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At least 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Effect of Redox-Inactive Metal Ion–Nickel(III) Interactions on the Redox Properties and Proton-Coupled Electron Transfer Reactivity

We report Mononuclear nickel(II) and nickel(III) complexes of a bisamidate-bisalkoxide ligand, (NMe 4 ) 2 [Ni- II (HMPAB)] (1) and (NMe 4 )[Ni III (HMPAB)] (2), respectively, have been synthesized and characterized by various spectroscopic techniques including X-ray crystallography. The reaction of redox-inactive metal ions (M n+ = Ca 2+ , Mg 2+ , Zn 2+ , Y 3+ , and Sc 3+ ) with 2 resulted in 2-M n+ adducts, which was assessed by an array of spectroscopic techniques including X-ray absorption spectroscopy (XAS), electron paramagnetic resonance (EPR), and reactivity studies. The X-ray structure of Ca 2+ coordinated to Ni(III) complexes, 2Ca 2+ T, was determined and exhibited an average Ni-Ca distance of 3.1253 angstrom, close to the metal ions' covalent radius. XAS analysis of 2-Ca 2+ and 2-Y 3+ in solution further revealed an additional coordination to Ca and Y in the 2-M n+ adducts with shortened Ni-M distances of 2.15 and 2.11 Å, respectively, implying direct bonding interactions between Ni and Lewis acids (LAs). Such a short interatomic distance between Ni(III) and M is unprecedented and was not observed before. EPR analysis of 2 and 2-M n+ species, moreover, displayed rhombic signals with g av > 2.12 for all complexes, supporting the +III oxidation state of Ni. The Ni III /Ni II redox potential of 2 and 2-M n+ species was determined, and a plot of E 1/ 2 of 2-M n+ versus pK a of [M(H 2 O) n ] m+ exhibited a linear relationship, implying that the Ni III /Ni II potential of 2 can be tuned with different redox-inactive metal ions. Reactivity studies of 2 and 2-M n+ with different 4-X-2,6-ditert-butylphenol (4-XDTBP) and other phenol derivatives were performed, and based on kinetic studies, we propose the involvement of a proton-coupled electron transfer (PCET) pathway. Analysis of the reaction products after the reaction of 2 with 4-OMe-DTBP showed the formation of a Ni(II) complex (1a) where one of the alkoxide arms of the ligand is protonated. A pK a value of 24.2 was estimated for 1a. The reaction of 2-M n+ species was examined with 4-OMe-DTBP, and it was observed that the k 2 values of 2-M n+ species increase by increasing the Lewis acidity of redox-inactive metal ions. However, the obtained k 2 values for 2-M n+ species are much lower compared to the k 2 value for 2. Such a variation of PCET reactivity between 2 and 2-M n+ species may be attributed to the interactions between Ni(III) and LAs. Our findings show the significance of the secondary coordination sphere effect on the PCET reactivity of Ni(III) complexes and furnish important insights into the reaction mechanism involving high-valent nickel species, which are frequently invoked as key intermediates in Ni-mediated enzymatic reactions, solar-fuel catalysis, and biomimetic/synthetic transformation reactions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Reactivity of Iridium Complexes of a Triphosphorus-Pincer Ligand Based on a Secondary Phosphine. Catalytic Alkane Dehydrogenation and the Origin of Extremely High Activity

The selective functionalization of alkanes and alkyl groups is a major goal of chemical catalysis. Toward this end, a bulky triphosphine with a central secondary phosphino group, bis(2-di-t-butyl-phosphinophenyl)phosphine ( tBu P H PP), has been synthesized. When complexed to iridium, it adopts a meridional (“pincer”) configuration. The secondary phosphino H atom can undergo migration to iridium to give an anionic phosphido-based–pincer ( tBu PPP) complex. Stoichiometric reactions of the ( tBu PPP)Ir complexes reflect a distribution of steric bulk around the iridium center in which the coordination site trans to the phosphido group is quite crowded; one coordination site cis to the phosphido is even more crowded; and the remaining site is particularly open. The ( tBu PPP)Ir precursors are the most active catalysts reported to date for dehydrogenation of n-alkanes, by about 2 orders of magnitude. The electronic properties of the iridium center are similar to that of well-known analogous ( R PCP)Ir catalysts. Accordingly, DFT calculations predict that ( tBu PPP)Ir and ( tBu PCP)Ir are, intrinsically, comparably active for alkane dehydrogenation. While dehydrogenation by ( R PCP)Ir proceeds through an intermediate trans-(PCP)IrH 2 (alkene), ( tBu PPP)Ir follows a pathway proceeding via cis-(PPP)IrH 2 (alkene), thereby circumventing unfavorable placement of the alkene at the bulky site trans to phosphorus. ( tBu PPP)Ir and ( tBu PCP)Ir, however, have analogous resting states: square planar (pincer)Ir(alkene). Alkene coordination at the crowded trans site is therefore unavoidable in the resting states. Furthermore, the resting state of the ( tBu PPP)Ir catalyst is destabilized by the architecture of the ligand, and this is largely responsible for its unusually high catalytic activity.

02 PETROLEUM↗
DOE OSTI2022

Understanding Metal–Organic Framework Nucleation from a Solution with Evolving Graphs

A mechanistic understanding of metal–organic framework (MOF) synthesis and scale-up remains underexplored due to the complex nature of the interactions of their building blocks. In this work, we investigate the collective assembly of building units at the early stages of MOF nucleation, using MIL-101(Cr) as a prototypical example. Using large-scale molecular dynamics simulations, we observe that the choice of solvent (water and N,N-dimethylformamide), the introduction of ions (Na+ and F–) and the relative populations of MIL-101(Cr) half-secondary building unit (half-SBU) isomers have a strong influence on the cluster formation process. Additionally, the shape, size, nucleation and growth rates, crystallinity, and short and long-range order largely vary depending on the synthesis conditions. We evaluate these properties as they naturally emerge when interpreting the self-assembly of MOF nuclei as the time evolution of an undirected graph. Solution-induced conformational complexity and ionic concentration have a dramatic effect on the morphology of clusters emerging during assembly. While pure solvents lead to the rapid formation of a small number of large clusters, the presence of ions in aqueous solutions results in smaller clusters and slower nucleation. This diversity is captured by the key features of the graph representation. Principle component analysis on graph properties reveals that only a small number of molecular descriptors is needed to deconvolute MOF self-assembly. Furthermore, descriptors such as the average coordination number between half-SBUs and fractal dimension are of particular interest as they can be can be followed experimentally by techniques like by time-resolved spectroscopy. Ultimately, graph theory emerges as an approach that can be used to understand complex processes revealing molecular descriptors accessible by both simulation and experiment.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Rational design of a genetically encoded NMR zinc sensor

Elucidating the biochemical roles of the essential metal ion, Zn 2+ , motivates detection strategies that are sensitive, selective, quantitative, and minimally invasive in living systems. Fluorescent probes have identified Zn 2+ in cells but complementary approaches employing nuclear magnetic resonance (NMR) are lacking. Recent studies of maltose binding protein (MBP) using ultrasensitive 129 Xe NMR spectroscopy identified a switchable salt bridge which causes slow xenon exchange and elicits strong hyperpolarized 129 Xe chemical exchange saturation transfer (hyper-CEST) NMR contrast. To engineer the first genetically encoded, NMR-active sensor for Zn 2+ , we converted the MBP salt bridge into a Zn 2+ binding site, while preserving the specific xenon binding cavity. The zinc sensor (ZS) at only 1 μM achieved ‘turn-on’ detection of Zn 2+ with pronounced hyper-CEST contrast. This made it possible to determine different Zn 2+ levels in a biological fluid via hyper-CEST. ZS was responsive to low-micromolar Zn 2+ , only modestly responsive to Cu 2+ , and nonresponsive to other biologically important metal ions, according to hyper-CEST NMR spectroscopy and isothermal titration calorimetry (ITC). Protein X-ray crystallography confirmed the identity of the bound Zn 2+ ion using anomalous scattering: Zn 2+ was coordinated with two histidine side chains and three water molecules. Penta-coordinate Zn 2+ forms a hydrogen-bond-mediated gate that controls the Xe exchange rate. Metal ion binding affinity, 129 Xe NMR chemical shift, and exchange rate are tunable parameters via protein engineering, which highlights the potential to develop proteins as selective metal ion sensors for NMR spectroscopy and imaging.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Rational Design of Superconducting Metal Hydrides via Chemical Pressure Tuning

The high critical superconducting temperatures (T c s) of metal hydride phases with clathrate-like hydrogen networks have generated great interest. Herein, we employ the Density Functional Theory-Chemical Pressure (DFT-CP) method to explain why certain electropositive elements adopt these structure types, whereas others distort the hydrogenic lattice, thereby decreasing the T c . The progressive opening of the H 24 polyhedra in MH 6 phases is shown to arise from internal pressures exerted by large metal atoms, some of which may favor an even higher hydrogen content that loosens the metal atom coordination environments. The stability of the LaH 10 and LaBH 8 phases is tied to stuffing of their shared hydrogen network with either additional hydrogen or boron atoms. Furthermore, the predictive capabilities of DFT-CP are finally applied to the Y-X-H system to identify possible ternary additions yielding a superconducting phase stable to low pressures.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Combining the Best of Two Chelating Titans: A Hydroxypyridinone-Decorated Macrocyclic Ligand for Efficient and Concomitant Complexation and Sensitized Luminescence of f-Elements

An ideal chelator for f-elements features rapid kinetics of complexation, high thermodynamic stability, and slow kinetics of dissociation. Here we present the facile synthesis of a macrocyclic ligand bearing four 1-hydroxy-2-pyridinone units linked to a cyclen scaffold that rapidly forms thermodynamically stable complexes with lanthanides (Sm 3+ , Eu 3+ , Tb 3+ , Dy 3+ ) and a representative late actinide (Cm 3+ ) in aqueous media and concurrently sensitizes them. Extended X-ray absorption fine structure (EXAFS) spectroscopy revealed an increase in the Ln/An-O bond lengths following the trend Cm>Eu>Tb and EXAFS data were compatible with time-resolved luminescence studies, which indicated one to two water molecules in the inner metal coordination sphere of Eu(III) and two water molecules for the Cm(III) complex. Spectrofluorimetric ligand competition titrations against DTPA confirmed the high thermodynamic stability of DOTHOPO complexes, with pM values between 19.9(1) and 21.9(2).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Liquified SO 2 induced solid/cathode electrolyte interphase for lithium ion batteries

Formation of robust solid/cathode electrolyte interphases (S/CEI) is vital for long-term stability and high-performance operation of lithium-ion batteries (LIBs), particularly under high voltage regimes. However, engineering electrochemically stable S/CEIs that effectively suppress interfacial side reactions remains a key challenge. Herein, we introduce a liquefied sulfur dioxide (SO 2 )– ionic liquid complex as a fluorine-free multifunctional electrolyte additive for the first time that significantly improves the formation of sulfate/sulfite-rich S/CEI layers at both graphite and NMC811 interfaces. The unique SO 2 -N coordination with a 1,2,4-triazolide-based ionic liquid enables homogeneous SO 2 dissolution, resulting in controlled SO 2 decomposition during the initial electrochemical cycle. This decomposition yields sulfur-rich interphase species that stabilize the electrolyte-electrode interface, reduce impedance growth, and lessen electrolyte decomposition. Electrochemical tests show significantly improved cycle life, reduced polarization, and increased Coulombic efficiency for both anodes and cathodes. XPS confirms the presence of SO 2 -derived surface species that contribute to interfacial stability. In conclusion, this approach highlights a new direction for interphase engineering using liquefied gas additives and opens pathways for sulfur-based S/CEI chemistry in advanced battery systems.

Graphite↗
DOE OSTI2023

Choline Fluoride-Ethylene glycol deep eutectic solvent mixture – Synthesis and physicochemical properties

A critical factor in achieving tunability in DESs is varying the type of hydrogen bond acceptors (HBAs) and donors (HBDs). Choline halides (ChX), such as ChCl and ChBr, have been studied to investigate the effect of the choline anion on DESs. However, ChF-based DESs have been underrepresented in scientific research. ChF has excellent potential, such as high electron affinity, ionization potential, and strong hydrogen bond interactions. Moreover, ChF-based DES can lead to a deeper understanding of DESs due to the NMR-active 19F nuclear spin nature. We report the first synthesis and characterization of choline fluoride-EG (1:2, ChF:EG) DES, which we named “EthalineF.” We studied this mixture using various spectroscopic techniques, including NMR, FT-IR, Raman, and UV–vis spectroscopies. Polarity, density, viscosity, and conductivity measurements were collected as well. Transient absorption spectroscopy (TAS) was used to study the solvation dynamics of EthalineF. 19F NMR indicated that some fluoride anions (~15%) are coordinated to the choline cation. In EthalineF, the new type of observed fluoride anions is proposed to be a tight-binding choline-fluoride ion pair. Further, EthalineF has a larger solvodynamic radius than Ethaline. This can explain the lower conductivity for EthalineF compared to Ethaline despite the higher fluidity and solvation dynamics for EthalineF.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Insertion reactions and structural studies of [(NHC)CuH] 2 with nitrogen-based substrates

The stoichiometric and catalytic reactions of Cu-H dimers supported by N-heterocyclic carbenes (NHCs) have mainly focused on the insertions of aldehydes, ketones, CO 2 , and unsaturated hydrocarbons. Here we investigated the stoichiometric reactions of dimeric [(NHC)CuH] 2 (NHC = IPr*, 6Dipp) with unsaturated nitrogen-based substrates of PhN=NPh, N 3 Ad, pyrazine, and N 2 O. The spectroscopic and structural chacterizations of the resulting monomeric, two-coordinate Cu(I) complexes containing diphenyl hydrazido, triazenido, pyrazinyl, and hydroxide ligands are discussed. The hydrazido complex of (IPr*)Cu(NPh-NHPh) and triazenido complex of (IPr*)Cu(HNNNAd) are resistant to N—N bond cleavage and loss of N 2 , respectively, to form the corresponding amido complexes even when heated at 80 °C over several hours.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Lewis Acids and Electron-Withdrawing Ligands Accelerate CO Coordination to Dinuclear Cu I Compounds

A series of dinuclear molecular copper complexes were prepared and used to model the binding and Lewis acid stabilization of CO in heterogeneous copper CO 2 reduction electrocatalysts. Experimental studies (including measurement of rate and equilibrium constants) and electronic structure calculations suggest that the key kinetic barrier for CO binding may be a σ-interaction between CuI and the incoming CO ligand. The rate of CO coordination can be increased upon the addition of Lewis acids or electron-withdrawing substituents on the ligand backbone. Conversely, K eq for CO coordination can be increased by adding electron density to the metal centers of the compound, consistent with stronger π-backbonding. Lastly, the electrochemically measured kinetic results were mapped onto an electrochemical zone diagram to illustrate how these system changes enabled access to each zone.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Dipolar Heteronuclear Correlation Solid-State NMR Experiments between Half-Integer Quadrupolar Nuclei: The Case of 11 B– 17 O

With 73% of all NMR-active nuclei being quadrupolar, there is great interest in the development of NMR experiments that can probe the proximity of quadrupolar spins. Here, pulse sequences for magic-angle spinning (MAS) 11 B– 17 O resonance-echo saturation-pulse double-resonance (RESPDOR) and dipolar heteronuclear multiple quantum correlation (D-HMQC) solid-state NMR experiments were investigated. In these pulse sequences, rotational-echo double-resonance (REDOR) recoupling was used with central transition (CT)-selective π-pulses applied to either the 11 B or 17 O spins to recouple 11 B– 17 O dipolar interactions. 11 B{ 17 O} RESPDOR experiments on 17 O-enriched boric acid and benzene diboronic acid showed that application of dipolar recoupling on the 11 B channel yielded more signal dephasing than when recoupling is applied on the 17 O channel; however, short effective 11 B transverse relaxation time constants (T 2 ') hinder the acquisition of dephasing curves out to long recoupling durations. Application of REDOR recoupling to 17 O spins was found to produce significant dephasing without compromising the 11 B T 2 '. Comparison of experimental 11 B{ 17 O} RESPDOR curves to those of numerical simulations enabled the 17 O isotopic enrichment to be estimated. 2D 11 B{ 17 O} D-HMQC spectra were recorded with either 11 B or 17 O REDOR recoupling under a variety of radio frequency field conditions. Lastly, 2D 11 B{ 17 O} and 23 Na{ 17 O} D-HMQC spectra of an 17 O-enriched sodium borate glass were acquired to demonstrate the practical application of these heteronuclear correlation experiments to probe structural connectivity between two quadrupolar spins. Importantly, the high-field 2D 11 B– 17 O D-HMQC NMR spectrum revealed two unique 17 O sites correlating to 4-coordinate BO 4 ( [4] B), which were attributed to the [3] B–O– [4] B and [4] B–O– [4] B bridging O atoms. Furthermore, the heteronuclear correlation experiments outlined here should be applicable to a variety of quadrupolar spin pairs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Synthesis, crystal structure, EPR, and DFT studies of an unusually distorted vanadium(ii) complex

We report the synthesis and structure of the most highly distorted four-coordinate d 3 ion known to date that also serves as the second known example of a bis(biphenolato) transition metal complex. We demonstrate the application of density functional theory to calculate the magnetic parameters derived from the experimental and simulated EPR spectra.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Observing 3-hydroxyanthranilate-3,4-dioxygenase in action through a crystalline lens

The synthesis of quinolinic acid from tryptophan is a critical step in the de novo biosynthesis of nicotinamide adenine dinucleotide (NAD + ) in mammals. Herein, the nonheme iron-based 3-hydroxyanthranilate-3,4-dioxygenase responsible for quinolinic acid production was studied by performing time-resolved in crystallo reactions monitored by UV-vis microspectroscopy, electron paramagnetic resonance (EPR) spectroscopy, and X-ray crystallography. Seven catalytic intermediates were kinetically and structurally resolved in the crystalline state, and each accompanies protein conformational changes at the active site. Among them, a monooxygenated, seven-membered lactone intermediate as a monodentate ligand of the iron center at 1.59-Å resolution was captured, which presumably corresponds to a substrate-based radical species observed by EPR using a slurry of small-sized single crystals. Other structural snapshots determined at around 2.0-Å resolution include monodentate and subsequently bidentate coordinated substrate, superoxo, alkylperoxo, and two metal-bound enol tautomers of the unstable dioxygenase product. These results reveal a detailed stepwise O-atom transfer dioxygenase mechanism along with potential isomerization activity that fine-tunes product profiling and affects the production of quinolinic acid at a junction of the metabolic pathway.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Investigation of Americium-Containing Phosphates, Silicates, Borates, Molybdates, and Fluorides Synthesized via High-Temperature Flux Crystal Growth

The crystal chemistry of americium-containing extended structures was investigated, and several classes of americium-containing solid-state oxide materials were obtained in single-crystal form via high-temperature flux crystal growth. This enabled the structural characterization of rare examples of ternary, quaternary, and penternary americium-containing silicates K 3 Am (Si 2 O 7 ) and Cs 6 Am 2 Si 21 O 48 , phosphates Na 3 Am (PO 4 ) 2 and K 3 Am (PO 4 ) 2 , borates Ba 3 Am 2 (BO 3 ) 4 and AmBO 3 , borate halides Ca 5 Am(BO 3 ) 4 Cl, molybdates Li 0.5 Am 0.5 MoO 4 , and fluorides CsAm 2 F 7 . Using these crystallographic data, the ionic radii of Am 3+ with coordination numbers of six (0.975 Å), seven (1.052 Å), and nine (1.162 Å) were established. A maximum entropy method (MEM) analysis was performed on the single-crystal X-ray diffraction data that were collected for K 3 Nd(PO 4 ) 2 /K 3 Am(PO 4 ) 2 , K 3 NdSi 2 O 7 /K 3 AmSi 2 O 7 , and NdBO 3 /AmBO 3 , to qualitatively compare the ionicities of the Nd–O and Am–O bonds. In conclusion, Raman spectroscopy data were collected on single crystals of K 3 Am(PO 4 ) 2 and compared to the calculated Raman spectrum of K 3 Am(PO 4 ) 2 obtained from DFT calculations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Designing Heteroatom-Codoped Iron Metal–Organic Framework for Promotional Photoreduction of Carbon Dioxide to Ethylene

Rational engineering active sites and vantage defects of catalysts are promising but grand challenging task to enhance photoreduction CO 2 to high value-added C2 products. In this study, we designed an N,S-codoped Fe-based MIL-88B catalyst with well-defined bipyramidal hexagonal prism morphology via a facile and effective process, which was synthesized by addition of appropriate 1,2-benzisothiazolin-3-one (BIT) and acetic acid to the reaction solution. Under simulated solar irradiation, the designed catalyst exhibits high C 2 H 4 evolution yield of 17.7 μmol g -1 ∙h, which has been rarely achieved in photocatalytic CO 2 reduction process. The synergistic effect of Fe-N coordinated sites and reasonable defects in the N,S-codoped photocatalyst can accelerate the migration of photogenerated carriers, resulting in high electron density, and this in turn helps to facilitate the formation and dimerization of C-C coupling intermediates for C 2 H 4 effectively.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Crystallization of a Neptunyl Oxalate Hydrate from Solutions Containing Np V and the Uranyl Peroxide Nanocluster U 60 Ox 30

Uranyl peroxide nanoclusters are an evolving family of materials with potential applications throughout the nuclear fuel cycle. While several studies have investigated their interactions with alkali and alkaline earth metals, no studies have probed their interactions with the actinide elements. This work describes a system containing U 60 Ox 30 , [((UO 2 )(O 2 )) 60 (C 2 O 4 ) 30 ] 60- , and neptunium(V) as a function of neptunium concentration. Ultra-small and small angle X-ray scattering were used to observe these interactions in the aqueous phase, and X-ray diffraction was used to observe solid products. The results show that neptunium induces aggregation of U 60 Ox 30 when the neptunium concentration is ≤ 10 mM, whereas (NpO 2 ) 2 C 2 O 4 ·6H 2 O(cr) and studtite ultimately form at 15–25 mM neptunium. Finally, the latter result suggests that neptunium coordinates with the bridging oxalate ligands in U 60 Ox 30 , leaving metastable uranyl peroxide species in solution, and is an important finding given the potential application of uranyl peroxide nanoclusters in the recycling of used nuclear fuel.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Elucidating the Structure of the Eu‐EDTA Complex in Solution at Various Protonation States

Abstract Ethylenediaminetetraacetic acid (EDTA), which has two amine and four carboxylate protonation sites, forms stable complexes with lanthanide ions. This work analyzes the coordination structure, in atomic resolution, of the Eu 3+ ion complexed with EDTA in all its protonation states in aqueous solution. Eu‐EDTA complexes were modeled using classical molecular dynamics (MD) simulations using force field parameters optimized with ab initio molecular dynamics (AIMD) simulations. Structures from the MD simulations were used to predict extended X‐ray absorption fine structure (EXAFS) spectra and compared with EXAFS measurements of the Eu 3+ aqua ion and Eu‐EDTA complexes at pH 3 and 11. This work details how Eu‐EDTA complex coordination structures change with increasing protonation of the EDTA ligand in the complex, from the tightly bound unprotonated complex to the unbinding of the fully protonated EDTA ligand from the Eu 3+ ion as both become solvated by water. Agreement between predicted and measured EXAFS spectra supports the findings from simulation.

Chemistry↗
DOE OSTI2022

Integrated lignocellulosic biorefinery for efficient production of furans and photothermal materials

Integrated lignocellulosic biorefineries offer a great potential to valorize all the components in lignocellulose into products, including fuels, chemicals, and materials. However, because of lignocellulose recalcitrance, conversion of bioresources remains a techno-economic challenge for many lignocellulosic biorefineries. In this work, we have proposed a sustainable and profitable biorefinery strategy for lignocellulose fractionation and conversion. In this design, a biphasic solvent consisting of a molten salt hydrate LiCl·4H 2 O and γ-valerolactone (GVL) was initially used for separating hemicellulose from lignocellulose. More interestingly, 100 wt% of biorefinery products from lignin were directly converted to functional photothermal materials by coordinating with Fe 3+ for solar-thermal-electricity conversion. Attributed to this rational design, we report the techno-economic analysis predicts a revenue of 439.3 USD by processing 100 kg of lignocellulosic biomass using the above developed method.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗