Phenyl palladium(II) iodide complexes isolated after Sonogashira coupling of iodo-benzenes with terminal alkynes.

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-(tri-fluoro-meth-yl)phen-yl]iodido-bis-(tri-phenyl-phosphane)palladium(II), [Pd(C8H3F6)I(C18H15P)2], 1, (3,5-di-nitro-phen-yl)iodido-bis-(tri-phenyl-phosphane)palladium(II) ethyl acetate monosolvate, [Pd(C6H3N2O4)I(C18H15P)2]·C4H8O2, 2, (2,3,4-di-fluoro-phen-yl)iodido-bis-(tri-phen-yl-phosphane)palladium(II), [Pd(C6H2F3)I(C18H15P)2], 3, and (2,4,6-di-fluoro-phen-yl)iodido-bis-(tri-phenyl-phosphane)palladium(II) di-chloro-methane 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-(tri-fluoro-meth-yl)phenyl, 3,5-di-nitro-phenyl, 2,3,4-tri-fluoro-phenyl and 2,4,6-tri-fluoro-3,5-di-iodo-phenyl. The isolation of these complexes provides some insight into the possible fate of the palladium catalyst.