Turn-on fluorescence of ruthenium pyrene complexes in response to bovine serum albumin.

Two novel pyrene triphenylphosphine ruthenium conjugates act as fluorescent turn-on beacons for serum albumin, being non-fluorescent in aqueous media but exhibiting strong emission upon binding to BSA. The selective cytotoxicity of the compounds against tumour cells is enhanced upon irradiation by UV-light, paving the way for application in photodynamic therapy under two-photon excitation.

A ferrocene-based pseudopeptide chiroptical switch.

We present a double-stranded ferrocene pseudopeptide 2b which exhibits stimuli responsive chirality inversion triggered by solvent exchange or acid addition. Compound 2b exists as a mixture of self-assembled fast exchanging oligomers which macroscopically behave as a chiroptical switch with two stable states. The ferrocene group inversion results in a distinct CD signal in the visible part of the spectrum. The inversion is accomplished through a conformational change due to a rearrangement of hydrogen bonding forcing the rotation of ferrocene rings.