title: Modulation of Symmetry-Breaking Intramolecular Charge-Transfer Dynamics Assisted by Pendant Side Chains in π-Linkers in Quadrupolar Diketopyrrolopyrrole Derivatives.
abstract: The effect of the length of pendant side chains in centrosymmetric quadrupolar molecules on dynamics of their most perplexing photophysical phenomenon, i.e., symmetry-breaking intramolecular charge transfer, has been discovered. Unexpectedly, considerable influence of length of these pendant side chains in π-linkers arose as a structural factor enabling the control of the degree of fluorescence solvatochromism. The symmetry-breaking intramolecular charge-transfer dynamics has been described on quadrupolar diketopyrrolopyrrole derivatives possessing fluorene moieties as π-linkers and diarylamino groups as electron donors. On the basis of the evolution of transient fluorescence spectra obtained by a femtosecond broadband fluorescence up-conversion spectroscopy, it was found that the relative contribution of diffusive solvation and torsional relaxation in overall spectral relaxation can be modulated by the length of pendant side chain in π-linkers. Consequently, we demonstrated that this modulation plays a significant role in determining the photophysical properties of diketopyrrolopyrroles in a polar medium.
authors.affiliation: Department of Chemistry and Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University , Seoul 03722, Korea.
authors.forename: Woojae
authors.initials: W
authors.lastname: Kim
authors.affiliation: Department of Chemistry and Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University , Seoul 03722, Korea.
authors.forename: Jooyoung
authors.initials: J
authors.lastname: Sung
authors.affiliation: Institute of Organic Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Grzybowski
authors.affiliation: Institute of Organic Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Gryko
authors.affiliation: Department of Chemistry and Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University , Seoul 03722, Korea.
authors.forename: Dongho
authors.initials: D
authors.lastname: Kim