Topic
Norbornene
About: Norbornene is a research topic. Over the lifetime, 5628 publications have been published within this topic receiving 104495 citations. The topic is also known as: norbornylene & norcamphene.
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TL;DR: In this article, an absolute molecular weight determination of polynorbornene (PN) by means of light scattering and the three-dimensional shape of PN was also investigated, which yielded a close 0.5 exponent for the Mark-Houwink equation with solvents chlorobenzene and cyclohexane at 25°C expected for polymer molecules with confined conformation.
Abstract: Pd(II) catalysts with nitrilo ligands and BF4− counter ions give the best results in vinylic polymerization of norbornene. Absolute molecular weight determination of polynorbornene (PN) by means of light scattering and the three-dimensional shape of PN were also investigated. By correlation of molecular weights Mw with intrinsic viscosity (Staudinger-index) [η], yield a close to 0.5 exponent for the Mark-Houwink equation with solvents chlorobenzene and cyclohexane at 25°C expected for polymer molecules with confined conformation. The vinylic polymerization of norbornene with [(CH3CN)4Pd][BF4]2 (I) in nitromethane in the presence of ethylene results in PN with narrow molecular weight distribution. No termination and transfer reactions were found, nor any incorporation of ethylene could be detected.
88 citations
TL;DR: In this article, the same catalyst selectively affords homodimerization products from the starting allene, a process that may be conveniently fine tuned by addition of norbornene.
Abstract: Addition of catalytic amounts of a phosphite-based gold(I) catalyst efficiently triggers the intermolecular [2+2] cycloaddition of allenes and alkenes substituted by electron-donor groups. The reaction is fast and furnishes cyclobutane derivatives in a stereoselective manner using low catalyst loadings. Besides, the same catalyst selectively affords homodimerization products from the starting allene, a process that may be conveniently fine tuned by addition of norbornene.
88 citations
TL;DR: In this article, Norbornene derivatives containing laterally attached 2,5-bis(4'-n- alkoxybenzoyl OXY) mesogens were polymerized by controlled ring opening metathesis polymerization to provide polymers in high yield with 5-100 repeat units and narrow molecular weight distributions.
Abstract: : Norbornene derivatives containing laterally attached 2,5-bis(4'-n- alkoxybenzoyl OXY) mesogens were polymerized by controlled ring opening metathesis polymerization to provide polymers in high yield with 5-100 repeat units and narrow molecular weight distributions. Monomers with n>l displayed monotropic or enantiotropic nematic mesophases. All polymers displayed enantiotropic nematic mesophases regardless of the spacer, molecular weight or length or the n-alkoxy substituent. Constitutional isomers of poly(5-carbo(2', 5'-bis-4( methoxybenzoyloxy)benzyloxy)bicyclo(2.2.1)hep t-2-ene)s containing laterally attached mixed phenylester/benzylester units are amorphous. Side chain liquid crystal polymers (SCLCPs), living ring opening metathesis polymerization.
88 citations
88 citations
TL;DR: In this paper, a new class of side-chain liquid crystalline random terpolymers (SCLCP), its cross-linked network, and corresponding shape memory properties are described.
Abstract: We report synthesis and characterization of a new class of side-chain liquid crystalline random terpolymers (SCLCP), its cross-linked network (SCLCN), and the corresponding shape memory properties. The SCLCP comprising three monomers, 5-{15-(cholesteryloxycarbonyl)-pentadecyloxycarbonyl}-bicyclo[2.2.1]hept-2-ene (NBCh15), 5-(acryloyl butoxycarbonyl)-bicyclo[2.2.1]hept-2-ene (NBBA), and poly(ethylene glycol) functionalized norbornene (NBPEG), is synthesized by ring-opening metathesis polymerization (ROMP) using Grubbs catalyst second generation, resulting in a random terpolymer. Each monomer provides a specific function in the terpolymer: (1) NBCh15 affords liquid crystalline properties, (2) NBBA is a cross-linkable unit, and (3) NBPEG acts as an internal plasticizer. The mesomorphic structure of the terpolymer investigated by X-ray diffraction (XRD) exhibits highly interdigitated smectic A (SmA) mesophase comprising cholesteryl ester mesogens. The acrylate end group in the NBBA undergoes cross-linking by ...
88 citations