Chiral and achiral amine-functionalized norbornene monomers endo-/exo-N-(S)-(À)-a-methylbenzyl-5-norbornene-2,3dicarboximide (endo-/exo-(S)-MBnNDI), endo-/exo-N-phenyl-5-norbornene-2,3-dicarboximide (endo-/exo-PhNDI) and endo-/exo-N-cyclohexyl-5-norbornene-2,3-dicarboximide (endo-/exo-CHNDI) were synthesized and polymerized using 1st Generation Grubbs Catalyst, and the chiroptical properties of these polymers were studied. Specific rotations of higher M n poly(endo-(S)-MBnNDI)s were negatively large compared with those of lower M n polymers. Using (À)-spartaine (Sp) as a chiral additive, some polymers exhibited stronger chiroptical properties compared with polymers that were obtained without the chiral additive.
Seven novel types of acetylene monomers, 4-oxo-4-(prop-2-ynyloxy)butanoic acid ester derivatives (PSRs), having ester groups of 4¢-substituted phenyl (PSPRs: -H¼PSP; -CN¼PSPCN; -OCH 3 ¼PSPOC 1 ) or 4¢-substituted biphenyl (PSBPRs: -H¼PSBP; -CN¼PSBPCN; -OCH 3 ¼PSBPOC 1 ; -O(CH 2 ) 5 CH 3 ¼PSBPOC 6 ) as a pendant group were synthesized from 4-oxo-4-(prop-2-ynyloxy)butanoic acid (PS) with phenol derivatives and polymerized with a rhodium-catalyzed system. The structures and properties of the polymers were characterized and evaluated by nuclear magnetic resonance, infrared spectroscopy and gel permeation chromatography analyses. The polymerizations of the PSRs were carried out under nitrogen with Rh catalysts in tetrahydrofuran or toluene at 30 1C, producing a good yield of polymers. The resulting polymer showed a thermotropic mesophase as observed through polarized optical microscopy and differential scanning calorimetry. Polymer Journal ( In side-chain LC polymers in which the mesogenic groups are linked through flexible alkyl or poly(alkylene oxide) chains to the polymer backbone, the flexible spacer enables a partial decoupling of the motions of the polymer backbone and the mesogens; thus, mesogens have the potential to adopt flexible behavior similar to that of low-molecular-weight LC compounds.Polyacetylene is a p-conjugated polymer with at least four possible conformations (cis-transoid, cis-cisoid, trans-transoid and transcisoid). Yashima and co-workers reported the synthesis of cis-transoidal poly((4-carboxyphenyl)acetylene) by the polymerization of (4-carboxyphenyl)acetylene using a rhodium catalyst. The synthesized polymer folded into a preferred-handed helical conformation on complexation with non-racemic primary amines and amino alcohols. 3,4 Unfortunately, 1-alkynes, which have flexible methylene spacers, show a low polymerization ability and give low sterically controlled polyacetylenes. However, Noyori and co-workers reported that (nbd)Rh + [Z 6 -(C 6 H 5 )-B À (C 6 H 5 ) 3 ], a zwitterionic Rh(I) complex, functions as an excellent initiator of the polymerization of alkylated and aromatic monosubstituted acetylenes without trialkylsilanes. 5 The propargyl group is one of the least expensive compounds and facilitates the synthesis of acetylene derivatives. Despite this, most polyacetylenes are prepared from 1-alkyne derivatives in studies on LC
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