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.

Ring-Opening polymerization of cycloolefins with catalysts derived from ruthenium and iridium†

Abstract: An investigation was carried out on the polymerization of norbornene, cyclopentene and cyclooctene by the following iridium and ruthenium compounds: chlorobis(cyclooctene)iridium (1), carbonylchlorobis(cyclooctene)iridium (2), trifluoroacetatobis(cyclooctene)iridium (3), chloroiridic(IV) acid (4), dichloro(2,7-dimethylocta-2,6-diene-1,8-diyl)-ruthenium (5a), and bis(trifluoroacetato)-(2,7-dimethylocta-2,6-diene-1,8-diyl)ruthenium (5b). All the above catalysts were found to be very active for the polymerization of norbornene via ring-opening. Iridium catalysts were practically inactive for the polymerization of cyclopentene and cyclooctene, but gave copolymers of norbornene with cyclopentene and cyclooctene via ring-opening. The ruthenium catalysts displayed no activity for the polymerization of cyclopentene and cyclooctene, but it was found that after treatment with H2 they became active for the polymerization of cyclopentene. The results obtained from the reaction of norbornene and aliphatic olefins suggest that the above catalysts act by metathesis. The particular features of these catalysts were examined. Die Untersuchung der Polymerisation von Norbornen, Cyclopenten und Cycloocten wurde mit folgenden Iridium- und Ruthenium- Verbindungen durchgefuhrt: Chlorobis(cycloocten)iridium (1), Carbonylchlorobis(cycloocten)iridium (2), Trifluoroacetatobis(cycloocten)iridium (3), Chloriridiumsaure (4), Dichloro(2,7-dimethylocta-2,6-dien-1,8-diyl)ruthenium (5a) und Bis(trifluoracetato)-(2,7-dimethylocta-2,6-dien-1,8-diyl)ruthenium (5b). Diese Verbindungen erwiesen sich als sehr aktive Katalysatoren fur die Polymerisation von Norbornen durch Ringoffnung. Die Iridiumverbindungen waren praktisch inaktiv fur die Katalyse der Polymerisation von Cyclopenten und Cycloocten, gaben jedoch Copolymere des Norbornens mit Cyclopenten und Cycloocten uber eine Ringoffnung.Die Rutheniumverbindungen zeigten keinerlei Aktivitat fur die Polymerisation von Cyclo-penten und Cycloocten. Nach Behandlung mit Wasserstoff wurden sie jedoch aktiveKatalysatoren fur die Polymerisation von Cyclopenten. Die bei der Reaktion von Norbor-nen und den aliphatischen Olefinen erhaltenen Ergebnisse lassen darauf schliekn, daB die oben erwahnten Katalysatoren iiber eine Metathesis wirksam sind. Die speziellen Eigenschaften dieser Katalysatoren wurden untersucht.

Mixed ligand complexes of chromium(III) and iron(III): synthesis and evaluation as catalysts for oxidation of olefins

Abstract: The mixed ligand complexes Cr III (dpa)(L)Cl and Fe III (dpa)(L)(H 2 O) n Cl (where dpa = dipicolinic acid, l = ethylenediamine, 2,2-bipyridine or 1,10-phenanthroline, n = 1 or 2) were synthesized and characterized by elemental analysis and spectral, magnetic, conductance and electrochemical studies. The complexes were evaluated for their activity as catalysts for the epoxidation of olefins. The chromium complexes catalyzed epoxidation of olefins, viz., norbornene, cis -cyclooctene, styrene and cyclohexene with iodosylbenzene, to give corresponding epoxides. Oxidation of cyclohexene gave allylic oxidation products besides the epoxide. The iron complexes were nearly inactive as epoxidation catalysts under these conditions. Spectrophotometric and electrochemical measurements were used to deduce the cause of low catalytic activity.

Electrical devices including ethylene, alpha-olefin, vinyl norbornene elastomers and ethylene alpha-olefin polymers

Abstract: Elastomeric polymers including ethylene, alpha-olefin and vinyl norbornene are shown to have improved extrusion characteristics, improved electrical properties, improved cure characteristics compared to ethylene, alpha-olefin, non-conjugated diene elastomeric polymers containing non-conjugated dienes other than vinyl norbornene. The elastomeric polymers containing vinyl norbornene generally have a branching index below 0.5. Such elastomeric polymers are combined with up to 30 parts of metallocene catalyzed ethylene, alpha-olefin copolymers to improve physical properties.

Synthesis and Characterization of NiII and PdII Complexes Bearing N,N,S Tridentate Ligands and Their Catalytic Properties for Norbornene Polymerization

Abstract: A series of new N,N,S tridentate nickel(II) complexes [(ArN = CHC6H4NPh-2-SPh)NiBr] (Ar = 2,6-diisopropylphenyl, 1; Ar = 2,6-dimethylphenyl, 2; Ar = Ph, 3) and palladium(II) complexes [(ArN = CHC6H4NPh-2-SPh)PdCH3] (Ar = 2,6-diisopropylphenyl, 4; Ar = 2,6-dimethylphenyl, 5; Ar = Ph, 6) were synthesized and characterized. X-ray diffraction analyses of the single-crystal structures revealed that tridentate complexes 1, 2, 4, 5, and 6 featured a distorted square-planar coordination of the central metal. Compared to the bidentate metal complexes bearing anilido–imine ligands, the N,N,S tridentate metal complexes showed better stability. In the presence of methylaluminoxane (MAO), nickel complexes 1–3 showed moderate activity toward ethylene oligomerization at atmosphere pressure, but the palladium complexes were inactive. However, the nickel complexes exhibited high activity up to 8.20 × 106 g/(mol of Ni) h and palladium complexes showed very high activity up to 2.68 × 108 g/(mol of Pd) h toward norbornene polymerization with MAO as cocatalyst. The obtained polynorbornenes are vinylic addition polymers with high molecular weights. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)