Premium
An Internal Fluorescent Probe Based on Anthracene to Evaluate Cation–Anion Interactions in Imidazolium Salts
Author(s) -
Fei Zhaofu,
Zhu DunRu,
Yang Xue,
Meng Lingjie,
Lu Qinghua,
Ang Wee Han,
Scopelliti Rosario,
Hartinger Christian G.,
Dyson Paul J.
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201000253
Subject(s) - anthracene , chemistry , fluorescence , dimer , acetonitrile , hydrogen bond , salt (chemistry) , ion , stacking , crystallography , ring (chemistry) , photochemistry , molecule , inorganic chemistry , organic chemistry , physics , quantum mechanics
A series of fluorescent imidazolium‐based salts containing the cation [AnCH 2 MeIm] + (in which An=anthracene and Im=the imidazolium cation) with Cl − , BF 4 − , PF 6 − , SO 3 CF 3 − , [N(CN) 2 ] − , [N(SO 2 CF 3 ) 2 ] − , or PhBF 3 − anions have been prepared and characterized. X‐ray diffraction analysis of four of the salts reveals a number of CH⋅⋅⋅X‐type (X=O, N, F) hydrogen bonds between the hydrogen atoms from the imidazolium ring and in some cases from the anthracene ring with the electronegative atoms of the anions. Additionally, CH⋅⋅⋅π interactions can be found in all the salts analyzed by X‐ray diffraction, whereas π–π stacking is observed only in the salt containing the phenyltrifluoroborate anion. Fluorescence emission analysis in acetonitrile shows that the fluorescence of these salts varies significantly according to the nature of the anion, and correlates to the extent of ion pairing present in solution. Photodimerization of these salts was observed, and in one case a dimer has been isolated and characterized by X‐ray crystallography.