Formation of a long-lived radical pair in a Sn(iv) porphyrin-di(l-tyrosinato) conjugate driven by proton-coupled electron-transfer

The novel conjugate 1, featuring two l-tyrosinato residues axially coordinated to the tin centre of a Sn(iv)- tetraphenylporphyrin, is reported as the first example of a supramolecular dyad for photochemical PCET. It is noteworthy that the excitation of 1 in the presence of a suitable base is followed by photoinduced PCET leading to a radical pair state with a surprisingly long lifetime.