Pyrene‐Excimers‐Based Antenna Systems

Cicchi, Stefano; Fabbrizzi, Pierangelo; Ghini, Giacomo; Brandi, Alberto; Foggi, Paolo; Marcelli, Agnese; Righini, Roberto; Botta, Chiara

doi:10.1002/chem.200801379

Cited by 41 publications

(62 citation statements)

References 53 publications

(16 reference statements)

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“…Fluorescence resonance energy transfer (FRET), energy hopping or migration, and electron transfer between a donor and an acceptor are all photophysical processes whose efficiency depends strongly on the distance between the donor and acceptor [135][136][137]. The design of dendrimers used for this type of applications consists in placing many donors at the dendrimer periphery and a single acceptor molecule at the dendrimer focal point [3,36,[39][40][41][42][43][44][120][121][122][123]125]. As the dendrimer generation increases, the efficiency of the photophysical process of interest decreases according to the increased distance separating the donor from the acceptor [135][136][137].…”

Section: Internal Segmental Dynamics Of Pyrene-labeled Dendrimersmentioning

confidence: 99%

“…Over the years, the synthesis of several pyrene-labeled dendrimers has been reported in the literature [36,37,44,[120][121][122][123][124][125][126][127][128][129][130][131][132][133][134], but in many instances, the pyrene-labeled constructs were synthesised as pyrene-labeled dendrons to be attached onto a focal point bearing an acceptor molecule capable of communicating with the pyrenyl pendants [36,44,[120][121][122][123]. Consequently, these investigations focused on the photophysical process taking place between the pyrene donor and the acceptor rather than on excimer formation between pyrene pendants covalently attached to the chain ends of dendrimers.…”

Section: Internal Segmental Dynamics Of Pyrene-labeled Dendrimersmentioning

confidence: 99%

“…Consequently, these investigations focused on the photophysical process taking place between the pyrene donor and the acceptor rather than on excimer formation between pyrene pendants covalently attached to the chain ends of dendrimers. In effect, pyrene excimer formation has been investigated in earnest in only seven reports [44,120,[126][127][128]130,134] and the results of these are now described.…”

Section: Internal Segmental Dynamics Of Pyrene-labeled Dendrimersmentioning

confidence: 99%

“…From a theoretical standpoint however, the continuous increase in dendrimer density with generation number leads to the prediction that a crossover generation exists where the available free volume inside the dendrimer vanishes. Considering the importance of the end groups for applications, this decrease in free volume with increasing G led numerous theoreticians and experimentalists [4,[36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54] to question what became of the end groups in higher generation dendrimers as they might be trapped in the congested dendrimer interior. The first theory dealing with this issue was proposed by de Gennes and Hervet (DGH) [22].…”

Section: Introductionmentioning

confidence: 99%

“…A computational study carried out by Lescanec and Muthukumar [23] 12 years later contradicted the DGH prediction by finding that many terminal ends of a dendrimer do not remain at the dendrimer periphery but rather fold back into the dendrimer interior. Since then, numerous theoretical [12,13, and experimental [4,[36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54] studies have been conducted which led to the current consensus [55] that the end groups of dendrimers made of a flexible backbone are distributed throughout the dendrimer interior in a core-dense manner. Only in a few rare studies were the terminal groups found to lay at the dendrimer periphery, when the ends were subject to some repulsive electrostatic forces [35,56,57] or attractive hydrogen-bond interactions [58] or the dendrimer was made of stiff repeating units [50].…”

Section: Introductionmentioning

confidence: 99%

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Internal Dynamics of Dendritic Molecules Probed by Pyrene Excimer Formation

Duhamel

2012

Polymers

147

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Abstract:This review exposes the current poor understanding of the internal segmental chain dynamics of dendrimers in solution probed by monitoring the process of excimer formation between pyrene labels covalently attached to the chain ends of dendrimers. The review begins by covering the bases of fluorescence and the kinetics of pyrene excimer formation before describing a procedure based on the Model Free (MF) analysis that is used to analyze quantitatively the fluorescence decays acquired for dendrimers, the ends of which have been fully and covalently labeled with pyrene. Comparison of the various trends obtained by different research groups describing the efficiency of pyrene excimer formation with the generation number of dendrimers illustrates the lack of consensus between the few studies devoted to the topic. One possible reason for this disagreement might reside in the presence of minute amounts of unattached pyrene labels which act as potent fluorescent impurities and affect the analysis of the fluorescence spectra and decays in an uncontrolled manner. The review points out that the MF analysis of the fluorescence decays acquired with pyrene-labeled dendrimers enables one to account for the presence of unattached pyrene and to retrieve information about the internal segmental dynamics of the dendrimer. It provides guidelines that should enable future studies on pyrene-labeled dendrimers to yield results that are more straightforward to interpret.

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Section: Internal Segmental Dynamics Of Pyrene-labeled Dendrimersmentioning

confidence: 99%

Section: Internal Segmental Dynamics Of Pyrene-labeled Dendrimersmentioning

confidence: 99%

Section: Internal Segmental Dynamics Of Pyrene-labeled Dendrimersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Internal Dynamics of Dendritic Molecules Probed by Pyrene Excimer Formation

Duhamel

2012

Polymers

147

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Click Reactions: Azide‐Alkyne Cycloaddition

Jung¹,

Bräse²

2013

Kirk-Othmer Encyclopedia of Chemical Technology

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The term “Click‐chemistry” is a general concept that describes reactions of enormous interest because of their unique characteristics for the synthetic chemistry. Many typical Click‐reactions –among them the Diels Alder reaction and 1,3‐dipolar cycloaddition reactions– have been known for a long time. The most famous amongst them is the copper‐catalyzed azide‐alkyne cycloaddition (CuAAC) which opens up outstanding opportunities in various fields of science and technology. Since the development of the CuAAC by Meldal and Sharpless it gained enormous attention not only in the field of chemistry, but also in biology and materials sciences. In parallel to the development of new applications of the CuAAC, the need for further adaption of the original Click‐procedure e.g. for bioorthogonal approaches got obvious. Nowadays, the broader scope of the CuAAC‐reaction is often paid for with the abandoning of at least one of the mandatory Click requirements and the modified procedures do not stand the general criteria any more. This review will give an overview of the current progress of the famous CuAAC‐(Click)‐reaction, including postulated mechanisms and importance of additives. It will sum up the challenges that have been mastered under critical consideration of the fulfillment of the original Click‐criteria.

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Multi‐Pyrene Assemblies Supported on Stannoxane Frameworks: Synthesis, Structure and Photophysical Studies

Kundu

Metre

Yadav

et al. 2014

Chemistry An Asian Journal

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Organostannoxanes have been used as scaffolds for the preparation of multi-chromophore assemblies. A single-step synthesis procedure allows the preparation of compounds in which the number of chromophore units can be varied from two to six. Thus, the reactions of pyrene sulfonic acid (PySO3H) or C16H9CHNC6H3(COOH)2(LH2) with various organotin precursors gave pyrene-containing organostannoxanes, that is, [Ph3 SnPySO3]6 (1), [{(Me2Sn)2(μ3-O)(μ-OH)PySO3}2{(Me2Sn)2(μ3-O)(μ-OH)H2O}2⋅2 PySO3] (2), [{tBu2Sn(OH)PySO3}2] (3), [{(nBuSn)12(O)14(OH)6{PySO3}2] (4), and [{(nBu2Sn)L}3]2⋅C6H5CH3 (5). Compounds 1-5 were characterized by using X-ray crystallography. Compounds 1 and 5 are 24-membered macrocycles. Macrocycle 1 possesses intramolecular π-π stacking interactions. An unusual co-crystal of two tetrameric ladders in 2 was observed in which one of the components of the co-crystal is neutral whereas the other is dicationic and two pyrenesulfonate counterions are present to balance the overall charge. In the solid state these compounds reveal rich supramolecular structures. Photophysical studies on 1-5 reveal that interactions in the solid state lead to considerable broadening of the emission bands.

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Pyrene‐Excimers‐Based Antenna Systems

Cited by 41 publications

References 53 publications

Internal Dynamics of Dendritic Molecules Probed by Pyrene Excimer Formation

Internal Dynamics of Dendritic Molecules Probed by Pyrene Excimer Formation

Click Reactions: Azide‐Alkyne Cycloaddition

Multi‐Pyrene Assemblies Supported on Stannoxane Frameworks: Synthesis, Structure and Photophysical Studies

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