Thiophene-fused dinaphtho[8,1,2-opq:2′,1′,8′-uva]pentaphenes (DNPPs) were synthesized and characterized by using our previously reported strategy. The Suzuki-Miyaura coupling of the boronic acid ester of pyrene with dibromothiophenes, 2,3-dibromo- and 3,4-dibromothiophenes, afforded the corresponding bis(pyren-2-yl)thiophenes. The subsequent oxidation reaction afforded the desired π-expanded molecules. Reflecting the DNPP moieties, the obtained molecules show properties characteristic of π-expanded molecules, such as amphoteric multiredox behaviors and light absorption in the visible region. The oxidized product of 3,4-bis(pyren-2-yl)thiophene, which contains an ortho-quinoidal structure, i. e., benzo[c]thiophene, was isolated and spectroscopically characterized. Because these molecules possess the helicene structure, optical resolution of enantiomers has been carried out using high-performance liquid chromatography.
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