No abstract

Five kinds of polythiophenes bearing a crown ethereal subunit directly bonded to the thiophene ring have been prepared by the following organometallic polycondensation:,5-diyl with the crown ethereal subunit. Polythiophenes with alkoxy substituents (OCH3 and O(CH2)2OCH3) are also prepared by the organometallic polycondensation. The crown ethereal polymers exhibit photoluminescence in a range of 467-603 nm in both CHCl3 solutions and films. Their electroluminescence spectra essentially agree with the photoluminescence spectra. The crown ethereal polythiophenes have a high affinity toward Na + . After chemical oxidation (or p-doping) and reduction (or n-doping), the polymers show an electrical conductivity of 5.4 × 10 -7 to 1.8 S cm -1 . The Na-doped and electrically conducting state of crown ethereal polythiophenes shows some stability under air, which is attributed to the strong affinity of the polymer to Na + . Cyclic voltammetry of the crown and linear ethereal polythiophenes reveals a large difference (about 2 V) between n-doping and n-undoping potentials.

Optically pure (−)-(4-bromophenyl)ethynylmethyl(1-naphthyl)silane [( − )-1], (−)-1,2-diethynyl-1,2-dimethyl-1,2-di(1-naphthyl)disilane [( − )-2], and (+)-1,2-diethynyl-1,2-dimethyl-1,2-diphenyldisilane [(+)-3] were separated by a chromatographic technique on an optically active stationary phase. Polymerization via Heck reaction or dimerization of bis(ethynyl) groups of these compounds gave optically active polymers. The structures of the polymers were characterized by 1H, 13C, and 29Si NMR spectroscopies. Poly(1) and poly(2) have regular chemical structure. In poly(3), (E)-ene−yne is mixed with (E)-ene−(E)-ene and yne−yne structures. All the polymers are considered stereoregular concerning the configuration of the silicon atoms. The optical properties in solution were measured. Although the electronic absorption and fluorescence spectra of optically active polymers did not change compared with those of racemic polymers, the circular dichroism spectra showed a negative Cotton effect.