Co-ordination of the chiral N,O-ligand 2-[(1 S, 2 S, 5 R)(−)-menthol]-pyridine to molybdenum(VI) and vanadium(IV) oxo complexes : Crystal structures of [MoO 2{2-(−)-menthol-pyridine} 2] and [VO{2-(−)-menthol-pyridine} 2

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Reaction of the chiral 1-pyridin-2-yl-menthol ligand ( 1) with [VO(acac) 2] and [MoO 2(acac) 2] results in the formation of the metal–oxo complexes [VO(N–O) 2] ( 2) and [MoO 2(N–O) 2] ( 3), where N–O=2-[(−)-menthol]-pyridine. The molecular structures of ( 2) and ( 3) have been determined by single-crystal X-ray diffraction, which revealed the expected square-pyramidal geometry for ( 2) with the pyridine ring nitrogens mutually trans, and the expected slightly distorted octahedral arrangement of ( 3) with cis di-oxo ligands. Both metal–oxo compounds ( 2) and ( 3) have demonstrated the ability to catalyse the asymmetric oxidation of prochiral olefins and sulfides with H 2O 2 or tBuOOH as the oxidant.