Non-classical paramagnetic susceptibility and anisotropy in lanthanide coordination complexes: a combined experimental and theoretical study
Lead Research Organisation:
University of Southampton
Department Name: Sch of Chemistry
Abstract
Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.
Organisations
People |
ORCID iD |
| Ilya Kuprov (Principal Investigator) |
Publications
Goura J
(2017)
Heterometallic Zn3 Ln3 Ensembles Containing (ยต6 -CO3 ) Ligand and Triangular Disposition of Ln3+ ions: Analysis of Single-Molecule Toroic (SMT) and Single-Molecule Magnet (SMM) Behavior.
in Chemistry (Weinheim an der Bergstrasse, Germany)
Kuprov I
(2016)
Fokker-Planck formalism in magnetic resonance simulations.
in Journal of magnetic resonance (San Diego, Calif. : 1997)
Ma X
(2019)
Using Redox-Active p Bridging Ligand as a Control Switch of Intramolecular Magnetic Interactions.
in Journal of the American Chemical Society
Ma X
(2018)
A Redox-Active Bridging Ligand to Promote Spin Delocalization, High-Spin Complexes, and Magnetic Multi-Switchability
in Angewandte Chemie
Ma X
(2018)
A Redox-Active Bridging Ligand to Promote Spin Delocalization, High-Spin Complexes, and Magnetic Multi-Switchability
in Angewandte Chemie International Edition
Manukovsky N
(2017)
Time domain simulation of Gd3+-Gd3+ distance measurements by EPR.
in The Journal of chemical physics
Mason K
(2017)
PARASHIFT Probes: Solution NMR and X-ray Structural Studies of Macrocyclic Ytterbium and Yttrium Complexes.
in Inorganic chemistry
Orton H
(2016)
Using Paramagnetism to Slow Down Nuclear Relaxation in Protein NMR
in The Journal of Physical Chemistry Letters
Parker D
(2020)
How the Ligand Field in Lanthanide Coordination Complexes Determines Magnetic Susceptibility Anisotropy, Paramagnetic NMR Shift, and Relaxation Behavior
in Accounts of Chemical Research
Perlepe P
(2018)
Cr(pyrazine)2(OSO2CH3)2: A two-dimensional coordination polymer with an antiferromagnetic ground state
in Polyhedron
| Description | See the published papers. Briefly: [[[1]]] A detailed analysis of paramagnetic NMR shifts in a series of isostructural lanthanide complexes relevant to PARASHIFT contrast agents reveals unexpected trends in the magnetic susceptibility anisotropy that cannot be explained by the com-monly used Bleaney's theory. Ab initio calculations reveal that the primary assumption of Bleaney's theory - that thermal en-ergy is larger than the ligand field splitting - does not hold for the lanthanide complexes in question, and likely for a large fraction of lanthanide complexes in general. This makes the orientation of the magnetic susceptibility tensor differ signifi-cantly between complexes of different lanthanides with the same ligand: one of the most popular assumptions about isostructural lanthanide series is wrong. [[[2]]] Lanthanide ions accelerate nuclear spin relaxation by two primary mechanisms: dipolar and Curie. Both are commonly assumed to depend on the length of the lanthanide-nucleus vector, but not on its direction. Here we demonstrate that this is wrong - careful proton relaxation data analysis in a se-ries of isostructural lanthanide complexes (Ln=Tb, Dy, Ho, Er, Tm, Yb) reveals angular dependence in both Curie and dipolar relaxation. The reasons are: (a) that magnetic susceptibility anisotropy can be of the same order of magnitude as the isotropic part (contradicting the unstated assumption in Guéron's theory of the Curie relaxation process), and (b) that zero-field splitting can be much stronger than the electron Zeeman interaction (Bloembergen's original theory of the lanthanide-induced dipolar relaxation process makes the opposite assumption). These factors go beyond the well researched cross-correlation effects; they alter the relaxation theory treatment and make strong angular dependencies appear in the nuclear spin relaxation rates. Those dependencies are impossible to ignore - this is demonstrated both theoretically and experimentally, and suggests that a major revision is needed of the way lanthanide-induced relaxation data is used in structural biology. |
| Exploitation Route | See the outlook sections of the published papers. |
| Sectors | Chemicals,Digital/Communication/Information Technologies (including Software),Healthcare,Pharmaceuticals and Medical Biotechnology |
| URL | http://spindynamics.org |
| Description | All theoretical and software targets (Southampton part of the joint project) have been achieved - we found a better model for lanthanide-induced relaxation, added the corresponding module to the simulation software (Spinach, http://spindynamics.org), and published everything. |
| First Year Of Impact | 2018 |
| Sector | Chemicals,Digital/Communication/Information Technologies (including Software),Healthcare,Pharmaceuticals and Medical Biotechnology |
| Impact Types | Cultural,Societal |
| Title | Spinach library |
| Description | A large-scale open-source magnetic resonance simulation library, http://spindynamics.org |
| Type Of Material | Improvements to research infrastructure |
| Year Produced | 2019 |
| Provided To Others? | Yes |
| Impact | It became much easier for the community to perform relevant simiulations. |
| URL | http://spindynamics.org |
| Title | Spin dynamics simulation package |
| Description | The algorithms resulting from this project have been implemented into the open source simulation package, called Spinach, maintained by Kuprov group (http://spindynamics.org). |
| Type Of Technology | Software |
| Year Produced | 2012 |
| Open Source License? | Yes |
| Impact | See the published papers |
| URL | http://spindynamics.org |