Synthesis, Structural Analysis, and Visualization of a Library of Dendronized Polyphenylacetylenes

A library of eleven high cis‐content cis‐transoidal polyphenylacetylenes (PPAs) dendronized with self‐assembling dendrons was prepared from a library of fifteen convergently synthesized macromonomers. Using [Rh(CCPh)(nbd)(PPh3)2] (nbd=2,5‐norbornadiene) in the presence of 10 equiv of N,N‐dimethylaminopyridine, predictive control over molecular weight and narrow molecular weight distribution are obtained. The PPA backbone serves as a helical scaffold for the self‐assembling dendrons. The dendron primary structure dictates the diameter of the cylindrical PPAs in bulk, both in the self‐organized hexagonal columnar (${{\Phi}{{\hfill \atop {\rm h}\hfill}}}$) lattice determined by X‐ray diffraction (XRD) and in monolayers on highly ordered pyrolytic graphite (HOPG) and mica visualized by atomic force microscopy (AFM). Thermal and bulk phase characteristics of the cylindrical PPAs reinforces the generality that flexible polymer backbones adopt a helical conformation within the cylindrical macromolecules generated by polymers jacketed with self‐assembling dendrons. Dendronized helices: A library of dendronized polyphenylacetylenes (PPAs) has been prepared through living polymerization and structurally characterized in solution and bulk (see scheme). Retrostructural analysis of the library defines design principles for generating well‐ordered hexagonal columnar lattices of dendronized helical PPAs in bulk.