10.1021/jp5066902.s001
Raj Kumar Koninti
Raj Kumar
Koninti
Krishna Gavvala
Krishna
Gavvala
Abhigyan Sengupta
Abhigyan
Sengupta
Partha Hazra
Partha
Hazra
Excited
State Proton Transfer Dynamics of Topotecan
Inside Biomimicking Nanocavity
American Chemical Society
2015
spectrum
Excited State Proton Transfer Dynamics
state proton transfer
RM
state cationic form
molecule
emission
Topotecan
TPT
ESPT dynamics
OH
bulk
state zwitterionic form
2015-02-12 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Excited_State_Proton_Transfer_Dynamics_of_Topotecan_Inside_Biomimicking_Nanocavity/2196652
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.