Geminal bis(hypersilyl) compounds — the synthesis and structure of bis[tris(trimethylsilyl)silyl]silanes

2000 ◽  
Vol 78 (11) ◽  
pp. 1399-1404
Author(s):  
Thoralf Gross ◽  
Helmut Reinke ◽  
Hartmut Oehme
Keyword(s):  
Crystal Structure ◽  
Key Words ◽  
Trifluoromethanesulfonic Acid ◽  
Molar Ratio ◽  
Coupling Reactions ◽  
Subsequent Reaction ◽  
X Ray ◽  
A Value ◽  
Spatial Demand

Protodesilylation of diphenylsilane with trifluoromethanesulfonic acid and subsequent reaction of the obtained bis(trifluoromethanesulfonyloxy)silane with tris(trimethylsilyl)silyllithium (1) (molar ratio 1:2) afforded bis[tris(trimethylsilyl)silyl]silane (8). Methyl-bis[tris(trimethylsilyl)silyl]silane (3) and phenyl-bis[tris(trimethylsilyl)silyl]silane (10) were obtained by coupling reactions of 1 with MeHSiCl2 or PhHSiCl2, respectively, (2:1). By treatment with HCBr3, the H-silanes 3, 8, and10 were converted into the bromosilanes [(Me3Si)3Si]2SiR1R2 (9: R1 = R2 = Br; 11: R1 = Me, R2 = Br; 12: R1 = Ph, R2 = Br). X-ray crystal structure analyses, performed for 3, 10 and 12, confirmed the expected distortions of the molecular skeletons of the compounds. Thus, e.g., in 10, the spatial demand of the two extended hemispherical hypersilyl groups forces a widening of the Si-Si-Si angle at the central Si atom to a value of 128.3°.Key words: silanes, sterically congested, bis(hypersilyl)silanes, hypersilylsilanes, bis(hypersilyl)germanes, tris(trimethylsilyl)silylsilanes.

scholarly journals Preparation of pyridine-3,4-diols, their crystal packing and their use as precursors for palladium-catalyzed cross-coupling reactions

2010 ◽  
Vol 6 ◽  
Author(s):  
Tilman Lechel ◽  
Irene Brüdgam ◽  
Hans-Ulrich Reissig
Keyword(s):  
Crystal Structure ◽  
Crystal Packing ◽  
Cross Coupling ◽  
Crystal Structure Analysis ◽  
Coupling Reactions ◽  
X Ray ◽  
Cross Coupling Reactions ◽  
Fluorescence Measurements ◽  
Subsequent Conversion ◽  
Palladium Catalyzed

A series of trifluoromethyl-substituted 3-alkoxypyridinol derivatives has been deprotected to furnish pyridine-3,4-diol derivatives in good yields. The X-ray crystal structure analysis proved that a 1:1 mixture of pyridine-3,4-diols and their pyridin-4-one tautomers exist in the solid state. Subsequent conversion into bis(perfluoroalkanesulfonate)s were smoothly achieved. The obtained compounds were used as substrates for palladium-catalyzed coupling reactions. Fluorescence measurements of the biscoupled products showed a maximum of emission in the violet region of the spectrum.

Notizen: Bridging of Trigoldsulfonium Clusters by a Silver(I) Ion

1997 ◽  
Vol 52 (2) ◽  
pp. 301-304 ◽  
Author(s):  
Alexander Sladek ◽  
Hubert Schmidbaur
Keyword(s):  
Crystal Structure ◽  
Silver Atom ◽  
Metal Cluster ◽  
Phosphine Ligands ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Site Exchange ◽  
Mixed Metal Cluster ◽  
Short Contacts

Abstract Treatment of tris[(triphenylphosphine)gold(I)]-sulfonium tetrafluoroborate with AgBF4 (molar ratio 2:1) in tetrahydrofuran affords a hepta-nuclear mixed-metal cluster trication {[(Ph3P)6Au6AgS2](thf)}3+ as the tetrafluorobor­ate salt. The crystal structure of the compound has been determined by X-ray diffraction. The sil­ver atom is found in a bridging position between the two Au3S units with short contacts to both sulfur atoms and to three out of six gold atoms. The coordination sphere of the silver atom is complemented by a tetrahydrofuran molecule. In di(tri)chlorom ethane solutions there is rapid site exchange of the silver coordination as shown by virtual equivalence of the phosphine ligands on the NMR time scale at ambient temperature.

La6C2Br9: La-Tetraederdoppel mit endohedralen C4–-Ionen / La6C2Br9: La Bitetrahedral Clusters with Endohedral C4− Ions

2007 ◽  
Vol 62 (2) ◽  
pp. 143-147 ◽  
Author(s):  
Hansjürgen Mattausch ◽  
Constantin Hoch ◽  
Arndt Simon
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Molar Ratio ◽  
Single Crystal Diffraction ◽  
Space Group ◽  
X Ray

Monophasic La6C2Br9 was prepared by heating a mixture of LaBr3, lanthanum metal and carbon in a molar ratio of 3 : 3 : 2 at 840 °C for 5 d. The crystal structure was investigated by X-ray single crystal diffraction (space group C2/c, a = 14.234(3), b = 10.858(2), c = 14.588(3) Å , β = 106.80(3) °). In the structure the La atoms form edge-sharing double tetrahedra. The La tetrahedra are centered by single carbon atoms. The yellow crystals of La6C2Br9 are transparent and electrically insulating.

Synthese und Kristallstruktur eines polymeren Addukts von 2.2′ -Dipyridil mit Iod: C10H8N2I6 / Synthesis and Crystal Structure of a Polymeric Adduct of 2,2′-Dipyridil and Iodine: C10H8N2I6

1983 ◽  
Vol 38 (12) ◽  
pp. 1535-1538 ◽  
Author(s):  
Siegfried Pohl
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Molar Ratio ◽  
Polymeric Complex ◽  
Synthesis And Crystal Structure ◽  
X Ray

The reaction of 2,2′-dipyridil with iodine (I2; molar ratio 1:3) in CH2Cl2 solution yields the polymeric complex 2,2′-dipyridil(I2)3. The crystal structure of the compound was determined from single crystal X-ray data (monoclinic, C2/c, a = 3215.0(16), b = 439.9(1), c = 1824.1(9) pm, β = 130.79(3)°, Z = 4).2,2′-Dipyridil(I2)3 forms infinite chains of alternating I6 units and bifunctional dipyridil molecules

Synthesis and structure of a terminal dinitrogen complex of nickel

2005 ◽  
Vol 83 (4) ◽  
pp. 328-331 ◽  
Author(s):  
Rory Waterman ◽  
Gregory L Hillhouse
Keyword(s):  
Crystal Structure ◽  
Petroleum Ether ◽  
Key Words ◽  
X Ray ◽  
Dinitrogen Complex

Reaction of petroleum ether solutions of [(dtbpe)Ni]2(η2,µ-C6H6) (1, dtbpe = 1,2-bis(di-tert-butylphosphino)ethane) with triphenylphosphine under a dinitrogen atmosphere gives the Ni(0) dinitrogen adduct (dtbpe)Ni(N2)(PPh3) (2), which can be isolated as dark red crystals in 87% yield. The X-ray crystal structure of 2 reveals pseudotetrahedral geometry about Ni and a terminal dinitrogen ligand with Ni—N(1) = 1.830(2) Å, N(1)—N(2) = 1.112(2) Å, and Ni-N(1)-N(2) = 177.5(2)°. Key words: dinitrogen, nickel, X-ray.

Singly Charged λ6Si-Silicate Anions with an SiF5C Skeleton: Syntheses and Crystal Structure Analyses of the Ionic Hexacoordinate Silicon Compounds [Me3NH][F5SiCH2NMe2H]·H2O and [Me3NH][F5SiCH2NMe2H]·H2O

2000 ◽  
Vol 55 (1) ◽  
pp. 60-64
Author(s):  
Melanie Pülm ◽  
Joachim Becht ◽  
Reinhold Tacke
Keyword(s):  
Crystal Structure ◽  
Lewis Acids ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Coordination Polyhedra ◽  
Silicon Compounds ◽  
X Ray ◽  
Distorted Octahedra ◽  
Singly Charged ◽  
Crystalline Hydrates

The zwitterionic λ5Si-tetrafluorosilicates F4SiCH2NMe2H (1) and F4SiCH2NMe3 (2) behave as Lewis acids and react with [Me3NH]F (molar ratio 1:1) in aqueous solution to yield the ionic λ6Si-pentafluorosilicates [Me3NH][F5SiCH2NMe2H] (3) and [Me3NH][F5SiCH2NMe3] (4), respectively. These hexacoordinate silicon compounds contain singly charged λ6Si-silicate anions ([F5SiCH2NMe2H]- , [F5SiCH2NMe3]- ) with an SiF5C skeleton. Compounds 3 and 4 were isolated as the crystalline hydrates 3·H2O (yield 80%) and 4·H2O (yield 82%) which were structurally characterized by single-crystal X-ray diffraction. The Si-coordination polyhedra in the crystals of 3·H2O and 4·H2O are slightly distorted octahedra

Bildung von Arsensäure aus [As2Cl8]2Ionen und Ozon. Die Kristallstruktur von PPh4Cl · H3AsO4 / Formation of Arsenic Acid from [As2Cl8]2- Ions and Ozone. Crystal Structure of PPh4Cl · H3AsO4

1992 ◽  
Vol 47 (12) ◽  
pp. 1677-1680 ◽  
Author(s):  
Karin Ruhlandt-Senge ◽  
Alfred-Dirk Bacher ◽  
Ulrich Müller
Keyword(s):  
Crystal Structure ◽  
Low Temperatures ◽  
X Ray Diffraction ◽  
Arsenic Acid ◽  
Subsequent Reaction ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray

Reaction of ozone with (PPh4)2[As2Cl8] in CH2C12 at low temperatures yields a red compound, possibly an ozonide. Upon evaporation of the solvent at –78 °C the ozone is released again. At -40 °C or above a subsequent reaction yields PPh4[AsCl6], PPh4Cl · H3AsO4, and other products. The crystal structure of PPh4Cl · H3AsO3 was determined by X-ray diffraction (4253 observed reflexions, R = 0.031). It is triclinic, space group P1̅, and consists of H3AsO4 molecules joined to dimer units via H bridges and associated via O–H · · · Cl- bridges to strands. The packing of the PPh4+ ions is discussed. Products of the reaction of (PPh4)2[Sb2Cl8] with ozone in CH2C12 are PPh4[SbCl6] and (PPh4)2[SbOCl4]2 · 2 CH2Cl2.

Darstellung und Kristallstruktur von K49Tl108 / Preparation and Crystal Structure of K49T1108

1993 ◽  
Vol 48 (8) ◽  
pp. 1035-1040 ◽  
Author(s):  
Gerhard Cordier ◽  
Volker Müller
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray

K49T1108 was prepared from the elements (molar ratio K: Tl = 1:2) at 700 K. The crystal structure was determined by single crystal X-ray diffraction methods (a = 1728.7(1) pm, Pm 3, Z = 1, R = 0.086). It contains T112 icosahedra and Tl12 truncated tetrahedra (Kasper polyhedra). 20 truncated tetrahedra form Tl84-polyhedra (Samson polyhedra) by sharing hexagonal faces. These polyhedra are connected by common edges. Folded Tl13-chains connect the icosahedra and the Samson polyhedra to a framework. The truncated tetrahedra are occupied by potassium atoms.

Synthesis and sintering of SiC under high pressure and high temperature

1999 ◽  
Vol 14 (3) ◽  
pp. 906-911 ◽  
Author(s):  
S. K. Bhaumik ◽  
C. Divakar ◽  
S. Usha Devi ◽  
A. K. Singh
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
High Pressure ◽  
Silicon Powder ◽  
Synthesis Temperature ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microscopic Studies ◽  
Simultaneous Synthesis

Starting from elemental powders, simultaneous synthesis and compaction of SiC were conducted at 3 GPa pressure and temperatures in the range 2100–2900 K. The sintered compacts were characterized by x-ray diffraction, microhardness measurements, and microscopic studies. The efficiency of formation of SiC was dependent on the particle size of the silicon powder, crystallinity of the reactant carbon, molar ratio of silicon and carbon, and synthesis temperature and time. Carbon in excess of the stoichiometric amount was required to obtain compacts free from residual silicon. The SiC samples, with a Si: C molar ratio 1: 1.05, prepared at 2100 K for 300 s had a density and hardness of 3.21 g/cm3 (98.8% of theoretical density) and 22 GPa, respectively. The crystal structure of the SiC depended on the synthesis temperature. Pure β–SiC in the temperature range 2100–2500 K, and a mixture of α– and β–SiC above 2500 K were obtained. The β–SiC was highly crystalline and nearly defect-free.

The structure of the tetrachlorohydroxotellurate(IV) anion in KTeCl4(OH)•0.5H2O and KTeCl4(OH)

1991 ◽  
Vol 69 (4) ◽  
pp. 648-652 ◽  
Author(s):  
J. B. Milne ◽  
E. J. Gabe ◽  
C. Bensimon
Keyword(s):  
Crystal Structure ◽  
Key Words ◽  
Vibrational Spectroscopy ◽  
X Ray ◽  
Hydroxo Group

Three compounds containing the tetrachlorohydroxotellurate(IV) anion, [Formula: see text] K[TeCl4(OH)]•0.5H2O, and K[TeCl4(OH)], have been prepared. The crystal structure of K[TeCl4(OH)]•0.5H2O has been determined. The structure contains isolated square pyramidal TeCl4(OH)− anions with OH axial. Vibrational spectroscopy shows that [Formula: see text] and K[TeCl4(OH)]•0.5H2O both contain isolated anions but that, in K[TeCl4(OH)], the anion is polymerized with chloride bridging. The hydroxo group, like the fluoro group, acts to hinder coordination at the site trans to it on Te(IV). Key words: tellurium(IV) complexes, chlorotellurate(IV), X-ray structure, vibrational spectroscopy.

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