Excited state proton transfer dynamics of Topotecan inside biomimicking nanocavity

Raj Kumar Koninti, Krishna Gavvala, Abhigyan Sengupta, Partha Hazra

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


The excited state proton transfer (ESPT) dynamics of a potentially important anticancer drug, Topotecan (TPT), has been explored in aqueous reverse micelle (RM) using steady-state and time-resolved fluorescence measurements. Both the time-resolved emission spectrum and time-resolved area normalized emission spectrum infer the generation of excited state zwitterionic form of TPT from the excited state cationic form of TPT, as a result of ESPT process from the -OH group of TPT to the nearby water molecule. The ESPT dynamics were found to be severely retarded inside the nanocavities of RMs, yielding time constants of 250 ps to 1.0 ns, which is significantly slower than the dynamics obtained in bulk water (32 ps). The observed slow ESPT dynamics in RM compared to bulk water is mainly attributed to the sluggish hydrogen-bonded network dynamics of water molecules inside the nanocavity of RM and the screening of the sodium ions present at the interface.

Original languageEnglish
Pages (from-to)2363-2371
Number of pages9
JournalJournal of Physical Chemistry B
Issue number6
Publication statusPublished - Feb 12 2015
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry


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