Reactivity of ruthenium trihydrides with Broensted and Lewis acids. X-ray crystal structures of {Cp*Ru[C6H9P(C6H11)2]}BF4 and {{Cp*RuH[P(C6H11)3]}(.mu.-H)2Cu(.mu.-Cl)}2. Evidence for exchange coupling between two hydrogen atoms

1991 ◽  
Vol 10 (6) ◽  
pp. 1888-1896 ◽  
Author(s):  
Therese. Arliguie ◽  
Bruno. Chaudret ◽  
Felix A. Jalon ◽  
Antonio. Otero ◽  
Jose A. Lopez ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Exchange Coupling ◽  
Lewis Acids ◽  
Hydrogen Atoms ◽  
X Ray

Reactivity of a Phosphanylcarbene(λ5-Phosphaacetylene) with Lewis Acids: X-Ray Crystal Structures of the First Carbene-Gallane Complex andC-Gallyl-Substituted Phosphorus Ylide

1994 ◽  
Vol 33 (5) ◽  
pp. 578-580 ◽  
Author(s):  
Alan H. Cowley ◽  
François P. Gabbaï ◽  
Carl J. Carrano ◽  
Ladd M. Mokry ◽  
Marcus R. Bond ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Lewis Acids ◽  
X Ray ◽  
Phosphorus Ylide

Zur Struktur von Dihydroxonium Alkandisulfonaten / The Structure of Dihydroxonium Alkanedisulfonates

1994 ◽  
Vol 49 (11) ◽  
pp. 1467-1472 ◽  
Author(s):  
Peter Sartori ◽  
Ralf Jüschke ◽  
Roland Boese ◽  
Dieter Bläser
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Ionic Form ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Oxonium Ions

AbstractThe crystal structures of methanedisulfonic acid-(1) and 1,2-ethandisulfonic acid-dihydrate (2) have been determined from single crystal X-ray diffraction at T = 145 K (for 1) and T = 125 K (for 2). It has been found, that both acids exist in an ionic form as dihydroxonium sulfonates, but differ in the geometry of the sulfonate groups and in the positions of the hydrogen atoms at the oxonium ions.

scholarly journals Crystal structures of titanium–aluminium and –gallium complexes bearing twoμ2-CH3units

2017 ◽  
Vol 73 (5) ◽  
pp. 691-693 ◽  
Author(s):  
Tim Oswald ◽  
Mira Diekmann ◽  
Annika Frey ◽  
Marc Schmidtmann ◽  
Rüdiger Beckhaus
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Lewis Acids ◽  
Methyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Methyl Methyl ◽  
Low Valent ◽  
Titanium Aluminium ◽  
Gallium Complexes

The isotypic crystal structures of two titanocene complexes containing anEMe3unit (E =Al, Ga; Me = methyl) with twoμ2-coordinating methyl groups, namely [μ-1(η5)-(adamantan-1-yl-2κC1)cycylopentadienyl]di-μ2-methyl-methyl-2κC-[1(η5)-pentamethylcyclopentadienyl]aluminiumtitanium(III), [AlTi(CH3)3(C10H15)(C15H18)], and [μ-1(η5)-(adamantan-1-yl-2κC1)cycylopentadienyl]di-μ2-methyl-methyl-2κC-[1(η5)-pentamethylcyclopentadienyl]galliumtitanium(III), [GaTi(CH3)3(C10H15)(C15H18)], are reported. Reacting a dinuclear nitrogen-bridged low-valent titanium(III) complex with the Lewis acids AlMe3or GaMe3results in the loss of molecular dinitrogen and the formation of two monomeric titanocene(III) fragments bearing twoμ2-bridging methyl groups. Single crystal X-ray diffraction reveals the formation of a newE—C bond involving the pentafulvene ligand while the bridging and terminal methyl groups remain intact.

Two crystal structures of 10,10′-(l,4-phenylene-dimethylidene)-bis-9,10-H-anthracenone

1992 ◽  
Vol 200 (3-4) ◽  
Author(s):  
G. Dewald ◽  
M. Hanack ◽  
E.-M. Peters ◽  
L. Walz
Keyword(s):  
Crystal Structures ◽  
Diffraction Data ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
Space Group ◽  
X Ray ◽  
Crystal And Molecular Structures

AbstractThe crystal and molecular structures of dimorphic 10,10′-(1,4-phenylene-dimethylidene)-bis-9,10-H-anthracenone (1) have been determined using X-ray diffraction data. The compound crystallizes either in the monoclinic space groupSince all non-hydrogen atoms are of pure

1 : 1 Molecular Complexes of 4-Amino-N-(4,6-dimethylpyrimidin-2-yl)benzene-sulfonamide (Sulfamethazine) with Indole-2-carboxylic Acid and 2,4-Dinitrobenzoic Acid

2000 ◽  
Vol 53 (5) ◽  
pp. 383 ◽  
Author(s):  
Daniel E. Lynch ◽  
Pardeep Sandhu ◽  
Simon Parsons
Keyword(s):  
Hydrogen Bonding ◽  
Carboxylic Acid ◽  
Crystal Structures ◽  
Molecular Complexes ◽  
Average Difference ◽  
Hydrogen Atoms ◽  
X Ray ◽  
A Value ◽  
Hydrogen Bonding Interactions ◽  
Graph Set

The 1 : 1 molecular adducts of 4-amino-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide (Sulfamethazine) with respectively indole-2-carboxylic acid (1) and 2,4-dinitrobenzoic acid (2) have been prepared and their X-ray crystal structures determined. The acid groups in both structures form associative R22 (8) graph set hydrogen-bonding interactions across the N(11)–H/N(17) site of Sulfamethazine. Acomparison of the two distances between relevant non-hydrogen atoms in this configuration reveals that this association is not symmetrical. An average difference of 0.144 Å is observed for seven listed complexes of Sulfamethazine, five having been previously reported. This average difference compares with a value of 0.265 Å for the same interaction seen in carboxylic acid adducts of 2-aminopyrimidine.

Transmission electron microscope studies in special ceramics

1978 ◽  
Vol 36 (1) ◽  
pp. 268-269
Author(s):  
A. Zangvil ◽  
L.J. Gauckler ◽  
G. Schneider ◽  
M. Rühle
Keyword(s):  
Phase Diagrams ◽  
Crystal Structures ◽  
Thin Foil ◽  
Limited Extent ◽  
Complex Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Lattice Resolution

The use of high temperature special ceramics which are usually complex materials based on oxides, nitrides, carbides and borides of silicon and aluminum, is critically dependent on their thermomechanical and other physical properties. The investigations of the phase diagrams, crystal structures and microstructural features are essential for better understanding of the macro-properties. Phase diagrams and crystal structures have been studied mainly by X-ray diffraction (XRD). Transmission electron microscopy (TEM) has contributed to this field to a very limited extent; it has been used more extensively in the study of microstructure, phase transformations and lattice defects. Often only TEM can give solutions to numerous problems in the above fields, since the various phases exist in extremely fine grains and subgrain structures; single crystals of appreciable size are often not available. Examples with some of our experimental results from two multicomponent systems are presented here. The standard ion thinning technique was used for the preparation of thin foil samples, which were then investigated with JEOL 200A and Siemens ELMISKOP 102 (for the lattice resolution work) electron microscopes.

Crystal Structures of Fragments D and Double-D from Fibrinogen and Fibrin

1999 ◽  
Vol 82 (08) ◽  
pp. 271-276 ◽  
Author(s):  
Glen Spraggon ◽  
Stephen Everse ◽  
Russell Doolittle
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Crystal Structures ◽  
Structure And Function ◽  
X Ray ◽  
Long Period ◽  
And Function

IntroductionAfter a long period of anticipation,1 the last two years have witnessed the first high-resolution x-ray structures of fragments from fibrinogen and fibrin.2-7 The results confirmed many aspects of fibrinogen structure and function that had previously been inferred from electron microscopy and biochemistry and revealed some unexpected features. Several matters have remained stubbornly unsettled, however, and much more work remains to be done. Here, we review several of the most significant findings that have accompanied the new x-ray structures and discuss some of the problems of the fibrinogen-fibrin conversion that remain unresolved. * Abbreviations: GPR—Gly-Pro-Arg-derivatives; GPRPam—Gly-Pro-Arg-Pro-amide; GHRPam—Gly-His-Arg-Pro-amide

Synthesis of Sulfoquinovose and Sulfoquinovosyl Diacylglycerides, and a Fluorogenic Substrate for Sulfoquinovosidases

2019 ◽  
Author(s):  
Yunyang Zhang ◽  
Janice Mui ◽  
Thimali Arumaperuma ◽  
James P. Lingford ◽  
ETHAN GODDARD-BORGER ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Fluorogenic Substrate ◽  
Potassium Salts ◽  
X Ray ◽  
Sulfoquinovosyl Diacylglycerol ◽  
Sodium And Potassium

<p>The sulfolipid sulfoquinovosyl diacylglycerol (SQDG) and its headgroup, the sulfosugar sulfoquinovose (SQ), are estimated to harbour up to half of all organosulfur in the biosphere. SQ is liberated from SQDG and related glycosides by the action of sulfoquinovosidases (SQases). We report a 10-step synthesis of SQDG that we apply to the preparation of saturated and unsaturated lipoforms. We also report an expeditious synthesis of SQ and (<sup>13</sup>C<sub>6</sub>)SQ, and X-ray crystal structures of sodium and potassium salts of SQ. Finally, we report the synthesis of a fluorogenic SQase substrate, methylumbelliferyl a-D-sulfoquinovoside, and examination of its cleavage kinetics by two recombinant SQases.</p>

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