The platina-β-diketone Pt
2{(COMe)
2H}
2(μ-Cl)
2 (
A) was found to react with chelating
N,
N-ligands 2-(R
′NCR)C
5H
4N yielding acyl(hydrido)platinum(IV) complexes (
B) and with chelating
S,
S- and
...N,
S-donors RS–CH
2–CH
2–SR and 2-(RSCH
2)C
5H
4N yielding acyl(chloro)platinum(II) complexes Pt(COMe)Cl(RSCH
2CH
2SR) and Pt(COMe)Cl{2-(RSCH
2)C
5H
4N} (
C), respectively. Results gave evidence that hard donors like N tend to react yielding stable platinum(IV) type
B complexes whereas soft donors like S tend to react yielding platinum(II) type
C complexes.
The platina-β-diketone Pt
2{(COMe)
2H}
2(μ-Cl)
2 (
1) was found to react with chelating
N,
N-ligands 2(R
′NCR)C
5H
4N (R/R
′=Ph/OH, H/Ph, Me/Ph) to form acyl(hydrido)platinum(IV) complexes Pt(COMe)
2Cl(H){2-(R
′NCR)C
5H
4N} (R/R
′=Ph/OH
2a; H/Ph
2b; Me/Ph (
2c)). Reactions of complex
1 with chelating
S,
S- and
N,
S-donors (RS–CH
2–CH
2–SR, 2-(RSCH
2)C
5H
4N, R=Et, Ph,
t-Bu) afforded acyl(chloro)platinum(II) complexes Pt(COMe)Cl(RSCH
2CH
2SR) (R=Et,
3a; Ph,
3b;
t-Bu,
3c) and Pt(COMe)Cl{2-(RSCH
2)C
5H
4N} (R=Et,
4a; Ph,
4b;
t-Bu,
4c), respectively. All complexes were fully characterized by microanalysis, IR and NMR (
1H,
13C) spectroscopy. Furthermore, molecular structures of complexes
3b and
4b were determined by single-crystal X-ray diffraction analyses revealing close to square-planar configuration. In complex
4b the acetyl ligand is
trans to pyridine N atom (configuration index
SP-4-2). The reactions are discussed in terms of consecutive oxidative addition and reductive elimination reactions.
Critical edition and Spanish translation of the comforting letters written by Bartholomaeus Platina and Rodericus Sanctius de Arevalo to the count Francesco dell'Anguillara as reply to his request of ...comfort and freedom during his imprisonment in Castel Sant'Angelo. Before the critical edition appears a study of the Anguillara family and the circumstances leading to the imprisonment of Francesco. PUBLICATION ABSTRACT
O artigo retoma um tema que tem sido objeto de fortes polêmicas historiográficas, tais como a participação da Grã-Bretanha na independência do Uruguai, e o estuda da perspectiva do cônsul britânico ...em Montevidéu. Nessa direção, através da análise dos relatórios consulares de Thomas S. Hood, abordamse aspectos tais como a disparidade dos interesses britânicos na região e o percurso das posturas independentistas. Palavras-chave: Independência do Uruguai. Região platina. Interesses britânicos.
The dinuclear platina-β-diketone
1 was found to react with 2-(ROCH
2)C
5H
4N (R
=
Me,
2a; H,
2b) yielding a cationic mononuclear platina-β-diketone
3 and an acetyl(chloro)platinum(II) complex
4, ...respectively. This distinctly different reactivity of
1 with
2a on the one hand and with
2b on the other is discussed in terms of the HSAB concept and a deprotonation/reprotonation reaction.
The dinuclear platina-β-diketone Pt
2{(COMe)
2H}
2(μ-Cl)
2 (
1) was found to react with 2-(ROCH
2)C
5H
4N (R
=
Me,
2a; H,
2b) yielding a cationic mononuclear platina-β-diketone Pt{(COMe)
2H}{2-(MeOCH
2)C
5H
4N}Cl (
3) and an acetyl(chloro)platinum(II) complex Pt(COMe)Cl{2-(HOCH
2)C
5H
4N} (
4), respectively. The reaction of
1 with 8-(methylthio)quinoline (
5) resulted in the formation of Pt(COMe)Cl{8-(MeS)C
9H
6N} (
6). The identities of all complexes were established by microanalysis,
1H, and
13C NMR spectroscopy. Single-crystal X-ray diffraction analysis showed
6 to be square–planar platinum(II) complex with N and C atoms as well as Cl and S atoms in mutually
trans positions (configuration index:
SP-4-2). In accordance with this, quantum chemical calculations on the DFT level of theory revealed a higher stability of complex
6 having a
SP-4-2 configuration vs. the analogous complex in
SP-4-3 configuration. The distinctly different reactivity of
1 with
2a on the one hand and with
2b and
5 on the other is discussed in terms of the HSAB concept and a deprotonation/reprotonation reaction.
This paper provides an overview of the evolution of pollution problems in the Northeast Atlantic and associated responses and considers the effectiveness of these measures on environmental ...contamination. It identifies shortcomings in past practices and shows how marine environmental pollution may be perpetuated if new products and processes release novel contaminants or “emerging substances” without adequate management on a precautionary basis. The study concludes that it is necessary to develop innovative techniques capable of making reasonable quantitative estimates of not only environmental pathways, loads, and concentrations but also the socioeconomic drivers and “upstream” control measures (control, reduction, or elimination of emissions) so that a clear understanding of the causes and effects of our actions can be obtained. The development of a European Observatory for Emerging Substances to coordinate concerns, observations, and practices is suggested as a proactive approach for anticipating emerging problems.
Neste artigo, analisamos a atuação de dois jornalistas italianos, Gian Battista Cuneo e Luigi Rossetti, na Região Platina entre os anos de 1838 e 1860. Enfocando suas participações nos debates acerca ...da construção das nações na América, analisamos em que medida os autores modificaram e readaptaram suas idéias radicais, inspiradas no nacionalismo mazziniano, ao longo de suas atuações na imprensa da Região Platina.
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