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Guest-host interactions between dichroic dyes and anisotropic hosts.

Palsson, L.O.; Vaughan, H.L.; Smith, A.; Szablewski, M.; Cross, G.H.; Roberts, T.; Masutani, A.; Yasuda, A.; Beeby, A.; Bloor, D.


H.L. Vaughan

A. Smith

G.H. Cross

T. Roberts

A. Masutani

A. Yasuda

D. Bloor


The guest–host interaction between dichroic dyes and anistropic hosts has been investigated by means of optical spectroscopy. Two different TCNQ adducts; 2-{4-[(2,6-dimethylmorpholin-4-yl)(4-metylpiperidin-1-yl)methylene]cyclohexa-2,5-dien-1-ylidene} malononitrile (MORPIP) and 2-{4-[cyclohex-1-yltetrahydropyrimidin-2(1H-ylidene]cyclohexa-2,5-dien-1-ylidine} malononitrile (AMINO) have been examined dispersed in a range of nematic liquid crystal mixtures. The result is a substantial impact on the absorption and luminescence when compared to the situation in isotropic solvents. The excited state decay exhibits a complex behaviour showing a multi-exponential decay of the time-resolved luminescence. The photoluminescence quantum yields of the chromophores, also shows strong host dependence. For AMINO, we observe a trend which is indicative of a viscosity dependence. The observations are discussed in view of different solvent–solute interactions between guest and host.

Journal Article Type Article
Publication Date 2006-03
Journal Journal of Luminescence
Print ISSN 0022-2313
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 117
Issue 1
Pages 113-122
Keywords Absorption, Anistropic host, Dichroic dyes, Guest–host interactions, Hydrogen bonds, Isomerisation, Isotropic solvent, Liquid crystals, Luminescence.
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