Palladium(II) complexes with new bidentate phosphine-imine ligands for the Suzuki C-C coupling reactions in supercritical carbon dioxide

Newly designed perfluorinated phosphine-imine ligands (3a-c) have been synthesized from the 3-(heptadecafluorooctyl)aniline and 2-(diaryl)phosphinobenzaldehyde (diaryl: -Ph-2, 2a; -(3,5-(CH3)(2)Ph-2)2, 2b; -(3,5-(CF3)(2)Ph)(2), 2c) and complexed with dichloro(1,5-cyclooctadiene)palladium(II) to form supercritical carbon ;dioxide (ScCO2) soluble palladium(II) complexes (4a-c). All compounds were fully characterized using spectroscopic and analytical techniques, including P-31, H-1, F-19, C-13 NMR and FTIR spectroscopies and high resolution mass spectroscopy. These palladium(II) complexes having perfluoroctyl ponytails (-C8F17) are soluble in carbon dioxide at > 333 K under 122 atm of CO2 pressure. Homogenous palladium catalyzed Suzuki C-C coupling reactions using the novel catalysts were carried out at 353 K 135 atm. To the best of our knowledge, we applied the first example of hetereodonor bidentate ligands which are bearing both phosphine and imine group for the palladium catalyzed Suzuki C-C coupling reaction in ScCO2 solvent system.