Parahydrogen studies of H2 addition to Ir(I) complexes containing chiral phosphine-thioether ligands: implications for catalysis.

Ir(CO)[CpFe{η5-C5H3(PPh2)CH2SR}]Cl [R = Ph and tBu], containing a κ2:P,S ligand, undergoes H2 addition across the S–Ir–CO axis under kinetic control to form two distinct diastereoisomeric products, which then rearrange via S dissociation in a process that can be hijacked for useful catalysis, but ultimately form a single diastereoisomer of the thermodynamic product where the hydride ligands are trans to chloride and phosphine.