Chemistry Faculty Publications
Document Type
Article
Abstract
We present a study of the excited-state behavior of N(5)-ethyl-4a-hydroxyflavin (Et-FlOH), a model compound for bacterial bioluminescence. Using femtosecond pump-probe spectroscopy, we found that the Et-FlOH excited state exhibits multiexponential dynamics, with the dominant decay component having a 0.5 ps lifetime. Several possible mechanisms for fast excited-state decay in Et-FlOH were considered: (i) excited-state deprotonation of the -OH proton, (ii) thermal deactivation via (1)n,pi* -> (1)pi,pi* conical intersection, and (iii) excited-state release of OH(-) ion. These mechanisms were excluded based on transient absorption studies of two model compounds (N(5)-ethyl-4a-methoxyflavin, Et-FlOMe, and N(5)-ethyl-flavinium ion, Et-Fl(+)) and based on the results of time-dependent density functional theory (TD-DFT) calculations of Et-FlOH excited-states. Instead, we propose that the fast decay in Et-FlOH is caused by SI So internal conversion, initiated by the excited-state nitrogen planarization (sp(3) -> sp(2) hybridization change at the N(5)-atom of Et-FlOH S(1) state) coupled with out-of-plane distortion of the pyrimidine moiety of flavin.
Copyright Statement
Publisher PDF
Repository Citation
Zhou, Dapeng; Mirzakulova, Ekaterina; Khatmullin, Renat; Schapiro, Igor; Olivucci, Massimo; and Glusac, Ksenija D., "Fast Excited-state Deactivation In N(5)-ethyl-4a-hydroxyfiavin Pseudobase" (2011). Chemistry Faculty Publications. 153.
https://scholarworks.bgsu.edu/chem_pub/153
Publication Date
6-2011
Publication Title
Journal Of Physical Chemistry B
DOI
https://doi.org/10.1021/jp201903h
Start Page No.
7136
End Page No.
7143