The Coordination Chemistry of Pentafluorophenylphosphino Pincer Ligands to Platinum and Palladium

The synthesis of electron‐poor PCP pincer ligands 1,3‐((C₆F₅)₂PO)₂C₆H₄, 1,3‐((C₆F₅)₂PCH₂)₂C₆H₄, and 1‐((C₆F₅)₂PO)‐3‐(tBu₂PCH₂)C₆H₄, and their coordination chemistry to platinum and palladium is described. The most electron‐poor ligand 1,3‐((C₆F₅)₂PO)₂C₆H₄ (POCOPH) reacts with Group 10 metal chloride precursors to form a range of unusual cis, trans‐dimers of the type κ²‐P,P‐[(POCOPH)MCl(L)]₂ (M=Pt, Pd; L=Cl, Me), which undergo metallation to form [(POCOP)MCl] pincer complexes only under prolonged thermolysis. The formation of such cis,trans‐dimers during pincer complex formation can be mitigated through the use of starting materials with more strongly binding ancillary ligands, improving the overall rate of ligand metallation. Carbonyl complexes of the type [(PCP)M(CO)]⁺ were synthesised from the pincer chloride complexes by halide abstraction, and displayed large ν(C?O) values, from 2170–2111 cm^?1, confirming the electron‐poor nature of the compounds. The [(PCP)Pd(CO)]⁺ complexes also demonstrated the ability to reversibly bind carbon monoxide both in solution and the solid state, with the rate of decarbonylation increasing with increasing wavenumber for the C?O stretch.