Search results for "MR Spectroscopy"
showing 10 items of 125 documents
Neurochemical correlates of brain atrophy in fibromyalgia syndrome: a magnetic resonance spectroscopy and cortical thickness study
2020
(1) Background: Recently, a series of clinical neuroimaging studies on fibromyalgia (FM) have shown a reduction in cortical volume and abnormally high glutamate (Glu) and glutamate + glutamine (Glx) levels in regions associated with pain modulation. However, it remains unclear whether the volumetric decreases and increased Glu levels in FM are related each other. We hypothesized that higher Glu levels are related to decreases in cortical thickness (CT) and volume in FM patients. (2) Methods: Twelve females with FM and 12 matched healthy controls participated in a session of combined 3.0 Tesla structural magnetic resonance imaging (MRI) and single-voxel MR spectroscopy focused on the thalami…
Further orthometalated dinuclear palladium(iii) compounds with bridging N,S-donor ligands
2013
New dinuclear palladium(III) compounds of general formula Pd2[(C6H4)PPh2]2[N-S]2Cl2, N-S being 2-mercaptopyridinate, 3a; 2-mercapto-6-methylpyridinate, 3b; 2-quinolinethiolate, 3c; 2-mercaptopyrimidinate, 3d; 1-methyl-1H-imidazole-2-thiolate, 3e; 1-methyl-1H-benzimidazole-2-thiolate, 3f; 2-mercaptobenzothiazolate, 3g and 5-mercapto-1-methyltetrazolate, 3h have been obtained by oxidation with PhICl2 of the corresponding palladium(II) counterparts. The stability of the new compounds has been studied by (31)P NMR spectroscopy from 200 to 298 K. Compounds 3f-h were relatively stable until room temperature and they have been synthesized and characterized by (31)P, (1)H and (13)C NMR spectroscopy…
Cyclophosphazenes as versatile substrates in polymer chemistry
2004
In this article we present the synthesis of new cyclophosphazenes and their use as chain extenders, polymers compatibilizers, and monomers.
Expanding the Size of Catecholesters - Modified Ligands for the Hierarchical Assembly of Dinuclear Titanium(IV) Helicates
2015
Five 2,3-dihydroxybenzoic acid derivatives 1 – 5 were used as starting materials to obtain the corresponding methyl and ethyl esters. Those were applied as ligands in the hierarchical self-assembly of lithium-bridged dinuclear titanium(IV) complexes 1a–4a, 1b–3b, and 5b. The equilibria between the mononuclear triscatecholate complexes (monomer) and the dinuclear helicates (dimer) were observed by 1H NMR spectroscopy in [D6]DMSO and [D4]MeOH at room temperature.
Herstellung und 13 C‐NMR‐Spektroskopie isomerer 1,4‐Heterophosphorinanium‐Salze
1978
Die quartaren Diallylphosphonium-Salze 1–8 werden mit Natronlauge, Natriumhyrogensulfid. Ammoniak oder prim. Aminen zu den 1,4-Oxa- (9–14), 1,4-Thia- (15–21) und 1,4-Azaphosphorinanium-Salzen (22–36) umgesetzt. Die Konformation bzw. Konfiguration der in den meisten Fallen als Isomerengemische anfallenden Salze 9–36 wird 1H- bzw. 13C-NMR-spektroskopisch untersucht. Eine Abhangigkeit von der geometrischen Anordnung sowohl der 4JPH- als auch der vicinalen3JPC-Kopplungskonstanten konnte bei diesen nicht gespannten 1,4-Diheterocylohexanen festgestellt werden. Synthesis and 13C NMR Spectra of Isomeric 1,4-Heterophosphorinanium Salts The phosphonium salts 1–8 react with aqueous sodium hydroxide, s…
Di-n-butyltin(IV)-catalyzed dimethyl carbonate synthesis from carbon dioxide and methanol: An in situ high pressure 119Sn{1H} NMR spectroscopic study
2011
The reactivity of five di-n-butyltin(IV) complexes, n-Bu2Sn(OR)(2) (1), n-Bu2SnO (3), [n-Bu2Sn(OR)](2)O (4), (n-Bu2SnO)(2)(CO2) (6) and (n-Bu2SnO)(6)[(n-Bu2SnOR)(2)(CO3)](2) (7) (R = CH3), with CO2, suggested as possible catalyst precursors and key-intermediates for the direct synthesis of dimethyl carbonate from carbon dioxide and methanol, has been investigated using high-pressure Sn-119{H-1} NMR (HP-NMR) spectroscopy. Four of the five precursors studied, i.e. 3, 4, 6 and 7 give rise to an identical Sn-119{H-1} NMR pattern which can be explicitly attributed to the fingerprint of the dimeric form of the 1-methoxy-3-methylcarbonatotetrabutyldistannoxane {5}(2). However, with 1, a new pair o…
On the Ion-Pair Recognition and Indication Features of a Fluorescent Heteroditopic Host Based on a BODIPY Core
2014
A fluorescent heteroditopic host for ion pairs and zwitterionic species has been synthesized. Its affinity towards a series of anions, cations and ion pairs in acetonitrile has been assessed, and the spectroscopic response has been evaluated. Solid–liquid extraction experiments of inorganic salts, α-amino acids and γ-aminobutyric acid (GABA) into acetonitrile solutions were performed, and the resulting complexes were analyzed by UV/Vis absorption, fluorescence and 1H NMR spectroscopy. The discrimination patterns observed have been rationalized in terms of the molecular topologies of the host and guests.
Quantifying the Covalent Functionalization of Black Phosphorus
2020
Abstract A straightforward quantification method to consistently determine the overall functionalization degree of covalently modified two‐dimensional (2D) black phosphorus (BP) by Raman spectroscopy has been carried out. Indeed, the successful reductive methylation of the BP lattice using sodium intercalation compounds and exhibiting different functionalization degrees has been demonstrated by 31P‐magic angle spinning (MAS) NMR spectroscopy. Furthermore, the correlation of 31P‐MAS NMR spectroscopy and statistical Raman spectroscopy (SRS) revealed the first method to determine the functionalization degree of BP solely by evaluating the intensities of distinct peaks in the Raman spectra of t…
Large-Scale Recombinant Production of the SARS-CoV-2 Proteome for High-Throughput and Structural Biology Applications
2021
The highly infectious disease COVID-19 caused by the Betacoronavirus SARS-CoV-2 poses a severe threat to humanity and demands the redirection of scientific efforts and criteria to organized research projects. The international COVID19-NMR consortium seeks to provide such new approaches by gathering scientific expertise worldwide. In particular, making available viral proteins and RNAs will pave the way to understanding the SARS-CoV-2 molecular components in detail. The research in COVID19-NMR and the resources provided through the consortium are fully disclosed to accelerate access and exploitation. NMR investigations of the viral molecular components are designated to provide the essential…
Core oligosaccharide of Escherichia coli B—the structure required for bacteriophage T4 recognition
2015
Abstract The structure of Escherichia coli B strain PCM 1935 core oligosaccharide has been investigated by 1H and 13C NMR spectroscopy, MALDI-TOF MS and ESI MSn. It was concluded that the core oligosaccharide is a pentasaccharide with the following structure: ESI MS/MS analysis revealed that the glycine (a minor component) is linked to the →3,7)- l -α- d -Hepp-(1→ residue.