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Photo‐Responsive Soft Ionic Crystals: Ion‐Pairing Assemblies of Azobenzene Carboxylates
Author(s) -
Yamakado Ryohei,
Hara Mitsuo,
Nagano Shusaku,
Seki Takahiro,
Maeda Hiromitsu
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.201701925
Subject(s) - azobenzene , pairing , liquid crystal , crystallography , ion , phase (matter) , crystal (programming language) , materials science , ionic bonding , phase transition , chemistry , diffraction , photochemistry , molecule , organic chemistry , optics , optoelectronics , physics , condensed matter physics , superconductivity , computer science , programming language
Abstract This report delineates the design and synthesis of negatively charged azobenzene derivatives that form photo‐responsive ion‐pairing assemblies. The azobenzene carboxylates possessing aliphatic chains were prepared as photo‐responsive anions that promote the formation of ion‐pairing dimension‐controlled assemblies, including mesophases, when used in conjunction with a tetrabutylammonium (TBA) cation. The photo‐responsive properties of the ion pairs and the precursory carboxylic acids in the bulk state were examined by polarized optical microscopy (POM) and X‐ray diffraction (XRD), demonstrating that liquid crystal (LC)–liquid and crystal–liquid phase transitions occurred, depending on the number and lengths of the aliphatic chains of each assembly. An ion pair exhibited photo‐induced crystal–crystal phase transitions upon switching between two irradiation wavelengths (365/436 nm).