Photophysical investigation of similarities between starburst dendrimers and anionic micelles

Gopidas, Karical R.; Leheny, A. R.; Caminati, Gabriella; Turro, Nicholas J.; Tomalia, Donald A.

doi:10.1021/ja00019a034

Cited by 169 publications

(127 citation statements)

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“…The main experimental data about the geometric character of particular sites has come from NMR relaxation times for molecules able to partially penetrate the dendrimer [12].…”

Section: Introductionmentioning

confidence: 99%

Molecular modelling of dendrimers for nanoscale applications

et al. 2000

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Abstract. Dendrimers are well defined, highly branched macromolecules that radiate from a central core and are synthesized through a stepwise, repetitive reaction sequence that guarantees complete shells for each generation, leading to polymers that are monodisperse. The synthetic procedures developed for dendrimer preparation permit nearly complete control over the critical molecular design parameters, such as size, shape, surface/interior chemistry, flexibility, and topology. Recent results suggest that dendritic polymers may provide the key to developing a reliable and economical fabrication and manufacturing route to functional nanoscale materials that would have unique properties (electronic, optical, opto-electronic, magnetic, chemical, or biological). In turn, these could be used in designing new nanoscale devices. In this paper, we determine the 3D molecular structure of various dendrimers with continuous configurational Boltzmann biased direct Monte Carlo method and study their energetic and structural properties using molecular dynamics after annealing these molecular representations.

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“…The main experimental data about the geometric character of particular sites has come from NMR relaxation times for molecules able to partially penetrate the dendrimer [12].…”

Section: Introductionmentioning

confidence: 99%

Molecular modelling of dendrimers for nanoscale applications

et al. 2000

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“…erties of 1, studied using single-photon timing SPT and femtosecond transient absorption, were reported 1 . The hydrodynamic volume calculated 1 The values of the quantum yield in this Letter were 0.65 for 1 and 0.82 for 2, but they were remeasured using rhodamine 101 as Ž w x. a reference and these values should be corrected see Ref. from anisotropy decay measurements led to a value of 4 nm as a rigid rotor diameter for 1.…”

Section: Introductionmentioning

confidence: 99%

Intramolecular evolution from a locally excited state to an excimer-like state in a multichromophoric dendrimer evidenced by a femtosecond fluorescence upconversion study

Karni

Jordens

Belder

et al. 1999

Chemical Physics Letters

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Intramolecular evolution from a locally excited state to an excimer-like state in a multichromophoric dendrimer evidenced by a femtosecond fluorescence upconversion study Karni, Y.; Jordens, S.; Belder, G. De; Schweitzer, G.; Hofkens, J.; Gensch, T.; Maus, M.; Schryver, F.C. De; Herrmann, Andreas; Müllen, K.Published in: Chemical Physics Letters IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document VersionPublisher's PDF, also known as Version of record Publication date: 1999Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Karni, Y., Jordens, S., Belder, G. D., Schweitzer, G., Hofkens, J., Gensch, T., ... Müllen, K. (1999). Intramolecular evolution from a locally excited state to an excimer-like state in a multichromophoric dendrimer evidenced by a femtosecond fluorescence upconversion study. Chemical Physics Letters, 310, 73-78. CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. AbstractA time-resolved fluorescence upconversion study on a polyphenylene dendrimer with eight peryleneimide chromophores Ž . Ž . on the surface 1 and on a monochromophoric model compound 2 is reported. The time-dependent fluorescence spectra of the dendrimer show that the initial excitation is into a locally excited chromophore. They further indicate the existence of a decay channel that leads to excited state interaction between chromophores in one dendrimer which takes place on a 5 ps timescale. q 1999 Elsevier Science B.V. All rights reserved. IntroductionDendrimers are highly branched macromolecular systems whose structure can be defined on a molecuw x lar level 1,2 and as such have been attracting a lot of attention not only from the synthetic point of view w x 3 , but also from the point of view of their physical w x and chemical properties 4-7 .Within the research group, these molecules have w x been chosen for single-molecule spectroscopy 8,9 because they allow to combine topographic and optical observation on a single-molecule level. In order to understand the dynamics of single-molecule spectroscopy, it is essential to evaluate the photophysical ) Corresponding

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“…6 Analysis of electron paramagnetic resonance (EPR) spectra of paramagnetic probes has provided insight into the characterization of water solutions of n.5-SBDs. 7,8 For example, identification and structural characterization by means of EPR of the complexes formed by Cu II with internal and external ligand groups in the n. 5-SBD structure have demonstrated that the SBDs show binding abilities with metal contraions that are very similar to biomacromolecules such as proteins.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Starburst Dendrimers by EPR. 3. Aggregational Processes of a Positively Charged Nitroxide Surfactant

et al. 1996

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The aggregation characteristics of aqueous solutions of a positively charged nitroxide surfactant (CAT16) in the presence and absence of half-generation polyamidoamine starburst dendrimers (n.5-SBDs) have been investigated by electron paramagnetic resonance (EPR). Computer simulation of the EPR spectra allowed the convenient extraction of several parameters that were related to the supramolecular structure of the aggregates formed by CAT16 and SBDs. From examination of the EPR spectra as a function of variation of the concentration of CAT16, the concentration of SBDs, and the ionic strength and application of the EPR parameters available from simulation of the spectra, a paradigm for the structure and dynamics of the aggregates formed by CAT16 in the presence and absence of SBDs under various conditions is deduced. A study of the fluorescence quenching of pyrene in the presence of CAT16 is compared to a previous investigation of the interaction of SBDs with cationic surfactants. It is concluded that at low SBD concentration, for earlier generation SBDs (G < 3.5), whose size is smaller than or comparable to the size of the CAT16 micellar aggregates, the SBDs act as "guests" that bind to the micelles that serve as "hosts". In contrast, at low SBD concentration of the later generation SBD (G > 3.5), the size of the SBD is now larger than that of the micelles so that the latter can serve as "guests" for the former. A bilayer aggregate of the surfactant on the SBD is proposed. Finally, at high concentration of the later generation SBD, it is proposed that because of the large number of sites compared to the number of surfactants, an aggregate in which two or more SBDs are bridged by bilayers is formed by the surfactant and coexists with CAT16 micelles.

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Photophysical investigation of similarities between starburst dendrimers and anionic micelles

Cited by 169 publications

References 2 publications

Molecular modelling of dendrimers for nanoscale applications

Molecular modelling of dendrimers for nanoscale applications

Intramolecular evolution from a locally excited state to an excimer-like state in a multichromophoric dendrimer evidenced by a femtosecond fluorescence upconversion study

Characterization of Starburst Dendrimers by EPR. 3. Aggregational Processes of a Positively Charged Nitroxide Surfactant

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