A Reversible Rhodamine B Based pH Probe with Large Pseudo‐Stokes Shift. Issue 7 (11th June 2019)

• Record Type: Journal Article
• Authors: Bao, Guochen; Wong, Ka‐Leung; Tanner, Peter A.
• Is Part Of: ChemPlusChem. Volume 84:Issue 7(2019)
• Page Start: 816
• Page End: 820
• Publication Date: 2019-06-11
• Subjects: fluorescence -- FRET -- pH sensors -- rhodamine -- spirolactams; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/cplu.201900263
• Languages: English
• ISSNs: 2192-6506

Abstract

Abstract: A reversible and sensitive pH probe DPE−Rh operates by Förster resonance energy transfer from 1, 2‐diphenylethyne (DPE) to Rhodamine B (Rh). In the presence of H +, the spirolactam ring of the Rhodamine B unit was opened and this resulted in ca. 1000‐fold enhancement of fluorescence intensity with linear change over the pH range of 2.0 to 5.5. The Förster resonance energy transfer offered this probe an effective excitation–emission wavelength shift of around 240 nm with about 100 % quenching of the donor emission. The response of the sensor is tolerant towards a wide range of metal ions and the sensing mechanism was deduced by 1 H NMR spectrometry. This FRET‐based molecule not only provides a sensitive pH probe, but also suggests an effective strategy to eliminate the interference of excitation light. Abstract : In a reversible pH probe, H + activates the effective FRET from 1, 2‐diphenylethyne and turns on the rhodamine emission, providing around 1000‐fold signal enhancement in the pH range 2.0–5.5. The FRET process results in an effective excitation−emission wavelength shift of around 240 nm with almost 100 % quenching of the donor emission. This probe is tolerant towards a wide range of metal ions.