Covalently linked ferrocene-polyoxometalate dyads for light-induced radical generation

The design of photoactive donor-acceptor dyads offers major opportunities for fundamental and applied studies in photochemistry and solar energy technologies. Here, we report a noble metal-free dyad obtained by covalent anchoring of a ferrocene moiety to a Dawson-type polyoxotungstate. The resulting dyad shows visible light photoinduced charge-separation and electron transfer from the ferrocene to the polyoxometalate, which can in turn be used for the photoinduced generation of radicals. Mechanistic studies using time-resolved spectroscopy and spectro-electrochemistry shed light at the underlying mechanisms of operation. The study presents a blueprint for the design of covalent photosensitizer-polyoxometalate dyads based on earth-abundant elements.