A Rigid, Chiral Dendronized Polymer with a Thermally Stable, Right-Handed Helical Conformation
writer：Afang Zhang,* Francisco Rodríguez-Ropero, David Zanuy, Carlos Alemán,* E. W. Meijer, A. Dieter Schlü
keywords：helical polymer, dendronized polymer, proline
source：期刊
specific source：Chem. Eur. J. 2008, 14, 6924– 6934
Issue time：2008年
First- and second-generation dendronized polymethacrylates PG1 and PG2 carrying chiral 4-aminoproline-based dendrons were obtained on the half-gram scale in high molar masses (by spontaneous (radical) polymerization of the corresponding vinyl macromonomers. NMR spectroscopic studies on PG2 together with its unprecedented high glass transition temperature (Tg>200 8C, decomp) and structural parameters provided by atomistic MD simulations show this polymer to be rather rigid. Optical rotation and CD measurements revealed that PG2 adopts a helical conformation that remains unchanged over wide ranges of temperature and solvent polarity. It is also retained when the polymer is deprotected (and thus positively charged, de-PG2) at its terminal amino groups, by which the mass and steric demand of the dendrons is reduced by roughly 50%. Molecular dynamics simulations on models of PG2 reveal its helical conformation to be right-handed, irrespective of backbone tacticity, and initial results also indicate that de-PG2 retains the right-handedness.