Reversible Heterochiral Aggregation/Dissociation of Bis(2-hydroxyphenyl)diamides Driven by UV/Vis Irradiation


  • This work was financially supported by a Grant-in-Aid for Scientific Research on Innovative Areas (NK) from MEXT. A.N. thanks the JSPS for a predoctral fellowship. Akinobu Matsuzawa is gratefully acknowledged for X-ray crystallographic analysis of the heterochiral aggregate of 3 b.


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Light to dissolve: (R)- and (S)-diamides bearing a hydrogen-bonding framework (red in picture) and a trans-azobenzene unit (blue) form an insoluble heterochiral aggregate, which can be dissolved by photoisomerization of the azobenzene unit to the cis conformation by UV irradiation (365 nm). The insoluble aggregate was formed again by subsequent irradiation with visible light (>422 nm). The precipitation and dissolution is manifestly reversible.