1435898-03-5Relevant articles and documents
Control of the helical chirality of enantiopure sulfinyl (Z)-azobenzene-based photoswitches
Nunez, Irene,Merino, Estibaliz,Lecea, Mercedes,Pieraccini, Silvia,Spada, Gian Piero,Rosini, Carlo,Mazzeo, Giuseppe,Ribagorda, Maria,Carreno, M. Carmen
, p. 3397 - 3406 (2013/07/11)
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 after photoisomerization. Highly congested E-azobenzenes 5 c 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. The chiroptical properties of this three-state enantiopure switch can be externally tuned both photochemically and/or thermally. Theoretical CD spectra calculated by using time-dependent DFT methods support the existence of two atropoisomeric E isomers and only one Z isomer with (M) helicity. Complementary to the classical azobenzene-based switches, the photoswiching event is promoted under green/blue light and do not occur under UV irradiation. Switch hitter: ortho,ortho-Disubstituted azobenzene phothoswitches were synthesized from (S)-2-(p-tolylsulfinyl)-p-benzoquinone and arylhydrazines. The sulfoxide unidirectionally controlled helical chirality in the Z isomer. The (E)-azobenzenes showed two diastereoconformers that converged upon irradiation to a Z isomer with defined helicity (M). The chiroptical properties of this switch were tuned photochemically and/or thermally (see figure). Copyright
