A new class of enantiopure ortho,ortho-disubstituted azobenzene photoswitches has been synthesized from (S)-2-(p-tolylsulfinyl)benzoquinone and arylhydrazines. The sulfoxide acts as a unidirectional controller of the helical chirality that arises in the Z isomer. Highly congested E-azobenzenes showed two atropisomeric diastereoconformers in the solid state that converged upon irradiation into a unique Z isomer with defined helicity (M), as evident in the X-ray structure and circular dichroism spectroscopy. Complementary to the classical azobenzenebased switches, the photoswiching event is promoted under green/blue light and does not occur under UV irradiation.
I. Nunez, E. Merino, M. Lecea, S. Pieraccini, G. P. Spada, C. Rosini, et al. (2013). CONTROL OF THE HELICAL CHIRALITY OF ENANTIOPURE SULFINYL (Z)-AZOBENZENE-BASED PHOTOSWITCHES. CHEMISTRY-A EUROPEAN JOURNAL, 19, 3397-3406 [10.1002/chem.201203243].
CONTROL OF THE HELICAL CHIRALITY OF ENANTIOPURE SULFINYL (Z)-AZOBENZENE-BASED PHOTOSWITCHES
PIERACCINI, SILVIA;SPADA, GIAN PIERO;
2013
Abstract
A new class of enantiopure ortho,ortho-disubstituted azobenzene photoswitches has been synthesized from (S)-2-(p-tolylsulfinyl)benzoquinone and arylhydrazines. The sulfoxide acts as a unidirectional controller of the helical chirality that arises in the Z isomer. Highly congested E-azobenzenes showed two atropisomeric diastereoconformers in the solid state that converged upon irradiation into a unique Z isomer with defined helicity (M), as evident in the X-ray structure and circular dichroism spectroscopy. Complementary to the classical azobenzenebased switches, the photoswiching event is promoted under green/blue light and does not occur under UV irradiation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
