Bildung siliciumorganischer Verbindungen, 47. Die Kristall- und MolekülStruktur von 1,3,5,7- Tetramethyl-tetrasila-adamantan

Formation of organosilicon compounds. 47. The crystal land molecular structure of 1,3,5,7-tetramethyl-tetrasila-adamantan 1,3,5,7- Tetramethyl-tetrasila-adamantan, Si₄C₁₀H₂₄, is a pyrolysis product of Si(CH₃)₄. It crystallizes in the monoclinic space group P2₁/c with a = 8.859 Å, b = 9.844 Å, c = 18.316 Å, β = 91.04°, Z = 4. The molecule exhibits T_d-symmetry within the experimental error. The mean bond lengths Si? C are 1.889 Å and 1.866 Å for the Si? CH₃ and Si? CH₂ bonds respectively.     

Bildung siliciumorganischer Verbindungen. LX. Die Kristall- und MolekülStruktur des Heptamethyl-tetrasila-[2,2,2]-barrelans Si4C11H28

Formation of Organosilicon Compounds. LX. Crystal and Molecular Structure of Heptamethyl-tetrasila-[2,2,2]-barrelan Si₄C₁₁H₂₈ 1,1,3,5,5,7,7-Heptamethyl-1,3,5,7-tetrasila-[2,2,2]-barrelan Si₄C₁₁H₂₈ crystallizes in the orthorhombic space group Pn2₁a with a = 12.293, b = 9.903, c = 14.018 Å and Z = 4 formula units. The six-membered rings have the skew-boat conformation with a torsion angle of 23.5° with respect to the molecular axis. The skew-boat conformation results from the interaction of CH₃- and CH₂- groups. The mean value for the bond length is Si? C = 1.881 Å. The distances Si? CH₂ = 1.873 Å are somewhat smaller than the others (1.887 Å).     

Bildung siliciumorganischer Verbindungen. LIX. Die Kristall- und MolekülStruktur des Dodecamethyl-heptasila-[4,4,4]-propellans Si7C19H48

Formation of Organosilicon Compounds. LIX. Crystal and Molecular Structure of Dodecamethyl-heptasila-[4,4,4]-propellan Si₇C₁₉H₄₈ 1,1,3,3,7,7,9,9,11,11,13,13-Dodecamethyl-1,3,5,7,9,11,13-heptasila-[4,4,4]-propellan Si₇C₁₉H₄₈ crystallizes in the monoclinic space group P2₁/c with a = 11.499, b = 11.411, c = 22.171 Å, β = 96.95° and Z = 4 formula units. The three independent six-membered rings of the molecule have the same skew-boat-conformation. Along the central Si? C? bond the mean value of the torsion angle within the six-membered rings is 19°. The mean value for the bond length is Si-C = 1.893 Å, but the bond length diminishes within the polycyclic system from the axial C-atom to the outer members of the rings (1.916; 1.880; 1.864 Å). The interatomic distances between CH₃- groups and from CH₃- groups to CH₂- groups shows the twisted conformation to be a result of the contacts between these groups.     

Bildung siliciumorganischer Verbindungen. LIV. Die Kristall- und Molekülstruktur des Tetramethyl-octasila-dodecascaphans Si8C17H36

Formation of Organosilicon Compounds. LIV. Crystal and Molecular Structure of Tetramethyl-octasila-dodecascaphan 3,7,11,15-Tetramethyl-1,3,5,7,9,11,13,15-octasila-dodecascaphan crystallizes in the cubic space group F4 3c–T with a = 17.074(10) Å. In the unit cell there are four molecules of each of the two chiral forms which are arranged in the way of the NaCl-structure. The molecules have the symmetry 23-T with torsion angles of 19° in the twelve six-membered rings with skew-boat conformation. In the polycyclic skeleton the bond length Si? C are nearly the same (1.885(2) Å, 1.893(5) Å and 1.888(6) Å), whereas the bond length Si? CH₃ is slightly shorter (1.874(8) Å). The shortest distances between H-atoms are 2.59 and 2.68 Å (intramolecular) and 2.72 and 2.73 Å (intermolecular) respectively. The thermal motions of all atoms can be reduced to a rigid-body motion. Diffuse scattering (dependent on temperature) is observed and discussed.     

Zur Kristall- und MolekülStruktur des Hexaphenyldiplumbans

The unit cell dimensions of hexaphenyldiplumbane (space group P2₁/c) have been newly determined: a = 17.16 ± 0.01, b = 9.410 ± 0.002, c = 21.60 ± 0.015 Å; β = 116.8 ± 0.2°; Z = 4; d (calc.) = 1.87, d_25°C(obs.²)) = 1.8₈ g · cm^?3. According to the evalution of 1800 independent reflections, and in contrary to a former investigation²), only molecules with an uniform Pb–Pb distance of 2.83 ± 0.01 Å exist in crystalline hexaphenyldiplumbane.     

Bildung siliciumorganischer Verbindungen. 94. Die Kristallstruktur des Hexaphenyltrisilacyclohexans Si3C39H36

Formation of Organosilicon Compounds. 94. Crystal Structure of Hexaphenyltrisilacyclohexane Si₃C₃₉H₃₆ 1.1.3.3.5.5-Hexaphenyl-1.3.5-trisilacyclohexane crystallizes monoclinically in the space group P2₁/n (No. 14) with a = 1718.3 pm, b = 1769.2 pm, c = 1091.4 pm, β = 90.72° and Z = 4 molecules per unit cell. The trisilacyclohexane sceleton is present in a flattened twist boat conformation with mean bond angles of 110.0° at the Si atoms and 117.9° at the C atoms, respectively. The mean bond lengths are d(Si? C) = 187.1 pm in the six membered ring and 187.9 pm to the substituents.     

Die Kristall- und MolekülStruktur des N,N′-Diformylanilins

Crystal and Molecular Structure of N,N′-Diformylaniline N,N′-diformylaniline crystallizes in the monoclinic space group P2₁/n with Z = 8 and a = 856.1(2), b = 1277.6(3), c = 1306.1(3) pm, β 92.29(2)°, V = 1427.4(5) · 10⁶ pm³. As shown by X-ray structure determination (2642 symmetry independent reflections, R_W = 0.034) the molecule exists in two enantiomeric forms. The molecular structure can be described by two planes; the angle between the plane of the aromatic ring and the plane of the N,N′-diformylamino group is 70.1 resp. 108.3°. The results are compared with those obtained for other derivats.     

Die Kristall- und MolekülStruktur von S4N4·2C7H8

Crystal and Molecular Structure, of S₄N₄ · 2C₇H₈ The structure of the title compound has been determined from threedimensional X-ray data. Crystals are monoclinic, with unit cell dimenions a = 16.532 Å, b = 8.563 Å, c = 10.880 Å, β = 103.2°, space group C? C2/c and Z = 4. Least squares refinement, by use of 1132 independent reflections measured on a diffractometer has reached 3.9%. In the S₄N₄·2C₇H₈ molecules the organic components are linked to two sulfur atoms of the S₄N₄, ring each.     

Beiträge zur Chemie des Schwefels. 115. Kristall- und MolekülStruktur von Benzopentathiepin

Contributions to the Chemistry of Sulfur. 115. Crystal and Molecular Structure of Benzopentathiepine The structure of benzopentathiepine has been determined from three-dimensional single-crystal X-ray data. The crystal are monoclinic, space group P2₁/c, with 4 molecules in the unit cell of dimensions a = 6.942(4) Å, b = 10.223(10) Å, c = 13.015(8) Å, β = 102,15(10)°. The conformation of the seven-membered ring is the chair form. Details of the conformation are discussed. Bond distances, bond angles, and dihedral angles are compared with those in other molecules, which have similar structure.     

Die Kristall- und Molekülstruktur des Hexaphenyldiplumbans

Crystal and Molecular Structure of Hexaphenyldiplumbane The crystal and molecular structure of (C₆H₅)₆Pb₂ (space group and lattice parameters see above) has been newly determined from 4541 independent reflexes by the heavy atom method; the positions of all atoms, except the H atoms have been refined to give R = 0.053. The unit cell contains two crystallographically independent molecules. (Mean values of bond lengths and angles see above).     

Bildung siliciumorganischer Verbindungen. XXXII. Das Carbosilan Si7C16H36

Si₇C₁₆H₃₆ (1) can be separated from the pyrolysis products of Si(CH₃)₄ by columnchromatography. Its structure is shown to consist of two 1,3,5,7-tetrasilaadamantane skeletons which are connected through the C-atoms 2 and 4 and the Si-atom 3, by analysis of the 100 and 220 MHz PMR spectra in connection with double resonance. Except for the framework bonds carbon atoms are saturated by hydrogen, silicon atoms by CH₃ groups. (1) is a very stable compound (m.p. 225°C without decomposition).     

Die Kristall- und MolekülStruktur von (S4N3)2SbCI5

The structure of (S₄N₃)₂SbCI₅ has been determined by X-ray methods using least-squares′ refinement. The compound crystallises monoclinic; C–P2₁/c, a = 9.24 Å, b = 17.77 Å, c = 11.29 Å, β = 110.06°, Z = 4. The antimony atom has a fivefold coordination the geometry being derived from a deformed octahedron, the S₄N-rings retained their planar shape.     

Bildung siliciumorganischer Verbindungen, 79. NMR-spektroskopische Untersuchung der 1,3,5-Trisilacyclohexane und 1,3,5,7-Tetrasilaadamantane

Formation of Organosilicon Compounds. 79. NMR-Spectroscopical Investigation of 1,3,5-Trisilacyclohexanes and 1,3,5,7-Tetrasilaadamantanes For several groups of isomeric 1,3,5-trisilacyclohexanes and 1,3,5,7-tetrasilaadamantanes, structure assignment and conformation analysis of given by elucidation of their ¹H-NMR spectra.     

Bildung siliciumorganischer Verbindungen. 92 [1]. Bildung und Struktur des Oktamethyl-hexasila-hexascaphans

Formation of Organosilicon Compounds. 92. Formation and Structure of Octamethylhexasila-hexascaphane By rearrangement and abstraction of CH₄ at the presence of AlBr₃ 2 forms 3 , and 6 forms 7 , which is also obtained reacting 8 and 9 under the same condition. Lithination of 1, 1, 3, 5, 5, 7, 7, 9, 9-Nonamethyl-1, 3, 5, 7, 9-pentasiladecaline yields 12 , which is trapped with me₃SiCl to form 6 . Convertation of 13 to 14 leads to 8 by reaction with ClSi(CH₂—Sime₃)₃. Compound 7 is characterized by NMR and mass spectroscopy as well as X-ray structural analysis. 1, 3, 5, 7, 9, 9, 11, 11-Octamethyl-1, 3, 5, 7, 9, 11-hexasila-hexascaphane 7 crystallizes in the monoclinic space group P2₁/n (No. 14) with a = 3296.7 pm, b = 1536.2 pm, c = 891.9 pm, β 91.71° and Z = 8 formular units. Both crystallographic independent molecules have approximately the symmetry C₂. The differences of corresponding bond lengths, bond angles and torsion angles are unimportant. But there is a distinct dependence of the Si? C bond length relative to the function of the bond in the molecule (Averages: Si? C) (endo) = 188.4 pm, Si? C (exo) = 187.6 (pm).     

Bildung siliciumorganischer Verbindungen. L. Untersuchungen zur Hydrierung,Methylierung und Spaltung des Octachloro-hexasila-asterans Si6Cl8C6H8

Formation of Organosilicon Compounds. L. Investigations on Hydrogenation, Methylation, and Decomposition of Octachlorohexasila-asteran Si₆Cl₈C₆H₈ Compound (a) reacts with LiAlH₄ (1:2) to form (b), respectively (c) (ratio 1:5). (b), (c) and the intermediates containing Si? H-groups can be rechlorinated to (a) by means of Cl₂. With a excess of LiAlH₄ (1:10) (a) is cleaved to compound (d) under hydrogenation. (a) is methylated to (e) resp. (f) by CH₃MgCl. (a) doesn't react with Cl₂ and Br₂; (f) is cleaved by HBr to yield (g). The different sterical conditions of the secondary and teriary Si---Cl-groups allow preparation of the partially chlorinated compounds (b) and (e).     

Die Kristall- und Molekülstruktur des dimeren Dimethylaminodimethylindiums

Crystal and Molecular Structure of Dimeric Dimethylaminodimethylindium Dimeric dimethylamino-dimethylindium was prepared by splitting off methane from the adduct Me₃In? NHMe₂ and characterized by its vibrational spectra. The structure – determined by X-ray analysis – has shown to have the monoclinic space group P2₁/c with a = 7.601, b = 7.336, c = 14.927 Å and β = 119.9°. Patterson, Fourier and Difference synthesis were used for determing the structure, which was refined by least square analysis to an R value of 0.068.     

Bildung siliciumorganischer Verbindungen. 101. Darstellung,Struktur und Eigenschaften eines Octamethyl-octasila-heptacyclooctadecans Si8C18H40

Formation of Organosilicon Compounds. 101. Preparation, Structure, and Properties of an Octamethyl-octasilaheptacyclooctadecane, Si₈C₁₈H₄₀ The title compound Si₈C₁₈H₄₀ 1 (systematic name: 1,3,5,7,9,11,11,15-Octamethyl-1,3,5,7,9,11,13,15-octasila-heptacyclo[7,7,1,1^3,15, 0^2,7, 0^4,13, 0^5,10, 0^13,17]octadecane) can be derived from a polycyclic frame of condensed trisilacyclohexane rings presenting the chair-as well as the boat-conformation. This frame is a part of the very frequent 4H-III modification of silicon carbide and represents the smallest molecular unit, which shows all the essential details of this structure namely the adamantane-frame and the wurtzitane-frame. The mean Si? C bond distance is 188.6 pm. Particularly the six-membered rings form nearly ideal conformations.     

Die Kristall- und MolekülStruktur des Bis-(cis-1-mercapto-2-p-brombenzoyl-äthylen)-nickel(II)

Crystal and Molecular Structure of Bis(cis-1-mercapto-2-p-brominebenzoylethylen)nickel(II) From a x-ray analysis of bis(cis-1-mercapto-2-p-brominebenzoyl-ethylen)-nickel(II) distances Ni? S and Ni? O of 2.14 Å and 1.88 Å, respectively, follow for the planar square nickel complex Ni[S₂O₂]. The sulfur atoms are arranged in cis-position. The C? C distance in the sulfur neighbourhood is shortened, but the difference between the two C? C bonds in the chelate ring is less than in bis(thioisobutyrylacetonato)nickel(II). This indicates a strenthening of the quasiaromatic character in the chelate system of the investigated structure.     

Bildung siliciumorganischer Verbindungen. XXXVII1,3,5,7-Tetrasila-adamantane aus der Pyrolyse des (CH3)3SiCl und Auftrennung des Pyrolysegemisches

Further separation of the pyrolysis products of (CH₃)₃SiCl can be achieved by reaction with LiAlH₄/LiH (transfer of SiCl to SiH groups). By means of adsorptions chromatography a separation is obtained into 4 groups of components. By application of gel chromatography (sephadex LH 20) separation is improved, thus fractions of carbosilanes are found with average molecular weights between 5000 and 200. A given mixture of the compounds [5], [9], [10] has been separated by means of gel chromatography so that pure compounds were obtained. The mixture of the 1,3,5,7-Tetrasila-adamantanes, which are formed in the pyrolysis of (CH₃)₃SiCl, is separated by gel chromatography (efficiency control of separation is performed by NMR and mass spectrography of the different fractions), a concentration of some compounds is obtained, some of them are isolated purely by further operations. The ratio of the compounds [1], [2], [3], [4], found in the pyrolysis products, is 170:26:3:1. Derivatives are formed with SiH, SiCl, and SiCH₃ groups by complete or respectively partial hydrogenation. Comparing the values of the chemical shift of the CH₃-protones [measured in τ) a linear decrease is found in the compounds [9], [4], [3], [2].     

Bildung siliciumorganischer Verbindungen. 95. Die Kristallstruktur eines Hexadecamethyl-octasila-dispiro-[5.1.5.1]-tetradecans,Si8C22H65

Formation of Organosilicon Compounds. 95. Crystal Structure of a Hexadecamethyloctasila-dispiro [5.1.5.1]tetradecane, Si₈C₂₂H₅₆ 1,1,3,3,5,5,7,7,9,9,11,11,13,13,14,14-Hexadecamethyl-1,3,5,7,9,11,13,14-octasila-dispiro[5.1.5.1]tetradecane crystallizes monoclinically in the space group P2₁/n (No. 14) with a = 1352.4 pm, b = 1215.5 pm, c = 1001.2 pm, β = 92.11° and Z = 2 molecules per unit cell. The dispiro system is formed by a central disilacyclobutane and two C-spiro connected trisilacyclohexane rings. The symmetry of the molecule is 2/m, with flattened six membered rings in chair conformation. The Si? C bonds are enlarged (192 pm) at the strained spiro region whereas the Si? C bonds are distinctly shortened (186 pm) at the opposite Si atoms in the six membered rings.