Tridentate κ3-P,P,C iridium complexes: influence of ligand saturation on intramolecular C-H bond activation.

Whereas κ3-P,C,P-based donor ligands are ubiquitous across synthetic chemistry, related unsymmetric systems having κ3-P,P,C-coordination are comparatively rare. In this contribution, we expose a new κ3-P,P,C ligand system, bearing a C3-anionic linker and its coordination chemistry with iridium. The title ligand has been coordinated in saturated and unsaturated forms. The degree of ligand saturation affected an onward (and unusual) oxidative rearrangement reaction.

Competitive gold/nickel transmetalation.

Transmetalation is a key method for the construction of element-element bonds. Here, we disclose the reactivity of [NiII(Ar)(I)(diphosphine)] compounds with arylgold(I) transmetalating agents, which is directly relevant to cross-coupling catalysis. Both aryl-for-iodide and unexpected aryl-for-aryl transmetalation are witnessed. Despite the strong driving force expected for Au-I bond formation, aryl scrambling can occur during transmetalation and may complicate the outcomes of attempted catalytic cross-coupling reactions.