Complexes of Rhodium(I) and Iridium(I) with the Chiral Tridentate Phosphane Pigiphos: Structure and Reactivity Studies

The chiral ferrocenyltriphosphane Pigiphos [bis{(S)-1-[(R)-2-(diphenylphosphanyl)ferrocenyl]ethyl}cyclohexylphosphane] forms four-coordinate complexes with IrI and RhI. The tridentate ligand assumes different conformations in the derivatives [Rh(CO)(Pigiphos)]OTf (4) and [IrCl(Pigiphos)] (1b), the latter also showing a drastic deviation from the square-planar geometry. Reactivity studies have focussed on the more reactive 1b. The HCl and O2 adducts have been characterized in solution.