| 초록 |
There has been growing interest in the synthesis of optically active helical polymers. Recently, we have newly developed helix-sense-selective polymerization of achiral phenylacetylene monomers using a chiral catalyst system, i.e. polymerization using the catalyst [Rh(nbd)Cl]2 in the presence of (R)-1-phenylethylamine ((R)-PEA) or (S)-1-phenylethylamine ((S)-PEA). The obtained poly(phenylacetylene)s have rigid and one-handed helical conformation in solution, which is stabilized by intramolecular hydrogen bonds. The achiral and bulky monomer, (4-ethynylphenyl)hydrogalvinoxyl (EPHG), also polymerized to give the corresponding polymer to show its Cotton effect in the CD spectrum though the polymer has no intramolecular hydrogen bonds in the polymer. Both [Rh(cod)Cl]2 and [Rh(nbd)Cl]2 promoted helix-sense-selective polymerization of EPHG in the presence of (R)-PEA. However, the CD patterns of the polymers were mirror image of each other in spite of the same chiral condition. |
