New Aryl Edge - Edge Packing Interactions Involving the N-Oxide Functional Group.

1999 ◽  
Vol 52 (11) ◽  
pp. 1047 ◽  
Author(s):  
Vi T. Nguyen ◽  
Marcia L. Scudder ◽  
A. Noman M. M. Rahman ◽  
Roger Bishop ◽  
Donald C. Craig
Keyword(s):  
Crystal Structures ◽  
Functional Group ◽  
Molecular Assembly ◽  
Potential Importance ◽  
Structural Analogue ◽  
Centrosymmetric Dimer ◽  
Supramolecular Synthons ◽  
Aryl Ring ◽  
X Ray ◽  
Packing Interactions

The X-ray crystal structures of 5b,6,12b,13-tetrahydropentaleno[1,2-b:4,5-b´]diquinoline 5,12-dioxide (5) and (6α,7α,14α,15α)-7,15-dibromo-6,7,14,15-tetrahydro-6,14-methanocycloocta[1,2-b:5,6-b´]diquinoline 5,13- dioxide (6) reveal two new packing modes of potential importance as supramolecular synthons for molecular assembly. Both involve intermolecular edge–edge association of an aryl ring and an N-oxide functionality. One is a bifurcated Ar–H···O(N)···H–Ar interaction which on repetition gives infinite chains of the molecules. The second is a 10-membered centrosymmetric dimer also involving Ar–H···O–N interactions but which merely links two neighbouring molecules of (6). The latter arrangement is a structural analogue of a recently reported dimeric centrosymmetric eight-membered Ar–H···N synthon.

Studies via X-ray analysis on intermolecular interactions and energy frameworks based on the effects of substituents of three 4-aryl-2-methyl-1H-imidazoles of different electronic nature and their in vitro antifungal evaluation

2018 ◽  
Vol 74 (11) ◽  
pp. 1447-1458 ◽  
Author(s):  
Mario A. Macías ◽  
Nerith-Rocio Elejalde ◽  
Estefanía Butassi ◽  
Susana Zacchino ◽  
Jaime Portilla
Keyword(s):  
Crystal Structure ◽  
Antifungal Activity ◽  
Crystal Structures ◽  
Intermolecular Interactions ◽  
Acid Base ◽  
Electronic Nature ◽  
Aryl Ring ◽  
X Ray ◽  
Base Properties

The crystal structures of 2-methyl-4-phenyl-1H-imidazole, C10H10N2, (3a), 4-(4-chlorophenyl)-2-methyl-1H-imidazole hemihydrate, C10H9ClN2·0.5H2O, (3b), and 4-(4-methoxyphenyl)-2-methyl-1H-imidazole, C11H12N2O, (3c), have been analyzed. It was found that the electron-donating/withdrawing tendency of the substituent groups in the aryl ring influence the acid–base properties of the 2-methylimidazole nucleus, changing the strength of the intermolecular N—H...N interactions. This behaviour not only influences the crystal structure but also seems to have an important effect on the antifungal activity. Considering the substituent groups, that is, H in (3a), Cl in (3b) and OMe in (3c), the formation of strong N—H...N connections has the probability (3a) > (3b) > (3c), while compound (3c) proves to be more active than (3a) and (3b) at all concentrations against C. neoformans.

Synthese und Eigenschaften von Benzylgallium(indium)-Verbindungen. Die Kristallstrukturen von [(PhCH2)2GaBr]2, [(PhCH2)2GaN(H)t-Bu]2 und [PhCH2InCl2(THF)2] / Synthesis and Properties of Benzylgallium(indium) Compounds. The Crystal Structures of [(PhCH2)2GaBr]2, [(PhCH2)2GaN(H)t-Bu]2 and [PhCH2InCl2(THF)2]

1996 ◽  
Vol 51 (5) ◽  
pp. 637-645 ◽  
Author(s):  
Thomas Kräuter ◽  
Bert Werner ◽  
Bernhard Neumüller
Keyword(s):  
Solid State ◽  
Crystal Structures ◽  
Coordination Sphere ◽  
Molar Ratio ◽  
Centrosymmetric Dimer ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Redistribution Reaction ◽  
Structure Determinations ◽  
Indium Compounds

(PhCH2)2GaBr (1) can be obtained by the redistribution reaction of GaBr3 with Ga(CH2Ph)3 in a molar ratio 1:2. Treatment of 1 or (PhCH2)2GaCl with one equivalent of LiN(H)t-Bu gives the diorganogallium amide [(PhCH2)2GaN(H)t-Bu]2 (2). The toluene-insoluble PhCH2InCl2 can be structurally investigated after dissolving in THF and crystallization as [PhCH2InCl2(THF)2] (3). 1 - 3 were characterized with NMR, IR and MS techniques as well as by X-ray structure determinations. 1 forms two crystallographic independent dimers while 2 is a centrosymmetric dimer in the solid state. 3 is a monomer with a trigonal-bipyramidal coordination sphere at the indium center.

scholarly journals Supramolecular synthon hierarchy in sulfonamide cocrystals with syn-amides and N-oxides

IUCrJ ◽  
2019 ◽  
Vol 6 (4) ◽  
pp. 751-760 ◽  
Author(s):  
Geetha Bolla ◽  
Ashwini Nangia
Keyword(s):  
Potential Energy ◽  
Crystal Structures ◽  
Electrostatic Potential ◽  
Crystal Engineering ◽  
Functional Group ◽  
The Body ◽  
Supramolecular Synthon ◽  
Supramolecular Synthons ◽  
Pharmaceutical Development ◽  
Electrostatic Potential Energy

Sulfonamide drugs are well known antibacterial and antimicrobial molecules for pharmaceutical development. Building a library of suitable supramolecular synthons for the sulfonamide functional group and understanding their crystal structures with partner coformer molecules continues to be a challenge in crystal engineering. Although a few sulfonamide cocrystals with amides and N-oxides have been reported, the body of work on sulfonamide synthons is limited compared with those that have carboxylic acids and carboxamides. To address this structural gap, the present work is primarily focused on sulfonamide–lactam and sulfonamide–syn-amide synthons with drugs such as celecoxib, hydrochlorothiazide and furosemide. Furthermore, the electrostatic potential of previously reported cocrystals has been recalculated to show that the negative electrostatic potential on the lactam and syn-amide O atom is higher compared with the charge on carboxamide and pyridine N-oxide O atoms. The potential of sulfonamide molecules to form cocrystals with syn-amides and lactams are evaluated in terms of the electrostatic potential energy for the designed supramolecular synthons.

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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