Skip to main content
SpringerLink
Log in

The origin of the longer wavelength emission in 2-(4-fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole and its analogue 2-phenylamino-5-(2-hydroxybenzono)-1,3,4-thiadiazole† ‡

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

Abstract

In aqueous solution, 2-(4-fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole (FABT) was found to emit dual emission and the longer wavelength emission was assigned to the combination of aggregation and conformational change. In a number of molecules that possess an intramolecular hydrogen bond between the proton donor and the acceptor, the longer wavelength emission is often observed due to the emission from the tautomer formed by excited state intramolecular proton transfer (ESIPT). Therefore, an analogue of FABT, 2-phenylamino-5-(2-hydroxybenzono)-1,3,4-thiadiazole (PHBT), was synthesized to determine the origin of the longer wavelength emission. The luminescence of PHBT and its methoxy derivatives was studied and compared with that of FABT. Theoretical calculations were also performed on both FABT and PHBT. Based on the experimental and theoretical investigations, the nonexistence of the keto tautomer in the ground state and the origin of the longer wavelength emission are divulged.

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

Similar content being viewed by others

References

  1. Y. Li, J. Geng, Y. Liu, S. Yu and G. Zhao, Thiadiazole-a Promising Structure in Medicinal Chemistry, ChemMedChem, 2013, 8, 27–41.

    Article  PubMed  CAS  Google Scholar 

  2. S. Haider, M. S. Alam and H. Hamid, 1,3,4-Thiadiazoles. A Potent Multi Targeted Pharmacological Scaffold, Eur. J. Med. Chem., 2015, 92, 156–177.

    Article  CAS  PubMed  Google Scholar 

  3. A. Aliabadi, 1,3,4-Thiadiazole Based Anticancer Agents, Anti-Cancer Agents Med. Chem., 2016, 16, 1301–1314.

    CAS  Google Scholar 

  4. M. M. Sekhar, U. Nagarjuna, V. Padmavathi, A. Padmaja, N. V. Reddy and T. Vijaya, Synthesis and Antimicrobial Activity of Pyrimidinyl 1,3,4–Oxadiazoles, 1,3,4-Thiadiazoles and 1,2,4-Triazoles, Eur. J. Med. Chem., 2018, 145, 1–10.

    Article  CAS  Google Scholar 

  5. G. Serban, O. Stanasel, E. Serban and S. Bota, 2-Amino-1,3,4-Thiadiazole as a Potential Scaffold for Promising Antimicrobial Agents, Drug Des., Dev. Ther., 2018, 12, 1545–1566.

    CAS  Google Scholar 

  6. S. Maddila, S. Gorle, C. Sampath and P. Lavanya, Synthesis and Anti-Inflammatory Activity of Some New 1,3,4-Thiadiazoles Containing Pyrazole and Pyrrole Nucleus, J. Saudi Chem. Soc., 2016, 20, S306–S312.

    Article  CAS  Google Scholar 

  7. N. Ö. Can, Ö. D. Can, D. Osmaniye and Ü. D. Özkay, Synthesis of Some Novel Thiadiazole Derivative Compounds and Screening Their Antidepressant-Like Activities, Molecules, 2018, 23, 716.

    Article  PubMed Central  CAS  Google Scholar 

  8. J. J. Luszczki, M. Karpińska, J. Matysiak and A. Niewiadomy, A. Characterization and Preliminary Anticonvulsant Assessment of Some 1,3,4-Thiadiazole Derivatives, Pharmacol. Rep., 2015, 67, 588–592.

    CAS  Google Scholar 

  9. B. Chudzik, K. Bonio, W. Dabrowski, D. Pietrzak, A. Niewiadomy, A. Olender, B. Pawlikowska-Pawlega and M. Gagoś, Antifungal Effects of a 1, 3,4-Thiadiazole Derivative Determined by Cytochemical and Vibrational Spectroscopic Studies, PLoS One, 2019, 14(9), 1–32.

    Google Scholar 

  10. B. Chudzik, K. Bonio, W. Dabrowski, D. Pietrzak, A. Niewiadomy, A. Olender, K. Malodobry and M. Gagoś, Synergistic Antifungal Interactions of Amphotericin B With 4-(5-Methyl-l,3,4-thiadiazole-2-yl)benzene-1,3-diol, Sci. Rep., 2019, 9, 12945.

    Google Scholar 

  11. M. Juszczak, J. Matysiak, M. Szeliga, P. Pożarowski, A. Niewiadomy, J. Albrecht and W. Rzeski, 2-Amino-1,3,4-thiadiazole Derivative (FABT) Inhibits the Extracellular Signal-Regulated Kinase Pathway and Induces Cell Cycle Arrest in Human Non-Small Lung Carcinoma Cells, Bioorg. Med. Chem. Lett., 2012, 22, 5466–5469.

    Article  CAS  Google Scholar 

  12. W. Rzeski, J. Matysiak and M. Kandefer-Szerszeń, Anticancer, Neuroprotective Activities and Computational Studies of 2-Amino-1,3,4-thiadiazole Based Compound, Bioorg. Med. Chem., 2007, 15, 3201–3207.

    CAS  Google Scholar 

  13. B. Valeur and J.-C. Brochon, New Trends in Fluorescence Spectroscopy. Applications to Chemical and Life Sciences, Springer Berlin Heidelberg, 2001.

  14. M. Strianese, M. Staiano, G. Ruggiero, T. Labella, C. Pellecchia and S. D’Auria, Fluorescence-Based Biosensors, in Methods in molecular biology, Clifton, N.J., 2012, vol. 875, pp. 193–216.

  15. E. M. Goldys, Fluorescence Applications in Biotechnology and Life Sciences, John Wiley & Sons, 2009.

  16. R. Kraayenhof, A. J. W. G. Visser and H. C. Gerritsen, Fluorescence Spectroscopy, Imaging and Probes. New Tools in Chemical, Physical and Life Sciences, Springer Berlin Heidelberg, 2002.

  17. D. M. Kamiński, A. A. Hoser, M. Gagoś, A. Matwijczuk, M. Arczewska, A. Niewiadomy and K. Woźniak, Solvatomorphism of 2-(4-Fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole Chloride, Cryst. Growth Des., 2010, 10, 3480–3488.

    Article  CAS  Google Scholar 

  18. M. Gagoś, A. Matwijczuk, D. Kamiński, R. Niewiadomy, R. Kowalski and G. P. Karwasz, Spectroscopic Studies of Intramolecular Proton Transfer in 2-(4-Fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole, J. Fluoresc., 2011, 21, 1–10.

    Article  PubMed  CAS  Google Scholar 

  19. D. M. Kamiński, A. Matwijczuk, D. Pociecha, E. Górecka, A. Niewiadomy, M. Dmowska and M. Gagoś, 2-(4-Fluorophenylamino)-5-(2,4-dihydroxyphenyl)-l,3,4-thiadiazole on the Molecular Organisation and Structural Properties of the DPPC Lipid Multibilayers, Biochim. Biophys. Acta, Biomembr, 2012, 1818, 2850–2859.

  20. A. A. Hoser, D. M. Kamiński, A. Matwijczuk, A. Niewiadomy, M. Gagoś and K. Woźniak, On Polymorphism of 2-(4-Fluorophenylamino)-5-(2,4-dihydroxybenzeno)-l,3,4-thiadiazole (FABT) DMSO Solvates, CrystEngComm, 2013, 15, 1978.

    Article  CAS  Google Scholar 

  21. A. Matwijczuk, D. Kamiński, A. Gïrecki, A. Ludwiczuk, A. Niewiadomy, S. Maćkowski and M. Gagoś, Spectroscopic Studies of Dual Fluorescence in 2-((4-Fluorophenyl)amino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole, J. Phys. Chem. A, 2015, 119, 10791–10805.

    Article  CAS  PubMed  Google Scholar 

  22. A. A. Hoser, D. M. Kamiński, A. Skrzypek, A. Matwijczuk, A. Niewiadomy, M. Gagoś and K. Wozniak, Interplay of Inter- and Intramolecular Interactions in Crystal Structures of 1,3,4-Thiadiazole Resorcinol Derivatives, Cryst. Growth Des., 2018, 18, 3851–3862.

    Article  CAS  Google Scholar 

  23. G. Czernel, A. Matwijczuk, D. Karcz, A. Górecki, A. Niemczynowicz, A. Szcześ, G. Gladyszewski, A. Matwijczuk, B. Gładyszewska and A. Niewiadomy, Spectroscopic Studies of Dual Fluorescence in 2-(4-Fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole: Effect of Molecular Aggregation in a Micellar System, Molecules, 2018, 23(11), 2861.

    Google Scholar 

  24. A. Matwijczuk, A. Górecki, M. Makowski, K. Pústuła, A. Skrzypek, J. Waś, A. Niewiadomy and M. Gagoś, Spectroscopic and Theoretical Studies of Fluorescence Effects in 2-Methylamino-5-(2,4-dihydroxyphenyl)-1,3,4-thiadiazole Induced by Molecular Aggregation, J. Fluoresc., 2018, 28, 65–77.

    Article  CAS  PubMed  Google Scholar 

  25. I. Budziakd, D. Karczb, M. Makowskie, Be. Myśliwa-Kurdzielc, K. Kasprzakf, A. Matwijczuka, E. Chruściela, A. Oniszczukf, L. Adwenta and A. Matwijczuka, Spectroscopic and theoretical investigation into substituent- and aggregation-related dual fluorescence effects in the selected 2-amino-1,3,4-thiadiazoles, J. Mol. Liq., 2019, 291, 111261.

    Google Scholar 

  26. I. Budziakd, D. Karcz, M. Makowski, K. Rachwał, K. Starza, A. Matwkijczuk, B. Myśliwa-Kurdziel, A. Oniszczuk, M. Combrzyński, A. Podleśna and A. Matwijczuk, Non-Typical Fluorescence Effects and Biological Activity in Selected 1,3,4-thiadiazole Derivatives: Spectroscopic and Theoretical Studies on Substituent, Molecular Aggregation, and pH Effects, Int. J. Mol. Sci., 2019, 20, 5494.

    Article  CAS  Google Scholar 

  27. A. S. Abo-Dena, Z. A. Muhammad and W. M. I. Hassan, Spectroscopic, DFT Studies and Electronic Properties of Novel Functionalized Bis-1,3,4-thiadiazoles, Chem. Pap., 2019, 73, 2803–2812.

    Article  CAS  Google Scholar 

  28. A. Matwijczuk, A. Górecki, D. Kamiński, B. Myśliwa-Kurdziel, L. Fiedor, A. Niewiadomy, G. P. Karwasz and M. Gagoś, Influence of Solvent Polarizability on The Keto-Enol Equilibrium In 4-(5-(Naphthalen-l-ylmethyl)-1,3,4-thiadiazol-2-yl]benzene-1,3-diol, J. Fluoresc., 2015, 25, 1867–1874.

    Article  CAS  PubMed  Google Scholar 

  29. A. Matwijczuk, D. Kluczyk, A. Górecki, A. Niewiadomy and M. Gagoś, Spectroscopic Studies of Fluorescence Effects in Bioactive 4-(5-Heptyl-1,3,4-thiadiazol-2-yl)benzene-1,3-diol and 4-(5-Methyl-1,3,4-thiadiazol-2-yl)benzene-1,3-diol Molecules Induced by pH Changes in Aqueous Solutions, J. Fluoresc., 2017, 27(4), 1201–1212.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  30. A. Matwijczuk, D. Karcz, K. Pustuła, M. Makowski, A. Górecki, D. Kluczyk, M. M. Karpińska, A. Niewiadomy and M. Gagoś, Spectroscopic and Theoretical Studies of Fluorescence Effects in Bio-active: 4-(5-(Methyl-1,3,4-thiadiazol-2-yl))benzene-1,3-diol and 4-(5-(Methylamino-1,3,4-thiadiazol-2-yl))benzene-1,3-diol Compounds: Effect of Molecular Aggregation and Amino Group Position, J. Lumin., 2018, 201, 44–56.

    Article  CAS  Google Scholar 

  31. D. Karcza, A. Matwijczukb, B. Borońc, B. Creavend, L. Fiedorc, A. Niewiadomyef and M. Gagoś, Isolation and Spectroscopic Characterization of Zn(II), Cu(II), and Pd(II) Complexes of 1,3,4-Thiadiazole-derived Ligand, J. Mol. Struct., 2017, 1128, 44–50.

    Article  CAS  Google Scholar 

  32. A. Matwijczuk, D. Kluczyk, A. Górecki, A. Niewiadomy and M. Gagoś, Solvent Effects on Molecular Aggregation in 4-(5-Heptyl-1, 3, 4-thiadiazol-2-yl) benzene-1, 3-diol and 4-(5-Methyl-1, 3, 4-thiadiazol-2-yl) benzene-1, 3-diol, J. Phys. Chem. B, 2016, 120(32), 7958–7969.

    Article  CAS  PubMed  Google Scholar 

  33. D. Kluczyk, A. Matwijczuk, A. Górecki, M. M. Karpińska, M. Szymanek, A. Niewiadomy and M. Gagoś, Molecular Organization of Dipalmitoylphosphatidylcholine Bilayers Containing Bioactive Compounds 4-(5-Heptyl-1,3,4-thiadiazol-2-yl) benzene-1,3-diol and 4-(5-Methyl-1,3,4-thiadiazol-2-yl) benzene-1,3-diols, J. Phys. Chem. B, 2016, 120(47), 12047–12063.

    CAS  PubMed  Google Scholar 

  34. A. Matwijczuk, D. Karcz, S. Wybraniec, D. Kluczyk, M. Gagoś and A. Niewiadomy, Spectroscopic Studies Of Dual Fluorescence Effects In A Selected 1,3,4-Thiadiazole Derivative In Organic Solvents And Aqueous Solutions, Tech. Trans., 2017, 13, 47–61.

    Google Scholar 

  35. A. Matwijczuk, D. Karcz, R. Walkowiak, J. Furso, B. Gładyszewska, S. Wybraniec, A. Niewiadomy, G. P. Karwasz and M. Gagoś, Effect of Solvent Polarizability on the Keto/Enol Equilibrium of Selected Bioactive Molecules from the 1,3,4-Thiadiazole Group with a 2,4-Hydroxyphenyl Function, J. Phys. Chem. A, 2017, 121(7), 1402–1411.

  36. L. Antonov, Tautomerism: Methods and Theories, John Wiley & Sons, 2003.

    Google Scholar 

  37. F. A. S. Chipem, A. Malakar and G. Krishnamoorthy, Intramolecular Proton Transfer in 2-(2′-Hydroxyphenyl) oxazolo[4,5-b]pyridine. Evidence for Tautomer in the Ground State, Photochem. Photobiol, 2015, 91, 298–305.

    Article  CAS  Google Scholar 

  38. F. A. S. Chipem and G. Krishnamoorthy, Temperature Effect on Dual Fluorescence of 2-(2′-Hydroxyphenyl)benzimidazole and Its Nitrogen Substituted Analogues, J. Phys. Chem. B, 2013, 117, 14079–14088.

    Article  CAS  PubMed  Google Scholar 

  39. F. A. S. Chipem and G. Krishnamoorthy, Comparative Theoretical Study of Rotamerism and Excited State Intramolecular Proton Transfer of 2-(2′-Hydroxyphenyl) benzimidazole, 2-(2′-Hydroxyphenyl)imidazo[4,5-b]pyridine, 2-(2′-Hydroxyphenyl)imidazo[4,5-c] pyridine and 8-(2′-Hydroxyphenyl)purine, J. Phys. Chem. A, 2009, 113, 12063–12070.

    Article  CAS  PubMed  Google Scholar 

  40. V. S. Padalkar, A. Tathe, V. D. Gupta, V. S. Patil, K. Phatangare and N. Sekar, Synthesis and Photo-Physical Characteristics of ESIPT Inspired 2-Substituted Benzimidazole, Benzoxazole and Benzothiazole Fluorescent Derivatives, J. Fluoresc, 2012, 22, 311–322.

    Article  CAS  PubMed  Google Scholar 

  41. J. E. Kwon and S. Y. Park, Advanced Organic Optoelectronic Materials: Harnessing Excited-State Intramolecular Proton Transfer (ESIPT) Process, Adv. Mater., 2011, 23, 3615–3642 and related references therein.

  42. Y. Li, Y. Zhao, Y. Yang, W. Shia and X. Fan, Excited State Hydrogen Bond and Proton Transfer of 2-(Benzo[d]thiazol-2-yl)-3-methoxynaphthalen-1-ol, Org. Chem. Front, 2019, 6, 2780–2787.

    Article  CAS  Google Scholar 

  43. J. Zhao, S. Ji, Y Chen, H. Guo and P. Yang, Excited State Intramolecular Proton Transfer (ESIPT). From Principal Photophysics to the Development of New Chromophores and Applications in Fluorescent Molecular Probes and Luminescent Materials, Phys. Chem. Chem. Phys., 2012, 14(25), 8803–8817 and related references therein.

  44. V. S. Padalkar and S. Shu, Excited-state Intramolecular Proton-Transfer (ESIPT)-Inspired Solid State Emitters, Chem. Soc. Rev., 2016, 45, 169–202 and related references therein.

  45. E. Heyer, K. Benelhadj, S. Budzák, D. Jacquemin, J. Massue and G. Ulrich, On the Fine-Tuning of the Excited-State Intramolecular Proton Transfer (ESIPT) Process in 2-(2′-Hydroxybenzofuran)benzazole (HBBX) Dyes, Chem. – Eur. J., 2017, 23, 7324–7336.

    Article  CAS  PubMed  Google Scholar 

  46. N. Klinhom, N. Saengsuwan, S. Sriyab, P. Prompinit, S. Hannongbua and S. Suramitr, Photophysical Properties for Excited-State Intramolecular Proton Transfer (ESIPT) Reaction of N-Salicylidene-o-Aminophenol. Experimental and DFT Based Approaches, Spectrochim. Acta, Part A, 2019, 206, 359–366.

    Article  CAS  Google Scholar 

  47. A. V. Gaenko, A. Devarajan, I. V. Tselinskii and U. Ryde, Structural and Photoluminescence Properties of Excited State Intramolecular Proton Transfer Capable Compounds - Potential Emissive and Electron Transport Materials, J. Phys. Chem. A, 2006, 110, 7935–7942.

    Article  CAS  PubMed  Google Scholar 

  48. C. W. Ghanavatkar, V. R. Mishra, N. Sekar, E. Mathew, S. S. Thomas and I. H. Joe, Benzothiazole Pyrazole Containing Emissive Azo Dyes Decorated with ESIPT Core: Linear and Non Linear Optical Properties, Z Scan, Optical Limiting, Laser Damage Threshold With Comparative DFT Studies, J. Mol. Struct, 2020, 1203, 127401.

    Google Scholar 

  49. D. Y. Chen, C. L. Chen, Y. M. Cheng, C. H. Lai, J. Y. Yu and B. S. Chen, Design and Synthesis of Trithiophene-Bound Excited-State Intramolecular Proton Transfer Dye: Enhancement on the Performance of Bulk Heterojunction Solar Cells, ACS Appl. Mater. Interfaces, 2010, 2(6), 1621–1629.

    CAS  Google Scholar 

  50. A. Felouat, M. Curtil, J. Massue and G. Ulrich, Excited-state Intramolecular Proton Transfer (ESIPT) Emitters Based on a 2-(2′-Hydroxy benzofuranyl)benzoxazole (HBBO) Scaffold Functionalised With Oligo(Ethylene Glycol) (OEG) Chains, New J. Chem., 2019, 43, 9162–9169.

    CAS  Google Scholar 

  51. F. Shi, S. Cui, H. Liu and S. Pu, A High Selective Fluorescent Sensor for Cu2+ in Solution and Test Paper Strips, Dyes Pigm., 2020, 173, 107914.

    Google Scholar 

  52. S. Sahu, M. Das, A. K. Bharti and G. Krishnamoorthy, Proton Transfer Triggered Proton Transfer: A Self-Assisted Twin Excited State Intramolecular Proton Transfer, Phys. Chem. Chem. Phys., 2018, 20, 27131–27139.

    Article  CAS  PubMed  Google Scholar 

  53. S. J. Singh, S. Rajamanickam, A. Gogoi and B. K. Patel, Synthesis of 2-Amino-Substituted-1,3,4-thiadiazoles via 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) Mediated Intramolecular C-S Bond Formation in Thiosemicarbazones, Tetrahedron Lett, 2016, 57, 1044– 1047.

  54. W. Koch and M. C. Holthausen, A Chemist’s Guide to Density Functional Theory, Wiley, 2001.

  55. E. Runge and E. K. U. Gross, Density-Functional Theory for Time-Dependent Systems, Phys. Rev. Lett, 1984, 52, 997– 1000.

    Article  CAS  Google Scholar 

  56. M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, G. Scalmani, V. Barone, B. Mennucci, G. A. Petersson, et al., Gaussian 09, Revision D.01, Gaussian, Inc., Wallingford, CT, 2013.

    Google Scholar 

  57. A. D. Becke, Density-functional Thermochemistry., III. The Role of Exact Exchange, J. Chem. Phys., 1993, 98, 5648–5652.

    Article  CAS  Google Scholar 

  58. J. Tomasi, B. Mennucci and R. Cammi, Quantum Mechanical Continuum Solvation Models, Chem. Rev., 2005, 105, 2999–3094.

    Article  CAS  PubMed  Google Scholar 

  59. S. K. Behera, A. Karak and G. Krishnamoorthy, Photophysics of 2-(4′-Amino-2′-hydroxyphenyl)-1 H -imidazo-[4,5-c]pyridine and Its Analogues: Intramolecular Proton Transfer versus Intramolecular Charge Transfer, J. Phys. Chem. B, 2015, 119, 2330–2344.

    Article  CAS  PubMed  Google Scholar 

  60. M. Mosquera, J. C. Penedo, M. C. R. Rodríguez and F. Rodríguez-Prieto, Photoinduced Inter- and Intramolecular Proton Transfer in Aqueous and Ethanolic Solutions of 2-(2′-Hydroxyphenyl)benzimidazole: Evidence for Tautomeric and Conformational Equilibria in the Ground State, J. Phys. Chem., 1996, 100, 5398–5407.

    Article  CAS  Google Scholar 

  61. C. Li, B. Hu and Y. F. Liu, Unraveling the effect of two different polar solvents on the excited-state intramolecular proton transfer of 4′-methoxy-3-hydroxyflavone fluorescent dye, Spectrochim. Acta, Part A, 2020, 225, 117487.

    Google Scholar 

  62. D. LeGourriérec, V. A. Kharlanov, R. G. Brown and W. Rettig, Excited-State Intramolecular Proton Transfer (ESIPT) in 2-(2′ -Hydroxyphenyl)-oxazole and -Thiazole, J. Photochem. Photobiol., A, 2000, 130, 101–111.

    Article  Google Scholar 

  63. J. Seo, S. Kim, O.-H. Kwon, K. H. Park, S. Y. Choi, Y. K. Chung, D.-J. Jang and S. Y. Park, Enhanced Solid-State Fluorescence in the Oxadiazole-Based Excited-State Intramolecular Proton-Transfer (ESIPT) Material: Synthesis, Optical Property, and Crystal Structure, J. Photochem. Photobiol., A, 2007, 191, 51–58.

    Article  CAS  Google Scholar 

  64. P. F. Barbara, L. E. Brus and P. M. Rentzepis, Intramolecular Proton Transfer and Excited-State Relaxation in 2-(2- Hydroxyphenyl)benzothiazole, J. Am. Chem. Soc., 1980, 102, 5631–5635.

    Article  CAS  Google Scholar 

  65. G. J. Woolfe, M. Melzig, S. Schneider and F. Dörr, The Role of Tautomeric and Rotameric Species in the Photophysics of 2-(2′- Hydroxyphenyl)Benzoxazole, Chem. Phys., 1983, 77, 213–221.

    Article  CAS  Google Scholar 

  66. H. K. Sinha and S. K. Dogra, Ground and Excited State Prototropic Reactions in 2-(o-Hydroxyphenyl)benzimidazole, Chem. Phys., 1986, 102, 337–347.

    Article  CAS  Google Scholar 

  67. S. Sahu, S. Dutta and G. Krishnamoorthy, An Unusual Deprotonation Trend in 2-(2′-Hydroxyphenyl)pyridoimidazoles, Phys. Chem. Chem. Phys., 2016, 18, 29905–29913.

    Article  CAS  PubMed  Google Scholar 

  68. Y. Wu, X. Peng, J. Fan and S. Gao, Fluorescence Sensing of Anions Based on Inhibition of Excited-State Intramolecular Proton Transfer, J. Org. Chem., 2007, 72, 62–70.

    Article  CAS  PubMed  Google Scholar 

  69. A. Malakar, M. Kumar, A. Reddy, H. T. Biswal, B. B. Mandal and G. Krishnamoorthy, Aggregation Induced Enhanced Emission of 2-(2′-Hydroxyphenyl)benzimidazole, Photochem. Photobiol. Sci., 2016, 15, 937–948.

    CAS  Google Scholar 

  70. S. K. Behera, A. Murkherjee, G. Sadhuragiri, P. Elumalai, M. Sathiyendiran, M. Kumar, B. B. Mandal and G. Krishnamoorthy, Aggregation Induced Enhanced and Exclusively Highly Stokes Shifted Emission from an Excited State Intramolecular Proton Transfer Exhibiting Molecule, Faraday Discuss., 2017, 196, 71–90.

    Article  CAS  PubMed  Google Scholar 

  71. A. Bhattacharyya, S. C. Makhal and N. Guchhait, Simple Chloro Substituted HBT Derivative Portraying Coupling of AIE and ESIPT Phenomenon: Ratiometric Detection of S2-and CN- in 100% Aqueous Medium, J. Photochem. Photobiol, A, 2020, 388, 112177.

    Google Scholar 

  72. Z. Hu, H. Zhang, Y. Chen, Q. Wang, M. R. J. Elsegood, S. J. Teat, X. Feng, M. M. Islam, F. Wu and B. Z. Tang, Tetraphenylethylene-based color-tunable AIE-ESIPT chromophores, Dyes Pigm., 2020, 175, 108175.

    Google Scholar 

  73. Y. Hong, J. W. Y. Lam and B. Z. Tang, Aggregation-Induced Emission: Phenomenon, Mechanism and Applications, Chem. Commun.., 2009, 4332–4353, and related references therein.

  74. Y. Hong, J. W. Y Lam and B. Z. Tang, Aggregation-induced emission, Chem. Soc. Rev., 2011, 40, 5361–5388 and related references therein.

Download references

Author information

Authors and Affiliations

  1. Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, India

    Reshmi Dani Ila, Surya Pratap Verma & G. Krishnamoorthy

Authors
  1. Reshmi Dani Ila
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Surya Pratap Verma
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. G. Krishnamoorthy
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to G. Krishnamoorthy.

Additional information

Dedicated to Professor S. K. Dogra on his 78th birthday.

Electronic supplementary information (ESI) available. CCDC 1921954 and 1921955. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c9pp00490d

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Ila, R.D., Verma, S.P. & Krishnamoorthy, G. The origin of the longer wavelength emission in 2-(4-fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole and its analogue 2-phenylamino-5-(2-hydroxybenzono)-1,3,4-thiadiazole† ‡. Photochem Photobiol Sci 19, 844–853 (2020). https://doi.org/10.1039/c9pp00490d

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1039/c9pp00490d

Search

Navigation