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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
ORIGINAL ARTICLE

Abstract

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.

Keywords

Cyclodextrin 2-aminobenzothiazole Solid complex pKa and pKa

Notes

Acknowledgement

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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