Molecular logic with ferrocene-rylene conjugates : a comparison of naphthalenediimide, naphthalimide and perylenediimide Pourbaix sensor designs

Abstract

Four molecules designed as Pourbaix sensors with rylene dyes (naphthalenediimide, 4-amino-1,8-naphthalimide, perylenediimide) are compared. Each molecule is constructed modularly according to an electron-donor–spacer–fluorophore–spacer–receptor format based on photoinduced electron transfer (PET). The modules consist of ferrocene as the electron donor, a tertiary alkyl amine as the proton receptor, and a rylene dye as the fluorophore connected by a methylene and ethylene spacer, respectively. The proton and oxidant-induced fluorescent spectral changes of the 4-amino-1,8-naphthalimide models include internal charge transfer (ICT) character. Two of the discussed logic gates switch on emitting fluorescence in the presence of acid (H+) and oxidant (Fe3+) according to two-input AND logic, while two of the logic gates remain off according to two-input PASS 0 logic.