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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Nebulization Prior to Isolation, Ionization, and Dissociation of the Neutral Serine Octamer Allows Its Characterization

Nebulization of enantiomerically mixed serine solutions, followed by ion deflection and gentle on-line protonation, is used to isolate and characterize the strongly preferred homochiral neutral serine octamer (Ser 8 ). The separation of the nebulization and ionization steps and the use of the enantiomeric l-serine ion (l-d 3 Ser) 8 H + as a soft protonating agent ensured that neutral (d-Ser) 8 was characterized without interference from serine octamer ((d-Ser) 8 H + ) ions. MS/MS experiments showed that the ionized neutral octamer and the protonated octamer formed directly by ESI have the same structures. Experiments in which the temperature of the heated transfer tube was varied indicate dissociation of the neutral octamer to the dimer. Field-free nebulization of racemic serine forms the separate homochiral species with very high chiral selectivity. We suggest that the homochiral preference is a property of (d-Ser)8 and that the preference observed earlier for (d-Ser) 8 H + is simply an expression of this feature of the neutral cluster.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Selective Synthesis of a Series of Isostructural M II Cu I Heterobimetallic Complexes Spontaneously Assembled by an Unsymmetrical Naphthyridine‐Based Ligand

Abstract Metal–metal cooperation is integral to the function of many enzymes and materials, and model complexes hold enormous potential for providing insights into the capabilities of analogous multimetallic cores. However, the selective synthesis of heterobimetallic complexes still presents a significant challenge, especially for systems that hold the metals in close proximity and feature open or reactive coordination sites for both metals. To address this issue, a rigid, naphthyridine‐based dinucleating ligand featuring distinct binding environments was synthesized. This ligand enables the selective synthesis of a series of M II Cu I bimetallic complexes (M=Mn, Fe, Co, Ni, Cu, Zn), in which each metal center exclusively occupies its preferred binding pocket, from simple chloride salts. The precision of this selectivity is evident from cyclic voltammetry, ESI‐MS and anomalous X‐ray diffraction measurements.

Nicolay, Amélie↗
DOE OSTI2022

Construction of Photo‐Responsive Pd 2 L 4 ‐Type Nanocages based on Feringa's Second‐Generation Motor and Its Guest Binding Ability for C 60

Abstract We present the construction of a M 2 L 4 ‐type metal‐organic nanocage featuring four endohedral Feringa's motor motifs and its adaptive encapsulation towards a C 60 guest molecule. The structure of the cage, though complicated on the 1 H NMR spectrum due to the adoption of mixed ligands, was unambiguously characterized with a combination of ESI‐MS, 2D DOSY, 13 C NMR and particularly the SAXS technique. The molecular motor within the cage demonstrated similar photophysical properties to the uncoordinated one, indicating the motor's function was not compromised when it was anchored in such a confined nanospace. Furthermore, the nanocage showed good guest encapsulation ability towards C 60 , and a guest induced‐fit behavior of the cage was revealed based on the extensive SAXS analysis and molecular dynamics simulation. The adaptive motorized nanocage reported here represents one of the very few examples of integrating individual motors into a discrete nanoconfined system and offers prospects to achieve its non‐equilibrium functions.

Chemistry↗
DOE OSTI2023

Pertechnetate/perrhenate–capped Zr/Hf–Dihydroxide Dimers: Elucidating Zr–TcO 4 Co–Mobility in the Nuclear Fuel Cycle

Spent nuclear fuel contains heavy element fission products that must be separated for effective reprocessing for a safe and sustainable nuclear fuel cycle. 93 Zr and 99 Tc are high-yield fission products that co-transport in liquid-liquid extraction processes. Here we seek atomic-level information of this co-extraction process, as well as fundamental knowledge about Zr IV (and Hf IV ) aqueous speciation in the presence of topology-directing ligands such as pertechnetate (TcO 4 – ) and non-radioactive surrogate perrhenate (ReO 4 – ). In this context, we show that the flat tetrameric oxyhydroxyl-cluster [M IV 4 (OH) 8 (H 2 O) 16 ] 8+ (and related polymers) is dissociated by perrhenate/pertechnetate to yield isostructural dimers, M 2 (OH) 2 (XO 4 – ) 6 (H 2 O) 6 • 3H 2 O (M=Zr/Hf IV ; X=Re/Tc VII ), elucidated by single-crystal X-ray diffraction. We used these model compounds to understand the pervasive 93 Zr- 99 Tc coextraction with further speciation studies in water, nitric acid, and tetrabutylphosphate (TBP) -kerosene; where the latter two media are relevant to nuclear fuel reprocessing. SAXS (small angle X-ray scattering), compositional evaluation, and where experimentally feasible, ESI-MS (electrospray ionization mass spectrometry) showed that perrhenate/pertechnetate influence Zr/Hf IV -speciation in water. Here, in Zr-XO 4 solvent extraction studies to simulate fuel reprocessing, we provide evidence that TcO 4 – enhances extraction of Zr IV , and compositional analysis of the extracted metal-complexes (Zr-ReO 4 study) is consistent with the crystallized Zr IV 2 (OH) 2 (Re VII O 4 – ) 6 (H 2 O) 6 •dimer.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2024

Probing Noncovalent Interaction Strengths of Host-Guest Complexes Using Negative Ion Photoelectron Spectroscopy

Noncovalent interactions (NCIs) are crucial for the formation and stability of host-guest complexes, which have wide-ranging implications across various fields, including biology, chemistry, materials science, pharmaceuticals, and environmental science. However, since NCIs are relatively weak and sensitive to bulk perturbation, direct and accurate measurement of their absolute strength has always been a significant challenge. This concept article aims to demonstrate the gas-phase electrospray ionization (ESI)-negative ion photoelectron spectroscopy (NIPES) as a direct and precise technique to measure the absolute interaction strength, probe nature of NCIs, and reveal the electronic structural information for host-guest complexes. Here, our recent studies in investigating various host-guest complexes that involve various types of NCIs such as anion–π, (di)hydrogen bonding, charge-separated ionic interactions, are overviewed. Finally, a summary and outlook are provided for this field.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Synthesis and Characterization of Gold Clusters Ligated with 1,3-Bis(dicyclohexylphosphino)propane

In this multidisciplinary study we combine chemical reduction synthesis of novel gold clusters in solution with high-resolution analytical mass spectrometry (MS) to gain insight into the composition of the gold clusters and how their size, ionic charge state and ligand substitution influences their gas-phase fragmentation pathways. Ultra small cationic gold clusters ligated with 1,3-bis(dicyclohexylphosphino)propane (DCPP) were synthesized for the first time and introduced into the gas phase using electrospray ionization (ESI). Mass-selected cluster ions were fragmented employing collision induced dissociation (CID) and the product ions were analysed using MS. The solutions were found to contain the multiply charged cationic gold clusters Au9L43+, Au13L53+, Au6L32+, Au8L32+ and Au10L42+ (L = DCPP). The gas-phase fragmentation pathways of these cluster ions were examined systematically employing CID combined with MS. In addition, CID experiments were performed on related gold clusters of the same size and ionic charge state but capped with 1,3-bis(diphenylphosphino)propane (DPPP) ligands containing phenyl functional groups at the two phosphine centers instead of cyclohexane rings. It is shown that this relatively small change in the molecular substitution of the two phosphine centers in diphosphine ligands (C6H11 versus C6H5) exerts a pronounced influence on the size of the species that are preferentially formed in solution during reduction synthesis as well as the gas-phase fragmentation channels of otherwise identical gold cluster ions. The mass spectrometry results indicate that in addition to the length of the alkyl chain between the two phosphine centers, the substituents at the phosphine centers also play a crucial role in determining the composition, size and stability of diphosphine ligated gold clusters synthesized in solution.

Johnson, Grant E.↗
DOE OSTI2016

Semiconductor-Based, Solar-Driven Photochemical Cells for Fuel Generation from Carbon Dioxide in Aqueous Solutions

There has been active interest to identify new methods to reduce CO 2 into usable fuel sources. In this work, we demonstrate two types of photo-electrochemical cells (PECs) that photoreduce CO 2 directly to formate in aqueous solutions both in the presence and absence of external bias or additional electron sources. The photocathodes were either a CuFeO 2 /CuO electrode or a bilayer of CdTe on NiO, whereas the photoanode was a bilayer of NiO x on CdS. The PECs were characterized by using both electrochemistry and spectroscopy, and the products formed from CO 2 reduction were characterized and quantified by using 1 H NMR spectroscopy and ESI-MS. In addition, an organohydride catalyst was tested in conjunction with the PECs, which not only showed a significant gain of 85 times in CO 2 reduction (27 μm formate without the catalyst, 2.3 mm formate with it) compared to the NiO/CdTe photocathode system but could also generate methanol under an external bias (10 μm).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Improved ion optics for introduction of ions into a 9.4-T Fourier transform ion cyclotron resonance mass spectrometer

Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry provides unparalleled mass accuracy and resolving power.[1],[2] With electrospray ionization (ESI), ions are typically transferred into the mass spectrometer through a skimmer, which serves as a conductance-limiting orifice. However, the skimmer allows only a small fraction of incoming ions to enter the mass spectrometer. An ion funnel, originally developed by Smith and coworkers at Pacific Northwest National Laboratory (PNNL)[3-5] provides much more efficient ion focusing and transfer. The large entrance aperture of the ion funnel allows almost all ions emanating from a heated capillary to be efficiently captured and transferred, resulting in nearly lossless transmission.

42 ENGINEERING↗
DOE OSTI2015

An Open Port Sampling Interface for Liquid Introduction Atmospheric Pressure Ionization Mass Spectrometry

RATIONALE: A simple method to introduce unprocessed samples into a solvent for rapid characterization by liquid introduction atmospheric pressure ionization mass spectrometry has been lacking. The continuous flow, self-cleaning open port sampling interface introduced here fills this void. METHODS: The open port sampling interface used a vertically aligned, co-axial tube arrangement enabling solvent delivery to the sampling end of the device through the tubing annulus and solvent aspiration down the center tube and into the mass spectrometer ionization source via the commercial APCI emitter probe. The solvent delivery rate to the interface was set to exceed the aspiration rate creating a continuous sampling interface along with a constant, self-cleaning spillover of solvent from the top of the probe. RESULTS: Using the open port sampling interface with positive ion mode APCI and a hybrid quadrupole time of flight mass spectrometer, rapid, direct sampling and analysis possibilities are exemplified with plastics, ballpoint and felt tip ink pens, skin, and vegetable oils. These results demonstrated that the open port sampling interface could be used as a simple, versatile and self-cleaning system to rapidly introduce multiple types of unprocessed, sometimes highly concentrated and complex, samples into a solvent flow stream for subsequent ionization and analysis by mass spectrometry. The basic setup presented here could be incorporated with any self-aspirating liquid introduction ionization source (e.g., ESI, APCI, APPI, ICP, etc.) or any type of atmospheric pressure sampling ready mass spectrometer system. CONCLUSIONS: The open port sampling interface provides a means to introduce and quickly analyze unprocessed solid or liquid samples with liquid introduction atmospheric pressure ionization source without fear of sampling interface or ionization source contamination.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Rapid sample classification using an open port sampling interface coupled with liquid introduction atmospheric pressure ionization mass spectrometry

An “Open Access”-like mass spectrometric platform to fully utilize the simplicity of the manual open port sampling interface for rapid characterization of unprocessed samples by liquid introduction atmospheric pressure ionization mass spectrometry has been lacking. The in-house developed integrated software with a simple, small and relatively low-cost mass spectrometry system introduced here fills this void. Software was developed to operate the mass spectrometer, to collect and process mass spectrometric data files, to build a database and to classify samples using such a database. These tasks were accomplished via the vendorprovided software libraries. Sample classification based on spectral comparison utilized the spectral contrast angle method. As a result, using the developed software platform near real-time sample classification is exemplified using a series of commercially available blue ink rollerball pens and vegetable oils. In the case of the inks, full scan positive and negative ion ESI mass spectra were both used for database generation and sample classification. For the vegetable oils, full scan positive ion mode APCI mass spectra were recorded. The overall accuracy of the employed spectral contrast angle statistical model was 95.3% and 98% in case of the inks and oils, respectively, using leave-one-out cross-validation. In conclusion, this work illustrates that an open port sampling interface/mass spectrometer combination, with appropriate instrument control and data processing software, is a viable direct liquid extraction sampling and analysis system suitable for the non-expert user and near real-time sample classification via database matching.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

A new triterpene diglycoside from the roots of Bupleurum chinense DC. and its inhibitory effect on adipogensis in 3T3-L1 cells

A new triterpene diglycoside, tibesaikosaponin V (TKV), was isolated from the methanol extract of the roots of Bupleurum chinense DC. by normal and reversed phase column chromatography. The chemical structure of this new compound was elucidated based on extensive spectroscopic analysis, including 1D and 2D NMR, HR-ESI-MS, and chemical degradation method. Our results indicated that TKV inhibited lipid accumulation and triacylglycerol content occurred without cytotoxicity to 3T3-L1 adipocytes. Furthermore, TKV significantly suppressed the mRNA expression of nuclear transcription factors such as, peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBPα). These results suggest that TKV shows the ability to inhibit 3T3-L1 preadipocyte differentiation of and may have therapeutic potential for obesity and its associated metabolic disorders.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

N, N’-disubstitutedphenyl-4-ethoxyl benzene-1, 3-disulfonamides: design, synthesis, and evaluation of anti-platelet aggregation activity

According to the bio-isosterism theory, a series of N, N’-disubstitutedphenyl-4-ethoxylbenzene-1, 3-disulfonamides (5a-p) were designed and synthesized by two steps of reactions including chlorosulfonation and ammonolysis. The structures of all compounds have been confirmed by IR, {sup 1}H-NMR, {sup 13}C-NMR, and ESI-MS spectra. The in vitro anti-platelet aggregation activities were evaluated by Born’s test induced by adenosine diphosphate (ADP) and arachidonic acid (AA), respectively. The biological evaluation results revealed that compound 5h had the lowest IC{sub 50} value (0.32 μM) and the highest inhibition rate (40.9 %) that of three positive control agents clopidogrel (0.41 μM, 23.5 %), aspirin (0.53 μM, 28.9 %), and picotamide (0.76 μM, 32.7 %). Afterwards, compounds with higher activities were selected to further study in vitro cytotoxicity via cell counting kit-8 (CCK-8) assay. The cytotoxicity results indicated that compound 5h had simultaneously the lowest cytotoxicity, while other compounds had no significant relationship between the anti-platelet activities and cytotoxicities. Based on above in vitro anti-platelet activity data, the SAR (Structure Activity Relationship) of the target compounds was preliminarily summarized. In general, N, N’-disubstitutedphenyl-4-ethoxylbenzene-1, 3-disulfonamides have the potential of further study and very likely become safer and more effective anti-platelet agents.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Highly Selective Detection of Cr{sup 3+} Ion with Colorimetric & Fluorescent Response Via Chemodosimetric Approach in Aqueous Medium

So far, very few numbers of chemosensors for Cr{sup 3+} ion have been reported. However, the main drawback of reported receptors are the lack of selectivity and other trivalent cations such as Fe{sup 3+}, Al{sup 3+} and anions like F{sup −} and {sup −}OAc frequently interfere with such assays. This paper present the synthesis, characterization & sensor studies of Schiff base containing naphthalene moiety which selectively detect Cr{sup 3+} ion by chemodosimetric approach. Using FT-IR, {sup 1}H NMR, {sup 13}C NMR and ESI mass spectroscopic techniques the probe was characterized. This receptor exhibit more selectivity and sensitivity towards Cr{sup 3+} than other divalent and trivalent cations like Mn{sup 2+}, Zn{sup 2+}, Co{sup 2+}, Ni{sup 2+}, Cd{sup 2+}, Cu{sup 2+}, Hg{sup 2+}, Fe{sup 3+}, and Al{sup 3+} ions. After the addition of chromium ion the receptor get change from yellow to colorless in aqueous medium. But no color change was observed on the addition of other metal ions. Using UV-Vis and PL studies, it was confirmed that the selective hydrolysis of imine group of receptor by Cr{sup 3+} ions takes place with high fluorescence enhancement that is corresponding to 1-naphthylamine. Receptor acts as selective chemodosimeter for Cr{sup 3+} ions with 2:1 stoichiometry and micro molar detection limit. This chemodosimetric approach was applied successfully for bio-imaging of HeLa cells.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Study of Specific Interaction between bis(p-phenylene)-34-crown-10-based Substituted Macrocycle and Ni{sup 2+}

A novel macrocyclic host has been synthesized for the determination of Ni (II) ions in aqueous solution (H{sub 2}O-CH{sub 3}CN, v/v = 1:1). Its molecular structure has been verified by {sup 1}H-NMR, {sup 13}C NMR and mass spectrometry (ESI).This probe shows selectivity towards the presence of Ni (II) ion among various alkali, alkaline earth, and transition metal ions. The formation of a new fluorescence band at 311 nm has been detected due to possible complex formation with increasing Ni{sup 2+} concentration in the range of 10{sup −5}–10{sup −4} M. The detection limit is calculated to be 5.22 μM. To our knowledge, it will be the first case for bis(p-phenylene)-34-crown-10 based molecules to recognize Ni{sup 2+} ions.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2018

A Dual-Target Fluorescent Probe with Response-Time Dependent Selectivity for Cd{sup 2+} and Cu{sup 2+}

A novel fluorescent probe (NT) was developed by merging 2-hydrazinylbenzothiazole with 2-hydroxy-1-naphthaldehyde for the detection of Cd{sup 2+} and Cu{sup 2+}. The probe alone is almost nonfluorescent due to the isomerization of C=N in the excited state. The addition of Cd{sup 2+} can cause an immediate strong green fluorescence owing to the suppression of C=N isomerization by Cd{sup 2+}-coordination. Furthermore, NT gives a delayed turn-on fluorescence response to Cu{sup 2+} although it is a vigorous fluorescence quencher, which was thanks to the inhibition of the electron transfer between excited fluorophore and paramagnetic Cu{sup 2+} by sulfur donor. Based on fluorescence spectra and ESI-MS analysis, the binding modes between NT and Cd{sup 2+}/Cu{sup 2+} were proposed.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2014

Picoelectrospray Ionization Mass Spectrometry Using Narrow-bore Chemically Etched Emitters

Electrospray ionization mass spectrometry (ESI-MS) at flow rates below ~10 nL/min has been only sporadically explored due to difficulty in reproducibly fabricating emitters that can operate at lower flow rates. Here we demonstrate narrow orifice chemically etched emitters for stable electrospray at flow rates as low as 400 pL/min. Depending on the analyte concentration, we observe two types of MS signal response as a function of flow rate. At low concentrations, an optimum flow rate is observed slightly above 1 nL/min, while the signal decreases monotonically with decreasing flow rates at higher concentrations. In spite of lower MS signal, the ion utilization efficiency increases exponentially with decreasing flow rate in all cases. No unimolecular response was observed within this flow rate range during the analysis of an equimolar mixture of peptides, indicating that ionization efficiency is an analyte-dependent characteristic in given experimental conditions. While little to no gain in signal-to-noise was achieved at ultralow flow rates for concentration-limited analyses, experiments consuming the same amount of analyte suggest that mass-limited analyses will benefit strongly from the use of low flow rates and avoiding unnecessary sample dilution. By operating under optimal conditions, consumption of just 500 zmol of sample yielded signal-to-noise ratios ~10 for some peptides. These findings have important implications for the analysis of trace biological samples.

Environmental Molecular Sciences Laboratory↗
DOE OSTI2015

Gas-Phase Fragmentation Pathways of Mixed-Addenda Keggin Anions: PMo12-nWnO403- (n = 0-12)

We report a collision-induced dissociation (CID) investigation of the mixed addenda polyoxometalate (POM) anions, PMo12-nWnO403- (n = 0-12). The anions were generated in solution using a straightforward single-step synthesis approach and introduced into the gas phase by electrospray ionization (ESI). Distinct differences in fragmentation patterns were observed for the range of mixed POMs examined in this study. CID of molybdenum-rich anions, PMo12- nWnO403- (n = 0-2), generates an abundant doubly charged fragment containing seven metal atoms (M) and twenty-two oxygen atoms (M7O222-) and its complementary singly charged PM5O18- ion, while the Lindqvist anion, (M6O192-) and its complementary PM6O21- ion are the dominant fragments of Keggin POMs containing more than two tungsten atoms, PMo12-nWnO403- (n = 3-12). The observed transition in the dissociation pathways with an increase in the number of W atoms may be attributed to the higher stability of tungsten-rich anions towards isomerization. We find that the observed distribution of Mo and W atoms in the major M6O192- and M7O222- fragment ions is different from that predicted by a random distribution indicating substantial segregation of the addenda metal atoms in the POMs. Electron detachment from the triply charged precursor anion resulting in formation of doubly charged anions is observed. This is a dominant dissociation pathway for mixed POMs having a majority (8-11) of W atoms and a minor channel for other precursors indicating a close competition between fragmentation and electron detachment pathways of POM anions.

13 isomerization↗
DOE OSTI2017

Adduct Formation in ESI/MS by Mobile Phase Additives

Adduct formation is a common ionization method in electrospray ionization mass spectrometry (ESI/MS). However, this process is poorly understood and complicated to control. We demonstrate possibilities to control adduct formation via mobile phase additives in ESI positive mode for 17 oxygen and nitrogen bases. Mobile phase additives were found to be a very effective measure for manipulating the formation efficiencies of adducts. An appropriate choice of additive may increase sensitivity by up to three orders of magnitude. In general, sodium adduct [M + Na]{sup +} and protonated molecule [M + H]{sup +} formation efficiencies were found to be in good correlation; however, the former were significantly more influenced by mobile phase properties. Although the highest formation efficiencies for both species were observed in water/acetonitrile mixtures not containing additives, the repeatability of the formation efficiencies was found to be improved by additives. It is concluded that mobile phase additives are powerful, yet not limiting factors, for altering adduct formation. .

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗