Intramolecular excimer formation with 1,3-di(1-pyrenyl)propane. Decay parameters and influence of viscosity

Zachariasse, Klaas A.; Duveneck, Gert L.; Busse, Ricarda A.

doi:10.1021/ja00316a038

Cited by 155 publications

(141 citation statements)

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“…[17] The observed ratio between the excimer and monomeric fluorescence quantum yield F F EXC /F F MON was plotted in Figure 1 as a function of the viscosity of the solvent. Despite the different molecular nature, the ratio decreased sharply as the h value increased [18] and became zero at high viscosity. Encouraged by the interesting properties of the first generation dendron, the synthesis of the two subsequent generations of the donor scaffold, that is, compounds 9 and 13, was also undertaken and achieved by following the same approach, with small variations, in excellent yield (Scheme 2 and Scheme 3).…”

Section: Resultsmentioning

confidence: 96%

“…Maximum caution must be used when manipulating these compounds, especially in large-scale reactions. 2 mmol), and [18]crown-6 (10 mg) in acetone (8 mL) was heated to reflux under nitrogen for 48 h. The reaction mixture was then evaporated to dryness and partitioned between water and dichloromethane. The organic layer was dried over Na 2 SO 4 , evaporated, and the solid crystallized in methanol to give the product as white crystals (0.165 g, 90 %).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Pyrene‐Excimers‐Based Antenna Systems

Cicchi

Fabbrizzi

Ghini

et al. 2008

Chemistry A European J

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A series of dendrimeric compounds bearing pyrene units were synthesized to afford light-harvesting antennae based on the formation of intramolecular excimers. The synthetic plan profited from the efficiency of the Huisgen reaction, the 1,3-dipolar cycloaddition of azides and terminal alkynes, which allowed ready assembly of the different building blocks. The three molecular antennae obtained, of increasing generation, revealed efficient energy transfer both in solution and in the solid state.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Pyrene‐Excimers‐Based Antenna Systems

Cicchi

Fabbrizzi

Ghini

et al. 2008

Chemistry A European J

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“…Fluorescence quantum yields were measured as in ref 6 Fluorescence decays were obtained using the time-correlated single-photon counting technique as previousely described. 15,16 The excitation wavelength was 337 or 356 nm, and the emission bandwidths were 4 nm. Alternate measurements (10 3 counts at the maximum per cycle) of the pulse profile and the sample emission were done until 3 × 10 4 counts at the maximum were reached.…”

Section: Methodsmentioning

confidence: 99%

β-Carbolines. 2. Rate Constants of Proton Transfer from Multiexponential Decays in the Lowest Singlet Excited State of Harmine in Water As a Function of pH

et al. 1996

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The -carbolines present a complex problem involving multiple equilibria in the excited state in hydrogenbonding solvents including water. Three excited state species exist: neutral, cation, and zwitterion. Here we examine the multiple equilibria and excited state kinetics of harmine, using time-resolved and steady state fluorescence techniques. From an analysis of the multiexponential decays, measured at the emission wavelengths of the three species as a function of the pH, seven unknowns (four rate constants and three reciprocal lifetimes) were determined. Data analysis was made both by a previously reported numerical method and by analytical solution of the differential equation set. The results obtained accurately describe the independently obtained steady-state fluorescence results. The dramatic modifications of the equilibria and rate constants between the ground and excited states can be understood on the basis of the significative changes in charge densities on the two nitrogen atoms of harmine upon excitation. Mechanisms are proposed for the formation of excited state cation and zwitterion beginning with the excited state neutral molecule.

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“…(6) The kinetics of excimer formation between pyrene labels covalently attached to a macromolecule are described by Scheme 2 where the parameters τ M and τ E0 represent the lifetime of the pyrene monomer and excimer, respectively. Two temperature regimes have been defined for excimer formation depending on whether a Steven-Ban plot [148] of the logarithm Ln(I E /I M ) (where I E and I M are the fluorescence intensity of the pyrene excimer and monomer, respectively) increases or decreases linearly with increasing 1/T [149]. In the high temperature regime, Ln(I E /I M ) increases with increasing 1/T and k −1 is large compared to 1/τ E0 .…”

Section: Fluorescence and Pyrene Excimer Formationmentioning

confidence: 99%

“…The first study of intramolecular pyrene excimer formation was reported by Zachariasse in 1976 for a series of n-alkanes terminated at both ends with a 1-pyrenemethyl group [151]. It was followed by numerous others that provided information about the ensemble of conformations adopted by the short alkane chain as it folds to bring its two ends in close proximity to form an excimer [152][153][154][155][156][157][158][159][160]. The scope of these studies was then expanded to include the end-to-end cyclization (EEC) of polymer chains by covalently attaching a pyrenyl group at both ends of a series of poly(ethylene oxide) (Py 2 -PEO) [78].…”

Section: Analysis Of the Kinetics Of Excimer Formation For Pyrene-labmentioning

confidence: 99%

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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Intramolecular excimer formation with 1,3-di(1-pyrenyl)propane. Decay parameters and influence of viscosity

Cited by 155 publications

References 2 publications

Pyrene‐Excimers‐Based Antenna Systems

Pyrene‐Excimers‐Based Antenna Systems

β-Carbolines. 2. Rate Constants of Proton Transfer from Multiexponential Decays in the Lowest Singlet Excited State of Harmine in Water As a Function of pH

Internal Dynamics of Dendritic Molecules Probed by Pyrene Excimer Formation

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