Phenyl palladium(II) iodide complexes isolated after Sonogashira coupling of iodobenzenes with terminal alkynes

Abstract

The structures of four palladium complexes serendipitously isolated after palladium-catalyzed Sonogashira coupling of aryl iodides with terminal alkynes are reported, namely [3,5-bis(trifluoromethyl)phenyl]iodidobis(triphenylphosphane)palladium(II), [Pd(C8H3F6)I(C18H15P)2], 1, (3,5-dinitrophenyl)iodidobis(triphenylphosphane)palladium(II) ethyl acetate monosolvate, [Pd(C6H3N2O4)I(C18H15P)2]·C4H8O2, 2, (2,3,4-difluorophenyl)iodidobis(triphenylphosphane)palladium(II), [Pd(C6H2F3)I(C18H15P)2], 3, and (2,4,6-difluorophenyl)iodidobis(triphenylphosphane)palladium(II) dichloromethane disolvate, [Pd(C6H2F3)I(C18H15P)2]·2CH2Cl2, 4. These complexes were isolated as red/orange crystals that co-eluted with the organic products of each reaction during flash chromatography. These complexes are oxidative addition products ArPdI(PPh3)2 where Ar = 3,5-bis(trifluoromethyl)phenyl, 3,5-dinitrophenyl, 2,3,4-trifluorophenyl and 2,4,6-trifluoro-3,5-diiodophenyl. The isolation of these complexes provides some insight into the possible fate of the palladium catalyst.

Keywords

• crystal structure
• oxidative addition
• aryl palladium iodide