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α‐ and β‐[Bmim][BiCl 4 (2,2′‐bpy)]: Two Polymorphic Bismuth‐Containing Ionic Liquids with Crystallization‐Induced Phosphorescence
Author(s) -
Shen Nannan,
Li Jianrong,
Wu Zhaofeng,
Hu Bing,
Cheng Chuchu,
Wang Zeping,
Gong Liaokuo,
Huang Xiaoying
Publication year - 2017
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.201703552
Subject(s) - phosphorescence , ionic liquid , bismuth , luminescence , supramolecular chemistry , crystallization , chemistry , intermolecular force , crystallography , ionic bonding , chloride , inorganic chemistry , crystal structure , ion , materials science , molecule , organic chemistry , fluorescence , catalysis , physics , optoelectronics , quantum mechanics
This work reports the syntheses, structures, and luminescence properties of two supramolecular polymorphic compounds composed of a hybrid bismuth(III) chloride anion and an imidazolium cation, namely α‐ ( 1 ) and β‐ ( 2 ) [Bmim][BiCl 4 (2,2′‐bpy)] (Bmim=1‐butyl‐3‐methyl imidazolium; 2,2′‐bpy=2,2′‐bipyridine). They are the first two examples of Bi 3+ ‐containing ionic liquids (ILs). Their different packing modes may be ascribed to the rotational flexibility of the butyl group on the [Bmim] + cation. A comparative study of the weak intermolecular interactions present in the two polymorphs has been performed by Hirshfeld surface and two‐dimensional fingerprint analyses. Investigations of the luminescence properties revealed that crystallization induced greenish‐yellow phosphorescence with quantum yields of 26.07 % for 1 and 36.59 % for 2 , which are among the highest hitherto reported for hybrid halobismuthate compounds. The difference in phosphorescence may be attributed to the different weak interactions in 1 and 2 , especially π–π contacts. This work opens the way to further research on new types of polymorphism‐dependent luminescent materials based on a combination of rotationally isomeric IL cations with organic decorated bismuth(III) chloride anions.