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An electron spin resonance study of poly(α‐ethynylnaphthalene) polymerized with [Rh(norbornadiene)Cl] 2 and WCl 6 as catalysts
Author(s) -
Tabata Masayoshi,
Yokota Kazuaki,
Namioka Makoto
Publication year - 1995
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1995.021960920
Subject(s) - norbornadiene , polymerization , electron paramagnetic resonance , catalysis , polymer chemistry , chemistry , resonance (particle physics) , materials science , photochemistry , nuclear magnetic resonance , polymer , organic chemistry , physics , atomic physics
Poly(α‐ethynylnaphthalene)s (PENAPs) obtained with the Rh complex [Rh(norbornadiene)Cl] 2 as a stereoregular polymerization catalyst of monosubstituted acetylene monomers and WCl 6 were studied by using the electron spin resonance (ESR) method to inspect the geometrical structure with respect to the CC bond in the main chain where π‐radicals called solitons may be stabilized in the conjugated polymer chain. In PENAP obtained as the immobile unpaired electrons were found to be stabilized in the polymer chain, indicating a short and restricted conjugated chain, i. e., formation of a cis‐transoid polymer. In PENAP obtained with WCl 6 as catalyst more mobile unpaired electrons were found to be stabilized in the conjugated polymer chain not only at room temperature but also at lower temperature, indicating the presence of a π‐conjugated main chain, i. e. of a trans‐transoid polymer. Moreover it was found, interstingly, that the clearly resolved ESR spectrum with the hyperfine structure (solitin) could be observed at higher temperature, i. e., ca. 300°C.