Knowledge Bank

Photo-oxidation of $Re2$(CO)$\mathrm{<mrow\; data-mjx-texclass="ORD">10</mrow>}$ in low-temperature matrices containing $O2$ generates alongside free CO and $CO2$, the binary oxide $Re2$$O7$. The reaction appears to be initiated by Re-Re bond cleavage and proceeds via at least two detectable oxorhenium carbonyl species. Infrared spectroscopic studies, including isotopic studies with $\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}O$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}CO$, suggest that these intermediates are most likely to be $(CO)5Re-C-O-Re(CO)5$ and $O=Re(CO)5$. Similar photo-oxidation experiments have also been carried out on the compounds $Re(CO)5Cl,Re(CO)5Me$ and $CpRe(CO)3$. The last two compounds appear to give rise to the organometalic oxides $MeReO3$ and $CpReO3$.