Polyoxometalate-catalyzed insertion of oxygen from O₂ into tin-alkyl bonds

The polyoxometalate H₅PV₂Mo₁₀O ₄₀ mediates the insertion of an oxygen atom from H₅PV ₂Mo₁₀O₄₀ into the tin-carbon bond of n-Bu ₄Sn 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-Bu ₄Sn^•+-H₅PV^IVV ^VMo₁₀O₄₀. The H₅PV ^IVV^VMo₁₀O₄₀ moiety was identified by UV-vis and EPR. DFT calculations show that n-Bu₄Sn ^•+-H₅PV^IVV^VMo ₁₀O₄₀ 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.