skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: A DFT perspective on organometallic lanthanide chemistry
Computational studies of the coordination chemistry and bonding of lanthanides have grown in recent decades as the need for understanding the distinct physical, optical, and magnetic properties of these compounds increased. Density functional theory (DFT) methods offer a favorable balance of computational cost and accuracy in lanthanide chemistry and have helped to advance the discovery of novel oxidation states and electronic configurations. This Frontier article examines the scope and limitations of DFT in interpreting structural and spectroscopic data of low-valent lanthanide complexes, elucidating periodic trends, and predicting their properties and reactivity, presented through selected examples.  more » « less
Award ID(s):
2102568
PAR ID:
10544126
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
RSC
Date Published:
Journal Name:
Dalton Transactions
Volume:
53
Issue:
2
ISSN:
1477-9226
Page Range / eLocation ID:
410 to 417
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. (, Israel Journal of Chemistry)
    Abstract Machine learning (ML) has become a central focus of the computational chemistry community. I will first discuss my personal history in the field. Then I will provide a broader view of how this resurgence in ML interest echoes and advances upon earlier efforts. Although numerous changes have brought about this latest wave, one of the most significant is the increased accuracy and efficiency of low‐cost methods (e. g., density functional theory or DFT) that have made it possible to generate large data sets for ML models. ML has also been used to bypass, guide, or improve DFT. The field of computational chemistry thus finds itself at a crossroads as ML both augments and supersedes traditional efforts. I will present what I believe the role of the computational chemist will be in this evolving landscape, with specific focus on my experience in the development of autonomous workflows in computational materials discovery for open‐shell transition‐metal chemistry. 
    more » « less
  2. ; ; ; ; ; (, Journal of The Electrochemical Society)
    Increasing lanthanide demand to support clean energy goals drives the need to develop more efficient approaches to separate adjacent lanthanides. Most approaches for lanthanide separations are not very selective and are based on small differences in lanthanide ionic radii. Concentrated potassium carbonate media has shown some potential to enable oxidation of praseodymium (Pr) and terbium (Tb) to their tetravalent states, which could ultimately enable a separation based on differences in oxidation states, but very little is known regarding the system’s chemistry. This work completes a detailed examination of cerium (Ce) redox chemistry in concentrated carbonate media to support the development of Pr and Tb oxidation studies. The half-wave potential (E 1/2 ) of the Ce(III)/(IV) redox couple is evaluated under various solution conditions and computational modeling of carbonate coordination environments is discussed. Cyclic voltammetry shows higher carbonate concentrations and temperatures can lower the potential required to oxidize Ce(III) by 54 mV (3.5 to 5.5 M) and 39 mV (from 10 °C to 70 °C). Chronoabsorptometry shows Ce(III) and Ce(IV) carbonate complexes are chemically stable and reversible. Computational modelling suggests the most likely coordination environment for the Ce(IV) complex is Ce(CO 3 ) 4 (OH) 5− which is less entropically favorable than the lowest energy Ce(III) complex, Ce(CO 3 ) 4 5− . 
    more » « less
  3. ; ; ; (, Chemical Science)
    Introducing spin onto organic ligands that are coordinated to rare earth metal ions allows direct exchange with metal spin centres. This is particularly relevant for the deeply buried 4f-orbitals of the lanthanide ions that can give rise to unparalleled magnetic properties. For efficacy of exchange coupling, the donor atoms of the radical ligand require high-spin density. Such molecules are extremely rare owing to their reactive nature that renders isolation and purification difficult. Here, we demonstrate that a 2,2′-azopyridyl (abpy) radical ( S = 1/2) bound to the rare earth metal yttrium can be realized. This molecule represents the first rare earth metal complex containing an abpy radical and is unambigously characterized by X-ray crystallography, NMR, UV-Vis-NIR, and IR spectroscopy. In addition, the most stable isotope 89 Y with a natural abundance of 100% and a nuclear spin of ½ allows an in-depth analysis of the yttrium–radical complex via EPR and HYSCORE spectroscopy. Further insight into the electronic ground state of the radical azobispyridine-coordinated metal complex was realized through unrestricted DFT calculations, which suggests that the unpaired spin density of the SOMO is heavily localized on the azo and pyridyl nitrogen atoms. The experimental results are supported by NBO calculations and give a comprehensive picture of the spin density of the azopyridyl ancillary ligand. This unexplored azopyridyl radical anion in heavy element chemistry bears crucial implications for the design of molecule-based magnets particularly comprising anisotropic lanthanide ions. 
    more » « less
  4. ; (, Structure and bonding)
    This chapter describes a personal journey through the periodic table in which an undergraduate starting research in boron hydride chemistry developed into a professorial researcher in rare earth chemistry. The chapter details how the periodic table became a career guide through connections and developments that led the boron chemist into the rare earth field. Also presented is the evolution of reductive rare-earth chemistry which started with just a few +2 lanthanide ions, Eu(II), Yb(II), and Sm(II), and now extends to +2 ions for all the rare earth metals, i.e. Sc, Y, and the lanthanides, La-Lu. The special reactivity of Sm(II), which led to the first lanthanide-based dinitrogen reduction is described, as well as the rare earth dinitrogen reduction that led to the new Ln(II) ions. Periodic trends in these developments are discussed and speculation on the future of the rare-earth elements in terms of periodic properties is also presented. 
    more » « less
  5. ; ; ; ; ; ; (, Angewandte Chemie International Edition)
    Abstract Lanthanide triflates have been used to incorporate NdIIIand SmIIIions into the 2.2.2‐cryptand ligand (crypt) to explore their reductive chemistry. The Ln(OTf)3complexes (Ln=Nd, Sm; OTf=SO3CF3) react with crypt in THF to form the THF‐soluble complexes [LnIII(crypt)(OTf)2][OTf] with two triflates bound to the metal encapsulated in the crypt. Reduction of these LnIII‐in‐crypt complexes using KC8in THF forms the neutral LnII‐in‐crypt triflate complexes [LnII(crypt)(OTf)2]. DFT calculations on [NdII(crypt)]2+], the first NdIIcryptand complex, assign a 4f4electron configuration to this ion. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email