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ACS Applied Materials & Interfaces Nov 2023Surface impurities can have a significant influence on hydrogen uptake of materials. Examples such as the hydrogen spillover effect demonstrate that even very small...
Surface impurities can have a significant influence on hydrogen uptake of materials. Examples such as the hydrogen spillover effect demonstrate that even very small surface impurity quantities can lead to order-of-magnitude changes in the total amount of hydrogen taken up by a material. In this work, we report the first experimental demonstration of promoted deuterium uptake in Ru thin films by Sn. Deuterium plasma exposures were carried out for Ru-capped targets covered by Sn up to a few atoms in thickness. After the exposure, the residual Sn content and the deuterium retention were measured to quantify the Sn etching and the deuterium uptake, respectively. By increasing the amount of Sn from zero to one atomic layer on Ru, we found after the exposure that the Sn content stays unchanged while the deuterium uptake rate severely increases with the Sn content by 2-3 orders of magnitude. These results can be understood by simulations using a reaction-diffusion model with multiple surface species and the lateral surface migration of deuterium. By contrast, as the as-deposited Sn content goes above one atomic layer, Sn removal takes place, and the deuterium uptake rate decreases with the as-deposited Sn content. Possible explanations are proposed by considering the interplay between Sn etching and deuterium uptake. In all, this work provides insights into interactions between multiple surface species in relation to plasma-induced hydrogen uptake. By further development, this could eventually lead to a potential mitigation method to circumvent the promoted hydrogen uptake in Ru-capped films.
PubMed: 37991270
DOI: 10.1021/acsami.3c11245 -
ACS Applied Materials & Interfaces Oct 2023In recent years, the hybrid silicon-molecular electronics technology has been gaining significant attention for applications in sensors, photovoltaics, power generation,...
In recent years, the hybrid silicon-molecular electronics technology has been gaining significant attention for applications in sensors, photovoltaics, power generation, and molecular electronics devices. However, Si-H surfaces, which are the platforms on which these devices are formed, are prone to oxidation, compromising the mechanical and electronic stability of the devices. Here, we show that when hydrogen is replaced by deuterium, the Si-D surface becomes significantly more resistant to oxidation when either positive or negative voltages are applied to the Si surface. Si-D surfaces are more resistant to oxidation, and their current-voltage characteristics are more stable than those measured on Si-H surfaces. At positive voltages, the Si-D stability appears to be related to the flat band potential of Si-D being more positive compared to Si-H surfaces, making Si-D surfaces less attractive to oxidizing OH ions. The limited oxidation of Si-D surfaces at negative potentials is interpreted by the frequencies of the Si-D bending modes being coupled to that of the bulk Si surface phonon modes, which would make the duration of the Si-D excited vibrational state significantly less than that of Si-H. The strong surface isotope effect has implications in the design of silicon-based sensing, molecular electronics, and power-generation devices and the interpretation of charge transfer across them.
PubMed: 37768872
DOI: 10.1021/acsami.3c11598 -
Journal of the American Society For... May 2024This paper sheds light on the meaning of hydrogen/deuterium exchange-mass spectrometry (HDX-MS) data. HDX-MS data provide not structural information but dynamic...
This paper sheds light on the meaning of hydrogen/deuterium exchange-mass spectrometry (HDX-MS) data. HDX-MS data provide not structural information but dynamic information on an analyte protein. First, the reaction mechanism of backbone amide HDX reaction is considered and the correlation between the parameters from an X-ray crystal structure and the protection factors of HDX reactions of cytochrome is evaluated. The presence of H-bonds in a protein structure has a strong influence on HDX rates which represent protein dynamics, while the solvent accessibility only weakly affects the HDX rates. Second, the energy diagrams of the HDX reaction at each residue in the presence and absence of perturbation are described. Whereas the free energy change upon mutation can be directly measured by the HDX rates, the free energy change upon ligand binding may be complicated due to the presence of unbound analyte protein in the protein-ligand mixture. Third, the meanings of HDX and other biophysical techniques are explained using a hypothetical protein folding well. The shape of the protein folding well describes the protein dynamics and provides Boltzmann distribution of open and closed states which yield HDX protection factors, while a protein's crystal structure represents a snapshot near the bottom of the well. All biophysical data should be consistent yet provide different information because they monitor different parts of the same protein folding well.
Topics: Crystallography, X-Ray; Cytochromes c; Deuterium Exchange Measurement; Hydrogen Bonding; Hydrogen Deuterium Exchange-Mass Spectrometry; Models, Molecular; Protein Conformation; Protein Folding; Proteins; Thermodynamics
PubMed: 38639434
DOI: 10.1021/jasms.4c00044 -
Rapid Communications in Mass... Sep 2023Deuterium-labeled organic compounds, reagents, and drugs are widely used in many scientific research fields. Isotopic purity as the feature parameter of deuterated...
Rapid characterization of isotopic purity of deuterium-labeled organic compounds and monitoring of hydrogen-deuterium exchange reaction using electrospray ionization-high-resolution mass spectrometry.
RATIONALE
Deuterium-labeled organic compounds, reagents, and drugs are widely used in many scientific research fields. Isotopic purity as the feature parameter of deuterated compounds is of great importance. In this article, we used electrospray ionization with high-resolution mass spectrometry (ESI-HRMS) to study isotopic purity of deuterium-labeled organic compounds based on assigning and distinguishing the corresponding H/D (hydrogen-deuterium) isotopolog ions of deuterated compounds.
METHODS
We systematically considered the specific requirements of accuracy and resolution of ESI-HRMS when measuring isotopic purity and demonstrated some actual cases using ESI-HRMS and ultraperformance liquid chromatography (UPLC)-HRMS. Meanwhile, ESI-HRMS/MS of deuterated compounds was performed to obtain more information on deuterium-labeled position characterization.
RESULTS
Two isotopic purity calculation methods based on the relative abundance in ESI-HRMS and UPLC-HRMS of H/D isotopolog ions (D -D ) were compared, which gave consistent isotopic purity values and were in good agreement with the certified isotopic purity values. We further studied and monitored the H/D exchange reaction of ethyl 3-(4-bromophenyl)-3-oxopropanoate (EBPO) by evaluating the dynamic isotopic purity changes in EBPO-D in the H/D exchange reaction in situ.
CONCLUSION
The isotopic purity characterization methods using ESI-HRMS discussed in this article have some outstanding advantages: rapid, highly sensitive, very low sample consumption (even below nanogram level), and deuterated solvent-free. Thus, this low-impact analytical method requires less time and is cost effective and might have good application potential for in-situ isotopic purity analysis and for monitoring the H/D exchange reactions.
PubMed: 36479749
DOI: 10.1002/rcm.9453 -
Chemical Communications (Cambridge,... Dec 2023Photochemical reductive deamination of alpha-amino aryl alkyl ketones under photosensitizer-free conditions is presented. This protocol features high efficiency and...
Photochemical reductive deamination of alpha-amino aryl alkyl ketones under photosensitizer-free conditions is presented. This protocol features high efficiency and selectivity. A plausible reaction pathway is proposed based on ultraviolet-visible absorption investigation, control experiments and deuterium-labelling studies. Mechanistic study reveals that the alpha-hydrogen atom of the ketone product originated from water.
PubMed: 37997158
DOI: 10.1039/d3cc04837c -
Catalysis Science & Technology Aug 2023The preparation of compounds labelled with deuterium or tritium has become an essential tool in a range of research fields. Hydrogen isotope exchange (HIE) offers direct... (Review)
Review
The preparation of compounds labelled with deuterium or tritium has become an essential tool in a range of research fields. Hydrogen isotope exchange (HIE) offers direct access to said compounds, introducing these isotopes in a late stage. Even though the field has rapidly advanced with the use of transition metal catalysis, alkali-metal bases, used as catalysts or under stoichiometric conditions, have also emerged as a viable alternative. In this minireview we describe the latest advances in the use of alkali-metal bases in HIE processes, showcasing their synthetic potential as well as current challenges in the field. It is divided in different sections based on the isotope source used, emphasizing their benefits, disadvantages and limitations. The influence on the choice of alkali-metal in these processes as well as their possible mechanistic pathways are also discussed.
PubMed: 38013748
DOI: 10.1039/d3cy00825h -
Spectrochimica Acta. Part A, Molecular... Dec 2023Raman spectroscopy of cells cultured in a deuterated substrate is a promising approach to the characterization of mass transfer and enzymatic reactions in living cells....
Raman spectroscopy of cells cultured in a deuterated substrate is a promising approach to the characterization of mass transfer and enzymatic reactions in living cells. Here, we studied the potential of this approach using the example of yeast cells cultured under aerobic and anaerobic conditions. In our experiments, unadapted to DO Saccharomyces cerevisiae were cultured in a medium with different concentrations of deuterium oxide and deuterated glucose. It has been shown that the addition of even 10% heavy water leads to a general decrease in the amount of lipids in cells. In the Raman spectra of cells cultured at high concentrations of DO, additional peaks are found, which are associated with the deuteration of entire chemical groups. We observed a similar effect in the ethanol synthesized by yeast fermentation, the deuteration of which also depends on the concentration of DO. The results on the characterization of cell deuteration turned out to be in qualitative agreement with the known estimate that aerobic metabolism is 15 times more active than ethanol fermentation. The results of our work determine new limitations and prospects for further application and development of the Raman method of spectroscopy of deuterium tags.
Topics: Saccharomyces cerevisiae; Spectrum Analysis, Raman; Ethanol; Fermentation; Glucose
PubMed: 37607454
DOI: 10.1016/j.saa.2023.123262 -
Nature Communications Jun 2024Carboxylic acids are widely available and generally inexpensive from abundant biomass feedstocks, and they are suitable and generic coupling partners in synthetic...
Carboxylic acids are widely available and generally inexpensive from abundant biomass feedstocks, and they are suitable and generic coupling partners in synthetic chemistry. Reported herein is an electroreductive coupling of stable and versatile carboxylic acids with (hetero)arenes using protons as the hydrogen source. The application of an earth-abundant titanium catalyst has significantly improved the deoxygenative reduction process. Preliminary mechanistic studies provide insights into the deoxygenative reduction of in-situ generated ketone pathway, and the intermediacy generation of ketyl radical and alkylidene titanocene. Without the necessity of pressurized hydrogen or stoichiometric hydride as reductants, this protocol enables highly selective and straightforward synthesis of various functionalized and structurally diverse alkylbenzenes under mild conditions. The utility of this reaction is further demonstrated through practical and valuable isotope incorporation from readily available deuterium source.
PubMed: 38862567
DOI: 10.1038/s41467-024-49355-1 -
Scientific Reports Sep 2023In vivo deuterated water (HO) labeling leads to deuterium (H) incorporation into biomolecules of proliferating cells and provides the basis for its use in cell kinetics...
In vivo deuterated water (HO) labeling leads to deuterium (H) incorporation into biomolecules of proliferating cells and provides the basis for its use in cell kinetics research. We hypothesized that rapidly proliferating cancer cells would become preferentially labeled with H and, therefore, could be visualized by deuterium magnetic resonance imaging (dMRI) following a brief period of in vivo systemic HO administration. We initiated systemic HO administration in two xenograft mouse models harboring either human colorectal, HT-29, or pancreatic, MiaPaCa-2, tumors and HO level of ~ 8% in total body water (TBW). Three schemas of HO administration were tested: (1) starting at tumor seeding and continuing for 7 days of in vivo growth with imaging on day 7, (2) starting at tumor seeding and continuing for 14 days of in vivo growth with imaging on day 14, and (3) initiation of labeling following a week of in vivo tumor growth and continuing until imaging was performed on day 14. Deuterium chemical shift imaging of the tumor bearing limb and contralateral control was performed on either day 7 of 14 after tumor seeding, as described. After 14 days of in vivo tumor growth and 7 days of systemic labeling with HO, a clear deuterium contrast was demonstrated between the xenografts and normal tissue. Labeling in the second week after tumor implantation afforded the highest contrast between neoplastic and healthy tissue in both models. Systemic labeling with HO can be used to create imaging contrast between tumor and healthy issue, providing a non-radioactive method for in vivo cancer imaging.
Topics: Humans; Animals; Mice; Heterografts; Deuterium; Magnetic Resonance Imaging; Transplantation, Heterologous; Administration, Cutaneous; Disease Models, Animal; Neoplasm Seeding
PubMed: 37679461
DOI: 10.1038/s41598-023-41163-9 -
Angewandte Chemie (International Ed. in... Nov 2023Deuterium labelling of organic compounds is an important process in chemistry. We report the first example of photocatalytic dehalogenative deuteration of both...
Deuterium labelling of organic compounds is an important process in chemistry. We report the first example of photocatalytic dehalogenative deuteration of both arylhalides and alkylhalides (40 substrates) over a metal-organic framework, MFM-300(Cr), using CD CN as the deuterium source at room temperature. MFM-300(Cr) catalyses high deuterium incorporation and shows excellent tolerance to various functional groups. Synchrotron X-ray powder diffraction reveals the activation of halogenated substrates via confined binding within MFM-300(Cr). In situ electron paramagnetic resonance spectroscopy confirms the formation of carbon-based radicals as intermediates and reveals the reaction pathway. This protocol removes the use of precious-metal catalysts from state-of-the-art processes based upon direct hydrogen isotope exchange and shows high photocatalytic stability, thus enabling multiple catalytic cycles.
PubMed: 37783657
DOI: 10.1002/anie.202306267