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 Experiment Videos

Lithium pinacolone enolate solvated by hexamethylphosphoramide.

Jie Guang1, Qiyong Peter Liu1, Russell Hopson1

  • 1Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.

Journal of the American Chemical Society
|May 3, 2015
PubMed
Summary

We determined the crystal structure of a lithium pinacolone enolate tetramer (T3) and found it is the major species in solution with sufficient HMPA. Minor impurities form a mixed lithium hydroxide aggregate.

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

Structures of <i>rac</i>-2,4:3,5-di-methyl-ene xylitol -derivatives.

Acta crystallographica. Section E, Crystallographic communications·2023
Same author

Long-Term Variations in Global Solar Radiation and Its Interaction with Atmospheric Substances at Qomolangma.

International journal of environmental research and public health·2022
Same author

Identification of a Vitamin-D Receptor Antagonist, MeTC7, which Inhibits the Growth of Xenograft and Transgenic Tumors <i>In Vivo</i>.

Journal of medicinal chemistry·2022
Same author

Reactivity of a biomimetic W(iv) bis-dithiolene complex with CO<sub>2</sub> leading to formate production and structural rearrangement.

Dalton transactions (Cambridge, England : 2003)·2019
Same author

Spray-dried plasma deficient in high-molecular-weight multimers of von Willebrand factor retains hemostatic properties.

Transfusion·2018
Same author

Single-donor spray-dried plasma.

Transfusion·2018

Area of Science:

  • Organometallic Chemistry
  • Crystallography
  • Nuclear Magnetic Resonance (NMR) Spectroscopy

Background:

  • Lithium enolates are crucial intermediates in organic synthesis.
  • Understanding their aggregation and solvation is key to controlling reactivity.
  • Hexamethylphosphoramide (HMPA) is a common ligand for lithium enolates.

Purpose of the Study:

  • To elucidate the crystal structure of a substoichiometric, HMPA-solvated lithium pinacolone enolate tetramer.
  • To determine the solution behavior and major species formed under varying HMPA concentrations.
  • To investigate the influence of steric effects on aggregate formation and solvation.

Main Methods:

  • X-ray diffraction analysis for crystal structure determination.
  • Nuclear Magnetic Resonance (NMR) spectroscopy, including HMPA titration and diffusion coefficient-formula weight (D-FW) analysis.

Related Experiment Videos

  • Preparation and characterization of related lithium enolate aggregates.

    • Main Results:

    • The crystal structure of the HMPA-trisolvated lithium pinacolone enolate tetramer (T3) was determined, revealing reduced spatial symmetry.
    • NMR studies confirmed T3 as the major species in hydrocarbon solution with >0.6 equiv HMPA.
    • A minor mixed aggregate, pseudo-T4, containing lithium hydroxide was identified due to moisture contamination.
    • Steric effects were found to dominate the formation and solvation of pinacolone enolate aggregates.
    • An unusual mixed aggregate involving lithium diisopropyl amide and lithium oxide was also described.

    Conclusions:

    • The substoichiometric HMPA-solvated lithium pinacolone enolate tetramer (T3) is a stable species in hydrocarbon solution.
    • Moisture contamination can lead to the formation of significant byproducts, such as mixed lithium hydroxide aggregates.
    • Steric factors play a critical role in dictating the structure and solvation of lithium enolate aggregates.