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

Abstract

The design of covalently linked photoactive donor-acceptor dyads offers major opportunities for photocatalysis and solar energy conversion. 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. The separated charges can be used for the photoinduced, oxidative and reductive activation of organic peroxides to generate oxygen-based radicals. Structural and mechanistic studies using in situ spectroscopy, time-resolved spectroscopy and spectro-electrochemistry as well as quantum chemical calculations shed light on the underlying photoinduced reactivity. The study presents a blueprint for the design of photoactive covalent photosensitizer-polyoxometalate dyads based on earth-abundant elements.