The reaction of HMn(CO)5 with RMn(CO)5 (R = CH3,p-CH3C6H4, or CH2CH2CH=C(Ph)CH3) gives Mn2-(CO)9(η1-RCHO) complexes. It is suggested that these Mn2(CO)9(η1-aldehyde) complexes may provide a model for a previously unobserved intermediate in the formation of aldehydes from the hydroformylation of olefins. The η1-aldehyde ligand is weakly bound to the manganese, as evidenced by its facile displacement by ligands such as CO, PPh3, and CH3CN. The kinetics of the reaction of HMn(CO)5 with (CO)5Mn(CH2CH2CH=C(Ph)CH3) were studied by 1H NMR at 25 °C in C6D6. The reaction is first-order in the manganese alkyl complex, and the rate of the reaction decreases slightly with increasing concentration of HMn(CO)5. A negligible isotope effect (kH/kD = 1.04 ± 0.09) was found for the reaction of (CO)5Mn(CH2CH2CH= C(Ph)CH3) with DMn(CO)5. The reaction of Mn2(CO)9(η1-CH3CHO) with excess HMn(CO)5 takes several days at room temperature and produces ethanol and the manganese cluster complex Mn3(CO)9(μ3-OEt)2(μ 2-OEt).
|Number of pages||11|
|Journal||Journal of the American Chemical Society|
|Publication status||Published - Feb 27 1991|
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