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Control of the Helical Chirality of Enantiopure Sulfinyl ( Z )‐Azobenzene‐Based Photoswitches
Author(s) -
Núñez Irene,
Merino Estíbaliz,
Lecea Mercedes,
Pieraccini Silvia,
Spada Gian Piero,
Rosini Carlo,
Mazzeo Giuseppe,
Ribagorda María,
Carreño M. Carmen
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201203243
Subject(s) - enantiopure drug , azobenzene , photoisomerization , helicity , chirality (physics) , photoswitch , chemistry , photochemistry , molecular switch , isomerization , sulfoxide , irradiation , stereochemistry , crystallography , physics , enantioselective synthesis , molecule , organic chemistry , quantum mechanics , catalysis , chiral symmetry breaking , quark , nambu–jona lasinio model
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.