Polynaphthylene : Development and Function of Precisely Nano-Structure Controlled Polymer

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The asymmetric oxidative coupling polymerization (AOCP) leading to polybinaphthols in a highly cross-coupling selective or stereocontrolled manner was attained. The reaction of 2-naphthol and 3-hydroxy-2-naphthoate derivatives with the CuCl-(S)-2,2'-isopropylidenebis(4-phenyl-2-oxazoline) [(S)Phbox] catalyst proceeded in a highly cross-coupling selective manner with a moderate enantioselectivity. The AOCP of methyl 6,6'-dihydroxy-2,2'-binaphthalene-7-carboxylate with the CuCl-(S)Phbox catalyst gave a polymer with a high cross-coupling selectivity (head-to-tail regioselectivity). The copolymerization of 6,6'-dihydroxy-2,2'-binaphthalene and dihexyl 6,6'-dihydroxy-2,2'-binaphthalene-7,7'-dicarboxylate also afforded a polymer with the high cross-coupling selectivity, that is, a copolymer with a mainly alternating structure. Novel catalyst system, VOSO_4-(R)Phbox, for the AOCP of 2,3-dihydroxy-naphthalene (DHN) was developed. The enantioselectivity during the polymerization was evaluated to be 80% ee (S), a value much higher than that observed for the polymerizations with the copper(I)-based catalyst systems and the typical oxovanadium(IV) catalysts reported for the asymmetric oxidative homo-coupling producing the 1,1'-bi-2-naphthol derivatives. The OCP of DHN was also accomplished by the novel designed catalyst system, dinuclear copper(II) complexes. The polymerization proceeded under mild conditions to produce a polymer in a good yield.