Abstract
| - Two series of novel fully conjugated oligomers, oligothiophene-functionalized 9,9‘-spirobifluorenederivatives, have been developed in this contribution. First, four 9,9‘-spirobifluorene bromidederivatives (compounds 1a−d) are prepared through various synthetic routes. Oligothiophenederivatives with or without substituents are synthesized through the Grignard and Suzuki couplingreactions. The Negishi coupling reactions between oligothienylzinc chloride and various 9,9‘-spirobifluorene bromides with Pd(PPh3)4 as catalyst successfully produce the desired compounds,unsubstituted oligothiophene-functionalized 9,9‘-spirobifluorene derivatives, compounds 2 to 4a−d. Since the Negishi coupling reactions afford regioregularly head-to-tail (H−T) oligo(4-n-hexylthiophene)-functionalized 9,9‘-spirobifluorene derivatives in poor yields, the Suzuki couplingreactions between sodium 4-n-hexylthienyl-2-boronate 8, and various 9,9‘-spirobifluorene-basedbromides 1a−d and 9−16 are employed to produce highly regioregular head-to-tail oligothiophene-functionalized 9,9‘-spirobifluorene derivatives (compounds 5 to 7a−d) in very high yields. We alsoinvestigate the effect of solvents on the Suzuki coupling reactions. The structure and purity of allcompounds are verified by FT-IR, 1H and 13C NMR, MS, and elemental analysis.
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