67486-19-5Relevant academic research and scientific papers
New carboalkoxybis(triphenylphosphine)palladium(II) cationic complexes: Synthesis, characterization, reactivity and role in the catalytic hydrocarboalkoxylation of ethene. X-ray structure of trans-[Pd(COOMe)(TsO)(PPh3)2]·2CHCl3
Amadio,Cavinato,Dolmella,Ronchin,Toniolo,Vavasori
, p. 103 - 110 (2009)
The cationic complexes trans-[Pd(COOR)(H2O)(PPh3)2](TsO) have been synthesised by reacting cis-[Pd(H2O)2(PPh3)2](TsO)2·2H2O with CO in ROH (R = Me and Et), practically under room conditions, or by methathetical exchange of trans-[Pd(COOMe)Cl(PPh3)2] with Ag(TsO) (R = n-Pr, iso-Pr, n-Bu, iso-Bu, sec-Bu). They have been characterised by IR, 1H NMR and 31P NMR spectroscopies. The X-ray investigation of trans-[Pd(COOMe)(TsO)(PPh3)2] reveals that the palladium center is surrounded in a virtually square planar environment realized by two PPh3 trans to each other, the carbon atom of the carbomethoxy ligand and an oxygen atom of the p-toluensulfonate anion, with two crystallization molecules of CHCl3. The Pd-O-S angle, 151.9 (3)°, is very wide, probably due to the interaction of one CHCl3 molecule with the complex inner core. The carbomethoxy derivatives react with R′OH yielding the corresponding R′ carboalkoxy derivative (R′ = Et, n-Pr and iso-Pr); ethene does not insert into the Pd-COOMe bond; decarbomethoxylation occurs when treated with TsOH/H2O in MeOH at 50 °C. All the carboalkoxy are precursors for the catalytic carboalkoxylation of ethene if used in combination of PPh3 and TsOH, better in the presence of some water. Experimental evidences are more in favor of the so-called "hydride" mechanism rather than the "carbomethoxy" mechanism.
On the mechanism of hydroesterification of styrene using an in situ-formed cationic palladium complex
Seayad,Jayasree,Damodaran,Toniolo,Chaudhari
, p. 100 - 107 (2007/10/03)
The mechanism of hydroesterification of styrene using in situ-formed Pd(OTs)2(PPh3)2 from Pd(OAc)2, PPh3 and TsOH in methanol has been investigated by isolation and characterisation of catalytically active intermediates. From reaction mixtures, Pd-hydridocarbonyl and Pd-acyl complexes were isolated and characterised, based on which a Pd hydride mechanism has been proposed. Formation of palladium hydride species has also been confirmed by 31P-NMR experiments.
