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Unusual light spectroscopic properties of a 2-Pyridone-based multi-ring-fused Fluorescent Scaffold
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
2010 (English)In: Journal of Fluorescence, ISSN 1053-0509, E-ISSN 1573-4994, Vol. 20, no 6, 1249-53 p.Article in journal (Refereed) Published
Abstract [en]

UV-VIS absorption and fluorescence spectroscopic properties of six related polyaromatic 2-pyridones have been studied. Excitation of the lowest and rather weak and structure-less transition [epsilon (max) (430 nm) approximately 3,000 mol-1dm3cm-1] gives rise to a broad fluorescence band in the visible region, for these compounds. These S0 <--> S1 transitions are compatible with symmetrically forbidden transitions, promoted by intensity borrowing, as is revealed by fluorescence depolarisation data. With one exception, all compounds exhibit strong fluorescence, with quantum yields in glycerol varying between 40% and 70%. The corresponding fluorescence lifetimes range from 11 ns to 17 ns, while the radiative lifetimes are very similar ( approximately 26 ns), for all compounds. Interestingly and rarely observed, the calculated radiative lifetimes for the weak absorption band are significantly longer, i.e. between 37 and 40 ns.

Place, publisher, year, edition, pages
Springer , 2010. Vol. 20, no 6, 1249-53 p.
Keyword [en]
2-pyridone derivatives, fluorescence quantum yield, fluorescence lifetime, fluorescence spectrum, radiative lifetime, intensity borrowing
URN: urn:nbn:se:umu:diva-34290DOI: 10.1007/s10895-010-0676-3ISI: 000285363400012PubMedID: 20490634OAI: diva2:320367
Swedish Research Council, 550021103
Available from: 2010-05-25 Created: 2010-05-25 Last updated: 2011-02-18Bibliographically approved
In thesis
1. Optical characterization of potential drugs and drug delivery systems
Open this publication in new window or tab >>Optical characterization of potential drugs and drug delivery systems
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This Thesis is a characterization study on substances having potency as drugs as well as on a lipid based drug-delivery matrix. The optical properties of newly synthesized molecules with proven pilicide properties have been characterized with several spectroscopic methods. These methods include optical absorption and fluorescence as well as time-resolved fluorescence. Upon covalently linking compounds with high quantum yields of fluorescence to specific parts of the pilicide, the biological impact was found to increase for some of the derivatives. Furthermore, by expanding the aromatic part of the pilicide molecule, a significant increase in the inherent fluorescence was obtained. The S0-S1 absorption band for these molecules was found to originate from an impure electronic transition, vibronically promoted by intensity borrowing from higher electronic states.

Included in this Thesis is the measurement of how deeply some in this class of newly synthesized molecules become situated when placed inside ganglioside GM1 micelles, and how the molecules’ reorientation is affected. By means of radiation-less energy transfer, it was shown that the molecules place themselves close to the hydrophobic-hydrophilic interface inside the GM1 micelles. As a consequence they are exposed to a densely packed environment, which inhibits the free tumbling of the molecule. This restricted tumbling could be measured by means of time-resolved depolarization experiments.

The release of drug-like fluorescent molecules is investigated from a lipid mixture, which upon equilibrium with water forms a mixture of inverted hexagonal and cubic phases. The lipid matrix displayed an extended release over the course of weeks, in vitro, for molecules having a large variation in hydrophobicity.

Place, publisher, year, edition, pages
Umeå: Kemiska institutionen, Umeå universitet, 2011. 35 p.
Pilicide, Ganglioside GM1 micelles, Drug Delivery, Elecronic Energy Transfer, UV-Vis Absorption, Fluorescence Spectroscopy
National Category
Physical Chemistry
Research subject
Physical Chemistry
urn:nbn:se:umu:diva-40177 (URN)978-91-7459-157-6 (ISBN)
Public defence
2011-03-11, KBC-huset, KB3A9, Umeå Universitet, Umeå, 10:00 (English)
Available from: 2011-02-18 Created: 2011-02-16 Last updated: 2011-02-18Bibliographically approved

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Rosenbaum, ErikSellstedt, MagnusAlmqvist, FredrikJohansson, Lennart B-Å
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