Hydrogen Atoms Research Articles

Lewis Base-Enhanced C-H Bond Functionalization Mediated by a Diiron Imido Complex.

Herein, we investigate the effects of ligand design on the nuclearity and reactivity of metal-ligand multiply bonded (MLMB) complexes to access an exclusively bimetallic reaction pathway for C-H bond functionalization. To this end, the diiron alkoxide [Fe2(PhDbf)2] (1) was treated with 3,5-bis(trifluoromethyl)phenyl azide to access the diiron imido complex [Fe2(PhDbf)2(μ-NC8H3F6)] (2a) that promotes hydrogen atom abstraction (HAA) from a variety of C-H and O-H bond containing substrates. A diiron bis(amide) complex [Fe2(PhDbf)2(μ-NHC8H3F6)(NHC8H3F6)] (3) was generated, prompting the isolation of the analogous bridging amide terminal alkoxide [Fe2(PhDbf)2(μ-NHC8H3F6)(OC19H15)] (4) and the asymmetric pyridine-bound diiron imido [Fe2(PhDbf)2(μ-NC8H3F6)(NC5H5)] (6a). We found that 6a is competent for toluene amination, indicating the effect of Lewis base-enhanced C-H bond functionalization. Mechanistic investigations suggest that the bimetallic bridging imido complex is the reactive intermediate as no monometallic species is detected during the time course of the reaction.

Spontaneous Reactions by Atomic Hydrogen – An Extraordinary Reactant for Atomic Layer Deposition of Platinum

Spontaneous Reactions by Atomic Hydrogen – An Extraordinary Reactant for Atomic Layer Deposition of Platinum

Remote Activation Catalysis: Interparticle Hydrogen Spillover-Assisted Cumene Synthesis from Propane and Benzene.

Hydrogen spillover, particularly when involving "interparticle" hydrogen spillover, offers a unique opportunity to enhance catalytic efficiency by remote activation of surface acidity. Building on this concept, this study aims to investigate physically mixed alumina-supported platinum nanoparticles (Pt/Al2O3) and zirconia-supported tungsten oxide (WO3/ZrO2) in promoting the direct synthesis of cumene from benzene and propane at 300 °C. The reaction with Pt/Al2O3 alone afforded propylene as the only product, indicating the successive reaction route of Pt-catalyzed dehydrogenation of propane, followed by acid-catalyzed alkylation. WO3/ZrO2 with 18 wt.% WO3 loading resulted in high benzene conversion (≈5.0%) and cumene selectivity (≈87.5%), which possesses poly tungstate species on the surface that is active for the acid-catalyzed alkylation. UV-vis-near infrared spectroscopy, X-ray photoelectron spectroscopy, and in situ Fourier-transform infrared spectroscopy analyses revealed that atomic hydrogen abstracted from propane spills over from Pt/Al2O3 particles to WO3/ZrO2 particles to form Brønsted acid sites on the poly tungstate species, whose activity for alkylation between benzene and propylene is double that of the parent WO3/ZrO2.

A Unique Intramolecular Redox Reaction by Unidirectional Migration of Three Hydrogen Atoms: Theoretical Elucidation of the 3H-Transfer Sequence.

The intramolecular migration of three hydrogen atoms from one moiety of a gaseous radical cation to the other prior to fragmentation is an extremely rare type of redox reaction. Within the scope of this investigation, this scenario requires an ionized but electron-rich arene acceptor bearing a para-(3-hydroxyalkyl) residue. The precise mechanism of such unidirectional 3H transfer processes, including the order of the individual H transfer steps, has remained unclear in spite of previous isotope labelling and recent infrared ion spectroscopy (IRIS) studies. Herein, the details of this peculiar process have been investigated for ionized 4-(N,N-dimethylaminophenyl)-2-butanol, 2, by state-of-the-art density functional theory (DFT) calculations. The energetically most favorable pathway consists of a sequence of successive 1,4-, 1,6- and 1,5-H steps. During these steps the secondary alcohol functionality is oxidized to a carbonyl group and the radical-cationic aniline ring is reduced to an ionized 2,3-dihydroaniline unit. Several alternative sequences, such as three successive 1,5-H shifts, could be excluded. A concomitant unidirectional 2H migration reaction of the ion 2 was also investigated and the intermediacy of ion-neutral complexes (INCs) enabling sequential hydride and proton transfer was confirmed by the calculations.

Ruthenium-Catalyzed Deconstruction of Polyolefins: A Strategy to Up-cycle the Waste Polyethylene to Value-Added Alkenes.

Synthesis of value-added products from post-consumer waste polyolefins is fascinating as well as challenging. Here we report ruthenium-catalyzed up-cycling of the polyethylene to long-chain alkene derivatives. The developed methodology mainly involves two steps i.e., dehydrogenation of polyethylene through hydrogen atom transfer and its metathesis using the HG-II catalyst. The dehydrogenation of polyethylene using ruthenium catalysis derived up to 3.38%, of double bonds; with 90% of the recovered polyolefin material. The obtained unsaturated polyethylene was subjected to cross-metathesis with ethylene using HG-II catalytic system. This resulted in the synthesis of predominantly dodecene (C12) derivatives, with 58% selectivity, along with other derivatives of varying chain lengths. The overall reaction produced terminal and internal olefins in the ratio 1:0.8 respectively. The dehydrogenation of polyethylene and its deconstruction was confirmed by NMR spectroscopy, Gel Permeation Chromatography (GPC) and Differential Scanning Calorimetry (DSC). The origin of C12 selectivity has been demonstrated by control experiments. The scope of the methodology was extended to post-consumer waste polyethylene gave high conversion of value-added dodecene derivatives as a major product.

Computational Investigation of the Role of Metal Center Identity in Cytochrome P450 Enzyme Model Reactivity.

Mononuclear Fe enzymes such as heme-containing cytochrome P450 enzymes catalyze a variety of C-H activation reactions under ambient conditions, and they represent an attractive platform for engineering reactivity through changes to the native enzyme. Using density functional theory, we study both native Fe and non-native group 8 (Ru, Os) and group 9 (Ir) metal centers in an active site model of P450. We quantify how changing the metal changes spin state preferences throughout the catalytic cycle. Our calculations reveal an intermediate-spin ground state for all Fe intermediates while the heavier metals prefer low-spin ground states across most intermediates in the reaction cycle. We also study the rate-determining hydrogen atom transfer (HAT) step and the subsequent rebound step. We observe comparable HAT barriers for Fe and Ru, a much higher barrier for Os, and the lowest HAT barrier for Ir. Rebound steps are barrierless for all metals, and the rebound intermediate for Fe is most significantly stabilized. Examination of ground spin states of all intermediates in the reaction cycle reveals spin-allowed pathways for the group 8 metals and spin-forbidden energetics for the group 9 Ir with potential two-state reactivity. Our work highlights the differences between the group 8 metals and the group 9 Ir, and it suggests that engineered P450 enzymes with Ru in particular result in improved enzyme reactivity toward C-H hydroxylation.

Light-Driven Stepwise Reduction of Aliphatic Carboxylic Esters to Aldehydes and Alcohols.

The reduction of carboxylic esters to aldehydes and alcohols is a fundamental functional group transformation in chemistry. However, the inertness of carbonyl group and the instability of ketyl radical anion intermediate impede the reduction of carboxylic esters via photochemical strategy. Herein, we described the reduction of aliphatic carboxylic esters with synergistic dual photocatalysis via phenolate-catalyzed single electron transfer process and thiol-catalyzed hydrogen atom transfer process. The competitive back electron transfer process was effectively inhibited by protonation of the ketyl-type radical anion. This protocol enabled the efficient reduction of carboxylic esters to alcohols under mild conditions. By interruption of the reduction with prolinol, the step-controlled reduction of carboxylic esters to aldehydes was accomplished. The developed process was also successfully applied to the preparation of deuterated alcohols and aldehydes from esters with D2O as the deuterium source.

Establishing Thermodynamic Graphs of Nitrogenous Radical Cations Abstracting Hydrogen Atoms and Their Applications in Photoredox Reactions

Establishing Thermodynamic Graphs of Nitrogenous Radical Cations Abstracting Hydrogen Atoms and Their Applications in Photoredox Reactions

Reactions of Hydrogen-Passivated Silicon Vacancies in α-Quartz with Electron Holes and Hydrogen.

We used density functional theory with a hybrid functional to investigate the structure and properties of [4H]Si (hydrogarnet) defects in α-quartz as well as the reactions of these defects with electron holes and extra hydrogen atoms and ions. The results demonstrate the depassivation mechanisms of hydrogen-passivated silicon vacancies in α-quartz, providing a detailed understanding of their stability, electronic properties, and behaviour in different charge states. While fully hydrogen passivated silicon vacancies are electrically inert, the partial removal of hydrogen atoms activates these defects as hole traps, altering the defect states and influencing the electronic properties of the material. Our calculations of the hydrogen migration mechanisms predict the low energy barriers for H+, H0, and H-, with the lowest barrier of 0.28 eV for neutral hydrogen migration between parallel c-channels and a similar barrier for H+ migration along the c-channels. The reactions of electron holes and hydrogen species with [4H]Si defects lead to the breaking of O-H bonds and the formation of non-bridging oxygen hole centres (NBOHCs) within the Si vacancies. The calculated optical absorption energies of these centres are close to those attributed to individual NBOHCs in glass samples. These findings can be useful for understanding the role of [4H]Si defects in bulk and nanocrystalline quartz as well as in SiO2-based electronic devices.

The effect of the natural antioxidants extracted from Glycyrrhiza glabra (licorice) on the cryopreservation of chicken breast meat

Background: Chicken meat is highly nutritious, valued for its unique properties and versatility in culinary applications. Also, preparation methods and natural additives to its diet play an important role in estimating the nutritional value of its meat by increasing consumer acceptance of it from health, nutritional, and material aspects. Objective: This study was conducted to determine the effect of licorice as a natural antioxidant on cold-preserved chicken meat. Methods: Phenolic compounds were quantified using the colorimetric method with Folin's reagent, measuring absorbance at 765 nm, and results were expressed in terms of gallic acid equivalents per gram of dry weight. Gallic acid was used as a reference solution to prepare the standard curve with concentrations ranging between 20-120 μg/mL to determine the quantity of phenolic compounds. Determination of antioxidant activity was done using the DPPH method by taking 0.5 mL of the extract solution at concentrations ranging from 50-300 μg/mL and mixing with 3 mL of methanolic DPPH solution. The mixture was mixed for 1 min with a vortex mixer, and samples were measured by spectrophotometer at 517 nm. Moisture, ash, fat, protein, and pH were determined according to the methods mentioned by AOAC. Thiobarbituric acid-reactive substances (TBARS) were estimated by mixing 0.5 g of the sample with 2.5 mL of TBA solution. The mixture was heated in a boiling water bath for 10 min to orange color, chilled by adding 1 mL of chloroform and centrifuged at 5000 rpm for 25 min, and the absorbance was read at 532 nm wavelength. Total microorganisms, molds, and yeast were counted. Results: Protein content increased proportionally with higher concentrations of ethanolic licorice root extract. The gradual increase in protein content in samples is attributed to their antimicrobial effect, which leads to the preservation of meat from microbial growth and the action of proteolytic enzymes. The increase in protein during refrigerated storage is due to the decrease in moisture and increase in dry matter reflected in the increase in protein. The reduced acidity in chicken meat treated with licorice root ethanolic extract is attributed to its antimicrobial effects, which limit the growth of microorganisms responsible for metabolizing nitrogenous compounds. Licorice extracts, rich in phenolic compounds, reduce lipid oxidation. The observed decrease in thiobarbituric acid-reactive substances with increasing extract concentration is due to the antioxidant properties of these phenolics with the hydroxyl group attached to the aromatic ring capable of giving hydrogen atoms and inhibiting free radicals. This study found that the growth of microorganisms could be lowered by licorice extract containing phenolic compounds, flavonoids, tannins, and alkaloids, which showed a significant antimicrobial effect. Conclusion: This study examined how natural antioxidants, like licorice Glycyrrhiza glabra, affected the cryopreservation of chicken breast. Keywords: Licorice root extract, chicken breast, antioxidants, total phenol, Meat science

Operando Unveiling of Hydrogen Spillover Mechanisms on Tungsten Oxide Surfaces.

Hydrogen spillover is an important process in catalytic hydrogenation reactions, facilitating H2 activation and modulating surface chemistry of reducible oxide catalysts. This study focuses on the operando unveiling of platinum-induced hydrogen spillover on monoclinic tungsten trioxide (γ-WO3), employing ambient pressure X-ray photoelectron spectroscopy, density functional theory calculations and microkinetic modeling to investigate the dynamic evolution of surface states at varied temperatures. At room temperature, hydrogen spillover results in the formation of W5+ and hydrogen intermediates (hydroxyl species and adsorbed water), facilitated by Pt metal clusters. With increasing temperature, water desorption, reverse hydrogen spillover and surface-to-bulk diffusion of hydrogen atoms compete with each other, leading initially to reoxidation and then further reduction of W atoms in the near-surface. The combined experimental results and simulations provide a comprehensive understanding of the mechanisms underlying hydrogen interaction with reducible metal oxides, lending insights of relevance to the design of enhanced hydrogenation catalysts.

Liquid Metal Nanobiohybrids for High-Performance Solar-Driven Methanogenesis via Multi-Interface Engineering.

Nanobiohybrids for solar-driven methanogenesis present a promising solution to the global energy crisis. However, conventional semiconductor-based nanobiohybrids face challenges such as limited tunability and poor biocompatibility, leading to undesirable spontaneous electron and proton transfer that compromise their structural stability and CH4 selectivity. Herein, we introduced eutectic gallium-indium alloys (EGaIn), featuring a self-limiting surface oxide layer surrounding the liquid metal core after sonication, integrated with Methanosarcina barkeri (M. b). The well-designed M. b-EGaIn nanobiohybrids exhibited superior performance, achieving a maximum CH4 yield of 455.64 ± 15.99 μmol g-1, long-term stability across four successive 7-day cycles, and remarkable CH4 selectivity of >99%. These improvements stem from enhanced proton-coupled electron transfer involving hydrogen atoms at the core-shell interface, further facilitated by the elevated expression of hydrogenases at the abiotic-biotic interface. This study provides an insightful concept for nanobiohybrid design through multi-interface engineering, advancing sustainable and scalable CO2-to-biofuel conversion under ambient conditions.

Rationally designed universal passivator for high-performance single-junction and tandem perovskite solar cells

Interfacial trap-assisted nonradiative recombination hampers the development of metal halide perovskite solar cells (PSCs). Herein, we report a rationally designed universal passivator to realize highly efficient and stable single junction and tandem PSCs. Multiple defects are simultaneously passivated by the synergistic effect of anion and cation. Moreover, the defect healing effect is precisely modulated by carefully controlling the number of hydrogen atoms on cations and steric hindrance. Due to minimized interfacial energy loss, L-valine benzyl ester p-toluenesulfonate (VBETS) modified inverted PSCs deliver a power conversion efficiency (PCE) of 26.28% using vacuum flash processing technology. Moreover, by suppressing carrier recombination, the large-area modules with an aperture area of 32.144 cm2 and perovskite/Si tandem solar cells coupled with VBETS passivation deliver a PCE of 21.00% and 30.98%, respectively. This work highlights the critical role of the number of hydrogen atoms and steric hindrance in designing molecular modulators to advance the PCE and stability of PSCs.

Liquid Metal Nanobiohybrids for High‐Performance Solar‐Driven Methanogenesis via Multi‐Interface Engineering

Nanobiohybrids for solar‐driven methanogenesis present a promising solution to the global energy crisis. However, conventional semiconductor‐based nanobiohybrids face challenges such as limited tunability and poor biocompatibility, leading to undesirable spontaneous electron and proton transfer that compromise their structural stability and CH4 selectivity. Herein, we introduced eutectic gallium–indium alloys (EGaIn), featuring a self‐limiting surface oxide layer surrounding the liquid metal core after sonication, integrated with Methanosarcina barkeri (M. b). The well‐designed M. b–EGaIn nanobiohybrids exhibited superior performance, achieving a maximum CH4 yield of 455.64 ± 15.99 μmol g−1, long‐term stability across four successive 7‐day cycles, and remarkable CH4 selectivity of >99%. These improvements stem from enhanced proton‐coupled electron transfer involving hydrogen atoms at the core–shell interface, further facilitated by the elevated expression of hydrogenases at the abiotic–biotic interface. This study provides an insightful concept for nanobiohybrid design through multi‐interface engineering, advancing sustainable and scalable CO2‐to‐biofuel conversion under ambient conditions.

Nucleophilic and Electrophilic Molybdenum Terminal Oxo Complexes by Coordination-Induced Bond Weakening of Hydroxo O-H Bonds.

The extent of coordination-induced bond weakening in aquo and hydroxo ligands bonded to a molybdenum(III) center complexed by a dianionic, pentadentate ligand system was probed by reacting the known complex (B2Pz4Py)Mo(III)-NTf2, I, with degassed water or dry lithium hydroxide. The aquo adduct was not observed, but two LiNTf2-stabilized hydroxo complexes were fully characterized. Computational and experimental work showed that the O-H bond in these complexes was significantly weakened (to ≈57 kcal mol-1), such that these compounds could be used to form the diamagnetic, d2 neutral terminal molybdenum oxo complex (B2Pz4Py)Mo(IV)O, 2, by hydrogen atom abstraction using the aryl oxyl reagent ArO• (Ar = 2,4,6-tri-tert-butylphenyl). Oxidation of the neutral hydroxo derivative further facilitated the production of 2 by significantly enhancing the acidity of the hydroxyl proton. Speciation in these processes was probed by electrochemical and chemical experiments. The terminal oxo complex 2 was smoothly oxidized by one electron to the cationic [(B2Pz4Py)Mo(V)O]+[A]- derivatives [2]+[A]- (A = NTf2 or Al[OC(CF3)3]4 depending on the oxidizing agent used). Both Mo(IV) and Mo(V)+ oxo complexes were fully characterized with their nucleophilic and electrophilic reaction behavior probed by conducting reactions with the Lewis acid B(C6F5)3 and the Lewis base PPh3. Neutral oxo complex 2 reacts only with the Lewis acid, while the cationic [2]+[A]- reacts only with PPh3, the former by adduct formation and the latter via phosphine oxidation.

Integrated analysis of cellulose structure and properties using solid-state low-field H-NMR and photoacoustic spectroscopy

In this study, we explore the structural intricacies of cellulose, a polymer composed of glucose monomers arranged in a linear chain, primarily investigated through solid-state NMR techniques. Specifically, we employ low-field proton nuclear magnetic resonance (H-NMR) to delve into the diverse hydrogen atom types within the cellulose molecule. The low-field H-NMR technique allows us to discern these hydrogen atoms based on their distinct chemical shifts, providing valuable insights into the various functional groups present in cellulose. Our focus extends to the examination of anomeric protons of glucose units and protons linked to carbon atoms engaged in glycosidic linkages within cellulose chains, which exist in diverse crystalline and amorphous forms. Solid-state low-field H-NMR spectroscopy aids in characterizing the crystallinity degrees and amorphous regions within cellulose, revealing time-dependent changes in free induction decay (FID) signals. Complementing this, we investigate the photo-absorption properties of cellulose fibers under both continuous and modulated irradiation using reversed double-beam photoacoustic spectroscopy (RDB-PAS). This photoacoustic approach allows us to observe ultraviolet- and visible light-induced processes, including electron trap filling and reductive changes on the fiber surface. Our findings suggest that RDB-PAS is a feasible method for estimating the electron trap distribution, serving as a potential measure of the density of crystalline cellulose defects. This integrated approach of combining solid-state low-field H-NMR and RDB-PAS techniques offers a comprehensive understanding of cellulose structure and properties, enhancing our ability to characterize its diverse features.

Visible-Light-Induced Synthesis of Esters via a Self-Propagating Radical Reaction.

We herein disclose a visible-light-induced synthesis of O-aryl esters through the cross-dehydrogenative coupling of aldehydes with phenols using BrCCl3, in which phenolate functions as both a substrate and a photosensitizer. This transition-metal- and photocatalyst-free visible-light-induced esterification is suitable for a wide range of substrates and gives moderate to excellent yields (up to 95%). Mechanistic studies provided evidence of a self-propagating radical reaction involving homolytic cleavage of the aldehydic C-H bond and the formation of acyl bromides. BrCCl3 serves as an oxidant and a hydrogen atom transfer (HAT) agent.

Cyclodehydrogenation of molecular nanographene precursors catalyzed by atomic hydrogen

Atomically precise synthesis of graphene nanostructures on semiconductors and insulators has been a formidable challenge. In particular, the metallic substrates needed to catalyze cyclodehydrogenative planarization reactions limit subsequent applications that exploit the electronic and/or magnetic structure of graphene derivatives. Here, we introduce a protocol in which an on-surface reaction is initiated and carried out regardless of the substrate type. We demonstrate that, counterintuitively, atomic hydrogen can play the role of a catalyst in the cyclodehydrogenative planarization reaction. The high efficiency of the method is demonstrated by the nanographene synthesis on metallic Au, semiconducting TiO2, Ge:H, as well as on inert and insulating Si/SiO2 and thin NaCl layers. The hydrogen-catalyzed cyclodehydrogenation reaction reported here leads towards the integration of graphene derivatives in optoelectronic devices as well as developing the field of on-surface synthesis by means of catalytic transformations. It also inspires merging of atomically shaped graphene-based nanostructures with low-dimensional inorganic units into functional devices.

Understanding Dioxygen Activation in the Fe(III)-Promoted Oxidative Dehydrogenation of Amines: A Computational Study

Hydrogenation and dehydrogenation reactions are fundamental in chemistry and essential for all living organisms. We employ density functional theory (DFT) to understand the reaction mechanism of the oxidative dehydrogenation (ODH) of the pyridyl-amine complex [FeIIIL3]3+ (L3, 1,9-bis(2′-pyridyl)-5-[(ethoxy-2″-pyridyl)methyl]-2,5,8-triazanonane) to the mono-imine complex [FeIIL4]2+ (L4, 1,9-bis(2′-pyridyl)-5-[(ethoxy-2″-pyridyl)methyl]-2,5,8-triazanon-1-ene) in the presence of dioxygen. The nitrogen radical [FeIIL3N8•]2+, formed by deprotonation of [FeIIIL3]3+, plays a crucial role in the reaction mechanism derived from kinetic studies. O2 acts as an oxidant and is converted to H2O. Experiments with the deuterated ligand L3 reveal a primary C-H kinetic isotope effect, kCH/kCD = 2.30, suggesting C-H bond cleavage as the rate-determining step. The DFT calculations show that (i) 3O2 abstracts a hydrogen atom from the α-pyridine aliphatic C-H moiety, introducing a double bond regio-selectively at the C7N8 position, via the hydrogen atom transfer (HAT) mechanism, (ii) O2 does not coordinate to the iron center to generate a high-valent Fe oxo species observed in enzymes and biomimetic complexes, and (iii) the experimental activation parameters (ΔH≠ = 20.38 kcal mol−1, ΔS≠ = −0.018 kcal mol−1 K−1) fall within in the range of values reported for HAT reactions and align well with the computational results for the activated complex [FeIIL3N8•]2+···3O2.

Pressure-Induced Dehydration and Reversible Recrystallization of Dihydrogen-Bonded Sodium Borohydride Dihydrate NaBH4·2H2O.

Sodium borohydride dihydrate (NaBH4·2H2O) forms through dihydrogen bonding between the hydridic hydrogen of the BH4- ion and the protonic hydrogen of the water molecule. High-pressure structural changes in NaBH4·2H2O, observed up to 11 GPa through X-ray diffraction and Raman scattering spectroscopy, were analyzed to assess the influence of dihydrogen bonds on its crystal structure. At approximately 4.6 GPa, certain dihydrogen bonds were broken, leading to the decomposition of NaBH4·2H2O into ambient pressure phase of NaBH4 (α-NaBH4) and ice VII. Upon further compression beyond 6.6 GPa, NaBH4 gradually transformed into its high-pressure phase, γ-NaBH4. During decompression, γ-NaBH4 reverted to α-NaBH4 at the pressure between 4.4 and 2.7 GPa and subsequently reacted with ice VII, resulting in the recrystallization of NaBH4·2H2O. This recrystallization, occurring during decompression from 4.4 to 2.7 GPa, is identical to the starting sample and can be termed "decompression-induced recrystallization", highlighting the strength of the dihydrogen bonds in NaBH4·2H2O. In addition, density functional theory calculations were used to evaluate the pressure dependence of hydrogen-hydrogen (H-H) distances in NaBH4·2H2O. As pressure increased, the number of dihydrogen bonds within the unit cell rose from seven at near-ambient pressure to 12 at approximately 4.5 GPa just before the dehydration, indicating that each hydrogen atom in the water molecule formed dihydrogen bonds with around three hydrogens from the BH4- ions just prior to dehydration. Such pressure tuning of dihydrogen bonds may lead to the creation of new energy storage materials.