Visible light induced oxygenation of alkenes with water sensitized by silicon-porphyrins with the second most earth-abundant element

• Si(IV)-porphyrin induces the photochemical oxygenation of alkenes with water.
• Water serves as both electron and oxygen atom donor.
• The Si(IV) utilized is the Earth's the second most abundant element.

Silicon as the second most abundant element on Earth was effectively utilized as the central atom in the porphyrin to induce photochemical oxygenation of alkenes as the first example of photocatalytic reaction through activation of water molecule in the presence of K2PtCl6 as an electron acceptor. Oxygen atom of water was confirmed to be incorporated in the oxygenated product by the photoreaction with H218O. The excited triplet state of silicon porphyrin was revealed to be responsible for the photochemical oxygenation. The one-electron oxidized silicon porphyrin was predicted by DFT calculation to have its spin population mostly on the axially ligated hydroxyl oxygen atom. The oxyl radical character of the axial ligand could rationalize the oxygenation reaction.

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