| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 1998: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1997: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Research Abstract |
Aromatizing polymerization of 1 , 2-diisocyanobenzene derivatives was mediated by optically active organopalladium(II) complexes bearing 1,1 -binaphth-2-yl groups to give optically active poly(quinoxaline-2,3-diyl)s with varying screw-sense selectivities, which crucially depended upon the substituents on the binaphthyl groups. The most effective catalyst, which has 7 -methoxy- 1,1 binaphthyl group, induced the formation of a single screw-sense. In contrast, a catalyst with 2 methoxy-l, l -binaphthyl group only afforded polymers with less than 20% screw-sense selectivity. In the cases of parent l, l'-binaphthyl and 2'-tert-butyldimethylsiloxy-l, l -binaphthyl derivatives, the selectivities ranged from 63% ee to 84% ee Isolation and structural analyses (single-crystal X- ray diffraction and ^1H NMR spectroscopy) of intermediary [oligo(quinoxalinyl)]palladium complexes revealed that the screw-sense selection in the polymerization may be decisively governed by the diastereomeric ratios of the (terquinoxalinyl)palladium(II) complex intermediate. The [oligo(quinoxalinyl)]palladium complexes were reacted with lithium diphenyiphosphide to give the corresponding [oligo(quinoxalinyl)]diphenylphosphine in reasonable yields. The optically active, helical tertiary phosphine was found to coordinate to palladium(II) in the reaction with allylpalladium chloride dimer to give the corresponding mono(phosphine)chloro(allyl)palladium(II) complexes.
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