Photoresponsive Organogel Based on Supramolecular Assembly of Tris(phenylisoxazolyl)benzene

Takeharu Haino; Hiroshi Saito

doi:10.1071/CH09653

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Photoresponsive Organogel Based on Supramolecular Assembly of Tris(phenylisoxazolyl)benzene

Takeharu Haino ^A ^B and Hiroshi Saito ^A

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^A Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan.

^B Corresponding author. Email: haino@sci.hiroshima-u.ac.jp

Australian Journal of Chemistry 63(4) 640-645 https://doi.org/10.1071/CH09653
Submitted: 15 December 2009 Accepted: 9 February 2010 Published: 8 April 2010

Abstract

Azobenzene-substituted tris(phenylisoxazolyl)benzene 1 was developed as a photoresponsive gelator. A detailed study of the self-assembly of the trans- and cis-isomers in solution revealed that the planar trans-isomer assembled to form molecular stacks along its C ₃ axis, whereas the cis-isomer did not owing to steric requirements. Based on diffusion ordered spectroscopy experiments, the size of the aggregates formed from the trans-isomer were roughly four times as large as those of the cis-isomer. The photoinduced gel-to-sol transition was achieved by irradiation with UV light at 360 nm. Solid-state morphologies of the trans- and cis-isomers were quite contrastive; the trans-isomer created fibrous supramolecular networks with a lot of voids in which solvent molecules could be immobilized, whereas the cis-isomer never created such fibrous morphologies. The trans–cis structural change of the azobenzene moieties obviously regulates the gelation ability of 1.

Acknowledgements

This work is supported by Grant-in-Aid for Scientific Research (no. 18350065, no. 21350066) of Japan Society for the Promotion of Science. We acknowledge financial support from Yamada Science Foundation.

References

Photoresponsive Organogel Based on Supramolecular Assembly of Tris(phenylisoxazolyl)benzene

Abstract

Acknowledgements

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