π-Conjugated Donor-Acceptor Copolymers Constituted of π-Excessive and π-Deficient Arylene Units. Optical and Electrochemical Properties in Relation to CT Structure of the Polymer
摘要:
Various π-conjugated copolymers constituted of π-excessive thiophene, selenophene, or furan units (Ar) and π-deficient pyridine or quinoxaline (Ar') units have been prepared in high yields by the following organometallic polycondensation methods: (i) n XArAr'X + n Ni(0)Lm → (-ArAr')-n (X = halogen, Ni(0)Lm = zerovalent nickel complex), (ii) n XArX + n Me3SnAr'SnMe3 → (-ArAr')-n (palladium catalyzed), and (iii) a XArX + b XAr'X + (a + b)Ni(0)Lm → (-Ar)x(Ar')-y. Powder X-ray diffraction analysis confirms an alternative structure of a polymer prepared by the method ii. The copolymers have a molecular weight of 5.4 × 103 to 3.3 × 105 and an [η] value of 0.37 to 4.4 dL g-1. ππ* absorption bands of the copolymers generally show red shifts from those of the corresponding homopolymers, (-Ar)-n and (-Ar')-n, and the red shifts are accounted for by charge-transferred CT structures of the copolymers. For example, an alternative copolymer of thiophene and 2,3-diphenylquinoxaline gives rise to an absorp...
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DOI:
10.1021/ja961550t
被引量:
年份:
1996
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