反应详情

To a stirred solution of ‘salen’ ligand (7e) (43 mg, 0.045 mmol, 1 equiv.) in 5 mL CH2Cl2, a methanolic (2 mL) solution of cobalt (II) acetate tetrahydrate (11.4 mg, 45 μmol, 1.0 equiv.), was added via cannula, under Ar. The Co(II)-salen complex precipitated out as a red solid. After filtration, the Co(II) complex was taken up in CH2Cl2 or toluene (2 mL) and stirred with acetic acid (>10 equiv.) or 3,5-dinitrobenzoic acid (1 equiv.) open to the air. The oxidation was followed by TLC, formation of a greenish-brown spot of lower Rf {Co-(III) complex} from the visibly red, higher Rf spot characteristic of the Co-(II) salen. When TLC indicated the completion of the reaction (2-12 h), the solvent was evaporated, and the Co(III)-salen complex further dried in vacuo. The Co(III) carboxylate complexes so prepared were used for HKR experiments, under ISES (bilayer) conditions or under neat ‘Jacobsen’ (conventional) conditions.

1. customThe Co(II)-salen complex precipitated out as a red solid
2. filtrationAfter filtration
3. customthe completion of the reaction (2-12 h)
4. customthe solvent was evaporated
5. customthe Co(III)-salen complex further dried in vacuo
6. customThe Co(III) carboxylate complexes so prepared