title: Effects of solvent polarity and solvent viscosity on the fluorescent properties of molecular rotors and related probes.
abstract: Fluorescent molecular rotors belong to a group of twisted intramolecular charge transfer complexes (TICT) whose photophysical characteristics depend on their environment. In this study, the influence of solvent polarity and viscosity on several representative TICT compounds (three Coumarin derivatives, 4,4-dimethylaminobenzonitrile DMABN, 9-(dicyanovinyl)-julolidine DCVJ), was examined. While solvent polarity caused a bathochromic shift of peak emission in all compounds, this shift was lowest in the case of molecular rotors. Peak intensity was influenced strongly by solvent viscosity in DMABN and the molecular rotors, but polarity and viscosity influences cannot be separated with DMABN. Coumarins, on the other hand, did not show viscosity sensitivity. This study shows the unique suitability of molecular rotors as fluorescent viscosity sensors.
authors.affiliation: Department of Biological Engineering, University of Missouri-Columbia, Columbia, MO 65211, USA. HaidekkerM@missouri.edu
authors.forename: M A
authors.initials: MA
authors.lastname: Haidekker
authors.forename: T P
authors.initials: TP
authors.lastname: Brady
authors.forename: D
authors.initials: D
authors.lastname: Lichlyter
authors.forename: E A
authors.initials: EA
authors.lastname: Theodorakis
mesh_terms: D005456:Fluorescent Dyes / Q000737:chemistry*; D015335:Molecular Probes / Q000737:chemistry*; D015394:Molecular Structure; D012997:Solvents / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D014783:Viscosity
chemical_list: D005456:Fluorescent Dyes; D015335:Molecular Probes; D012997:Solvents