Novel rhodamine probe for colorimetric and fluorescent detection of Fe3+ ions in aqueous media with cellular imaging

Muthaiah Shellaiah, Natesan Thirumalaivasan, Basheer Aazaad, Kamlesh Awasthi, Kien-Wen Sun*, Shu-Pao Wu, Ming-Chang Lin, Nobuhiro Ohta

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    5 Scopus citations


    A novel rhodamine-pyridine conjugated spectroscopic probe RhP was synthesized and its X-ray single crystalline properties were revealed with tabulation. The RhP displayed a distinct pale-pink colorimetric and “turn-on” fluorescent response to Fe3+ in aqueous media [H2O:DMSO (95:5, v/v)] than that of other interfering ions. During the Fe3+ recognition, the absorption (UV–Vis) and photoluminescence (PL) spectral studies revealed new peaks at 561 and 592 nm, respectively. The 1:1 stoichiometry and binding sites were verified by Job's plot, ESI-mass, and 1H NMR titrations. Subsequently, LOD and binding constant for RhP + Fe3+ complex were estimated as 102.3 nM and 6.265 × 104 M−1 from linear fitting and Benesi-Hildebrand plots, correspondingly. Sensor reversibility of RhP + Fe3+ by EDTA was demonstrated by UV/PL and TRPL investigations. Moreover, the photoinduced energy transfer mechanism and band gap changes were established from the DFT interrogations. Lastly, cellular imaging studies were carried out to authenticate the real applicability of RhP in Fe3+ detection.

    Original languageEnglish
    Article number118757
    JournalSpectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
    StatePublished - 5 Dec 2020


    • Colorimetric recognition
    • Fluorescent “turn-on”
    • Nanomolar detection
    • Photoinduced energy transfer
    • Reversible Fe sensor
    • Rhodamine-pyridine conjugate


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