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Reactions of carbonylchlorogold(I) with thiolates and thiols. Crystal and molecular structures of NaL(H2O)/(AuCl)3S-t-Bu, ......
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N,N-dialkycarbamato oligonuclear complexes of iron(II), including [Fe4(μ4-O)(O2CNPri2)6]2, the first crystallographically established uncharged μ-oxo complex of iron(II)
No full textCyclopentadienyl-diethylcarbamato derivatives of zirconium(IV) and hafnium(IV), M(C5H5)(O2CNEt2)3: synthesis and use as precursors for chemical implantation on a silica surface
No full textReactions of carbonylchlorogold(I) with thiolates and thiols. Crystal and molecular structures of [NaL(H2O)][(AuCl)3SBut], [NaL][AuCl2], [NaL]4[AuCl2]2[Au4Cl6S2] and [NaL]2[Au4Cl6S2] (L= 1,4,7,10,13-pentaoxacyclopentadecane)
No full textPreparation and characterization of dialkylcarbamato derivatives of niobium and tantalum
No full texthe mononuclear compounds M(O(2)CNR(2))(n) (M = Nb or Ta, R = Et, n = 5; M = Nb, R = Et or Pr-i, n = 4) have been prepared by treating the corresponding metal chlorides or their adducts, i,e. [NbCl4(thf)(2)](thf = tetrahydrofuran), with CO2-NHR(2) in toluene. The molecular structures of Ta(O(2)CNEt(2))(5) and Nb(O(2)CNEt(2))(4) have been solved by X-ray diffraction methods. The tantalum atom is eight-co-ordinated, being surrounded by three bi- and two mono-dentate diethylcarbamato groups, in a slightly distorted square-antiprismatic arrangement. The niobium compound consists of mononuclear units, where the niobium atom is dodecahedrally co-ordinated to eight oxygen atoms of four bidentate diethylcarbamate ligands. The reaction of [NbCl3(dme)] (dme = 1,2-dimethoxyethane) with CO2-NHR(2)(R = Et or Pr-i) gave the corresponding dialkylcarbamates; on the basis of spectroscopic and magnetic data these niobium(III) derivatives are suggested to be dinuclear with bridging and terminal carbamato groups. Improved yields of [M(2)(eta(6)-C(6)Me(6))(2)Cl-4] (M = Nb or Ta), which are the precursors to the dialkylcarbamates of niobium(II) and tantalum(II), have been obtained. The [M(2)(eta(6)-C(6)Me(6))(2)Cl-4]-CO2-NHPr2i system (M = Nb or Ta) in toluene gave metal(II) dialkylcarbamato complexes of analytical composition M(eta(6)-C(6)Me(6))(O2CNPr2i)(2): these substantially diamagnetic compounds are suggested to be dinuclear with bridging carbamato groups, a metal-metal bond and axially co-ordinated hexamethylbenzene
Eight-coordinate chelate complexes of zirconium(IV) and niobium(IV): X-ray diffractometric and EPR investigations
No full textThe N,N-diethylcarbamato derivative of zirconium(IV), Zr(OzCNEt2)4 has been studied by X-ray crystallography. Crystal data:
CzoH4oN4OsZr, monoclinic, space group C2/c, a = 14.057(1), b= 12.168(1), c= 16.746(2) A, /3= 108.071(4) °, Z=4, Dr = 1.356,
F(000) = 1168, T= 213 K. The compound is isotypic with the corresponding niobium(IV) derivative with a dodecahedral coordination at
the zirconium atom. B y reaction of NbC14 (THF) 2 with TI (hfacac), the hexafluoroacetylacetonato deft vati ve of niobium ( IV ), Nb (hfacac) 4,
has been prepared and structurally characterized. The compound crystallizes in the orthorhombic space group Pna2~ with the following cell
constants: a = 10.399(4), b = 15.852(9), c = 119.073( 1 ) A. It is not isotypic with the corresponding zirconium(IV) derivative, Zr(hfacac)4.
Crystal data: CzoH4F24OsZr, monoclinic, space group P21/n, a = 11.974(4), b=20.451(6), c= 13.140(3) ]~, /3= 104.487(11) °, Z=4,
Dc = 1,960, F(000) = 1776, T= 223 K. Although in both compounds the central metal atom shows a square antiprismatic coordination, the
coordination mode of the ligands is different and slight deviations from the D4(llll) and C2(llss) ideal geometries have been observed in the
case of niobium and zirconium, respectively. An EPR study has been performed on the Nb(1V) derivatives as diluted solid solutions in frozen
organic solvents or in the diamagnetic matrix of the corresponding zirconium(IV) compound. The EPR spectra have confirmed the presence
of r~on-interacting paramagnets in the solid solutions and, in the case of Nb(O2CNEt2)4, the point symmetry of the paramagnetic centre has
been found to be in agreement with the results of the X-ray investigation. An EPR spectrum of rhombic symmetry has been observed for the
hexafluoroacetylacetonato derivative of Nb(IV) when diluted in frozen THF solution or in Zr(hfacac)~
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
Variations 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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