US EPA

7623871 

Journal Article 

Folding-Induced Through-Space Magnetic Interaction of Poly(1,3-phenyleneethynylene)-Based Polyradicals 

Kaneko, T; Abe, H; Teraguchi, M; Aoki, T; , 

2013 

1 

Macromolecules
ISSN: 0024-9297
EISSN: 1520-5835 

AMER CHEMICAL SOC 

WASHINGTON 

2583-2589 

10.1021/ma302314n 

WOS:000317438300008 

https://pubs.acs.org/doi/10.1021/ma302314n
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We synthesized poly(1,3-phenyleneethynylene)s bearing galvinoxyl moieties. The absorption ratio of the anion form in 1 M KOH methanol solution between 309 and 294 nm (A(309)/A(294)) decreased with increasing degree of polymerization. The wide-angle X-ray scattering of the powder, which was prepared by precipitation in dilute hydrochloric acid solution from the anion form in 1 M KOH methanol solution, showed a crystalline peak at 2 theta = 28 degrees. Polymers in which the chiral diethynyl-1,1'-binaphthyl moiety was inserted into the poly(1,3-phenyleneethynylene) chain were synthesized, and clear Cotton effects were observed in the absorption region of the galvinoxyl anion chromophore in the CD spectra taken in 1 M KOH-MeOH solution, indicating an excess of one-handed folded helical conformation. A relatively strong antiferromagnetic interaction was observed for the polyradicals prepared by precipitating the anionic form from alkaline methanol solution accompanied with oxidation using aqueous K3Fe(CN)(6) solution. These observations suggest that the relatively strong antiferromagnetic interaction of the polyradicals was caused by the close packing between galvinoxyl radicals induced by the formation of the folded helical structure.