Axially Chiral Allenyl Gold Complexes

Unprecedented allenyl gold complexes have been achieved starting from tri­phenyl­pro­pargyl­phos­pho­nium bromide. Two different coordination modes of the allene isomer of tri­phenyl­phos­pho­nium­pro­pargylide to gold have been found depending on the gold oxidation state. Bromo-, pentafluorophenyl-, and triphenylphosphine–gold­(I) allenyl complexes were prepared in which the α carbon coordinates to the gold­(I) center. A chiral pentafluorophenyl–gold­(III) allenyl complex with the gold atoms coordinated to the γ carbon was also prepared. All the complexes have been structurally characterized by X-ray diffraction showing the characteristic distances for a CCC unit.