title: Efficient photochromic transformation of a new fluorenyl diarylethene: one- and two-photon absorption spectroscopy.
abstract: Efficient reversible phototransformation of a new diarylethene-fluorene derivative, 1,2-bis(5-(9,9-didecyl-7-nitro-9H-fluoren-2-yl)-2-methylthiophen-3-yl)cyclopent-1-ene (1), was demonstrated in organic media under low-intensity laser excitation. Linear photophysical characterization of 1 was performed at room temperature in solvents of different polarity and viscosity. Significantly, close to unity quantum yield for the cyclization reaction of 1 was shown in nonpolar solutions. The lifetimes of the excited states of the open (OF) and closed (CF) forms of 1 were measured by a femtosecond transient absorption technique, and corresponding values of ∼0.7 and ∼0.9 ps were shown in dichloromethane (DCM), respectively. Degenerate two-photon absorption (2PA) spectra of the OF and CF of 1 were obtained over a broad spectral range by the open aperture Z-scan method under 1 kHz femtosecond excitation. The values of 2PA cross sections of the OF in DCM (∼50-70 GM) were found to increase up to 1 order of magnitude (∼600 GM) after cyclization to the CF. The nature of cyclization and cylcoreversion processes were investigated by quantum chemistry with employment of DFT-based methods implemented in the Gaussian'09 program. The potential of 1 for application in optical data storage was shown using poly(methyl methacrylate)-doped films and two-photon fluorescence microscopy readout.
authors.affiliation: Department of Chemistry, University of Central Florida, P.O. Box 162366, Orlando, Florida 32816, United States.
authors.forename: Gheorghe
authors.initials: G
authors.lastname: Luchita
authors.forename: Mykhailo V
authors.initials: MV
authors.lastname: Bondar
authors.forename: Sheng
authors.initials: S
authors.lastname: Yao
authors.forename: Ivan A
authors.initials: IA
authors.lastname: Mikhailov
authors.forename: Ciceron O
authors.initials: CO
authors.lastname: Yanez
authors.forename: Olga V
authors.initials: OV
authors.lastname: Przhonska
authors.forename: Artem E
authors.initials: AE
authors.lastname: Masunov
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Belfield
mesh_terms: D000042:Absorption; D003500:Cyclization; D005449:Fluorenes / Q000138:chemical synthesis / Q000737:chemistry*; D007536:Isomerism; D008027:Light; D008856:Microscopy, Fluorescence; D017785:Photons; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011789:Quantum Theory; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: D005449:Fluorenes; D012997:Solvents; D019904:Polymethyl Methacrylate