistence of structure I and structure II hydrate were caused by occurrences of metastable hydrate structure. PACS No.: 82.75Fq

scholarly journals Crystal structures and comparisons of huntite aluminum borates REAl3(BO3)4 (RE = Tb, Dy and Ho)

2020 ◽  
Vol 76 (3) ◽  
pp. 339-343 ◽  
Author(s):  
Saehwa Chong ◽  
Brian J. Riley ◽  
Zayne J. Nelson ◽  
Samuel N. Perry
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Structural Parameters ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Slow Cooling ◽  
Spontaneous Crystallization ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

Three huntite-type aluminoborates of stoichiometry REAl3(BO3)4 (RE = Tb, Dy and Ho), namely, terbium/dysprosium/holmium trialuminium tetrakis(borate), were synthesized by slow cooling within a K2Mo3O10 flux with spontaneous crystallization. The crystal structures were determined using single-crystal X-ray diffraction (SC-XRD) data. The synthesized borates are isostructural to the huntite [CaMg3(CO3)4] structure and crystallized within the trigonal R32 space group. The structural parameters were compared to literature data of other huntite REAl3(BO3)4 crystals within the R32 space group. All three borates fit well into the trends calculated from the literature data. The unit-cell parameters and volumes increase linearly with larger RE cations whereas the densities decrease. All of the crystals studied were refined as inversion twins.

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