A fluorescent AND logic gate based on a ferrocene-naphthalimide-piperazine format responsive to acidity and oxidizability

Jake C Spiteri (1) , Alex D Johnson (1) , Sergey Denisov (2) , Gediminas Jonusauskas (3) , Nathan Mcclenaghan (2) , David C Magri (1)

1 Department of Chemistry [Msida]
2 ISM - Institut des Sciences Moléculaires
3 LOMA - Laboratoire Ondes et Matière d'Aquitaine

A novel fluorescent molecular logic gate 1 is demonstrated as a two-input AND logic gate for the detection of acidity and oxidizability. Designed according to an electron-donor–spacer–fluorophore–spacer–receptor' format, the modules are represented by ferrocene as the electron donor, 1,8-naphthalimide as the fluorophore and piper-azine as the proton receptor. In the presence of elevated concentrations of H + and Fe 3+ , the molecule switches 'on' emitting at λ max = 530 nm with Φ f = 0.060 at 10 −4 M H + and 50 μM Fe 3+. The H + binding and apparent Fe 3+ binding constants determined by fluorimetric titrations in 1:1 (v/v) methanol/water are log β H+ = 8.1 and log β Fe3+ = 4.7. Modulation of the fluorescence output results from controlling competing photoinduced electron transfer (PET) at the ferrocene end and internal charge transfer (ICT) at the piperazine end. Time-resolved fluorescence spectroscopy reveals a single fluorescent lifetime of 5.8 ns, while from absorption transient spec-troscopy a remarkable fast decay signal < 2 ps is observed. Comparison is made with methylpiperazine 2 and piperazine fluorescent pH indicator 3 as model compounds.

Mots clés: Naphthalimide; Ferrocene; Photoinduced electron transfer; Pourbaix sensor; Molecular logic gate; Fluorescence

Domaines: Chimie-Physique [physics.chem-ph]

Jake C Spiteri, Alex D Johnson, Sergey Denisov, Gediminas Jonusauskas, Nathan Mcclenaghan, et al.. A fluorescent AND logic gate based on a ferrocene-naphthalimide-piperazine format responsive to acidity and oxidizability. Dyes and Pigments, 2018, 157, pp.278-283. ⟨10.1016/j.dyepig.2018.04.060⟩. ⟨hal-01848447⟩