Polypyridyl Ru( ii )-derivatized polypropylacrylate polymer with a terminal water oxidation catalyst. Application of reversible addition–fragmentation chain transfer polymerization

A Ru(II) polypyridyl-derivatized polypropylacrylate end-capped with a water-oxidation-catalyst (WOC) has been synthesized by using reversible addition-fragmentation chain transfer polymerization (RAFT) followed by click reaction and end-group functionalization. In cyclic voltammograms in propylene carbonate, chromophore oxidation occurs at 1.27 V vs. NHE and the Ru(III/II) wave for the catalyst at 0.84 V vs. NHE. Upon excitation of the Ru(II) chromophore, excited-state energy migration occurs by site-to-site, -Ru(II)*- → -Ru(II)-, energy transfer hopping along the polymer chain, in part, reaching the terminal catalyst site where -Ru(II)*- → -Ru(II)-OH2(2+) energy transfer is favored by ΔG(en) = -2100 cm(-1). Added MV(2+) as an electron transfer acceptor oxidizes the -Ru(II)*- excited state on the polymer to Ru(III), -Ru(II)*- + MV(2+) → -Ru(III)- + MV(+), and ultimately, the catalyst, by site-to-site electron transfer hopping and oxidation, [Formula: see text]. Oxidation is followed by relatively slow, diffusional back electron transfer from MV˙(+) to Ru(III) sites on the polymer chain. The mixed chromophore-catalyst polymer is a water oxidation catalyst with potential for enhanced light harvesting and water oxidation.