Syntheses of helical polymers through the combination of axially dissymmetric segments

Wholly aromatic polymers with various helical structures were prepared through the combination of two axially dissymmetric bifunctional compounds. The palladium-catalyzed condensation of (R)-2,2-diethoxy-6,6'-dibromo-1,1'-binaphthyl with (R)-1,1'-binaphthyl-2,2'-diamine and the reaction of (S)-2,2-diethoxy-6,6'-dibromo-1,1'-binaphthyl with (S)-1,1'-binaphthyl-2,2'-diamine produced helical polyamines, and the chiral conformation was confirmed by their circular dichroism. spectra and large specific rotations. The combination of (R)-2,2-diethoxy-6,6'-dibromo-1,1'-binaphthyl and (S)-1,1'-binaphthyl-2,2'-diamine afforded polyamines with a zigzag conformation. The condensation of (R)-2,2'-dimethylbiphenyl-6,6'-dicarbonyl chloride with (R)-2,2'-diamino-6,6'-dimethylbiphenyl and the reaction of (S)-2,2'-dimethylbiphenyl-6,6'-dicarbonyl chloride with (S)-2,2'-diamino-6,6'-dimethylbiphenyl predominantly yielded cyclic dimers and tetramers because of the steric proximity of the reactive groups of the propagating species. The experimental results indicated that the structures of the obtained polymers depended on the combination of the chirality of the bifunctional atropisomeric compounds and the position of the functional groups on the aromatic rings. (C) 2004 Wiley Periodicals, Inc.