2,089 publications from this institution
Nanoparticles of CdO2 and ZnO2 are shown to oxidize toluene primarily to benzaldehyde in the 160-180 °C range, around which temperature the nanoparticles decompose to give the oxides. The product selectivity and other features of the reaction are explained taking into account the various byproducts formed in the reaction. These metal peroxides also activate the CH bonds of cyclohexane. It is possible to bring down the reaction temperature by partially substituting the Zn in ZnO2 with Ni.
No abstract is provided for this article.
LaNiO 3 loses oxygen in well-defined equilibrium stages. Electron diffraction studies show the presence of super-structure due to vacancy ordering in an anion-deficient sample.
Magnetic and electron transport properties of four series of manganates of the composition La0.5−x Ln x Sr0.5MnO3 (Ln=Pr, Nd, Gd and Y) have been investigated to examine how the ferromagnetic metallic nature of the parent La compound changes over to antiferromagnetic insulating behavior, with change in Ln and x due to the associated changes in the A-site cation radius as well as the size disorder. When Ln=Pr and Nd, there is a transition from the tetragonal I4/mcm structure to the orthorhombic Immm and Imma structures at x=0.2 and 0.35, respectively. There is a gradual evolution of the properties from those of La0.5Sr0.5MnO3 to those of Pr0.5Sr0.5MnO3 or Nd0.5Sr0.5MnO3 with increase in x. Thus, when x>0.2 and >0.35, respectively, the Pr- and Nd-substituted manganates show ferromagnetic transitions followed by antiferromagnetic transitions at low temperatures, with the ferromagnetic T C decreasing with increasing x. The Gd and Y series of compounds are all orthorhombic and show a decrease in T C with the increase in x, the ferromagnetism disappearing at high x. At a value of x corresponding to the A-site cation radius of Pr0.5Sr0.5MnO3, the Gd and Y series of compounds exhibit ferromagnetism in the 250–300K region and undergo an antiferromagnetic transition on cooling. The T C−T N gap is sensitive to the disorder arising from the size mismatch.
The interface between toluene and water has been employed to prepare ultrathin Janus nanocrystalline films of metal oxides, metal chalcogenides and gold, wherein the surface on the organic-side is hydrophobic and the aqueous-side is hydrophilic. We have changed the nature of the metal precursor or capping agent in the organic layer to increase the hydrophobicity. The strategy employed for this purpose is to increase the length of the alkane chain in the precursor or use a perfluroalkane derivative as precursor or as a capping agent. The hydrophobicity and hydrophilicity of the Janus films have been determined by contact angle measurements. The morphology of hydrophobic and hydrophilic sides of the film have been examined by field emission scanning electron microscopy.
Solubility of a non-polar solute in non-polar solvents is shown to depend on solvent refractive index.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
No abstract is provided for this article.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Review: (brief discussion of structure and properties of the families of oxide superconductors discovered since 1986 with special attention to the states of copper and oxygen in the cuprates; listing of experimental observations related to the superconducting and normal states that have to be explained by theoretical models; overview of the current theoretical models; indication of possible future directions; more than 85 refs.
Open-framework metal phosphates occur as one-dimensional (1D) chains or ladders, two-dimensional (2D) layers, and complex three-dimensional (3D) structures. Zero-dimensional monomers have also been isolated recently. These materials are traditionally prepared by hydrothermal means, in the presence of organic amines, but the reactions of amine phosphates with metal ions provide a facile route for the synthesis, and also throw some light on the mode of formation of these fascinating architectures. Careful studies of the transformations of monophasic zinc phosphates of well-characterized structures show that the 1D structures transform to 2D and 3D structures, while the 2D structures transform to 3D structures. The zero-dimensional monomers transform to 1D, 2D, and 3D structures. There is reason to believe that the 0D monomers, comprising four-membered rings, are the most basic structural units of the open-framework phosphates and that after an optimal precursor state, such as the ladder structure, is formed, further building may occur spontaneously. Evidence for the occurrence of self-assembly in the formation of complex structures is provided by the presence of the structural features of the one-dimensional starting material in the final products. These observations constitute the beginning of our understanding of the building-up principle of such complex structures.
C70 films deposited on highly oriented pyrolytic graphite (HOPG), Ag(110), Ag(111) and Pt(110) substrates have been investigated by scanning tunnelling microscopy. Interesting observations on novel molecular arrangements, as well as orientational disorder, are presented. Solid solutions of C60 and C70 show interesting packing of these molecules when deposited on HOPG.
Two layered tin(II) oxalate structures have been prepared by hydrothermal methods in the presence of structure-directing organic amines. The crystal data for these structures are as follows: oxalate I, [(CH3)2NH(CH2)2NH(CH3)2]2+[Sn2(C2O4)3]2-·H2O, monoclinic, space group C2/c (no. 15), a = 16.567 (8) Å, b = 10.851 (6) Å, c = 11.652 (6) Å, β = 102.62 (3)°, V = 2039.0 (1) Å3, Z = 4, M = 637.4(1), Dcalc = 2.825 g cm-3, Mo Kα, RF = 0.04; oxalate II, [C(NH2)3]2+[Sn4(C2O4)5]2-·2H2O, orthorhombic, space group Pbca (no. 61), a = 11.390 (1) Å, b = 14.742 (1) Å, c = 16.755 (1) Å, V = 2813.1 (1) Å3, Z = 8, M = 1070.8(1), Dcalc = 2.844 g cm-3, Mo Kα, RF = 0.06. In I, pseudo-pentagonal-bipyramidal SnO6 units form a puckered layered structure by sharing oxygens with the oxalate anions. The layers contain 8- and 12-membered apertures, and the amine (protonated N,N,N'N'-tetramethyl-1,2-diaminoethane) and water molecules are in the interlamellar region where they interact with the framework and with each other by hydrogen bonding. The lone pairs of the Sn(II) atoms point into the interlamellar region. Oxalate II contains both square-pyramidal SnO4 units and SnO6 units similar to those in I. These units together form a saw-tooth lamellar structure by linking through the oxalates. The sheets contain 20-membered corrugated rings, which hold two amine cations (guanidinium) and two water molecules, which interact with the framework via hydrogen bonding.
A zero-dimensional zinc phosphate, comprising a 4-membered ring, is shown to spontaneously transform at room temperature, to a linear chain structure consisting of corner-shared 4-membered rings, the latter transforming to a 3-dimensional sodalite-related structure under mild conditions.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDielectric and electron spin resonance spectroscopic studies of glassy crystalline states of organic compoundsR. Parthasarathy, K. J. Rao, and C. N. R. RaoCite this: J. Phys. Chem. 1984, 88, 1, 49–52Publication Date (Print):January 1, 1984Publication History Published online1 May 2002Published inissue 1 January 1984https://pubs.acs.org/doi/10.1021/j150645a012https://doi.org/10.1021/j150645a012research-articleACS PublicationsRequest reuse permissionsArticle Views31Altmetric-Citations6LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options Get e-Alerts
Procedure and steps needed to rate the kinematic chains from the structural error point of view are listed. All the 40, nine-link, two degree of freedom chains are rated. The transmission matrix concept to select the best frame and its modification to select the best actuator links are introduced. The results are correlated with the Hamming values of the links based on the link adjacency matrix and with the loop Hamming values. Some general conclusions are drawn so that the best combination of the frame and the actuator links can be chosen simply by the inspection of the chain. Best possible combinations for all the 40, nine-link two degree of freedom chains are tabulated.
Cu/Al 2 O 3 .
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNUCLEAR MAGNETIC RESONANCE STUDIES OF HYDROGEN BONDING. II. ALCOHOLSJeff C. Davis Jr., Kenneth S. Pitzer, and C. N. R. RaoCite this: J. Phys. Chem. 1960, 64, 11, 1744–1747Publication Date (Print):November 1, 1960Publication History Published online1 May 2002Published inissue 1 November 1960https://doi.org/10.1021/j100840a035RIGHTS & PERMISSIONSArticle Views150Altmetric-Citations79LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (450 KB) Get e-Alerts
