It is shown that the proton chemical-shift anisotropy of hydrate crystals affect dipolar powder pattern at 7.0 T. This may be clearly observed via an asymmetric envelope of dipolar spinning sidebands in magic-angle spinning proton spectra.
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http://dx.doi.org/10.1006/jmre.1997.1209 | DOI Listing |
Quant Imaging Med Surg
January 2025
Paul. C. Lauterbur Research Centers for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
Background: Brain temperature signifies the thermal homeostasis of the tissue, and may serve as a marker for neuroprotective therapy. Currently, it remains challenging to map the human brain temperature with high spatial resolution. The thermal dependence of chemical exchange saturation transfer (CEST) effects of endogenous labile protons may provide a promising mechanism for the absolute brain temperature imaging.
View Article and Find Full Text PDFRSC Adv
January 2025
Department of Physics and Chemistry, Faculty of Education, Alexandria University Egypt.
A novel series of azo dyes was successfully synthesized by combining amino benzoic acid and amino phenol on the same molecular framework azo linkage. The structural elucidation of these dyes was carried out using various spectroscopic techniques, including UV-vis, FT-IR, NMR spectroscopy, and HRMS. Surprisingly, the aromatic proton in some dyes exhibited exchangeability in DO, prompting a 2D NMR analysis to confirm this phenomenon.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Memorial University of Newfoundland, Chemistry, Department of Chemistry, 230 Elizabeth avenue, A1B 3X7, St. John's, CANADA.
Developing the mechanism for MOF formation is crucial for the rapid development of new materials. This work demonstrates that Deuterium-NMR spectroscopy is the optimal inter-laboratory methodology for understanding the in-situ kinetics of metal-organic framework (MOF) formation. This method is facile, affordable, and allows for the isolation and monitoring of individual reagents by using one deuterated component while the remaining components are protonated.
View Article and Find Full Text PDFMolecules
January 2025
Institute of Organic Synthesis and Coal Chemistry of the Republic of Kazakhstan, 1 Alikhanov St., Karaganda 100008, Kazakhstan.
The synthetic availability and wide range of biological activity of hydrazides and hydrazones make them attractive subjects for investigation. In this study, we focused on synthesis of 2-methyl-5-nitro-6-phenylnicotinohydrazide-based hydrazones derived from the corresponding substituted aldehydes. The structure of the obtained compounds was studied using NMR spectroscopy and DFT calculations.
View Article and Find Full Text PDFMagn Reson Med
January 2025
Mouse Imaging Centre (MICe), Hospital for Sick Children, Toronto, Ontario, Canada.
Purpose: Brain temperature is tightly regulated and reflects a balance between cerebral metabolic heat production and heat transfer between the brain, blood, and external environment. Blood temperature and flow are critical to the regulation of brain temperature. Current methods for measuring in vivo brain and blood temperature are invasive and impractical for use in small animals.
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