Polyoxometalate-Catalyzed Insertion of Oxygen from O2 into Tin–Alkyl Bonds

The polyoxometalate H5PV2Mo10O40 mediates the insertion of an oxygen atom from H5PV2Mo10O40 into the tin-carbon bond of n-Bu4Sn through its activation by electron transfer to yield 1-butanol and (n-Bu3Sn)2O. The reaction is initiated by electron transfer from n-Bu4Sn to H5PV(V)2Mo10O40 to yield the ion pair n-Bu4Sn(•+)-H5PV(IV)V(V)Mo10O40. The H5PV(IV)V(V)Mo10O40 moiety was identified by UV-vis and EPR. DFT calculations show that n-Bu4Sn(•+)-H5PV(IV)V(V)Mo10O40 is relatively unstable and forms more stable Bu(+) and Bu3Sn(+) cations coordinated to the polyoxometalate, which were also identified by ESI-MS. Products are released at higher temperatures. In the presence of molecular oxygen as the terminal oxidant the reaction is catalytic.