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Optically active copolymers of pairs of three monomers, triphenyl (methyl methacrylate)and one or two pyridyl substituted methyl methacrylate homologues, were obtained by helix-sense-selective copolymerization using complexes of organolithium with chiral ligand as anionicinitiators in toluene at low temperature. The copolymers obtained with (-)-sparteine (Sp) and(S,S)-(+)-and (R, R)-(-)-2, 3-dimethoxy-1, 4-bis (dimethylamino) butanes((+)-and (-)-DDB) complexes of organolithium showed low optical activity, but PMP complex with N, N-diphenylethyleneamine monolithium amide (PMP-DPEDA-Li) was effective in synthesizingcopolymers of high optical rotation ([α]_D~(25) about+320~1370°)which were comparable to thoseof relative homopolymers with one-handed helical structure. 相似文献
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Ab initio and density functional theory calculations have been carried out to investigate the reaction of hydroxyl radical (OH) and 1,1,1-trichloroethane (CH3CCl3). The potential energy surface has been given according to the relative energies calculated at the MP2/cc-pVTZ level after the spin projection (PMP2). Five reaction channels were identified and the intramolecular hydrogen bonding was observed in some transition state structures. The barrier heights and reaction enthalpies calculated for all possible channels show that the hydrogen abstraction channel is predominant kinetically and thermodynamically. The contribution from other channels was predicted to be minor. 相似文献