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YOYO1_TA_ChenJ_20170923.pdf (1.19 MB)
Charge Transfer Initializes Photoexcited YOYO-1 Intramolecular Rotation and Fluorescent Quenching
Preprints are manuscripts made publicly available before they have been submitted for formal peer review and publication. They might contain new research findings or data. Preprints can be a draft or final version of an author's research but must not have been accepted for publication at the time of submission.
submitted on 23.10.2017 and posted on 25.10.2017by Jixin Chen, Lei Wang, Joseph R. Pyle
YOYO-1 is a commonly used cyanine dye for DNA
staining that is fluorescently bright in DNA but very dim in water. The major
assumption of its excited electron decay pathway is thermal relaxation via the
rotation at a bridging methine that connects the two moieties of the molecule,
i.e. photo-isomerization. In this report, we use femtosecond transient
absorption spectroscopy to directly measure the excited electron decay, the
hole refill, and the hot ground state rise and decay. The data suggest that the
first step of the photo-isomerization involves a charge transfer to quench the
holes and vibrational activation of the molecules to a hot ground state.