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.
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.
