Tetramethylsilane (TMS) is well-known as a reference standard of H, C and Si NMR chemical shifts. In the present study, we have observed TMS molecules in gaseous and liquid solutions. In the gas phase, the shielding parameters of TMS are monitored as the functions of density when xenon and krypton are applied as the buffer gases. It permits the evaluation of shielding in an isolated TMS molecule which is determined from the measurements of frequency and available nuclear magnetic moments. Having the shielding constants of an isolated TMS molecule, it is possible to proceed with the evaluation of H, C and Si TMS shielding in liquid state, which is extremely useful for the complete referencing of NMR spectra for protons, carbon-13 and silicon-29 nuclei. Consequently, the readings of chemical shifts and shielding parameters can be practically performed in the same experiment.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.jmr.2020.106716 | DOI Listing |
Langmuir
January 2025
College of Pharmacy, Henan University of Chinese Medicine, Zhengzhou 450046, China.
The development of probes for the efficient detection of volatile organic compounds is crucial for both human health protection and environmental monitoring. In this study, we successfully synthesized a ratiometric fluorescent sensing material [Eu-UiO-67 (1:1)], featuring dual-emission fluorescence peaks via a one-pot method. This material demonstrated exceptional ratiometric fluorescence recognition properties for liquid styrene and isoprene, achieving low limit of detections (LODs) of 6.
View Article and Find Full Text PDFSci Adv
January 2025
New Cornerstone Science Laboratory, State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, China.
Small organic molecules are essential building blocks of our universe, from cosmic dust to planetary surfaces to life. Compared to their well-known gaseous and liquid forms that have been extensively studied, small organic molecules in the form of ice at low temperatures receive much less attention. Here, we show that supercooled small-molecule droplets can be drawn into highly uniform amorphous ice microfibers with lengths up to 5 cm and diameters down to 200 nm.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Environmental Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea.
Trichloroethylene (TCE) is widely used in various industrial applications, leading to significant environmental and public health concerns due to its toxicity and persistence. Current nonthermal liquid-phase TCE treatment methods, including electrochemical processes, typically produce liquid byproducts that require additional separation steps, limiting their efficiency. To overcome these challenges, this study introduces an innovative electrochemical approach for the direct conversion of TCE gas into less harmful gaseous products, utilizing a Cu/Ni alloy 3D foam electrode integrated with a poly(vinyl alcohol) (PVA)-sodium polyphosphate (SPP) gel membrane system.
View Article and Find Full Text PDFJ Environ Radioact
January 2025
Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, 87545, NM, USA.
Noble gas transport through geologic media has important applications in the prediction and characterization of measured gas signatures related to underground nuclear explosions (UNEs). Retarding processes such as adsorption can cause significant species fractionation of radionuclide gases, which has implications for measured and predicted signatures used to distinguish radioxenon originating from civilian nuclear facilities or from UNEs. Accounting for the effects of variable water saturation in geologic media on tracer transport is one of the most challenging aspects of modeling gas transport because there is no unifying relationship for the associated tortuosity changes between different rock types, and reactive transport processes such as adsorption that are affected by the presence of water likewise behave differently between gas species.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!