1,721,071 research outputs found
Alkylamino imidazolium aurate salts: synthesis, structures and applications
No full textWe have recently described the synthesis and characterization of amino-functionalized N-heterocyclic carbene complexes of silver(I), Ag(I)-NHCs, using the Boc-protected and deprotected 1-(2-aminoethyl)-3-methyl imidazolium salts [NH2(CH2)2ImMe]X, [1]X (X = I, PF6) as carbene precursors [1].
We are now presenting the preparation of a new gold(III)-alkylamino imidazolium aurate salt [Cl3AuNH2(CH2)2ImMe)][AuCl4] (2). Demonstrating the great versatility of the amino-functionalized imidazolium salts, such compound is an useful precursor for the preparation of gold nanoparticle (AuNPs) films via the layer-by-layer (LBL) assembly method [2]. Assembling appropriate polyelectrolytes such as poly(ethyleneimine) (PEI) on Indium Tin Oxide Glasses (ITO) a monolayer film of 2 can be easily grafted on the surface and after subsequent reduction, well controlled, in size and distribution, immobilized AuNPs can be generated. The morphology of the AuNPs layers was investigated by using AFM and SEM microscopy and X-ray diffraction (XRD).
References
[1] L. Busetto, M.C. Cassani, C. Femoni, A. Macchioni, R. Mazzoni, D. Zuccaccia, J. Organomet. Chem. 693, 2579 (2008).
[2] J.F. Quinn, A.P.R. Johnston, G.K. Such, A.N. Zelikin, F. Caruso, Chem. Soc. Rev. 36, 707 (2007)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Electron-Sink Features of Homoleptic Transition-Metal Carbonyl Clusters
No full textMetal cluster chemistry is at the cutting edge between molecular and solid-state chemistry and has therefore had a great impact on the researchers working on organic, coordination, and solid-state chemistry, catalysis, physics, and materials science. The development of new sophisticated synthetic techniques has led to enormous progress in the synthesis of this diverse class of compounds. The number of clusters is growing rapidly, since the possible variations in the metal and ligand sphere are numerous. Modern bonding theories, such as the isolobal principle, have allowed a better understanding of the structures and properties of metal clusters, and thus paved the way for the usage of these versatile materials. Catalysis and nanomaterials are just two of the very promising application-oriented fields.
Seventy six contributions, written by world experts in this research field, provide extensive coverage of different aspects of cluster chemistry, ranging from synthesis, structure determination, and dynamics to applications. Up-to-date information, including an impressive collection of structural data and illustrations, extensive coverage of the most important publications of the last decade, and many more features make this three-volume set a complete single-source guide for all researchers working in the area of cluster chemistry
The chemistry of htdridocarbonylferrates revisited: syntheses and structures of the new [H2Fe4(CO)12]2– and [HFe5(CO)14]3– amions, and the [Fe(DMF)4][Fe4(CO)12(6-2-CO)(-H)]2 adduct containing an unprecedented isocarbonyl
No full textThe di-hydride di-anion [H2Fe4(CO)(12)](2-) has been quantitatively obtained by protonation of the previously reported mono-hydride tri-anion [HFe4(CO)(12)](3-) in DMSO and structurally characterised in its [NEt4](2)[H2Fe4(CO)(12)] salt. It shows some subtle but yet significant differences in the stereochemistry of the ligands in comparison to the heavier Ru-4 and Os-4 congeners. The study of the reactivity of these [H4-nFe4(CO)(12)](n-) (n = 2,3) species allowed the serendipitous isolation and structural characterization of the new pentanuclear [HFe5(CO)(14)](3-) mono-hydride tri-anion. Attempts to obtain the latter in better yields led to the discovery of intermolecular CO/H- mutual exchange reactions and isolation and structural characterization of the [Fe(DMF)(4)][Fe-4(CO)(12)(mu(5)-eta(2)-CO)(mu-H)](2)center dot 0.5CH(2)Cl(2) and [M+][Fe-4(CO)(12)(mu(4)-eta(2)-CO)(mu-H)](-) (M = K, Cs) adducts, the former containing an unprecedented isocarbonyl group. The isolation of new tetranuclear and, above all, pentanuclear hydridocarbonylferrates indicates that it is possible to further expand the chemistry of homoleptic Fe carbonyl specie
Modulation of Electronic Behaviour of Metal Carbonyl Clusters
No full textOrganometallic chemistry is an area which touches on, and plays an active role in, all of the traditional divisions of chemistry: inorganic, organic, physical and theoretical. This timely book provides overviews of recent original developments in these areas, including: the synthesis of main group, transition metal and lanthanide organometallics; applications to homogeneous catalysis; structural and theoretical studies; and enantioselective processes. As these topics are currently part of a stream of exciting research with potentially important industrial applications, this title presents informed accounts of state-of-the-art research which will be of great interest to readers. Written by some of the foremost groups in the field and handsomely illustrated throughout, each chapter also provides an extensive bibliography. By introducing areas that are likely to play a prominent role in organometallic chemistry in the near future, Perspectives in Organometallic Chemistry provides an authoritative source of ideas, particularly for all those engaged in research
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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