Nuclear singlet states often display lifetimes that are much longer than conventional nuclear spin relaxation times. Here we investigate the effect of dissolved paramagnetic species on the singlet relaxation of proton pairs in solution. We find a linear correlation between the singlet relaxation rate constant T and the longitudinal relaxation rate constant T. The slope of the correlation depends on the nature of the paramagnetic relaxation agent, but typically, singlet states are between two to three times less sensitive to paramagnetic relaxation than conventional nuclear magnetization. These observations may be interpreted using a model of partially-correlated local fields acting on the nuclear sites. We explore the effect on singlet relaxation of adding a metal-ion-chelating agent to the solution. We also investigate the effect of ascorbate, which reacts with dissolved oxygen.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1039/c1cp20471h | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Spectroscopic Signatures of Phonon Character in Molecular Electron Spin Relaxation.
ACS Cent Sci
December 2024
Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States.
Spin-lattice relaxation constitutes a key challenge for the development of quantum technologies, as it destroys superpositions in molecular quantum bits (qubits) and magnetic memory in single molecule magnets (SMMs). Gaining mechanistic insight into the spin relaxation process has proven challenging owing to a lack of spectroscopic observables and contradictions among theoretical models. Here, we use pulse electron paramagnetic resonance (EPR) to profile changes in spin relaxation rates ( ) as a function of both temperature and magnetic field orientation, forming a two-dimensional data matrix.
View Article and Find Full Text PDFManganese Oxide Nanoparticles for MRI-Based Multimodal Imaging and Theranostics.
Molecules
November 2024
Department of Life Sciences and Coimbra Chemistry Center-Institute of Molecular Sciences (CQC-IMS), Faculty of Science and Technology, University of Coimbra, 3004-531 Coimbra, Portugal.
Manganese-based MRI contrast agents have recently attracted much attention as an alternative to Gd-based compounds. Various nanostructures have been proposed for potential applications in in vivo diagnostics and theranostics. This review is focused on the discussion of different types of Mn oxide-based nanoparticles (MnO NPs) obtained at the +2, +3 and +4 oxidation states for MRI, multimodal imaging or theranostic applications.
View Article and Find Full Text PDFMR Imaging Reveals Dynamic Aggregation of Multivalent Glycoconjugates in Aqueous Solution.
Inorg Chem
December 2024
Departments of Chemistry, Molecular Biosciences, Neurobiology, and Radiology, Northwestern University, Evanston, Illinois 60208, United States.
Glycoconjugates forming from the conjugation of carbohydrates to other biomolecules, such as proteins, lipids, or other carbohydrates, are essential components of mammalian cells and are involved in numerous biological processes. Due to the capability of sugars to form multiple hydrogen bonds, many synthetic glycoconjugates are desirable biocompatible platforms for imaging, diagnostics, drugs, and supramolecular self-assemblies. Herein, we present a multimeric galactose functionalized paramagnetic gadolinium (Gd(III)) chelate that displays spontaneous dynamic aggregation in aqueous conditions.
View Article and Find Full Text PDFDiamagnetic Carrier-Doping-Induced Continuous Electronic and Magnetic Crossover in One-Dimensional Coordination Polymers.
J Am Chem Soc
December 2024
Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
The potential to introduce tunable electrical conductivity and molecular magnetism through carrier doping in metal-organic coordination polymers is particularly promising for nanoelectronics applications. Precise control of the doping level is essential for determining the electronic and magnetic properties. In this study, we present a series of one-dimensional coordination polymers, {(HNEt)[CuCo(L)]} (HNEt = triethylammonium, L = 1,2,4,5-tetrakis(methanesulfonamido)benzene), doped with diamagnetic Cu carriers.
View Article and Find Full Text PDFSynthesis and Relaxivity study of amino acid-branched radical dendrimers as MRI contrast agents for potential brain tumor imaging.
Acta Biomater
December 2024
Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus UAB, E-08193 Bellaterra, Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina, Instituto de Salud Carlos III, Campus UAB, 08913 Bellaterra, Spain. Electronic address:
This study introduces a series of water-soluble radical dendrimers (G0 to G5) as promising magnetic resonance imaging (MRI) contrast agents that could potentially address clinical safety concerns associated with current gadolinium-based contrast agents. By using a simplified synthetic approach based on a cyclotriphosphazene core and lysine-derived branching units, we successfully developed a G5 dendrimer containing up to 192 units of 2,2,6,6-Tetramethylpiperidinyloxy (TEMPO) radical. This synthesis offers advantages including ease of preparation, purification, and tunable water solubility through the incorporation of glutamic acid anion residues.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!