Platinum group metal complexes of arylphosphine ligands containing perfluoroalkyl ponytails; crystal structures of [RhCl2(η5-C5Me5){P(C6H4C6F13-4)3}] and cis- and trans-[PtCl2{P(C6H4C6F13-4)3}2]

Abstract

The triarylphosphine ligands PPh_3–x(C₆H₄C₆F₁₃-4)_x, x = 1, 2 or 3, reacted with [{RhCl₂(η⁵-C₅Me₅)}₂], [{RhCl(CO)₂}₂], [{IrCl(COD)}₂], [PdCl₂(MeCN)₂] or [PtCl₂(MeCN)₂] to yield the complexes [RhCl₂(η⁵-C₅Me₅)L] 1–3, trans-[RhCl(CO)L₂] 4–6, trans-[IrCl(CO)L₂] 7–9, trans-[PdCl₂L₂] 11–13 or cis-/trans-[PtCl₂L₂] 14–16 respectively. Spectroscopic studies and structural studies (EXAFS for 4–9, 11–15 and X-ray single crystal for 3 and 16) indicated that the aryl groups are fairly good insulators of the electronic influence of the perfluoroalkyl substituents whilst solubility studies indicated that at least six C₆F₁₃ units are necessary for preferential perfluorocarbon solvent solubility and that the type of metal complex is important, i.e. the Vaska’s analogues 6 and 9 are perfluorocarbon solvent soluble whereas the dichloride complexes 13 and 16 are not. Studies on the addition of dioxygen to 7–10 identified a stepwise reduction in rate following the introduction of the perfluoroalkyl ponytails.