FRET versus PET: ratiometric chemosensors assembled from naphthalimide dyes and crown ethers

Abstract

Novel bi-chromophoric naphthalimide derivatives containing benzo-15-crown-5 and N-phenyl-aza-15-crown-5 receptor moieties BNI2 and BNI3 were designed and prepared. Significant Förster resonance energy transfer (FRET) from donor (D) amido-naphthalimide to acceptor (A) amino-naphthalimide chromophores as well as photoinduced electron transfer (PET) between the N-aryl receptor and amido-naphthalimide fragment was revealed by the steady-state and time-resolved UV/Vis absorption and fluorescence spectroscopy. Upon the addition of alkaline-earth metal perchlorates to an acetonitrile solution of ligands, FRET mediated fluorescence enhancement was observed, which was a result of inhibition of the PET competitive deactivation pathway. The studied compounds provide an opportunity to register a two-channel fluorescence response upon selective excitation of either of the photoactive units and, thus, might be of interest as ratiometric probes.

Synthesis and spectral properties of fluorescent dyes based on 4-styryl-1,8-naphthalimide

“…The derivatives of imide of naphthalic acid (1,8 naph thalimide) are practically important class of organic fluo rophores, which are used in many areas of science and technology, such as optical brightening, 10 fluorescent crack detection, 11 solar energy conversion, 12 fabrication of the optical memory elements, 13 and electrolumines cent devices. 14 Intensive fluorescence in the visible spec trum, high photostability, and high values of Stokes shift of 1,8 naphthalimides along with the simplicity of syn thetic modifications aimed to molecular structure of this type make these compound attractive for the application as a photoactive component of ratiometric chemosensors suitable for the analysis of ions in living cells 15,16 as well as fluorescent dyes for applications in biology and medi cine. 17,18 It has been shown in earlier works devoted to the spectroscopic study of 1,8 naphthalimide derivatives that the introduction of polarizing substituents having strong electron donating properties in positions 4 and 5 of the naphthalene nucleus leads to a bathofluoric shift of the emission band.…”

Synthesis and studies of two proton–receptor fluorescent probes based on 1,8‐naphthalimide

“…When an analytical species interacts with a receptor moiety, the photophysical properties of a fluorophore moiety undergo some changes that lead to a signal, thereby confirming guest binding [42,43]. Herein, annihilation of the PET process occurred and recovery of fluorescence of the system ensued [41,[44][45][46][47]. The protonation of the piperazine N-amine would increase the oxidation potential of the receptor and as such would be thermodynamically infeasible for electron transfer [48,49].…”

Detection of Al3+ and Fe3+ Ions with Phthalocyanine‐Merocyanine 540 Dye‐Based Fluorescence Resonance Energy Transfer

“…1 In recent years, FRET has been widely applied in the design of fluorescence sensors for different types of analytes, such as metal ions, anions, drug actives, and biological molecules. [2][3][4][5][6][7][8] Iron is one of the transition metals that plays a major role in biological metabolism and chemical reactions. This metal acts as a cofactor in many enzymatic reactions, besides carrying oxygen in the human body.…”