Cationic, Neutral, and Anionic Hydrides of Iridium with PSiP Pincers.

This work describes synthetic routes from the known precursor [IrClH{κP,P,Si-Si(Me)(CH-2-PiPr)}] (1) to new hydride and polyhydride derivatives. Substituting the chloride ligand with triflate leads to the five-coordinate complex [IrH{κO-OS(CF)}{κP,P,Si-Si(Me)(CH-2-PiPr)}] (2), which can undergo reversible coordination of water (HO) or dihydrogen (H) to generate respectively the cationic derivative [IrH{κP,P,Si-Si(Me)(CH-2-PiPr)}(OH)](CFSO) (3) or the neutral trans-hydride-dihydrogen [IrH{κO-OS(CF)}{κP,P,Si-Si(Me)(CH-2-PiPr)}(η-H)] (6) in equilibrium. The use of acetonitrile or carbon monoxide (CO) excess instead of water produces stable analogues of 3 (complexes 4 or 5, respectively).

Iridium compounds with kappa-P,P,Si (biPSi) pincer ligands: favoring reactive structures in unsaturated complexes.

The structure, coordination properties, insertion processes, and dynamic behavior in solution of the five-coordinate complexes [IrXH(biPSi)] (biPSi = kappa-P,P,Si-Si(Me){(CH(2))(3)PPh(2)}(2); X = Cl (1), Br (2), or I (3)) have been investigated. The compounds are formed as mixtures of two isomers, anti and syn, in slow equilibrium in solution. The equilibrium position depends on the halogen and the solvent.