Electron spin resonance study of radical formation in cis-poly(phenylacetylene)/ferric acetylacetonate-triethylaluminum (PPA/Fe-Al). 1. Procedure for line-shape and saturation analysis

Langner, Andreas

doi:10.1021/ma00210a013

Cited by 3 publications

(1 citation statement)

References 8 publications

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“…ESR spectra of the poly(PA-co-pNPA) copolymers were recorded and are discussed on the basis of the results already obtained in the cases of analogous monosubstituted polyacetylenes. [15][16][17][18][19]28 In particular, Langner 29 and Langner and Ehrlich 30 reported the development of a method for the interpretation of ESR spectra of conjugated polymers and the application to a cis-polyphenylacetylene obtained with Fe-Al catalyst, which induces the formation of cis-cisoid units and cyclohexadienyl radicals. The ESR spectra of pristine poly(PA-co-pNPA) copolymers are unsymmetrical and extremely anisotropic, as we have already observed in the case of the homopolymer PpNPA, 19 unlike the featureless resonance signals characteristic of most conjugated polymers.…”

Section: Esrmentioning

confidence: 99%

Copolymers of phenylacetylene and para‐nitrophenylacetylene with nonlinear optical properties: Further insight on the conformational structure

Sone

D’Amato

Mawatari

et al. 2004

J. Polym. Sci. A Polym. Chem.

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Copolymers of phenylacetylene (PA) and para‐nitrophenylacetylene (pNPA), named poly(PA‐co‐pNPA), were obtained in different PA/pNPA ratios and different reaction conditions with Rh(I) catalysts. The structure of the copolymers was investigated with IR, laser Raman, 1H NMR, electron spin resonance (ESR), and diffuse reflective ultraviolet–visible (DRUV) light spectroscopies. The pristine polymers had a cis–transoidal structure as the predominant conformation with some trans sequences. Detailed ESR studies supported by computer simulation and conformation analysis have suggested that the trans sequences were due to pNPA sequences and that the cis‐CC bond sequences of pNPA were associated with a stabilized cis radical formed by four to five of pNPA monomers. This particular stabilization was probably the reason for the higher reactivity of pNPA as compared with PA. These cis sequences were preferentially cleaved to generate π radicals. The compression and, to a minor extent, thermal treatment of poly(PA‐co‐pNPA) samples induced a cis‐to‐trans isomerization, leading to a trans–transoidal form with a planar zigzag structure and with a conjugation length up to n = 24 repeat units, determined by DRUV and Raman experiments. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2365–2376, 2004

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Section: Esrmentioning

confidence: 99%

Copolymers of phenylacetylene and para‐nitrophenylacetylene with nonlinear optical properties: Further insight on the conformational structure

Sone

D’Amato

Mawatari

et al. 2004

J. Polym. Sci. A Polym. Chem.

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Electron paramagnetic resonance and magnetic susceptibility studies of new substituted poly(acetylene) derivatives

Alexander¹,

Feast²,

Friend³

et al. 1992

J. Mater. Chem.

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A series of triphenylmethyl-substituted poly(acety1enes) has been studied by electron paramagnetic resonance (EPR) spectroscopy, and compared to poly(phenylacety1ene) (PPA) as a reference material. All the polymers were found to exhibit spin concentrations varying between 10l6 and lo1' spinsg-', and thus were only very weakly paramagnetic. The target polyradical, poly[(4-ethynylphenyI)diphenylmethyl], was shown to display a small reversible increase in spin concentration with increasing temperature between 220 and 370 K. Magnetic susceptibility measurements on this polymer confirmed an increase in the molar ratio of spins in the temperature range 200-340 K. This polymer did not display bulk ferromagnetic behaviour, and the spin concentrations observed together with the results of elemental analysis and IR spectroscopy, suggested that spin pairing may have taken place after generation of free-radical sites on the polymer, although no firm evidence for this could be obtained.

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Structural Differences between Polypentynoates Bearing Mesogenic Moieties Polymerized with RH Complex and WCl₆Catalysts. A¹³C-NMR and Raman Study

Minakawa

Tabata

Yokota

1996

Journal of Macromolecular Science, Part A

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Electron spin resonance study of radical formation in cis-poly(phenylacetylene)/ferric acetylacetonate-triethylaluminum (PPA/Fe-Al). 1. Procedure for line-shape and saturation analysis

Cited by 3 publications

References 8 publications

Copolymers of phenylacetylene and para‐nitrophenylacetylene with nonlinear optical properties: Further insight on the conformational structure

Copolymers of phenylacetylene and para‐nitrophenylacetylene with nonlinear optical properties: Further insight on the conformational structure

Electron paramagnetic resonance and magnetic susceptibility studies of new substituted poly(acetylene) derivatives

Structural Differences between Polypentynoates Bearing Mesogenic Moieties Polymerized with RH Complex and WCl₆Catalysts. A¹³C-NMR and Raman Study

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Electron spin resonance study of radical formation in cis-poly(phenylacetylene)/ferric acetylacetonate-triethylaluminum (PPA/Fe-Al). 1. Procedure for line-shape and saturation analysis

Cited by 3 publications

References 8 publications

Copolymers of phenylacetylene and para‐nitrophenylacetylene with nonlinear optical properties: Further insight on the conformational structure

Copolymers of phenylacetylene and para‐nitrophenylacetylene with nonlinear optical properties: Further insight on the conformational structure

Electron paramagnetic resonance and magnetic susceptibility studies of new substituted poly(acetylene) derivatives

Structural Differences between Polypentynoates Bearing Mesogenic Moieties Polymerized with RH Complex and WCl6Catalysts. A13C-NMR and Raman Study

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Structural Differences between Polypentynoates Bearing Mesogenic Moieties Polymerized with RH Complex and WCl₆Catalysts. A¹³C-NMR and Raman Study