Journal of Fluorescence

, Volume 27, Issue 2, pp 689–699 | Cite as

Photophysical and Photoprototropic Characteristics of 2-Aminobenzothiazole in β-Cyclodextrin Medium

  • Rajaram Rajamohan
  • Sundarrajulu Kothai Nayaki
  • Meenakshisundaram Swaminathan


The formation of stable inclusion complexes between neutral and monocationic species of 2-aminobenzothiazole (2ABT) with β-CDx is observed with significant enhancement in absorbance and fluorescence intensity. The stoichiometry of the 2ABT and 2ABTH with β-CDx is found to be 1:1 at pH 6.8 and 1.1. Their binding constant values for neutral and monocationic species are found to be 1239.3 and 1259.2 M−1, respectively. Lifetime analysis, FT-IR spectral and SEM image analysis strongly supports the formation of the inclusion complex between 2ABT and β-CDx. Photoprototropic study shows that there is no remarkable difference in the pK a and pK a* in aqueous and β-CDx media, which is rules out the formation of the inclusion complex with –NH2 group of 2ABT inside the cavity of β-CDx i.e., the –NH2 group of 2ABT is in aqueous environment. Based on stoichiometry, binding constant and acidity constant values, the structure of the 1:1 complex is proposed.


Cyclodextrin 2-aminobenzothiazole Solid complex pKa and pKa



We are grateful to the National Centre for Ultrafast Processes, University of Madras, Chennai, for the assistance in the measurements of the fluorescence lifetimes.


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Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  • Rajaram Rajamohan
    • 1
  • Sundarrajulu Kothai Nayaki
    • 2
  • Meenakshisundaram Swaminathan
    • 3
  1. 1.Department of ChemistryS.K.P Engineering CollegeTiruvannamalaiIndia
  2. 2.Chemistry Section, FEATAnnamalai UniversityAnnamalainagarIndia
  3. 3.Centre for ResearchKalasalingam UniversityKrishnankoilIndia

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