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Quantitative Characterization of the Molecular Dimensions of Flexible Dendritic Macromolecules by Pyrene Excimer Fluorescence

dc.contributor.authorMcNelles, Stuart A.
dc.contributor.authorThoma, Janine L.
dc.contributor.authorAdronov, Alex
dc.contributor.authorDuhamel, Jean
dc.date.accessioned2021-01-15T15:01:02Z
dc.date.available2021-01-15T15:01:02Z
dc.date.issued2018-02-12
dc.descriptionThis document is the Accepted Manuscript version of a Published Work that appeared in final form in Macromolecules, copyright © American Chemical Society after peer review and technical editing by publisher. To access the final edited and published work see https://doi.org/10.1021/acs.macromol.8b00008.en
dc.description.abstractEight pyrene labeled dendrons (PyLDs) were prepared with a polyester backbone of bis(hydroxymethyl)propionic acid and the monomer and excimer fluorescence decays of the PyLDs were acquired and fitted according to the recently introduced model free analysis (MFA). The average rate constant of pyrene excimer formation <k> retrieved from the MFA of the decays was found to scale as (2N1)×l3/<LPy2>1.5 where N represents the number of ground-state pyrene labels in a dendrimer where one of the pyrene is already excited, l is the average bond length, and <LPy2> is the average squared end-to-end distance between every two pyrene labels. The remarkable agreement found between these two quantities, namely <k> and (2N1)×l3/<LPy2>1.5 which were determined experimentally and mathematically, respectively, provides strong support to the notion that pyrene excimer fluorescence (PEF) responds to <LPy2> for pyrene labels attached to macromolecular constructs. In turn, <LPy2>0.5 can be used as a measure of the dimension of the macromolecular object onto which the pyrene labels are covalently attached. Since (2N1)/<LPy2>1.5 is the local concentration of ground-state pyrenes in the PyLD, the ratio <k>/[(2N1)/<LPy2>1.5] yields the bimolecular rate constant for excimer formation kdiff which was found to equal 5.0 (±0.6)×109 s for the PyLDs. Consequently, this study demonstrates that PEF applied to macromolecules yields a quantitative measure of their dimension and internal dynamics and since the rate constant of excimer formation is not distance-dependent, provides a much simpler mathematical alternative to experiments based on fluorescence resonance energy transfer (FRET).en
dc.description.sponsorshipNatural Sciences and Engineering Research Council of Canadaen
dc.identifier.urihttps://doi.org/10.1021/acs.macromol.8b00008
dc.identifier.urihttp://hdl.handle.net/10012/16668
dc.language.isoenen
dc.publisherAmerican Chemical Societyen
dc.relation.ispartofseriesMacromolecules;
dc.subjectpyrene, dendrimer, fluorescenceen
dc.titleQuantitative Characterization of the Molecular Dimensions of Flexible Dendritic Macromolecules by Pyrene Excimer Fluorescenceen
dc.typeArticleen
dcterms.bibliographicCitationStuart A. McNelles, Janine L. Thoma, Alex Adronov, and Jean Duhamel Macromolecules 2018 51 (4), 1586-1590 DOI: 10.1021/acs.macromol.8b00008en
uws.contributor.affiliation1Faculty of Scienceen
uws.contributor.affiliation2Chemistryen
uws.peerReviewStatusRevieweden
uws.scholarLevelFacultyen
uws.typeOfResourceTexten

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