Skip to main content
SpringerLink
Log in

Selectively probing ferric ions in aqueous environments using protonated and neutral forms of 7-azaindole as a multiparametric chemosensor

  • Original Papers
  • Published:
Photochemical & Photobiological Sciences Aims and scope Submit manuscript

Abstract

7-azaindole (7AI) dimer is a model molecule for DNA study and understanding the mutagenic behavior based on the excited-state proton transfer process in hydrogen-bonded networks. The neutral and protonated forms of 7AI monomer with significant fluorescence (FL) intensity fit the fluorescent sensor strategy to recognize selective metal ions. Out of several metal ions (Fe3+, Al3+, Fe2+, Pb2+, Ba2+, Ni2+, Zn2+, Mg2+, Ca2+, Cu2+, Hg2+ and Cd2+), the absorption, fluorescence and fluorescence lifetime of 7AI in the aqueous medium are selectively sensitive to the ferric (Fe3+) ions. The absolute value of absorption intensity increases linearly with concentration of a particular metal ions. FL intensity of both the forms of 7AI decreases gradually with Fe3+ ions and trails the linear Stern–Volmer relation. The formation of non-fluorescent complexes was confirmed with Benesi-Hildebrand and Job plots, along with FL and FL decays. The FL lifetime of the protonated form of 7AI, which is 0.83 ± 0.01 ns, is nearly constant with Fe3+ ions concentrations, confirming the static quenching mechanism. The limit of detection (LoD) of Fe3+ ions over the long range of 16–363 µM for the neutral and protonated forms of 7AI is 0.46 ± 0.02 and 0.49 ± 0.02 µM, respectively, estimated using FL spectra. Additionally, the linear plot of absorbance with Fe3+ ions of both the forms of 7AI can also act as a calibration curve with very close LoDs, as obtained by FL spectra. Thus, the multi-parameters-based probe for detecting the Fe3+ ions over long-range in real aqueous environments with operational, high sensitivity, fast response (< 5 s), and good selectivity (over 12 metal ions) is undoubtedly a superior approach over other methods.

Graphical abstract

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10

Similar content being viewed by others

Data availability

All data generated or analysed during this study are included in this published article and its supplementary information file.

References

  1. Taylor, C. A., El-Bayoumi, M. A., & Kasha, M. (1969). Excited-state two-proton tautomerism in hydrogen-bonded N-heterocyclic base pairs. PNAS, 63, 253–260.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  2. Douhal, A., Kim, S. K., & Zewail, A. H. (1995). Femtosecond molecular dynamics of tautomerization in model base pairs. Nature, 378, 260.

    Article  CAS  PubMed  Google Scholar 

  3. Chen, Y., Rich, R. L., Gai, F., & Petrich, J. W. (1993). Fluorescent species of 7-azaindole and 7-azatryptophan in water. Journal of Physical Chemistry, 97, 1770–1780. https://doi.org/10.1021/j100111a011

    Article  CAS  Google Scholar 

  4. Smirnov, A. V., English, D. S., Rich, R. L., Lane, J., Teyton, L., Schwabacher, A. W., Luo, S., Thornburg, R. W., & Petrich, J. W. (1997). Photophysics and biological applications of 7-azaindole and its analogs. The Journal of Physical Chemistry B, 101, 2758–2769. https://doi.org/10.1021/jp9630232

    Article  CAS  Google Scholar 

  5. Takeuchi, S., & Tahara, T. (1998). Femtosecond ultraviolet-visible fluorescence study of the excited-state proton-transfer reaction of 7-azaindole dimer. Journal of Physical Chemistry A, 102, 7740–7753. https://doi.org/10.1021/jp982522v

    Article  CAS  Google Scholar 

  6. Sekiya, H., & Sakota, K. (2008). Excited-state double-proton transfer in a model DNA base pair: Resolution for stepwise and concerted mechanism controversy in the 7-azaindole dimer revealed by frequency- and time-resolved spectroscopy. Journal of Photochemistry and Photobiology C: Photochemistry Reviews, 9, 81–91. https://doi.org/10.1016/j.jphotochemrev.2008.04.001

    Article  CAS  Google Scholar 

  7. Joshi, H. C., & Antonov, L. (2021). Excited-state intramolecular proton transfer: A short introductory review. Molecules, 26, 1475. https://doi.org/10.3390/molecules26051475

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  8. Chou, P.-T., Liu, Y.-I., Wu, G.-R., Shiao, M.-Y., Yu, W.-S., Cheng, C.-C., & Chang, C.-P. (2001). Proton-transfer tautomerism of β-carbolines mediated by hydrogen-bonded complexes. The Journal of Physical Chemistry B, 105, 10674–10683. https://doi.org/10.1021/jp011031z

    Article  CAS  Google Scholar 

  9. Hung, F.-T., Hu, W.-P., & Chou, P.-T. (2001). The ground- and excited-state (1nπ* and 1ππ*) carboxylic acid-catalyzed proton (hydrogen atom)-transfer energy surfaces in 3-formyl-7-azaindole. Journal of Physical Chemistry A, 105, 10475–10482. https://doi.org/10.1021/jp012663o

    Article  CAS  Google Scholar 

  10. Fujino, T., Arzhantsev, S. Y., & Tahara, T. (2001). Femtosecond time-resolved fluorescence study of photoisomerization of trans-azobenzene. Journal of Physical Chemistry A, 105, 8123–8129. https://doi.org/10.1021/jp0110713

    Article  CAS  Google Scholar 

  11. Catalán, J., Pérez, P., del Valle, J. C., de Paz, J. L. G., & Kasha, M. (2004). H-bonded N-heterocyclic base-pair phototautomerizational potential barrier and mechanism: The 7-azaindole dimer. PNAS, 101, 419–422.

    Article  PubMed  Google Scholar 

  12. Chapman, C. F., & Maroncelli, M. (1992). Excited-state tautomerization of 7-azaindole in water. Journal of Physical Chemistry, 96, 8430–8441.

    Article  CAS  Google Scholar 

  13. Mehata, M. S., Singh, A. K., & Sinha, R. K. (2017). Investigation of charge-separation/change in dipole moment of 7-azaindole: Quantitative measurement using solvatochromic shifts and computational approaches. Journal of Molecular Liquids, 231, 39–44.

    Article  CAS  Google Scholar 

  14. Nakajima, A., Hirano, M., Hasumi, R., Kaya, K., Watanabe, H., Carter, C. C., Williamson, J. M., & Miller, T. A. (1997). High-resolution laser-induced fluorescence spectra of 7-azaindole-water complexes and 7-azaindole dimer. Journal of Physical Chemistry A, 101, 392–398. https://doi.org/10.1021/jp9614411

    Article  CAS  Google Scholar 

  15. Guha Ray, J., & Sengupta, P. K. (1994). Luminescence behavior of 7-azaindole in AOT reverse micelles. Chemical Physics Letters., 230, 75–81. https://doi.org/10.1016/0009-2614(94)01154-0

    Article  CAS  Google Scholar 

  16. Kwon, O. H., & Jang, D. J. (2005). Proton transfer of excited 7-azaindole in reverse-micellar methanol nanopools: Even faster than in bulk methanol. The Journal of Physical Chemistry B, 109, 8049–8052. https://doi.org/10.1021/jp050743c

    Article  CAS  PubMed  Google Scholar 

  17. Wu, Y.-S., Huang, H.-C., Shen, J.-Y., Tseng, H.-W., Ho, J.-W., Chen, Y.-H., & Chou, P.-T. (2015). Water-catalyzed, excited-State proton-transfer reactions in 7-azaindole and its analogues. The Journal of Physical Chemistry B, 119, 2302–2309.

    Article  CAS  PubMed  Google Scholar 

  18. Chen, K.-Y., & Lin, W.-C. (2015). A simple 7-azaindole-based ratiometric fluorescent sensor for detection of cyanide in aqueous media. Dyes and Pigments, 123, 1–7.

    Article  CAS  Google Scholar 

  19. Kaur, K., Chaudhary, S., Singh, S., & Mehta, S. K. (2016). azaindole modified imine moiety as fluorescent probe for highly sensitive detection of Fe3+ ions. Sensors and Actuators B, 232, 396–401.

    Article  CAS  Google Scholar 

  20. Mehata, M. S., Joshi, H. C., & Tripathi, H. B. (2002). Excited-state intermolecular proton transfer reaction of 6-hydroxyquinoline in protic polar medium. Chemical Physics Letters., 359, 314–320. https://doi.org/10.1016/S0009-2614(02)00716-9

    Article  CAS  Google Scholar 

  21. Mehata, M. S., Joshi, H. C., & Tripathi, H. B. (2002). Complexation of 6-hydroxyquinoline with trimethylamine in polar and non-polar solvents. Chemical Physics Letters, 366, 628. https://doi.org/10.1016/S0009-2614(02)01579-8

    Article  CAS  Google Scholar 

  22. Mehata, M. S. (2008). Proton translocation and electronic relaxation along a hydrogen-bonded molecular wire in a 6-hydroxyquinoline/acetic acid complex. The Journal of Physical Chemistry B, 112, 8383–8386. https://doi.org/10.1021/jp801811e. ibid, Photoinduced excited state proton rearrangement of 6-hydroxyquinoline along a hydrogen-bonded acetic acid wire. Chem. Phys. Lett. 436 (2007) 357–361. (doi.org/10.1016/j.cplett.2007.01.060).

    Article  CAS  PubMed  Google Scholar 

  23. Liu, Y. H., Mehata, M. S., & Liu, J. Y. (2011). Excited-state proton transfer via hydrogen-bonded acetic acid (AcOH) wire for 6-hydroxyquinoline. Journal of Physical Chemistry A, 115, 19–24. https://doi.org/10.1021/jp1101626

    Article  CAS  PubMed  Google Scholar 

  24. Liu, Z.-Y., Hu, J.-W., Chen, C.-L., Chen, Y.-A., Chen, K.-Y., & Chou, P.-T. (2018). Correlation among hydrogen bond, excited-state intramolecular proton-transfer kinetics and thermodynamics for −OH type proton-donor molecules. Journal of Physical Chemistry C, 122, 21833–21840. https://doi.org/10.1021/acs.jpcc.8b07433

    Article  CAS  Google Scholar 

  25. Jacquemina, D., Khelladib, M., De Nicolab, A., & Ulrichb, G. (2019). Turning ESIPT-Based triazine fluorophores into dual emitters: From theory to experiment. Dyes and Pigments, 163, 475–482. https://doi.org/10.1016/j.dyepig.2018.12.023

    Article  CAS  Google Scholar 

  26. Liu, X., Liu, X., Shen, Y., & Gu, B. (2020). A simple water-soluble ESIPT fluorescent probe for fluoride ion with large Stokes shift in living cells. ACS Omega, 5, 21684–21688. https://doi.org/10.1021/acsomega.0c02589

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  27. Liu, Z.-Y., Hu, J.-W., Haung, T.-H., Chen, K.-Y., & Chou, P.-T. (2020). Excited-state intramolecular proton transfer in the kinetic control regime. Physical Chemistry Chemical Physics: PCCP, 22, 22271–22278. https://doi.org/10.1039/D0CP03408H

    Article  CAS  PubMed  Google Scholar 

  28. Wang, C.-H., Liu, Z.-Y., Huang, C.-H., Chen, C.-T., Meng, F.-Y., Liao, Y.-C., Liu, Y.-H., Chang, C.-C., Li, E. Y., & Chou, P.-T. (2021). Chapter open for the excited-state intramolecular thiol proton transfer in the room-temperature solution. Journal of the American Chemical Society, 143, 12715–12724. https://doi.org/10.1021/jacs.1c05602

    Article  CAS  PubMed  Google Scholar 

  29. Yiannikourides, A., & Dada, G. O. L. (2019). A short review of iron metabolism and pathophysiology of iron disorders. Medicines, 6, 85. https://doi.org/10.3390/medicines6030085

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  30. Simcox, J. A., & McClain, D. A. (2013). Iron and diabetes risk. Cell Metabolism, 17, 329–341. https://doi.org/10.1016/j.cmet.2013.02.007

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  31. Torti, S. V., & Torti, F. M. (2013). Iron and cancer: More ore to be mined. Nature Reviews Cancer, 13(2013), 342–355. https://doi.org/10.1038/nrc3495

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  32. Mehata, M. S. (2021). An efficient excited-state proton transfer fluorescence quenching based probe (7-hydroxyquinoline) for sensing trivalent cations in aqueous environment. Journal of Molecular Liquids, 326, 115379. https://doi.org/10.1016/j.molliq.2021.115379

    Article  CAS  Google Scholar 

  33. Mehata, M. S., Joshi, H. C., & Tripathi, H. B. (2002). Fluorescence quenching of 6-methoxyquinoline: An indicator for sensing chloride ion in aqueous media. Journal of Luminescence, 99, 47–52. https://doi.org/10.1016/S0022-2313(02)00294-6

    Article  CAS  Google Scholar 

  34. Desai, N. K., Kolekar, G. B., & Patil, S. R. (2014). Off–on fluorescent polyanthracene for recognition of ferric and fluoride ions in aqueous acidic media: Application in pharmaceutical and environmental analysis. New Journal of Chemistry, 38, 4394. https://doi.org/10.1039/c4nj00675e

    Article  CAS  Google Scholar 

  35. Edison, T. N. J. I., Atchudan, R., Shim, J.-J., Kalimuthu, S., Ahn, B.-C., & Lee, Y. R. (2016). Turn-off fluorescence sensor for the detection of ferric ion in water using green synthesized N-doped carbon dots and its bio-imaging. Journal of Photochemistry and Photobiology B: Biology, 158, 235–242. https://doi.org/10.1016/j.jphotobiol.2016.03.010

    Article  CAS  PubMed  Google Scholar 

  36. Pandey, N., Mehata, M. S., Fatma, N., & Pant, S. (2020). Modulation of fluorescence properties of 5-aminoquinoline by Ag+ in aqueous media via charge transfer. Journal of Photochemistry and Photobiology A: Chemistry., 396, 112549. https://doi.org/10.1016/j.jphotochem.2020.112549

    Article  CAS  Google Scholar 

  37. Fatma, N., Mehata, M. S., Pandey, N., & Pant, S. (2020). Flavones fluorescence-based dual response chemosensor for metal ions in aqueous media and fluorescence recovery. Journal of Fluorescence, 30, 759–772. https://doi.org/10.1007/s10895-020-02540-z

    Article  CAS  PubMed  Google Scholar 

  38. Lashgari, N., Badiei, A., & Ziarani, G. M. (2016). A Fluorescent sensor for Al(III) and colorimetric sensor for Fe(III) and Fe(II) based on a novel 8-hydroxyquinoline derivative. Journal of Fluorescence, 26, 1885–1894. https://doi.org/10.1007/s10895-016-1883-3

    Article  CAS  PubMed  Google Scholar 

  39. Sharma, V., & Mehata, M. S. (2021). Synthesis of photoactivated highly fluorescent Mn2+-doped ZnSe quantum dots as effective lead sensor in drinking water. Materials Research Bulletin., 134, 111121. https://doi.org/10.1016/j.materresbull.2020.111121

    Article  CAS  Google Scholar 

  40. Sharma, P., & Mehata, M. S. (2020). Rapid sensing of lead metal ions in an aqueous medium by MoS2 quantum dots fluorescence turn-off. Materials Research Bulletin., 131, 110978. https://doi.org/10.1016/j.materresbull.2020.110978

    Article  CAS  Google Scholar 

  41. Sharma, P., & Mehata, M. S. (2020). Colloidal MoS2 quantum dots based optical sensor for detection of 2,4,6-TNP explosive in an aqueous medium. Optical Materials., 100, 109646. https://doi.org/10.1016/j.optmat.2019.109646

    Article  CAS  Google Scholar 

  42. Sharma, V., & Mehata, M. S. (2021). Rapid optical sensor for recognition of explosive 2,4,6-TNP traces in water through fluorescent ZnSe quantum dots. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 260, 119937. https://doi.org/10.1016/j.saa.2021.119937

    Article  CAS  PubMed  Google Scholar 

Download references

Acknowledgements

The work is financially supported by the Science and Engineering Research Board (EMR/2016/001110), Department of Science and Technology (DST), Govt. of India.

Author information

Authors and Affiliations

  1. Laser Spectroscopy Laboratory, Department of Applied Physics, Delhi Technological University, Bawana Road, Delhi, 110042, India

    Mohan Singh Mehata &  Aneesha

Authors
  1. Mohan Singh Mehata
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Aneesha
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

MSM: Conception and design of the study, resources, funding acquisition, supervision, drafting, revising and editing of the manuscript. A: Acquisition and analysis of steady-state results.

Corresponding author

Correspondence to Mohan Singh Mehata.

Ethics declarations

Conflict of interest

The authors declare that they have no conflicts of interest.

Consent to publish

All authors have approved the paper and agree with its publication.

Ethical approval

This article does not contain any studies with human participants or animals, clinical trial registration, or plant reproducibility performed by any authors.

Supplementary Information

Below is the link to the electronic supplementary material.

Supplementary file1 (DOCX 2486 KB)

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Mehata, M.S., Aneesha Selectively probing ferric ions in aqueous environments using protonated and neutral forms of 7-azaindole as a multiparametric chemosensor. Photochem Photobiol Sci 22, 1505–1516 (2023). https://doi.org/10.1007/s43630-023-00393-6

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s43630-023-00393-6

Keywords

Search

Navigation