Activation of EH (E=Sn, Si, S) bonds by cyclooctadieneiridium pyridine-2-carboxylate and related compounds

The complexes [Ir(O2CArN)(1,5-cod)] (1), containing the chelating ligands O2CArN=pyridine-2-carboxylate (O2CPic), isoquinoline-1-carboxylate (O2CIsoq), quinoline-2-carboxylate (O2CQuin) and pyrazine-2-carboxylate (O2CPyraz) are readily prepared in good yield from [Ir2(μ-OMe)2(1,5-cod)2] and NArCO2H. The 1H-NMR spectra of these compounds show temperature-dependent changes that are interpreted in terms of an interaction with the solvent. With Ph3SnH, Ph3SiH and C6F5SH complexes 1 react to give [Ir(O2CArN)(H)(SnPh3)(1,5-cod)] (2), [Ir(O2CArN)(H)(SiPh3)(1,5-cod)] (3) and [Ir(O2CArN)(H)(SC6F5)(1,5-cod)] (4), the reaction with Ph3SiH being reversible.