Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

The Role of Defect Geometry in Localized Emission from Monolayer Tungsten Dichalcogenides.

ACS nano·2026
Same author

Unique Metal-Ligand Proton Tautomerism Underlying the Reversible Electrocatalytic NAD<sup>+</sup>/NADH Interconversion.

Journal of the American Chemical Society·2026
Same author

Implications of Solvent Vapor Annealing on Crystallinity and Orientation of Covalent Organic Framework Thin Films.

ACS omega·2026
Same author

Mercaptan-Mediated Ethylene Formation in Sulfur Oxidative Ethane Dehydrogenation on Iron Sulfide (FeS<sub>2</sub>) Catalysts.

ACS catalysis·2026
Same author

General and selective nickel-electrocatalyzed cross-electrophile C*(<i>sp</i><sup>2</sup>)-C(<i>sp</i><sup>2</sup>) coupling.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same author

Broadly applicable hydrophilic additive enhances electrochemical transistor function.

Proceedings of the National Academy of Sciences of the United States of America·2026

Related Experiment Video

Updated: Jul 20, 2026

Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR
10:54

Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR

Published on: February 23, 2016

Metallocene polymerization catalyst ion-pair aggregation by cryoscopy and pulsed field gradient spin-echo NMR

Nicholas G Stahl1, Cristiano Zuccaccia, Tryg R Jensen

  • 1Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA.

Journal of the American Chemical Society
|May 2, 2003
PubMed
Summary

Homogeneous metallocene polymerization catalysts exist as 1:1 ion-pairs, not higher aggregates, under typical conditions. Pulsed field gradient spin-echo NMR and cryoscopy confirm this structural model for these important catalysts.

More Related Videos

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
14:55

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy

Published on: September 17, 2017

Covalent Immobilization of Proteins for the Single Molecule Force Spectroscopy
11:13

Covalent Immobilization of Proteins for the Single Molecule Force Spectroscopy

Published on: August 20, 2018

Related Experiment Videos

Last Updated: Jul 20, 2026

Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR
10:54

Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR

Published on: February 23, 2016

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
14:55

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy

Published on: September 17, 2017

Covalent Immobilization of Proteins for the Single Molecule Force Spectroscopy
11:13

Covalent Immobilization of Proteins for the Single Molecule Force Spectroscopy

Published on: August 20, 2018

Area of Science:

  • Organometallic Chemistry
  • Polymerization Catalysis
  • Physical Chemistry

Background:

  • Metallocene catalysts are crucial for olefin polymerization.
  • Understanding catalyst aggregation is vital for controlling polymerization.
  • Previous studies suggested potential aggregation of metallocene ion-pairs.

Purpose of the Study:

  • To investigate the aggregation state of homogeneous metallocene catalyst ion-pairs.
  • To determine if aggregation occurs under typical polymerization conditions.
  • To establish the predominant structural model of these catalysts in solution.

Main Methods:

  • Cryoscopic measurements in benzene for catalyst ion-pairs (1-6) at 10-18 millimolal concentrations.
  • Pulsed field gradient spin-echo (PGSE) NMR measurements for catalyst ion-pairs (1, 4, 6-9) at 0.8-10.0 millimolar concentrations.
  • Utilized (p-tolyl)4Si as an internal standard for PGSE NMR.

Main Results:

  • Cryoscopy data indicated minimal aggregation in the studied concentration range.
  • PGSE NMR diffusion measurements supported a monomeric 1:1 ion-pair structure.
  • No significant evidence for ion-quadruples or higher-order aggregates was observed.

Conclusions:

  • Homogeneous metallocene catalyst ion-pairs predominantly exist as 1:1 species.
  • Aggregation is not a significant phenomenon under the investigated conditions.
  • The 1:1 ion-pair model accurately describes these catalysts in solution.