Palladium® complexes oxygen ligands

In this sense, quinone oxygen-coordinated palladium complexes 2 and 3 with anthraquinone ligands bearing Al-heterocyclic coordination sites are synthesized and characterized (Fig. 3.2) [10]. 

NLO properties, 12, 771 from oxygenated ligands, 6, 842 with palladium, 8, 213 and Rh Cp complexes, 7, 160 trinuclear clusters, overview, 6, 835-871 Osmium complexes... 

Nitrogen nucleophiles, in a similar manner to oxygen- and sulfur-based functionality, undergo transition metal-catalyzed cross-coupling with halopyridines. The use of palladium(O) catalysts is most effective in combination with chelating bis-(phosphine) ligands such as BINAP that prevent the formation of pyridine-palladium complexes that... 

Bianchi, D., Bortolo, R., D Aloisio, R. and Ricci, M. (1999) Biphasic synthesis of hydrogen peroxide from carbon monoxide, water, and oxygen catalyzed by palladium complexes with bidentate nitrogen ligands. Angew. Chem. Int. Ed., 38, 706-708. 

Another problem associated with the use of a phosphine on a commercial scale is its conversion, due to the presence of a small amount of oxygen in the reaction zone, to the corresponding phosphine oxide, which will not act effectively as a ligand. The use of a phosphonium salt can minimize this type of conversion. Although the mechanism of the action of the phosphonium salt has not been made clear, it is considered, from the fact that aryl groups should be present, that a very rapid equilibrium with the corresponding phosphine may partially occur. Upon analysis of the actual reaction mixture, however, no trivalent phosphine is detected either in the reaction solution or in the palladium complex. 

An improved method for the synthesis of hydrogen peroxide from carbon monoxide, water and oxygen catalyzed by palladium complexes in presence of a quinone co-catalyst is described. The use of 1,4-naphthoquinone and 1,10-phenanthroline as palladium ligand resulted in a marked catalyst stabilization against deactivation processes such as polynuclear species formation and Pd-black precipitation, which are very fast operating in the absence of quinone. 

II.2.2 Palladium Complexes Containing Halogen and Oxygen Ligands... 

II.2.2 PALLADIUM COMPLEXES CONTAINING HALOGEN AND OXYGEN LIGANDS 45... 

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