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Cited by 385

The DOI matches its Crossref record; 31 of the 31 references it cites were found in a registry or an index.

Second Generation Light-Driven Molecular Motors. Unidirectional Rotation Controlled by a Single Stereogenic Center with Near-Perfect Photoequilibria and Acceleration of the Speed of Rotation by Structural Modification

Koumura, Nagatoshi, Geertsema, Edzard M., van Gelder, Marc B., Meetsma, Auke, Feringa, Ben L.·2002·Journal of the American Chemical Society

Abstract

Nine new molecular motors, consisting of a 2,3-dihydro-2-methylnaphtho[2,1-b]thiopyran or 2,3-dihydro-3-methylphenanthrene upper part and a (thio)xanthene, 10,10-dimethylanthracene, or dibenzocycloheptene lower part, connected by a central double bond, were synthesized. A single stereogenic center, bearing a methyl substituent, is present in each of the motors. MOPAC93-AM1 calculations, NMR studies, and X-ray analysis revealed that these compounds have stable isomers with pseudoaxial orientation of the methyl substituent and less-stable isomers with pseudoequatorial orientation of the methyl substituent. The photochemical and thermal isomerization processes of the motors were studied by NMR and CD spectroscopy. The new molecular motors all show two cis-trans isomerizations upon irradiation, each followed by a thermal helix inversion, resulting in a 360 degrees rotation around the central double bond of the upper part with respect to the lower part. The direction of rotation is controlled by a single stereogenic center created by the methyl substituent at the upper part. The speed of rotation, governed by the two thermal steps, was adjusted to a great extent by structural modifications, with half-lives for the thermal isomerization steps ranging from t(1/2)(theta) 233-0.67 h. The photochemical conversions of two new motors proceeded with near-perfect photoequilibria of 1:99.

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Metadata

Authors
Koumura, N., Geertsema, E. M., van Gelder, M. B., Meetsma, A., & Feringa, B. L.
Venue
Journal of the American Chemical Society
Published
2002-04-17
Volume
124
Issue
18
Pages
5037-5051
ISSN
  • 0002-7863 (ISSN-L)
  • 1520-5126
OpenAlex
W2005288482
Cited by
385
References
31
FWCI
12.87
Type
journal article
Language
en
Open access
closed

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