Interligand Interactions Affecting Site-Specific Metal Bonding. X-ray Crystal Structures of [Rh2(acetato)4(L)2], Where L = 2,4-Diamino-6-methyl-s-triazine, 2,6-Dimethyl-4-aminopyrimidine, and 2,6-Dimethylpyridine

1994 ◽  
Vol 33 (13) ◽  
pp. 3018-3020 ◽  
Author(s):  
Katsuyuki Aoki ◽  
Masamoto Inaba ◽  
Shousuke Teratani ◽  
Hiroshi Yamazaki ◽  
Yoshikatsu Miyashita
Keyword(s):  
Crystal Structures ◽  
Site Specific ◽  
X Ray ◽  
Metal Bonding ◽  
Specific Metal

Structure−Function Relationships inAnabaenaFerredoxin:  Correlations between X-ray Crystal Structures, Reduction Potentials, and Rate Constants of Electron Transfer to Ferredoxin:NADP+Reductase for Site-Specific Ferredoxin Mutants†,‡

Biochemistry ◽  
1997 ◽  
Vol 36 (37) ◽  
pp. 11100-11117 ◽  
Author(s):  
John K. Hurley ◽  
Anne M. Weber-Main ◽  
Marian T. Stankovich ◽  
Matthew M. Benning ◽  
James B. Thoden ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Structure Function ◽  
Crystal Structures ◽  
Rate Constants ◽  
Site Specific ◽  
X Ray ◽  
Reduction Potentials

Kristallstrukturen und elektronische Eigenschaften von Ge1/3NbS2 und Ge1/4NbS2 / Crystal Structures and Electronic Properties of Ge1/3NbS2 and Ge1/4NbS2

2002 ◽  
Vol 57 (12) ◽  
pp. 1367-1374 ◽  
Author(s):  
Regina Pocha ◽  
Dirk Johrendt
Keyword(s):  
Band Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Crystal Structures ◽  
Chemical Transport ◽  
X Ray ◽  
Metal Bonding ◽  
Band Structure Calculations ◽  
Metal Metal ◽  
Structure Calculations

Single crystals of the intercalation compounds Ge1/3NbS2 andGe1/4NbS2 have been prepared by heating of the elements at 1073 K and by chemical transport with iodine at 923 to 1073 K. Their crystal structures were determined by single crystal X-ray methods.Ge1/3NbS2 (P63/mcm, a=5.767(1), c=13.518(3) Å, Z = 6) crystallizes with a superstructureof 2H-NbS2, characterized by layers of edge-sharing NbS6 trigonal prisms. The Ge atoms in the octahedral voids of the van der Waals gap are sixfold coordinated by sulfur. The NbS2-sublattice of Ge1/4NbS2 (P63/mmc, a = 3.339(1), c = 37.326(7) Å , Z = 6) represents a new 6H-polymorph. Herein, the Ge atoms are located either in the centers of the octahedral voids (c. n. = 6) or shifted from this position along [001] (c. n. = 3 + 3). The unusual electronic state and the bonding situation of germanium in the van der Waal gaps of NbS2 and the metal-metal bonding are studied in detail by using DFT band structure calculations.

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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