O-bonded and S-bonded sulphinate complexes of iridium(I) and iridium(III). Ligand isomerisation accompanying change in co-ordination number

The four-co-ordinate iridium(I) compound, Ir(O2S-p-tolyl)(CO)(PPh3)2 has O-bonded sulphinate but uptake of carbon monoxide or dioxygen results in isomerisation to S-bonded sulphinate while addition of methyl iodide leaves the ligand O-bonded.