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Poly[( para ‐halogenated)phenylacetylene]s Prepared with a [Rh(norbornadiene)Cl] 2 Catalyst: Syntheses and Structure Elucidation
Author(s) -
Miyasaka Atsushi,
Sone Takeyuki,
Mawatari Yasuteru,
Setayesh Sepas,
Müllen Klaus,
Tabata Masayoshi
Publication year - 2006
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.200600308
Subject(s) - chemistry , norbornadiene , phenylacetylene , catalysis , unpaired electron , raman spectroscopy , crystallography , triethylamine , derivative (finance) , radical , photochemistry , polymer chemistry , medicinal chemistry , organic chemistry , physics , optics , financial economics , economics
Summary: pXPAs were stereospecifically polymerized using [Rh(nbd)Cl] 2 as catalyst in the presence of a mixed solvent, i.e., ethanol and triethylamine, at 20 °C. The resulting PpXPAs were characterized in detail in order to predict geometrical structures concerning cis and trans configurations in the main‐chain CC bonds using 1 H NMR, laser Raman, XRD, and ESR methods. The data showed that the PpXPAs have an extremely high content of the cis‐transoid form. Immobile unpaired electrons, ca. 1.2–3.1 × 10 17 spins · g −1 , called the cis radicals, were found to be stabilized even in the pristine cis PpXPAs. The observed g values of the pristine PpXPAs could be correlated with the spin‐orbit coupling constant ζ of the halogen atom at the para position of the phenyl.Second derivative ESR spectra of PpIPA observed (a) before and (b) after compression, and the suggested respective structures.