1,721,055 research outputs found
Ahmed Hussein, F. A. Devillanova, F. Isaia, G. Verani Copper(I) complexes with N-methylbenzothiazole-2-thione and -2-selone. Transit. Metal Chem., 1985, 10, 368.
No full textN-methylbenzothiazole-2-thione (bttme) and -2-selone (btseme) form complexes with CuX 2 (X=Cl, Br, NO 3, 1/2SO 4 or BF 4). The reaction, carried out in MeOH, produces complexes of copper(I), whose stoichiometry mainly depends on the ligand. Infrared evidence shows that the coordination occurs through the exo-sulphur and selenium atoms
F. Cristiani, F. Demartin, F. A. Devillanova, F. Isaia, V. Lippolis, G. Verani Spectroscopic studies of charge-transfer complexes of 1,4,7-trithiacyclononane with diiodine.
No full text1,4,7-Trithiacyclononane ([9]aneS3) reacts with molecular diiodine in CH2Cl2 to form a 1:1 adduct. The formation constant and the thermodynamic parameters of this adduct have been determined by UV-visible spectra of several solutions at the temperatures of 15, 20, 25, 30, and 35-degrees-C. The C-13 NMR spectra show that adducts with higher ligand/diiodine molar ratios are formed. Two neutral charge-transfer molecular compounds having formula 2[9]aneS3 . 4I2 (I) and [9]aneS3 . 3I2 . (II) have been obtained as crystals. The crystals of I are triclinic (a = 8.498(2) angstrom, b = 13.984(4) angstrom, c = 14.898(6) angstrom, alpha = 65.57(2)degrees, beta = 89.19(2)degrees, gamma = 81.26(2)degrees, Z = 2, space group P1BAR; R = 0.025) and contain units formed by two [9]aneS3 molecules connected by a diiodine molecule; one [9]aneS3 binds two other diiodine molecules, while the second binds only one other diiodine molecule. The crystals of II are monoclinic (a = 13.810(2) angstrom, b = 9.829(4) angstrom, c = 16.198(6) angstrom, beta = 113.41(2)degrees, Z = 4, space group P2(1)/c; R = 0.019) and contain molecules of [9]aneS3 binding three diiodine molecules. FT-Raman spectra in the characteristic nu(I-I) region, carried out on the solid adducts, are discussed in comparison with the structural parameters
Copper(I) complexes from CuX2(X = NO3, BF4, 1 2SO4) and some heterocyclic ligands containing the thioamido group
No full textComplexes of copper(I) CuLnX(n = 2, 3; X = NO3, BF4 1 2SO4) have been obtained by reacting the corresponding copper(II) salts with the following ligands HNCH2·CH2X·C = S (where X = NH, NMe, NEt, S, O and CH2). All the ligands bind the metal through the thioketonic sulphur, as shown by the IR spectroscopy. The copper(I) seems always to realize a trigonal planar geometry both with three molecules of ligands and with two ligands and
N.M.R. spectra of having O, S, or Se atoms in 2, 4.
No full textThe 13C N.M.R. spectra of a series of 5,5-dimethyl 2,4-dichalcogeno substituted imidazolidines are reported. The 13C chemical shifts are assigned by means of a CNDO/S calculation. On the whole the shielding effect of the di-homochalcogeno atoms on C-2 and C-4 increases in the order Se ≤ S O while for the di-hetero atoms no regular trends have been found. On the contrary the resonance of C-5 inside the ring moves downfield keeping one chalcogen atom constant and substituting the oxygen with sulphur and selenium
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
Copper(I) complexes of pentatomic heterocyclic selone donors.
No full textNew complexes of copper(I) with some heterocyclic pentatomic rings, X·CH2·CH2·NR·CSe, where X=CH2, NH, NMe, NEt, S and R=H, Me, Et, were prepared by reacting copper(II) chloride and bromide in MeOH. The stoichiometry of the complexes and the binding mode of the ligands have been discussed comparatively, together with those of the thione parents. It is noteworthy that the selone ligands with R=H (L) yield complexes of the type CuLnY, (n=1,2 or 3; Y=Cl or Br) like the corresponding thione ones. On the contrary, when R=Me or Et, the selonic ligands (L′) give complexes whose stoichiometries, Cu2L′Y2 and Cu3L′2Y3, differ from the thione homologues. The i.r. spectra of the complexes compared with those of the ligands support the coordinative bond via selenium atom
Heterocyclic pentaatomic molecules containing thio- and seleno-amido groups: linear relationship between nS/nSe lone pair ionization energies and 1:1 adduct formation constants with diiodine
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
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