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91.
Masood Parvez Atta‐ur‐Rahman M. Iqbal Choudhary Shehnaz Parveen Syed Abdul Majid Ayatollahi 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(2):233-234
In the title compound, 3β‐(dimethylamino)‐16α‐hydroxy‐14‐methyl‐4‐methylene‐9,19‐cyclo‐5α‐pregnan‐20‐one monohydrate, C25H39NO2·H2O, the pentacyclo steroidal alkaloid is composed of three six‐membered, one five‐membered and one three‐membered ring. The molecular dimensions are as expected. The structure is stabilized by hydrogen bonds involving H and O atoms of water and the alkaloid molecules, with strong N?O [2.829 (7) Å] and O?O [2.790 (6) and 2.949 (7) Å] interactions. 相似文献
92.
Choudhari Dinkar Chakravarty Debamitra Lande Dipali N. Parveen Sana Gejji Shridhar P. Kodam Kisan M. Salunke-Gawali Sunita 《Structural chemistry》2019,30(6):2257-2270
Structural Chemistry - Homologated (N)-n-alkylammonium salts of 2-bromo-3-oxido-1,4-naphthoquinone (BS-1 to BS-8) have been synthesized and characterized from the single crystal X-ray diffraction... 相似文献
93.
The interaction of a series of halophenols with sodium dodecyl sulphate and hexadecyltrimethylammonium bromide micelles was studied by different techniques (high-performance liquid chromatography, apparent acidity constant, spectral shift). The contributions of the halogens to the free energy of transfer from water to micelles are calculted. Correlations between the free energy of transfer for water/micellar solutions and for the classical octanol/water system are good. The application of micellar systems in chromatography and acid-base titrations is verified. 相似文献
94.
A. Chatterjee S. Kailas S. Saini S. K. Gupta M. K. Mehta 《Zeitschrift für Physik A Hadrons and Nuclei》1984,317(2):209-213
The absolute differential cross sections for the40Ca(α,α)40Ca reaction have been measured in the bombarding energy range from 4.33 to 5.68 MeV at the four laboratory angles 85°, 125°, 141° and 165°. An analysis of the data using multilevelR matrix theory has provided the spin-parities and widths of 29 levels in the compound nucleus44Ti. A comparison has been made with the levels deduced from the (α,γ) reaction and existing theoretical calculations of44Ti levels. 相似文献
95.
T. C. Awes M. A. Bloomer C. Blume D. Bock R. Bock D. Bucher G. Clewing S. Garpman R. Glasow H. Å. Gustafsson H. H. Gutbrod G. Hölker J. Idh P. Jacobs K. H. Kampert B. W. Kolb H. Löhner F. E. Obenshain A. Oskarsson I. Otterlund T. Peitzmann F. Plasil A. M. Poskanzer M. Purschke B. Roters S. Saini R. Santo H. R. Schmidt S. P. Sørensen K. Steffens P. Steinhaeuser E. Stenlund D. Stüken G. R. Young 《Zeitschrift fur Physik C Particles and Fields》1995,69(1):67-76
A detailed analysis of pair correlations of positive pions in the target fragmentation region is presented. Data on nuclear collisions at 200 GeV per nucleon were measured with the Plastic Ball in the WA80 experiment at the CERN SPS. The correlation functions are compared with analytical functions and with simulations incorporating Bose-Einstein symmetrization, final-state interactions and detector resolution. Source radii are shown to increase with increasing target size and with centrality. For central collisions the radii are larger than the geometrical sizes of the involved nuclei. 相似文献
96.
A. Lanzara N.L. Saini M. Brunelli F. Natali A. Bianconi P.G. Radaelli 《Zeitschrift für Physik B Condensed Matter》1997,104(4):699-702
Recent studies have shown that structural instabilities play a vital role in segregation of charge carriers in the perovskites. We have used extended x-ray absorption fine structure (EXAFS) to investigate the instability of the CuO6 octahedra of the La1:85Sr0:15CuO4 (LSCO) system showing high Tc superconductivity and the MnO6 octhahedra of the La0:75Ca0:25MnO3 (LCMO) system showing GMR (giant-magneto resistance) properties. Temperature dependent Cu K-edge EXAFS spectra on the LSCO and Mn K-edge on the LCMO systems are reported. The results show a similarity in the lattice instability of the two systems providing evidence for a similar phase segregation of localized and itinerant charge carriers in the two families of perovskite systems. 相似文献
97.
N.L. Saini J. Avila M.C. Asensio S. Tajima G.D. Gu N. Koshizuka A. Valletta A. Lanzara A. Bianconi 《Zeitschrift für Physik B Condensed Matter》1997,104(4):703-706
A complete Fermi surface in the normal state of superconducting Bi2Sr2CaCu2O8+δ at the optimum doping (T c = 91K) has been measured by angle scanning photoemission spectroscopy using synchrotron radiation. The Fermi surface reveals broken segments and hot spots of high photointensity along lines of k y = n:0:23Å?1 in the (π; π) direction. The pseudogap observed at (π,0) in underdoped materials is one of this missing segments. The results indicate the presence of characteristic subbands of a superlattice of quantum stripes. This is formed by an ordered array of ~ 14Å large stripes. 相似文献
98.
M. S. Hundal Geeta Sood Parveen Kapoor S. S. Tandon 《Journal of chemical crystallography》1988,18(5):601-607
The title compound C18H18N2O2S is monoclinic with unit-cell dimensionsa=8.849(10),b=9.185(11),c=20.257(9) Å,=109.28(10)°. The space group isP21/c, withZ=4. Data were measured by photographic methods. The structure was solved by direct methods. A full-matrix least-squares refinement converged toR=0.10. All atoms except sulfur were assigned individual isotropic thermal parameters. The conformation of the thiadiazepine ring system is distorted boat shaped, as indicated by torsion angle studies. 相似文献
99.
Simple Organic Salts Having a Naphthalenediimide (NDI) Core Display Multifunctional Properties: Gelation,Anticancer and Semiconducting Properties
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Following a supramolecular synthon rationale, a dicarboxylic acid derivative having a naphthalenediimide (NDI) core, namely, bis‐N‐carboxymethyl naphthalenediimide ( NDI‐G ), was reacted with n‐alkyl amines with varying alkyl chain lengths to generate a new series of primary ammonium dicarboxylate (PAD) salts. The majority of the salts (≈85 %) were found to gel various polar solvents. The gels were characterized by dynamic rheology and high‐resolution electron microscopy. Single‐crystal and powder X‐ray diffraction analyses were used to study the supramolecular synthon present in one of the gelator salts (i.e., S8 ). Charge‐transfer (CT)‐induced gelation with donor molecules such as anthracene methanol ( Ant ) and pyrene ( Py ) was also possible with S8 . The CT complex ( S8.Ant ) displayed anticancer activity as probed by cell migration assay on the highly aggresive breast cancer cell line MDA‐MB‐231 . The DMSO gel of S8.Ant also displayed semiconducting behavior. To the best of our knowledge, simple organic salts with an NDI core that display such mulitifunctional properties are hitherto unknown. 相似文献
100.
A series of mixed‐ligand‐based CdII/CoII coordination polymers (CPs) that were derived from two bis(pyridyl)–bis(amide) ligands, 4,4′‐oxybis(N‐(pyridin‐3‐yl)benzamide) ( LP ) and 4,4′‐oxybis(N‐(pyridin‐4‐yl)benzamide) ( LP1 ), and a variety of dicarboxylates isophthalates, terephthalates, 1,2‐carboxytranscinamates, and 1,3‐ and 1,4‐phenylene dicarboxylates were synthesized based on a rationale that they would occlude solvate guests inside their crystal lattice, thereby rendering these CPs suitable as metallogelators. The CPs were characterized by using single‐crystal X‐ray diffraction, elemental analysis, powder X‐ray diffraction (PXRD), FTIR spectroscopy, and thermogravimetric analysis (TGA). Structural analyses revealed that the majority of the CPs were lattice‐occluded molecular solids, which provided us with an opportunity to study their gelation behavior. We observed that, out of eight CPs that were tested, seven were able to produce metallogels. A thorough study of the rheological behavior of the metallogels was performed and CPG1 , CPG2 , CPG4 , and CPG5 were found to exhibit rheoreversible behavior, which was further confirmed by rheological experiments. Interestingly, ligand LP was found to form an aqueous gel, which was exploited to produce silver nanoparticles. 相似文献