Friday, November 28, 2014

 

 



Soy un nuevo usuario

Olvidé mi contraseña

Entrada usuarios

Lógica Matemáticas Astronomía y Astrofísica Física Química Ciencias de la Vida
Ciencias de la Tierra y Espacio Ciencias Agrarias Ciencias Médicas Ciencias Tecnológicas Antropología Demografía
Ciencias Económicas Geografía Historia Ciencias Jurídicas y Derecho Lingüística Pedagogía
Ciencia Política Psicología Artes y Letras Sociología Ética Filosofía


Dinickel Bisphenoxyiminato Complexes for the Polymerization of Ethylene and α-Olefins

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


  Descargar recurso   Descargar recurso   Descargar recurso

Detalles del recurso

Pertenece a: Caltech Authors  

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.

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 de la misma colección

  1. The surface chemistry of wheat gluten II. Measurements of surface viscoelasticity The dependence of surface viscoelasticity of gluten films at the interface on the pH and the ionic s...
  2. Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite Meteorites exposed to high pressures and temperatures during impact-induced shock often contain mine...
  3. Reduction of PG:1115+080 Images The data are three exposures in PC6 through F785LP obtained on March 3, 1991. The exposure times are...
  4. Oxidative Thymine Dimer Repair in the DNA Helix The metallointercalator Rh(phi)_2DMB^(3+) (phi, 9,10-phenanthrenequinone diimine; DMB, 4,4′-dimethyl...
  5. Climatic Limits on Landscape Development in the Northwestern Himalaya The interaction between tectonism and erosion produces rugged landscapes in actively deforming regio...

Valoración de los usuarios

No hay ninguna valoración para este recurso.Sea el primero en valorar este recurso.
 

Busque un recurso