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.
Bibliographical noteFunding Information:
The work at Yonsei University was supported by the Global Research Laboratory Program (2013K1A1A2A02050183) funded by the Ministry of Science, ICT & Future, Korea. The quantum calculations were supported by the National Institute of Supercomputing and Network (NISN)/Korea Institute of Science and Technology Information (KISTI) with supercomputing resources including technical support. D.T.G. thanks the National Science Center of the Republic of Poland (MAESTRO-2012/06/A/ST5/00216).
© 2016 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physical and Theoretical Chemistry