Synthesis, characterization and X-ray structure of trans-[Pd(COOCH3)(H2O)(PPh3)2](TsO), a possible intermediate in the catalytic hydroesterification of olefins (TsO= p-toluenesulfonate) (Articolo in rivista)

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  • Synthesis, characterization and X-ray structure of trans-[Pd(COOCH3)(H2O)(PPh3)2](TsO), a possible intermediate in the catalytic hydroesterification of olefins (TsO= p-toluenesulfonate) (Articolo in rivista) (literal)
Anno
  • 2003-01-01T00:00:00+01:00 (literal)
Alternative label
  • Cavinato G.1, Vavassori A.2, Toniolo L.2, Benetollo F.3 (2003)
    Synthesis, characterization and X-ray structure of trans-[Pd(COOCH3)(H2O)(PPh3)2](TsO), a possible intermediate in the catalytic hydroesterification of olefins (TsO= p-toluenesulfonate)
    in Inorganica Chimica Acta (Testo stamp.)
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Cavinato G.1, Vavassori A.2, Toniolo L.2, Benetollo F.3 (literal)
Pagina inizio
  • 183 (literal)
Pagina fine
  • 188 (literal)
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  • 343 (literal)
Rivista
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • 1. Department of Inorganic Chemistry (C.I.M.A.), University of Padua, 2. Department of Chemistry, University of Venice, 3. ICTIMA., C.N.R., Corso Stati Uniti, 35100 Padua , Italy (literal)
Titolo
  • Synthesis, characterization and X-ray structure of trans-[Pd(COOCH3)(H2O)(PPh3)2](TsO), a possible intermediate in the catalytic hydroesterification of olefins (TsO= p-toluenesulfonate) (literal)
Abstract
  • The complex trans-[Pd(COOCH3)(H2O)(PPh3)2](TsO) (I) has been synthesized by reacting trans-[Pd(COOCH3)Cl(PPh3)2] with AgTsO in methanol. It has been characterized by IR, 1H and 31P NMR spectroscopy. Crystals of trans-[Pd(COOCH3)(H2O)(PPh3)2](TsO)·(CH3OH) (II) have been obtained by re-crystallization of I in methanol. The structure of the complex has been determined by X-ray analysis. It shows a slightly distorted square planar conformation around the central palladium. The coordinated water molecule and the clathrated methanol form a contact with the uncoordinated TsO- anion, suggesting hydrogen bond interaction. Since I is a possible intermediate in the catalytic hydroesterification of olefins, its catalytic activity in the hydroesterification of ethylene has been tested at 100 °C under 45 atm of a 1/1 mixture of ethylene and CO in methanol as solvent, also in the presence of PPh3 and TsOH. Without addition of PPh3 and TsOH, I affords to traces of methylpropionate together with Pd(0) complexes and Pd metal. The same results are obtained when complex I is tested in the presence of PPh3, except that in this case formation of palladium metal is avoided. Using the system I/PPh3/TsOH=1/6/8, a TOF (mol of ester/mol Pd*h) of 1800 h-1 is obtained. We propose that the role of the acid TsOH is to favor the formation of a Pd–hydride intermediate and/or to reactivate the Pd(0) species, stabilized by the excess of PPh3, via an oxidative addition of the acid. Since the acid does not favor the formation of Pd-alkoxy species we suggest that complex I plays only a minor role in catalysis and that this occurs via a Pd-hydride species. (literal)
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