1,721,063 research outputs found
Gold(I) and Gold(III) Complexes with Anionic Oxygen Donor Ligands: Hydroxo, Oxo and Alkoxo Complexes
No full textThe chemistry of gold(I) and gold(III) hydroxo, oxo and
alkoxo complexes containing organic co-ligands is
reviewed. Due to the high reactivity of the gold-oxygen
bond most of these species can be employed as useful
intermediates in many important processes. Alkoxides
are by far the most numerous class among these
species, and both gold(I) and gold(III) complexes are
known with a variety of alkoxides. The recent discovery
of the catalytic activity of some gold(I) and gold(III)
fluoroalkoxides has enlivened the interest towards this
class of compounds leading to new applications for
previously known complexes, as is the case for a
gold(III) siloxo complex which has found use as a
precursor for CVD, as well as for the synthesis of new
alkoxo derivatives. Another well represented and well
known class of compounds are the gold(I) oxo
complexes [O(AuPR3)3]+ which are the most effective
aurating reagents. Gold(III) oxo complexes have been
synthesized only recently and much of their chemistry
is still largely to be explored. Preliminary studies
suggest their potential in the transfer of oxygen atoms.
Finally, some cationic gold(III) hydroxo complexes are
found to display significant, and in some cases
relevant, cytotoxic effects on cancer cell lines
Reaction of Carbon Monoxide with Cyclometallated Complexes of Palladium(II) and Platinum(II) Derived from a Chiral Alkylbipyridine Ligand
No full textADDUCTS AND CYCLOMETALATED DERIVATIVES OF PALLADIUM(II) WITH 2-(1-METHYLBENZYL)PYRIDINE RID D-3096-2011
No full textEpisodio di agalassia contagiosa da Mycoplasma capricolum subsp. capricolum in provincia di Bergamo: rilievi clinici, diagnosi e controllo.
No full text
GOLD(I) DERIVATIVES OF BETA-CARBOLINE ALKALOIDS - MONONUCLEAR AND DINUCLEAR COMPLEXES OF HARMINE AND HARMALINE - CRYSTAL AND MOLECULAR-STRUCTURE OF (L'-H)AU(PPH3) (L'=HARMINE) RID D-3096-2011
No full textRole of cyclometalation in controlling the rates of ligand substitution at platinum(II) complexes
No full textThe rates of chloride for triphenylphosphine substitution have been measured in dichloromethane for a series of cyclometalated [Pt(N-N-C)Cl] complexes containing a number of terdentate N-N-C. anionic ligands, derived from deprotonated alkyl-, phenyl-, and benzyl-6-substituted 2,2'-bipyridines. These rates have been compared with those of the corresponding [Pt(N-N)(C)Cl] (N-N = 2,2'-bipyridine; C = CH3 or C6H5) complexes having the same set of donor atoms but less constrained arrangements of the ligands. The reactions of the cyclometalated compounds occur as a single-stage conversion from the substrate to the ionic pair [Pt(N-N-C)(PPh3)]Cl products. There is no evidence by H-1 and P-31{H-1} NMR spectroscopy for the formation of other Pt(II) species or of concurrent ring-opening processes. In contrast, ih the monoalkyl- or monoaryl-2,2'-bipyridine complexes, chloride substitution is followed by subsequent slower processes which involve the detachment of one arm of the chelated 2,2'-bipyridine, fast cis to hans isomerization of the cis-[Pt(PPh3)(2)(eta (1)-bipy)(R)](+) transient intermediate, and, eventually, the release of free bipy, yielding trans-[Pt(PPh3)(2)(R)Cl] (R = Me or Ph). All reactions are first-order with respect to complex and phosphine concentration, obeying the simple rate law k(obsd) =: k(2)[PPh3]. The values of the second-order rate constant k(2) do not seem particularly sensitive to the nature of the bonded organic moiety (alkyl or aryl), to its structure (cyclometalated or not), to the size of the ring, or to the number of alkyl substituents on it. The effects are those foreseen on the basis of an associative mode of activation. The only exception to this pattern of behavior is constituted by the complex [Pt(bipy(phi)-H)Cl] (bipy(phi) = 6-phenyl-2,2(bipyridine), which features a significant rate enhancement with respect to the analogue [Pt(bipy)(Ph)Cl] complex. The results of this work, together with those of a previous paper, Suggest that there is not a specific role of cyclometalation in controlling the reactivity, unless an in-plane aryl ring becomes part of the pi -acceptor system of the chelated 2,2'-bipyridine, behaving as a cyclometalated analogue of the nitrogen terdentate 2,2':6',2 " -terpyridine
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
Electrochemical study of Au(III) compounds with substituted pyridine and 2,2’-bipyridine ligands
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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