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Multi-substituted pentacenes, such as 1,2,3,4,6,8,9,10,11,13-decasubstituted pentacenes (Type I), 1,2,3,4,6,13-hexasubstituted pentacenes (Type II), 1,2,3,4-tetrasubstituted pentacenes (Type III), and 2,3-disubstitutedpentacenes (Type IV), 1,2,3,4,6,11-hexasubstituted naphthacenes (Type V), 1,2,3,4-tetrasubstitutednaphthacenes (Type VI), and 2,3-disubstituted naphthacenes (Type VII), were prepared by a homologationmethod. The homologation method involved the conversion of phthalic acid ester derivatives to two ringextended phthalic acid ester derivatives via diynes and metallacyclopentadienes using transition metals,such as Zr and Rh. For the formation of pentacenes of Type III and Type IV and naphthacenes of TypeVII, trimethylsilyl-substituted diynes were used for zirconocene-mediated cyclization. Elimination of thetrimethylsilyl groups after the cyclization afforded nonsubstituted position on pentacenes or naphthacenes.Structures of 1,4,6,8,9,10,11,13-octaethyl-2,3-bis(methoxycarbonyl)pentacene (
9a) and 8,9,10,11-tetraethyl-2,3-bis(methoxycarbonyl)-1,4,6,13-tetrapropylpentacene (
9b) were determined by X-ray analysis. Thestructure of
9a had the herringbone packing system in the crystal like nonsubstituted pentacene. However,
9b, whose substituents at 1,4,6,13-positions were changed from Et to Pr at 1,4,6,13-positions of
9a, hadthe face parallel plane system in the crystal.
