A new redox-tunable near-IR dye based on a trinuclear ruthenium(II) complex of hexahydroxytriphenylene

Abstract

The complex [{Ru(bipy)₂}₃(µ³-L)]³⁺ (H₆L = hexahydroxytriphenylene), in which the tris-dioxolene bridging ligand is formally in the tris-semiquinone oxidation state [sq,sq,sq], undergoes three reversible ligand-centred oxidations to the [q,q,q] state (q = quinone); it exhibits very strong NIR absorption arising from Ru → L charge transfer whose maximum wavelength may be tuned over a wide range according to oxidation state.