title: Ultrafast twisting dynamics of thioflavin-T: spectroscopy of the twisted intramolecular charge-transfer state.
abstract: Understanding the excited-state properties of thioflavin-T (ThT) has been of immense importance, because of its efficient amyloid-sensing ability related to neurodegenerative disorders. The excited-state dynamics of ThT is studied by using sub-pico- and nanosecond time-resolved transient absorption techniques as well as density functional theory (DFT)/time-dependent DFT calculations. Barrierless twisting around the central C-C bond between two aromatic moieties is the dominant process that contributes to the ultrafast dynamics of the S1 state. The spectroscopic properties of the intramolecular charge-transfer state are characterized for the first time. The energetics of the S0 and S1 states has also been correlated with the experimentally observed spectroscopic parameters and structural dynamics. A longer-lived transient state populated with a very low yield has been characterized as the triplet state.
authors.affiliation: Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai-400085 (India).
authors.forename: Rajib
authors.initials: R
authors.lastname: Ghosh
authors.forename: Dipak K
authors.initials: DK
authors.lastname: Palit
mesh_terms: D052160:Benzothiazoles; D005456:Fluorescent Dyes / Q000737:chemistry*; D008958:Models, Molecular; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence; D013844:Thiazoles / Q000737:chemistry*; D013997:Time Factors
chemical_list: D052160:Benzothiazoles; D005456:Fluorescent Dyes; D013844:Thiazoles; C009462:thioflavin T
keywords: charge transfer; density functional calculations; structure-activity relationships; time-resolved spectroscopy; transient absorption spectroscopy