A rigid, chiral, dendronized polymer with a thermally stable, right-handed helical conformation

First- and second-generation dendronized polymethacrylates PG1 and PG2 carrying chiral 4-aminopro-line-based dendrons were obtained on the half-gram scale in high molar masses (PG1: Mn = 5 +— 106 g mol_1, PG2: Mn = 1 +— 106 gmol -1) by spontaneous (radical) polymerization of the corresponding vinyl macromonomers. NMR spectroscopic studies on PG2 together with its unprecedented high glass transition temperature (Tg> 200-ÝC, 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, dePG2) 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-VG2 retains the right-handedness. -© 2008 Wiley-VCH Verlag GmbH & Cu. KGaA