A series of vinyl biphenyl monomers containing chiral alkoxy terminals were synthesized and polymerized via conventional radical polymerization

atom transfer radical polymerization and anionic polymerizations.Optical polarimetry and circular dichroism spectroscopy were employed to characterize the chiroptical properties of model compounds

monomers and polymers.It was found that only the monomers with chiral alkoxy phenyl located at the ortho position of vinyl group were able to yield the polymers displaying a specific optical rotation ［α］25365 different obviously from their precursors and model compounds.These polymers also displayed cotton effects in the UVVis absorption region of biphenyl sidegroup

in a sharp contrast to the monomers

suggesting the formation of a chiral secondary structure of polymer backbone.For vinyl polymers

the most possible chiral structure was helical conformation of mainchain with an excess helix sense.Furthermore

the helical polymer containing chiral alkoxy group at metaposition

ie.P3M2St

showed an ［α］25365 value larger than that of monomer

while the helical polymer containing chiral alkoxy group at paraposition

ie.P4M2St

showed less intensive optical rotation than its monomer

indicating opposite helical sense of mainchain conformation.The reaction temperature and solvent were varied to study the effect of polymerization condition on the ［α］25365 value of polymers.It was found that the ［α］25365 value of polymers was independent on not only the polymerization condition employed but also the molecular weight of the polymer studied.The helical polymers obtained via anionic polymerization exhibited a larger difference in ［α］25365 from monomer than those resultant from radical polymerization

implying that the anionic polymerization had advantage of obtaining stereoregular structure.After removal of chiral alkoxy groups

the optically active helical polymers obtained showed optical rotations even larger than their precursor polymers although no stereogenic center was presented in the molecule

suggesting somewhat “memory effect”.