A novel dual-switch fluorescent probe for Cr(iii) ion based on PET–FRET processes

Abstract

Two different strategies for photoinduced electron transfer (PET) and fluorescence resonance energy transfer (FRET) have been designed and combined into one sensing system. The novel probe NNRhB was developed based on 1,8-naphthalimide and rhodamine moieties, in which two fluorophores are sensitive to the presence of Cr(3+) in different chromium ion concentration regimens. Therefore, the proposed sensing system represents dual-switch states and segmented detection behavior, with the fluorescence emission color spans from green to orange over an increasing Cr(3+) concentration gradient. When excited in the visible region, the initial emission band at 537 nm was enhanced. That was attributed to the suppression of the PET process, which arose from Cr(3+)-coordination with a 1,8-naphthalimide derivative. At a sufficiently high concentration of Cr(3+) (over 9 μM), the spirolactam rhodamine component in NNRhB converted to the opened form as a result of Cr(3+) coordination, which turned the emission color from green to orange via FRET. The fluorescence phenomena of the compound 1 and compound 2 split from compound NNRhB confirm our hypothesis of the spectral response mechanisms. Moreover, compared with a single fluorescent response in compound 1 or compound 2, the dual-switch fluorescent probe NNRhB shows a more sensitive and distinct visual detection ability for Cr(3+) ions. This probe affords a high selectivity and sensitivity to Cr(3+) from 30 nM to 80 μM; the detection limit was 0.14 nM. The results of practical application experiments suggest that the Cr(3+)-selective ligand prepared here may provide an effective strategy for detection of Cr(3+) in environmental and biological applications.

Design and synthesis of a new rhodamine B-based fluorescent probe for selective detection of glutathione and its application for live cell imaging

“…[31][32][33][34] On the basis of the spirolactam/ring-opened amide equilibrium of rhodamine, several fluorescence-based sensing systems for metal ions have been developed to serve as a fluorescent chemosensor to detect metal ions, such as Hg 2+ , Cu 2+ , Al 3+ , Cr 3+ , Mg 2+ , and Fe 3+ . [35][36][37][38][39][40][41][42][43] However, to the best of our knowledge, rhodamine B-based fluorescent probes for GSH are still rare. [44] Herein, we report the synthesis and characterization of a new rhodamine B-derivatized fluorescent chemosensor based on a maleimide moiety ,namely N-(2-(3',6'-bis(diethylamino)-3-oxospiro[isoindoline-1,9'-xanthen] -2-yl)ethyl)-3,5-bis(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)benzamide (Probe-M, Figure 1).…”

Design and synthesis of a novel chromium(III) selective fluorescent chemosensor bearing a thiodiacetamide moiety and two rhodamine B fluorophores

“…However, the major disadvantages of these methods include the demand for expensive and complex apparatus along with complicated sample pretreatments in these time-consuming processes [25,26]. Over the past several years, fluorescent chemosensors have been developed as useful sensors for various metal ions due to their simplicity, specificity and sensitivity monitoring with a fast response time [27][28][29].…”

A phenothiazine–rhodamine ratiometric fluorescent probe for Hg2+ based on FRET and ICT

“…Of these, fluorescence resonance energy transfer (FRET) is more advantageous than internal charge transfer (ICT) 8 and has become one of the most widely used sensing mechanisms, most notably in the rhodamine-based FRET system. [9][10][11][12][13][14] Rhodamine dyes have excellent photophysical properties, such as high fluorescence quantum yields, and large absorption coefficients. 15 The rhodamine fluorophore generally acts as the energy acceptor in FRET systems.…”