title: Anion-controlled dimer distance induced unique solid-state fluorescence of cyano substituted styrene pyridinium.
abstract: Molecular packing arrangements play a key role in dominating the photophysical properties of luminophores in aggregated state but fine control of the molecular packing is a great challenge. This article describes a unique cyano substituted styrene pyridinium with interesting solid-state fluorescence that can be finely tuned by simple change of counteranions. The dilute solutions of the organic salts (PyCl, PyNO3, PyOTs and PyPh4B) exhibit very weak fluorescence. The crystals of the organic salts (PyCl, PyNO3, and PyOTs) show much enhanced fluorescence compared with their dilute solutions. It is interesting that the emissions changed from bluish-green to deep-blue and fluorescence quantum yields increase from 2.5% to 13.1% with the increasing of steric hindrance of the anions from chloridion, nitrate, to p-toluenesulfonate. Crystal and DFT studies reveal that the enhanced fluorescence is ascribed to the formation of dimers and bigger anions induce larger molecular separation in dimers. Tetraphenylboron anion with very large steric hindrance impedes the formation of dimers and thus results in non-fluorescent salt (PyPh4B). Meanwhile, this unique dimeric packing endows the crystal of PyNO3with anisotropic fluorescence.
authors.affiliation: College of Chemistry &Chemical Engineering, Key Laboratory of Functional Inorganic Materials of Anhui Province, Anhui University, Hefei 230601, P. R. China.
authors.forename: Gaobin
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Faculty of Health Sciences, University of Macau, Taipa, Macau SAR, P. R. China.
authors.forename: Xuanjun
authors.initials: X
authors.lastname: Zhang
authors.affiliation: College of Chemistry &Chemical Engineering, Key Laboratory of Functional Inorganic Materials of Anhui Province, Anhui University, Hefei 230601, P. R. China.
authors.forename: Lin
authors.initials: L
authors.lastname: Kong
authors.affiliation: Faculty of Health Sciences, University of Macau, Taipa, Macau SAR, P. R. China.
authors.forename: Shichao
authors.initials: S
authors.lastname: Wang
authors.affiliation: College of Chemistry &Chemical Engineering, Key Laboratory of Functional Inorganic Materials of Anhui Province, Anhui University, Hefei 230601, P. R. China.
authors.forename: Yupeng
authors.initials: Y
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Crystal Materials, Shandong University, Jinan 502100, P. R. China.
authors.forename: Xutang
authors.initials: X
authors.lastname: Tao
authors.affiliation: College of Chemistry &Chemical Engineering, Key Laboratory of Functional Inorganic Materials of Anhui Province, Anhui University, Hefei 230601, P. R. China.|State Key Laboratory of Crystal Materials, Shandong University, Jinan 502100, P. R. China.
authors.forename: Jiaxiang
authors.initials: J
authors.lastname: Yang