Cyclization dynamics of polymers, 5. The effects of solvent on end‐to‐end cyclization of poly(ethylene oxide) probed by intramolecular pyrene excimer formation

Cheung, Seung‐Tong; Winnik, Mitchell A.; Redpath, A.E.C.

doi:10.1002/macp.1982.021830720

Cited by 54 publications

(74 citation statements)

References 18 publications

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“…In this ancies that exist between results reported by different laboratbries. Gross features of the theory have been confirmed in all experiments (2)(3)(4)(5)(6)(7)(8). Thus where sufficient data exist, one can quite reasonably draw straight lines through plots of log kc, vs. log N. The slopes frequently differ (although they fall in the range -1 to -1.8) and the magnitudes of kc, sometimes differ for the same polymer-solvent -chain length combination by more than one might anticipate from the precision of the indiway we could produce-a polymer of the form h O H , and a variety of chromophores could be attached to the other end via the hydroxy group.…”

Section: Design and Synthesissupporting

confidence: 64%

An exciplex probe for end-to-end cyclization of polystyrene. Cyclization dynamics of polymers. 15

Winnik¹,

Sinclair²,

Beinert³

1985

Can. J. Chem.

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An asymmetrically end-labelled polystyrene of low polydispersity has been synthesized. The labels are pyrene and dimethylaniline, which can form an emissive exciplex from excited pyrene. End-to-end cyclization rate constants (kl) have been calculated from fluorescence decay data in a variety of solvents. Steady-state measurements are also presented. Correction of the (k,)'s for differences in solvent viscosity yields cyclization rate constants of 0.7 X lo6 S -' in good solvents and about twice this in poor (sub-0) solvents. Cyclization rate constants (kl) in toluene and cyclohexane at 22OC obtained using this pyrene/dimethylaniline exciplex probe are compared with those obtained previously using a pyrenelpyrene excimer probe. [Traduit par le journal]

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Section: Design and Synthesissupporting

confidence: 64%

An exciplex probe for end-to-end cyclization of polystyrene. Cyclization dynamics of polymers. 15

Winnik¹,

Sinclair²,

Beinert³

1985

Can. J. Chem.

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“…20 The relation between the time constant of excimer emission buildup (τ 1 ) and solvent viscosity is shown in Figure 9. For both model and dendrimers, the increased solvent viscosity resulted in lower values of 1/τ 1 , i.e., in lower values of k 1 + k 2 + k 3 .…”

Section: Resultsmentioning

confidence: 99%

Segmental Mobility in Phosphorus-Containing Dendrimers. Studies by Fluorescent Spectroscopy

et al. 2001

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Steady-state fluorescence spectra and decays of excitations of a phosphorus-containing dendrimer labeled with 12 internal labels and of an iminophosphorane model compound bearing two labels dissolved in acetonitrile, diglyme, 1,4-dioxane, triethylene glycol, and cyclohexanol revealed that the interior of dendrimers contained many solvent molecules, and movements of internally located pyrene labels were not reduced by interactions with the dendrimer core. This conclusion was based on the following findings. A ratio of the intensities of pyrene-pyrene excimer and pyrene monomer emissions (IE/IM) decreased with increasing solvent viscosity but, with exception of acetonitrile solutions, was very close for the dendrimers and for the model. Monomer and excimer emission intensity decays were fitted with two-exponential functions with time constants τ1 and τ2 characterizing formation of pyrene-pyrene excimers and recovery of pyrene moieties in their ground state, respectively. For solvent viscosities varying from 3.44 × 10 -3 P (acetonitrile) to 4.78 × 10 -1 P (triethylene glycol), τ1 increased from 7.1 to 37.7 ns and from 6.2 to 34.9 ns for the model and for the dendrimer. In acetonitrile the rates of the pyrene-pyrene excimer formation were almost the same for the labels in solution and bound covalently in the interior of the dendrimer core. For more viscous solvents the extensive reduction of pyrene label mobility has been noticed for both the model and labeled dendrimer.

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“…10 In dilute solutions the intramolecular excimer formation between an excited-state pyrene and a ground-state pyrene is mainly through a diffusioncontrolled cyclization process. 15 Since the pyrene molecule is covalently attached to the polymer chain, the distance 0024-9297/91 / 2224-5775$02.50/0 © 1991 American Chemical Society Interactions between 8% hydrolyzed polyacrylamide Figure 3. Interactions between 37.2% hydrolyzed polyacrylaand polyethylene oxide) (PEO) or poly(vinylpyrrolidone) (PVP).…”

Section: Resultsmentioning

confidence: 99%

Effect of the degree of hydrolysis of polyacrylamide on its interactions with poly(ethylene oxide) and poly(vinylpyrrolidone)

Maltesh¹,

Somasundaran²,

Pradip³

et al. 1991

Macromolecules

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Intermolecular interactions between polyacrylamides hydrolyzed to varying degrees and polyvinylpyrrolidone) or polyethylene oxide) are investigated by using fluorescence spectroscopy. At low degrees of hydrolysis, interactions between hydrolyzed polyacrylamide and poly(vinylpyrrolidone) are weak, but at higher degrees of hydrolysis, the interactions are strong and similar to that in the presence of poly(acrylic acid). At higher degrees of hydrolysis and low pH values, interpolymer complexation between the carboxylic acid group of the hydrolyzed polyacrylamide and the poly(vinylpyrrolidone) is predominant over intramolecular complexation between the acid and the amide groups. There are no interactions between hydrolyzed polyacrylamide and polyethylene oxide) over the entire range of hydrolysis studied.

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Cyclization dynamics of polymers, 5. The effects of solvent on end‐to‐end cyclization of poly(ethylene oxide) probed by intramolecular pyrene excimer formation

Cited by 54 publications

References 18 publications

An exciplex probe for end-to-end cyclization of polystyrene. Cyclization dynamics of polymers. 15

An exciplex probe for end-to-end cyclization of polystyrene. Cyclization dynamics of polymers. 15

Segmental Mobility in Phosphorus-Containing Dendrimers. Studies by Fluorescent Spectroscopy

Effect of the degree of hydrolysis of polyacrylamide on its interactions with poly(ethylene oxide) and poly(vinylpyrrolidone)

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