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

Abstract

The structure of four bis(tri­phenyl­phosphine)phenyl­palladium(II) iodides isolated after completion of Sonogashira coupling reactions, in which the aryl iodide was used in slight excess, are reported.

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.