We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Donor-Acceptor (D-A)-Substituted Polyyne Chromophores: Modulation of Their Optoelectronic Properties by Varying the Length of the Acetylene Spacer.
- Authors
Štefko, Martin; Tzirakis, Manolis D.; Breiten, Benjamin; Ebert, Marc‐Olivier; Dumele, Oliver; Schweizer, W. Bernd; Gisselbrecht, Jean‐Paul; Boudon, Corinne; Beels, Marten T.; Biaggio, Ivan; Diederich, François
- Abstract
A series of donor-acceptor-substituted alkynes, 2 a- f, was synthesized in which the length of the π-conjugated polyyne spacer between the N, N-diisopropylanilino donor and the 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) acceptor was systematically changed. The effect of this structural change on the optoelectronic properties of the molecules and, ultimately, their third-order optical nonlinearity was comprehensively investigated. The branched N, N-diisopropyl groups on the anilino donor moieties combined with the nonplanar geometry of 2 a- f imparted exceptionally high solubility to these chromophores. This important property allowed for performing INADEQUATE NMR measurements without 13C labeling, which, in turn, resulted in a complete assignment of the carbon skeleton in chromophores 2 a- f and the determination of the 13C-13C coupling constants. This body of data provided unprecedented insight into characteristic 13C chemical shift patterns in push-pull-substituted polyynes. Electrochemical and UV/Vis spectroscopic studies showed that the HOMO-LUMO energy gap decreases with increasing length of the polyyne spacer, while this effect levels off for spacers with more than four acetylene units. The third-order optical nonlinearity of this series of molecules was determined by measuring the rotational averages of the third-order polarizabilities ( γrot) by degenerate four-wave mixing (DFWM). These latter studies revealed high third-order optical nonlinearities for the new chromophores; most importantly, they provided fundamental insight into the effect of the conjugated spacer length in D-A polyynes, that can be exploited in the future design of suitable charge-transfer chromophores for applications in optoelectronic devices.
- Subjects
POLYYNES; DIOLEFINS; CHROMOPHORES; ACETYLENE; NUCLEAR magnetic resonance; COUPLING constants; ULTRAVIOLET spectroscopy; OPTOELECTRONIC devices
- Publication
Chemistry - A European Journal, 2013, Vol 19, Issue 38, p12693
- ISSN
0947-6539
- Publication type
Article
- DOI
10.1002/chem.201301642