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 triple bond CPh)(nbd)(PPh(3))(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(h)) 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.
Percec
Virgil
V
Roy & Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA. percec@sas.upenn.edu
Rudick
Jonathan G
JG
Peterca
Mihai
M
Staley
Sasha R
SR
Wagner
Martin
M
Obata
Makoto
M
Mitchell
Catherine M
CM
Cho
Wook-Dong
WD
Balagurusamy
Venkatachalapathy S K
VS
Lowe
James N
JN
Glodde
Martin
M
Weichold
Oliver
O
Chung
Kyung J
KJ
Ghionni
Nicholas
N
Magonov
Sergei N
SN
Heiney
Paul A
PA