Thursday, October 23, 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 del mismo autor(es)

  1. Role of Oxido Incorporation and Ligand Lability in Expanding Redox Accessibility of Structurally Related Mn4 Clusters
  2. Toward Models for the Full Oxygen-Evolving Complex of Photosystem II by Ligand Coordination To Lower the Symmetry of the Mn_3CaO_4 Cubane: Demonstration That Electronic Effects Facilitate Binding of a Fifth Metal Synthetic model compounds have been targeted to benchmark and better understand the electronic struc...
  3. Dioxygen Reactivity with a Ferrocene–Lewis Acid Pairing: Reduction to a Boron Peroxide in the Presence of Tris(pentafluorophenyl)borane Ferrocenes, which are typically air-stable outer-sphere single-electron transfer reagents, were foun...
  4. How calcium affects oxygen formation Calcium is an essential component of the catalyst that forms oxygen from water during photosynthesis...
  5. Synthetic, Reactivity, and Mechanistic Studies Relevant ii To my father and my sister and the memory of my mother. Multumesc. iii Acknowledgments Looking ba...

Otros recursos de la misma colección

  1. The Opportunity Rover's Athena science investigation at Meridiani Planum, Mars The Mars Exploration Rover Opportunity has investigated the landing site in Eagle crater and the nea...
  2. Molecular dynamics simulation of cluster-ion fragmentation Recent experiments have shown that it is possible to “bounce” low energy (few eV/atom) molecular ion...
  3. Columnar track damage in YBCO Ion damage tracks (columnar damage) in the high T_c superconductors have proven useful in understand...
  4. The Spirit Rover's Athena Science Investigation at Gusev Crater, Mars The Mars Exploration Rover Spirit and its Athena science payload have been used to investigate a lan...
  5. Kinetic relations and the propagation of phase boundaries in solids This paper treats the dynamics of phase transformations in elastic bars. The specific issue studied ...

Valoración de los usuarios

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

Busque un recurso