Tetranuclear Homo- and Heteroalumoxanes Containing Reactive Functional Groups: Syntheses and X-ray Crystal Structures of[{[LAl(Me)](μ-O)(MH2)}2]

2004 ◽  
Vol 43 (37) ◽  
pp. 4940-4943 ◽  
Author(s):  
Sanjay Singh ◽  
S. Shravan Kumar ◽  
Vadapalli Chandrasekhar ◽  
Hans-Jürgen Ahn ◽  
Marianna Biadene ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Functional Groups ◽  
X Ray

Synthesis of tetraarylborates via tetralithio intermediates and the effect of polar functional groups and cations on their crystal structures

2018 ◽  
Vol 47 (46) ◽  
pp. 16627-16637 ◽  
Author(s):  
Patryk Tomaszewski ◽  
Marcin Wiszniewski ◽  
Janusz Serwatowski ◽  
Krzysztof Woźniak ◽  
Krzysztof Durka ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Functional Groups ◽  
Structural Characterization ◽  
X Ray ◽  
Polar Functional Groups

The synthesis and X-ray structural characterization of functionalized (COOH, CHO, C(O)NHtBu, B(OH)2) tetraphenyl- and tetrakis(4′-biphenylyl)borates is reported.

scholarly journals Synthesis, Crystal Structures, and Molecular Properties of Three Nitro-Substituted Chalcones

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1589
Author(s):  
Alam Yair Hidalgo ◽  
Manuel Velasco ◽  
Eduardo Sánchez-Lara ◽  
Abraham Gómez-Rivera ◽  
Miguel A. Vilchis-Reyes ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Functional Groups ◽  
Direct Effect ◽  
Crystal Packing ◽  
Hirshfeld Surface ◽  
Stacking Interactions ◽  
Orthorhombic Space Group ◽  
Trans Conformation ◽  
Space Group ◽  
X Ray

Three functionalized chalcones containing combinations of nitro functional groups have been synthesized via Claisen-Schmidt condensation between 2-nitroacetophenone and nitrobenzaldehyde, and the crystal structures obtained ((E)-1,3-bis(2-nitrophenyl)prop-2-en-1-one, 1a, (E)-1-(2-nitrophenyl)-3-(3-nitrophenyl)prop-2-en-1-one, 1b and (E)-1-(2-nitrophenyl)-3-(4-nitrophenyl)prop-2-en-1-one, 1c), C15H10N2O5, are reported. Compounds 1a and 1c crystallized in the triclinic centrosymmetric space group P1¯, whereas compound 1b crystallized in the orthorhombic space group Pbca. The X-ray analysis reveals that structures 1a and 1b exhibits s-trans conformation, whereas structure 1c exists in s-cis conformation, concerning the olefinic double bonds. In addition, the results show that the position of the nitro substituent attached to the aromatic B-ring has a direct effect on the molecular coplanarity of these compounds. The Hirshfeld surface analysis suggests that the non-covalent π-π stacking interactions are the most important contributors for the crystal packing of 1a and 1b. In 1c, the crystal packing is mainly stabilized by weak intermolecular C―H···O interactions due to the planar nature of the molecule.

Tetranuclear Homo- and Heteroalumoxanes Containing Reactive Functional Groups: Syntheses and X-ray Crystal Structures of[{[LAl(Me)](μ-O)(MH2)}2]

2004 ◽  
Vol 116 (37) ◽  
pp. 5048-5051 ◽  
Author(s):  
Sanjay Singh ◽  
S. Shravan Kumar ◽  
Vadapalli Chandrasekhar ◽  
Hans-Jürgen Ahn ◽  
Marianna Biadene ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Functional Groups ◽  
X Ray

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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