Synthesis, structural, and retrostructural analysis of helical dendronized poly(1-naphthylacetylene)s

Structural and retrostructural analysis of chiral, nonracemic (poly [(3,4,5)dm8G1-1EN]), and achiral (poly[(3,4,5)l2G1-1EN]) poly(l-naphthylacetylene)s demonstrates new design principles for helical dendronized polyarylacetylenes. The oblate cylindrical dendronized polymers self-organize in a c2mm centered rectangular columnar (Phi(r-c)) lattice. An all cis-polyene backbone microstructure with very high cisoid character is introduced to rationalize features from small- and wide-angle X-ray diffraction experiments. More compact helical conformations are ideal for efficient communication or amplification of chirality over long distances. Peripheral chiral tails select a preferred helical screw sense of the polyene backbone. In solution, the preferred helical conformation persists over a wide temperature range. In bulk, the naphthyl moiety facilitates a longer correlation length for helical order compared to an analogous minidendritic poly(phenylacetylene). These attributes suggest that the naphthyl moiety may be better suited for expressing helical chirality in monolayer domains. (c) 2007 Wiley Periodicals, Inc.