title: Solvatofluorochromic, non-centrosymmetric π-expanded diketopyrrolopyrrole.
abstract: A novel non-centrosymmetric π-expanded diketopyrrolopyrrole was designed and synthesized. Strategic placement of tert-butyl groups at the periphery of a diketopyrrolopyrrole allowed us to selectively fuse one moiety via tandem Friedel-Crafts-dehydration reactions, resulting in a non-centrosymmetric dye. The structure of the dye was confirmed by X-ray crystallography, revealing that it contains a nearly flat arrangement of four fused rings. Extensive photophysical studies of this new functional dye revealed that the intensity of its emission strongly depends on solvent polarity, which is typical for dipolar chromophores. In non-polar solvents, the fluorescence quantum yield is high whereas in polar solvents such as MeOH, it is 12%. However, upon two-photon excitation the compound behaves like a centrosymmetric dye, showing a two-photon absorption maximum at significantly shorter wavelengths than twice the wavelength of the one-photon absorption maximum.
authors.affiliation: Institute of Organic Chemistry of the Polish Academy of Sciences, 01-224 Warsaw, Poland. dtgryko@icho.edu.pl.
authors.forename: Marek
authors.initials: M
authors.lastname: Grzybowski
authors.affiliation: Institute of Organic Chemistry of the Polish Academy of Sciences, 01-224 Warsaw, Poland. dtgryko@icho.edu.pl.
authors.forename: Artur
authors.initials: A
authors.lastname: Jeżewski
authors.affiliation: Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland.
authors.forename: Irena
authors.initials: I
authors.lastname: Deperasińska
authors.affiliation: Universitetet i Tromsø - Norges Arktiske Universitet, Centre for Theoretical and Computational Chemistry Tromsø, Norway. kenneth.ruud@uit.no.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Friese
authors.affiliation: Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland.
authors.forename: Marzena
authors.initials: M
authors.lastname: Banasiewicz
authors.affiliation: Université de Bordeaux, ISM (UMR5255 CNRS), F 33400, Bordeaux, France. m.blanchard-desce@ism.u-bordeaux1.fr.
authors.forename: Vincent
authors.initials: V
authors.lastname: Hugues
authors.affiliation: Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland.
authors.forename: Bolesław
authors.initials: B
authors.lastname: Kozankiewicz
authors.affiliation: Université de Bordeaux, ISM (UMR5255 CNRS), F 33400, Bordeaux, France. m.blanchard-desce@ism.u-bordeaux1.fr.
authors.forename: Mireille
authors.initials: M
authors.lastname: Blanchard-Desce
authors.affiliation: Institute of Organic Chemistry of the Polish Academy of Sciences, 01-224 Warsaw, Poland. dtgryko@icho.edu.pl.
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Gryko