In this article a method to assess the location of paramagnetic centers in nanodiamonds was proposed. The nuclear magnetic relaxation of adsorbed He used as a probe in this method was studied at temperatures of 1.5-4.2 K and magnetic fields of 100-600 mT. A strong influence of the paramagnetic centers of the sample on the He nuclear spin relaxation time T was found. Preplating the nanodiamond surface with adsorbed nitrogen layers allowed us to vary the distance from He nuclei to paramagnetic centers in a controlled way and to determine their location using a simple model. The observed T minima in temperature dependences are well described within the frame of the suggested model and consistent with the concentration of paramagnetic centers determined by electron paramagnetic resonance. The average distance found from the paramagnetic centers to the nanodiamond surface (0.5 ± 0.1 nm) confirms the well-known statement that paramagnetic centers in this type of nanodiamond are located in the carbon shell. The proposed method can be applied to detailed studies of nano-materials at low temperatures.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1039/c7cp05898e | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Paramagnetic rim lesion formation is predicted by the initial gadolinium-enhancing lesion diameter.
Mult Scler
January 2025
Department of Neurology, University of Massachusetts Memorial Medical Center and University of Massachusetts Chan Medical School, Worcester, MA, USA.
Background: Paramagnetic rim lesions (PRLs) are a magnetic resonance imaging (MRI) marker of compartmentalized intraparenchymal inflammation.
Objectives: The primary objective was to investigate clinical, demographic, and MRI factors that may be predictive of the future formation of PRL.
Methods: This is a retrospective analysis of longitudinal data.
Ambient Temperature Isolation of a Monatomic Boron(0) Complex.
J Am Chem Soc
January 2025
Department of Chemistry, Charles E. Fipke Centre for Innovative Research, University of British Columbia, Okanagan Campus, 3247 University Way, Kelowna, BC V1V 1V7, Canada.
The first bottleable example of a neutral Group 13 atom bound only by neutral donor ligands (L) has been fully characterized by spectroscopic methods and its structure determined by a single-crystal X-ray diffraction study. A two-coordinate paramagnetic LB complex can readily be accessed through a facile reduction reaction and is stabilized by π-accepting cyclic (alkyl)(amino)carbene (CAAC) ligands. Further reduction of (CAAC)B leads to the isolation of a stable diamagnetic boride anion.
View Article and Find Full Text PDFPaddlewheel-type and half-paddlewheel-type diruthenium(II,II) complexes with 1,8-naphthyridine-2-carboxylate.
Dalton Trans
January 2025
Department of Chemistry, Graduate School of Natural Science and Technology, Shimane University, 1060, Nishikawatsu, Matsue, Shimane, 690-8504, Japan.
Paddlewheel-type diruthenium(II,II) complexes are paramagnetic with two unpaired electrons ( = 1) and can be utilized as versatile building blocks for higher-order structures, such as supramolecular complexes, coordination polymers, and metal-organic frameworks, although they are generally highly air-sensitive. In this study, we developed an air-stable paddlewheel-type diruthenium(II,II) complex with two electron-withdrawing 1,8-naphthyridine-2-carboxylate (npc) ligands, [Ru(μ-npc)(OCMe)] (1). The two acetate ligands in 1 can be replaced by other carboxylate ligands; the solvothermal reactions of 1 with benzoic acid (HOCPh) yields the heteroleptic [Ru(μ-npc)(OCPh)] (2), whereas its reaction with 1,8-naphthyridine-2-carboxylic acid (Hnpc) produces the homoleptic [Ru(μ-npc)(η-npc)] (3).
View Article and Find Full Text PDFLight-induced electron spin qubit coherences in the purple bacteria reaction center protein.
Phys Chem Chem Phys
January 2025
Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439, USA.
Photosynthetic reaction center proteins (RCs) provide ideal model systems for studying quantum entanglement between multiple spins, a quantum mechanical phenomenon wherein the properties of the entangled particles become inherently correlated. Following light-generated sequential electron transfer, RCs generate spin-correlated radical pairs (SCRPs), also referred to as entangled spin qubit (radical) pairs (SQPs). Understanding and controlling coherence mechanisms in SCRP/SQPs is important for realizing practical uses of electron spin qubits in quantum sensing applications.
View Article and Find Full Text PDFA Combined Approach to Extract Rotational Dynamics of Globular Proteins Undergoing Liquid-Liquid Phase Separation.
J Phys Chem B
January 2025
Department of Physical Chemistry, Sciences II, University of Geneva, 30 Quai Ernest Ansermet, Geneva 1211, Switzerland.
The formation of protein condensates (droplets) via liquid-liquid phase separation (LLPS) is a commonly observed phenomenon in vitro. Changing the environmental properties with cosolutes, molecular crowders, protein partners, temperature, pressure, etc. has been shown to favor or disfavor the formation of protein droplets by fine-tuning the water-water, water-protein, and protein-protein interactions.
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!