1) La descarga del recurso depende de la página de origen
2) Para poder descargar el recurso, es necesario ser usuario registrado en Universia


Opción 1: Descargar recurso

Opción 2: Descargar recurso

Opción 3: Descargar recurso

Detalles del recurso

Descripción

Dinuclear nickel phenoxyiminato olefin polymerization catalysts based on rigid p-terphenyl frameworks are reported. Permethylation of the central arene of the terphenyl unit and oxygen substitution of the peripheral rings ortho to the aryl–aryl linkages blocks rotation around these linkages, allowing atropisomers of the ligand to be isolated. The corresponding syn and anti dinickel complexes (25-s and 25-a) were synthesized and characterized by single-crystal X-ray diffraction. These frameworks limit the relative movement of the metal centers, restricting the metal–metal distance. Kinetics studies of isomerization of a ligand precursor (7-a) allowed the calculation of the activation parameters for the isomerization process (ΔH^‡ = 28.0 ± 0.4 kcal × mol^(–1) and ΔS^‡ = −12.3 ± 0.4 cal mol^(–1) K^(–1)). The reported nickel complexes are active for ethylene polymerization (TOF up to 3700 (mol C_2H_4) (mol Ni)^(−1) h^(–1)) and ethylene/α-olefin copolymerization. Only methyl branches are observed in the polymerization of ethylene, while α-olefins are incorporated without apparent chain walking. These catalysts are active in the presence of polar additives and in neat tetrahydrofuran. The syn and anti isomers differ in polymerization activity, polymer branching, and polymer molecular weight. For comparison, a series of mononuclear nickel complexes (26, 27-s, 27-a, 28, 30) was prepared and studied. The effects of structure and catalyst nuclearity on reactivity are discussed.

Pertenece a

Caltech Authors  

Autor(es)

Radlauer, Madalyn R. -  Day, Michael W. -  Agapie, Theodor - 

Id.: 55211188

Versión: 1.0

Estado: Final

Tipo:  application/pdf -  chemical/x-cif -  chemical/x-cif - 

Tipo de recurso: Article  -  PeerReviewed  - 

Tipo de Interactividad: Expositivo

Nivel de Interactividad: muy bajo

Audiencia: Estudiante  -  Profesor  -  Autor  - 

Estructura: Atomic

Coste: no

Copyright: sí

Formatos:  application/pdf -  chemical/x-cif -  chemical/x-cif - 

Requerimientos técnicos:  Browser: Any - 

Relación: [References] http://resolver.caltech.edu/CaltechAUTHORS:20120420-144952369
[References] http://authors.library.caltech.edu/30244/

Fecha de contribución: 29-mar-2014

Contacto:

Localización:
* Radlauer, Madalyn R. and Day, Michael W. and Agapie, Theodor (2012) Dinickel Bisphenoxyiminato Complexes for the Polymerization of Ethylene and α-Olefins. Organometallics, 31 (6). pp. 2231-2243. ISSN 0276-7333. http://resolver.caltech.edu/CaltechAUTHORS:20120420-144952369

Otros recursos del mismo autor(es)

  1. The one-electron oxidation product of a metallocenyl-terminated cyanine The 1-(2,3,4,5,1',2',3',4'-octa­methyl­ferrocen-1-yl)-3-(ruth­eno­cen­yl)­allylium cation readily un...
  2. Lewis Acid Accelerated Aryl Ether Bond Cleavage with Nickel: Orders of Magnitude Rate Enhancement Using AlMe_3 Study of the kinetics of intramolecular aryl ether C−O bond cleavage by Ni was facilitated by access...
  3. Tuning reactivity of biologically inspired clusters via metal and bridging anion composition Complex inorg. cofactors perform challenging catalytic transformations in biol. systems, such as pho...
  4. Proximal effects in bimetallic catalysts for olefin polymerization, in cross metathes and in multiblock polymers Proximity and sterics play a large role in polymn. and polymer chem. In the bimetallic polymn. catal...
  5. (Dicyclohexylphosphino)borane, BH_3PH(C_6H_(11))_2, a Precursor to Water-Soluble Phosphine Ligands (Dicyclohexylphosphino) borane is a precursor in the synthesis of water-soluble phosphines. The bora...

Otros recursos de la mismacolección

  1. Rapid Assessment of Earthquake Source Characteristics Recent studies emphasize the rapid assessment of earthquake source properties, such as moment magnit...
  2. Molecular Control of Flower Development The last decade has been an exciting period in plant molecular biology in general and in molecular s...
  3. Modeling the organization of the WUSCHEL expression domain in the shoot apical meristem Motivation: The above-ground tissues of higher plants are generated from a small region of cells sit...
  4. Contrasting cloud composition between coupled and decoupled marine boundary layer clouds Marine stratocumulus clouds often become decoupled from the vertical layer immediately above the oce...
  5. Colour formation on the wings of the butterfly Hypolimnas salmacis by scale stacking The butterfly genus Hypolimnas features iridescent blue colouration in some areas of its dorsal wing...

Aviso de cookies: Usamos cookies propias y de terceros para mejorar nuestros servicios, para análisis estadístico y para mostrarle publicidad. Si continua navegando consideramos que acepta su uso en los términos establecidos en la Política de cookies.