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Enantioselective alternating copolymerization of carbon monoxide with 1 heptene was carried out using palladium catalyst modified by 1,4 3,6 dianhydro 2,5 dideoxy 2,5 bis(diphenylphosphino) L iditol (DDPPI). The chiral diphosphine was proved to be effective at enantioselective copolymerization. The pure poly(1,4 ketone) was obtained by dissolving the copolymer containing spiroketal and 1,4 ketone units in 1,1,1,3,3,3 hexafluoro 2 propanol and reprecipitating with methanol. Optical rotation, elemental analysis, spectra of 1H|NMR, 13 C NMR and IR showed that our copolymer was optically active, isotatic, alternating poly(1,4 ketone) structure. The copolymerization was carried out at 45℃ for 48?h. Molecular weight: M n=4 02×10 3, M w/ M n=1 55 (GPC measurements with polystyrene standards). Optical rotation:[ α ] 20 589 =+63° (CH 2Cl 2, 5 0?mg/mL). T m=194℃, T g=11℃.
Enantioselective alternating copolymerization of carbon monoxide with 1 heptene was carried out using palladium catalyst modified by 1,4 3,6 dianhydro 2,5 dideoxy 2,5 bis (diphenylphosphino) L iditol (DDPPI). The chiral diphosphine was proved to be effective at enantioselective copolymerization. The pure poly (1,4 ketone) was obtained by dissolving the copolymer containing spiroketal and 1,4 ketone units in 1,1,1,3,3,3 hexafluoro 2 propanol and reprecipitating with methanol. Optical rotation, elemental analysis, spectra of 1H | NMR, 13 C NMR and IR showed that our copolymer was optically active, isotatic, alternating poly (1,4 ketone) structure. : M n = 4 02 × 10 3 M w / M n = 1 55 (GPC measurements with polystyrene standards). Optical rotation: [α] 20 589 = + 63 ° (CH 2 Cl 2, 50 mg / mL) T m = 194 ° C, T g = 11 ° C.