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Excited State Intramolecular Proton Transfer and Photophysics of a New Fluorenyl Two‐Photon Fluorescent Probe
Author(s) -
Morales Alma R.,
SchaferHales Katherine J.,
Yanez Ciceron O.,
Bondar Mykhailo V.,
Przhonska Olga V.,
Marcus Adam I.,
Belfield Kevin D.
Publication year - 2009
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200900032
Subject(s) - photochemistry , intramolecular force , fluorescence , chemistry , fluorene , benzothiazole , excited state , substituent , two photon absorption , absorption (acoustics) , ultrafast laser spectroscopy , laser induced fluorescence , materials science , atomic physics , laser , stereochemistry , optics , physics , organic chemistry , composite material , polymer
The steady‐state photophysical, NMR, and two‐photon absorption (2PA) properties of a new fluorene derivative ( 1 ) containing the 2‐(2′‐hydroxyphenyl)benzothiazole (HBT) terminal construct is investigated for use as a fluorescence probe in bioimaging. A comprehensive analysis of the linear spectral properties reveals inter‐ and intramolecular hydrogen bonding and excited state intramolecular proton transfer (ESIPT) processes in the HBT substituent. A specific electronic model with a double minimum potential energy surface is consistent with the observed spectral properties. The 2PA spectra are obtained using a standard two‐photon induced fluorescence method with a femtosecond kHz laser system, affording a maximum 2PA cross section of ∼600 GM, a sufficiently high value for two‐photon fluorescence imaging. No dependence of two‐photon absorption efficiency on solvent properties and hydrogen bonding in the HBT substituent is observed. The potential use of this fluorenyl probe in bioimaging is demonstrated via one‐ and two‐photon fluorescence imaging of COS‐7 cells.