Preparation of [C,N,O]-Pincer Osmium Complexes by Alkylidene Metathesis with a Methyl Group of 2,6-Diacetylpyridine

The complex [(η 6 - p -cymene)OsCl( CHPh)(IPr)]OTf ( 1 ) reacts with 2,6-diacetylpyridine in acetonitrile at 40 °C to give the [C,N,O]-pincer derivative [OsCl{κ 3 C, N, O -[ CHC(O)pyC(CH 3 )O]}(NCCH 3 )(IPr)]OTf ( 2 ), containing an alkylidene function at the terdentate ligand. Under the same conditions in dichloromethane, the neutral species OsCl(OTf){κ 3 C, N, O -[ CHC(O)pyC(CH 3 )O]}(IPr) ( 3 ) is formed.