Significant O–H Bond Weakening in CpMn(CO)₂(CH₃OH): Evidence for the Generation of the CpMn(CO)₂(CH₃O) Radical upon H Atom Abstraction by O₂

The UV–visible photolysis of CpMn­(CO)₃ in methanol generates CpMn­(CO)₂(CH₃OH), which upon H atom abstraction using either O₂, dpph, or H₂O₂ gives the CpMn­(CO)₂(CH₃O) radical complex. The radical with a lifetime of 10 to 20 min has been mainly characterized using FTIR and ESR spectroscopy and chemical oxidation studies. Together with density functional theory calculations, it is shown that the O–H bond is significantly weakened in the CpMn­(CO)₂(CH₃OH) complex compared to free methanol. NBO spin density analysis suggests that the bond cleavage is facilitated by the formation of the CpMn­(CO)₂(CH₃O) radical in which the electron spin is localized at the metal center rather than at the oxygen atom