Chiral and achiral charge-transfer chromophores with a dendralene-type backbone by electronically controlled Cycloaddition/Cycloreversion Cascades

Frank BB, Kivala M, Blanco BC, Breiten B, Schweizer WB, Laporta PR, Biaggio I, Jahnke E, Tykwinski R, Boudon C, Gisselbrecht JP, Diederich F (2010)

Publication Type: Journal article, Original article

Publication year: 2010

Journal

European Journal of Organic Chemistry Wiley-VCH Verlag

Original Authors: Frank B.B., Kivala M., Blanco B.C., Breiten B., Schweizer W.B., Laporta P.R., Biaggio I., Jahnke E., Tykwinski R.R., Boudon C., Gisselbrecht J.-P., Diederich F.

Publisher: Wiley-VCH Verlag

Pages Range: 2487-2503

Journal Issue: 13

DOI: 10.1002/ejoc.201000030

Abstract

Chiral and achiral push-pull chromophores have been prepared by cascades of sequential [2+2] cycloadditions of tetracyanoethene (TCNE) and tetrathiafulvalene (TTF) to different oligoynes. Thermal [2+2] cycloaddition of TCNE to donor-substituted alkynes, followed by electrocyclic ring-opening of the initially formed cyclobutenes, affords donor-substituted 1,1,4,4- tetracyanobuta-1,3-dienes (TCBDs). Similarly, TTF reacts with electron-deficient C=C bonds to give the corresponding buta-1,3-diene derivatives, 1,2-bis(1,3-dithiol2-ylidene)ethanes. Thus, achiral [AB]-type oligomers were synthesized from N,N-dialkylanilino (DAA)-substituted tetraynes and hexaynes and chiral [AB]-type oligomers from alkyne-substituted 1,1'-binaphthalenes. The [AB]-type oligomers exhibit complex conformational equilibria in solution, as revealed by H and C NMR spectroscopy. Therefore, the circular dichroism (CD) spectra of the chiral [AB]-type oligomers were measured to investigate whether a preferred conformation of the dendralene-type backbone is induced by the optically active 1,1'-binaphthalene moiety. Electrochemical studies by cyclic voltammetry (CV) and rotating-disk voltammetry (RDV) showed large cathodic shifts of the first oxidation potentials for some of the chiral and achiral [AB]-type oligomers due to sterically enforced rc-deconjugation of the acceptor and donor moieties. The new multivalent systems feature intense, bathochromicaliy shifted intramolecular charge-transfer (CT) bands in the UV/Vis spectra. Extended, donor-substituted TCBDs, which are obtained by mono-addition of TCNE to the hexaynes, exhibit low optical and electrochemical HOMO-LUMO gaps. In addition, a large thirdorder optical nonlinearity was measured for one of these TCBDs by degenerate four-wave mixing (DFWM). © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

Authors with CRIS profile

Rik Tykwinski Lehrstuhl für Organische Chemie I

Involved external institutions

Eidgenössische Technische Hochschule Zürich (ETHZ) / Swiss Federal Institute of Technology in Zurich CH Switzerland (CH) Lehigh University US United States (USA) (US) Université de Strasbourg (UDS) FR France (FR)

How to cite

APA:

Frank, B.B., Kivala, M., Blanco, B.C., Breiten, B., Schweizer, W.B., Laporta, P.R.,... Diederich, F. (2010). Chiral and achiral charge-transfer chromophores with a dendralene-type backbone by electronically controlled Cycloaddition/Cycloreversion Cascades. European Journal of Organic Chemistry, 13, 2487-2503. https://doi.org/10.1002/ejoc.201000030

MLA:

Frank, Brian B., et al. "Chiral and achiral charge-transfer chromophores with a dendralene-type backbone by electronically controlled Cycloaddition/Cycloreversion Cascades." European Journal of Organic Chemistry 13 (2010): 2487-2503.

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