1,721,175 research outputs found
Tracing iodine
No full textPierangelo Metrangolo and Giuseppe Resnati celebrate the bicentenary of the discovery of iodine — a good time to also bring to its conclusion an international project that aims to define and categorize halogen bonding
Halogen-bonded photoresponsive materials
No full textThe aim of the present review is to illustrate to the reader the state of the art on the construction of supramolecular azobenzene-containing materials formed by halogen bonding. These materials include several examples of polymeric, liquid crystalline or crystalline species whose performances are either superior to the corresponding performances of their hydrogen-bonded analogues or simply distinctive of the halogen-bonded specie
Proton in a Confined Space: Structural Studies of H+⊂Crypt-111 Iodide and Some Halogen-Bonded Derivatives
No full textInvited for the cover of this issue is the group of Giuseppe Resnati at the Politecnico di Milano. The image depicts proton cryptation by crypt-111, the smallest cryptand and an effective proton sponge. Read the full text of the article at 10.1002/chem.201701699
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
ORGANOMETALLIC FRAMEWORKS IN SUPRAMOLECULAR POLYMERS
No full textOrganometallic frameworks are useful modules in supramolecular systems creation [1]. In this respect, they can impart particular structural and electronic properties, simply by varying the ligands on the metal centre. In particular, using bifunctional ligands, it is possible to achieve infinite chains or designed supramolecular systems through the occurrence of non-covalent interactions such as hydrogen bond, halogen bond, electrostatic interaction, π-π interaction, etc. Here we report the preparation of some adducts we recently obtained on co-crystallization of trans-[PtL2(C≡C-4-py)2] (L = PCy3, PEt3) with 1,2-diiodoperfluoroethane, 1,4-diiodoperfluorobenzene and 4,4’-diiodo-2,2’,3,3’-octafluoro-trans-stilbene [2]. The halogen bond between the modules is confirmed by the X-ray structures, showing that both the organoplatinum derivative and the diiodofluorocarbons behave as bidentate and telechelic modules
C.T.-Adducts of S/Se donors with di-halogens as a source of information of the nature of the halogen bonding
No full textVariations on the Author
Full text link“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
Full text linkWe 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
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