title: Photophysical properties of octupolar triazatruxene-based chromophores.
abstract: The photophysical properties of three octupolar chromophores containing planar triazatruxene (TAT) as the central electron donor with different electron-withdrawing groups in the tribranched arrangement have been systematically investigated by means of steady state and transient spectroscopy. The multidimensional intramolecular charge transfer (ICT) properties of these tribranched chromophores related to the observed two-photon absorption (TPA) properties are explored by estimating the TPA essential factors (Mge and Δμge). Besides the large Stokes shift between steady state absorption and fluorescence spectra in different polar solvents, photoinduced ICT was further demonstrated by quantum-chemical calculations and transient absorption measurements. Both quantum calculations and spectral experiments show that a multidimensional ICT occurs from the electron-rich core to the electron-deficient periphery of these TAT derivatives. The results of solvation effects and the dynamics of the excited states show that the excited states of these three chromophores tend to exhibit an excitation localization on one of the dipolar branches, which is beneficial to achieve large Mge and Δμge, thus leading to enhanced TPA properties.
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China. andong@iccas.ac.cn.
authors.forename: Guiying
authors.initials: G
authors.lastname: He
authors.forename: Jinjun
authors.initials: J
authors.lastname: Shao
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Jiangpu
authors.initials: J
authors.lastname: Hu
authors.forename: Huaning
authors.initials: H
authors.lastname: Zhu
authors.forename: Xian
authors.initials: X
authors.lastname: Wang
authors.forename: Qianjin
authors.initials: Q
authors.lastname: Guo
authors.forename: Chunyan
authors.initials: C
authors.lastname: Chi
authors.forename: Andong
authors.initials: A
authors.lastname: Xia