Sodium-ion batteries are an alternative to lithium-ion batteries for large-scale applications. However, low capacity and poor rate capability of existing anodes are the main bottlenecks to future ...developments. Here we report a uniform coating of antimony sulphide (stibnite) on graphene, fabricated by a solution-based synthesis technique, as the anode material for sodium-ion batteries. It gives a high capacity of 730 mAh g(-1) at 50 mA g(-1), an excellent rate capability up to 6C and a good cycle performance. The promising performance is attributed to fast sodium ion diffusion from the small nanoparticles, and good electrical transport from the intimate contact between the active material and graphene, which also provides a template for anchoring the nanoparticles. We also demonstrate a battery with the stibnite-graphene composite that is free from sodium metal, having energy density up to 80 Wh kg(-1). The energy density could exceed that of some lithium-ion batteries with further optimization.
Despite the technological importance of urea perhydrate (percarbamide) and sodium percarbonate, and the growing technological attention to solid forms of peroxide, fewer than 45 peroxosolvates were ...known by 2000. However, recent advances in X-ray diffractometers more than tripled the number of structurally characterized peroxosolvates over the last 20 years, and even more so, allowed energetic interpretation and gleaning deeper insight into peroxosolvate stability. To date, 134 crystalline peroxosolvates have been structurally resolved providing sufficient insight to justify a first review article on the subject. In the first chapter of the review, a comprehensive analysis of the structural databases is carried out revealing the nature of the co-former in crystalline peroxosolvates. In the majority of cases, the coformers can be classified into three groups: (1) salts of inorganic and carboxylic acids; (2) amino acids, peptides, and related zwitterions; and (3) molecular compounds with a lone electron pair on nitrogen and/or oxygen atoms. The second chapter of the review is devoted to H-bonding in peroxosolvates. The database search and energy statistics revealed the importance of intermolecular hydrogen bonds (H-bonds) which play a structure-directing role in the considered crystals. H
O
always forms two H-bonds as a proton donor, the energy of which is higher than the energy of analogous H-bonds existing in isostructural crystalline hydrates. This phenomenon is due to the higher acidity of H
O
compared to water and the conformational mobility of H
O
. The dihedral angle H-O-O-H varies from 20 to 180° in crystalline peroxosolvates. As a result, infinite H-bonded 1D chain clusters are formed, consisting of H
O
molecules, H
O
and water molecules, and H
O
and halogen anions. H
O
can form up to four H-bonds as a proton acceptor. The third chapter of the review is devoted to energetic computations and in particular density functional theory with periodic boundary conditions. The approaches are considered in detail, allowing one to obtain the H-bond energies in crystals. DFT computations provide deeper insight into the stability of peroxosolvates and explain why percarbamide and sodium percarbonate are stable to H
O
/H
O isomorphic transformations. The review ends with a description of the main modern trends in the synthesis of crystalline peroxosolvates, in particular, the production of peroxosolvates of high-energy compounds and mixed pharmaceutical forms with antiseptic and analgesic effects.
Two new peroxosolvates of drug-like compounds were synthesized and studied by a combination of X-ray crystallographic, Raman spectroscopic methods, and periodic DFT computations. The enthalpies of ...H-bonds formed by hydrogen peroxide (H2O2) as a donor and an acceptor of protons were compared with the enthalpies of analogous H-bonds formed by water (H2O) in isomorphic (isostructural) hydrates. The enthalpies of H-bonds formed by H2O2 as a proton donor turned out to be higher than the values of the corresponding H-bonds formed by H2O. In the case of H2O2 as a proton acceptor in H-bonds, the ratio appeared reversed. The neutral O∙∙∙H-O/O∙∙∙H-N bonds formed by the lone electron pair of the oxygen atom of water were the strongest H-bonds in the considered crystals. In the paper, it was found out that the low-frequency Raman spectra of isomorphous crystalline hydrate and peroxosolvate of N-(5-Nitro-2-furfurylidene)-1-aminohydantoin are similar. As for the isostructural hydrate and peroxosolvate of the salt of protonated 2-amino-nicotinic acid and maleic acid monoanion, the Raman spectra are different.
Energy/enthalpy of intermolecular hydrogen bonds (H-bonds) in crystals have been calculated in many papers. Most of the theoretical works used non-periodic models. Their applicability for describing ...intermolecular H-bonds in solids is not obvious since the crystal environment can strongly change H-bond geometry and energy in comparison with non-periodic models. Periodic DFT computations provide a reasonable description of a number of relevant properties of molecular crystals. However, these methods are quite cumbersome and time-consuming compared to non-periodic calculations. Here, we present a fast quantum approach for estimating the energy/enthalpy of intermolecular H-bonds in crystals. It has been tested on a family of crystalline peroxosolvates in which the H∙∙∙O bond set fills evenly (i.e., without significant gaps) the range of H∙∙∙O distances from ~1.5 to ~2.1 Å typical for strong, moderate, and weak H-bonds. Four of these two-component crystals (peroxosolvates of macrocyclic ethers and creatine) were obtained and structurally characterized for the first time. A critical comparison of the approaches for estimating the energy of intermolecular H-bonds in organic crystals is carried out, and various sources of errors are clarified.
Abstract Despite the significance of H 2 O 2 -metal adducts in catalysis, materials science and biotechnology, the nature of the interactions between H 2 O 2 and metal cations remains elusive and ...debatable. This is primarily due to the extremely weak coordinating ability of H 2 O 2 , which poses challenges in characterizing and understanding the specific nature of these interactions. Herein, we present an approach to obtain H 2 O 2 –metal complexes that employs neat H 2 O 2 as both solvent and ligand. SnCl 4 effectively binds H 2 O 2 , forming a SnCl 4 (H 2 O 2 ) 2 complex, as confirmed by 119 Sn and 17 O NMR spectroscopy. Crystalline adducts, SnCl 4 (H 2 O 2 ) 2 ·H 2 O 2 ·18-crown-6 and 2SnCl 4 (H 2 O 2 )(H 2 O)·18-crown-6, are isolated and characterized by X-ray diffraction, providing the complete characterization of the hydrogen bonding of H 2 O 2 ligands including geometric parameters and energy values. DFT analysis reveals the synergy between a coordinative bond of H 2 O 2 with metal cation and its hydrogen bonding with a second coordination sphere. This synergism of primary and secondary interactions might be a key to understanding H 2 O 2 reactivity in biological systems.
The Telephone Interview for Cognitive Status-modified (TICS-M) is a well-established and widely used screening instrument for dementia and assessment of global cognitive function in older people. ...This study aimed to evaluate the psychometric properties of the TICS-M and to enhance the accuracy of the instrument using Rasch methodology. Partial Credit Rasch model was applied to the TICS-M scores. The sample selected for Rasch analysis consisted of 432 participants aged 70-90 years (M = 78.85, SD = 4.73) including 195 males (237 females), and 132 (30.56%) of whom were diagnosed with dementia after the baseline assessment. Initial analysis indicated good reliability of the TICS-M assessment scores, but there were three misfitting items and local dependency issues. Combining locally dependent and misfitting items into super-items achieved the best Rasch model fit for the TICS-M. This modification improved reliability of the assessment scores and resulted in no misfitting items, no local dependency, strict unidimensionality, and invariance across individual factors such as participants age, sex, diagnosis, and in-person neuropsychological assessment scores. Satisfying Rasch model expectations allowed for creation of a transformation table to convert raw TICS-M scores into interval-level data, which improves precision of the instrument. In summary, the TICS-M assessment scores demonstrated excellent reliability as reflected by Person Separation Index (PSI = 0.86) and met expectations of the unidimensional Rasch model after minor adjustments. The ordinal-to-interval transformation table can be used to increase accuracy of the TICS-M without altering its current format. These findings contribute to more accurate assessments of cognitive decline in older people and screening for conditions such as dementia.
Public Significance Statement
Rasch analysis is an advanced statistical method that is increasingly becoming a gold standard for examining and improving accuracy of clinical outcome measures. This study applied Rasch analysis to investigate measurement characteristics of the Telephone Interview for Cognitive Status-modified and performed important modifications to enhance its accuracy for capturing global cognition among older adults with and without dementia.
Solid peroxides are a convenient source of hydrogen peroxide, which once released can be readily converted to active oxygen species or to dissolved dioxygen. A zinc peroxide nanodispersion was ...synthesized and characterized, and its solubility was determined as a function of pH and temperature. We show that zinc peroxide is much more stable in aqueous solutions compared to calcium and magnesium peroxides and that it retains its peroxide content down to pH 6. At low pH conditions H2O2 release is thermodynamically controlled and its dissolution product, Zn(2+), is highly soluble, and thus, hydrogen peroxide release can be highly predictable. The Gibbs free energy of formation of zinc peroxide was found to be -242.0 ± 0.4 kJ/mol and the enthalpy of formation was -292.1 ± 0.7 kJ/mol, substantially higher than theoretically predicted before. The biocidal activity of zinc peroxide was determined by inactivation studies with Escherichia coli cultures, and the activity trend agrees well with the thermodynamic predictions.
Background
The modified Telephone Interview for Cognitive Status (TICS‐M) is a widely used tool for assessing global cognitive functions and screening for cognitive impairments. The tool was ...conceptualised to capture various cognitive domains, but the validity of such domains has not been investigated against comprehensive neuropsychological assessments tools. Therefore, this study aimed to explore the associations between the TICS‐M domains and neuropsychological domains to evaluate the validity of the TICS‐M domains using network analysis.
Materials and Methods
A longitudinal research design was used with a large sample of older adults (aged above 70 years; n = 1037 at the baseline assessment) who completed the TICS‐M and comprehensive neuropsychological assessments biennially. We applied network analysis to identify unique links between the TICS‐M domains and neuropsychological test scores.
Results
At baseline, there were weak internal links between the TICS‐M domains. The TICS‐M memory and language domains were significantly related to their corresponding neuropsychological domains. The TICS‐M attention domain had significant associations with executive function and visuospatial abilities. The TICS‐M orientation domain was not significantly associated with any of the five neuropsychological domains. Despite an attrition of almost 50% at wave four, weak internal links between the TICS‐M domains and most associations between TICS‐M and neuropsychological domains that were found initially, remained stable at least over two waves within the 6‐year period.
Conclusions
This study supports the overall structural validity of the TICS‐M screener in assessing enduring global cognitive function. However, separate TICS‐M cognitive domains should not be considered equivalent to the analogous neuropsychological domains.
Validate domains of the modified telephone interview for cognitive status using network analysis.
Tellurates have attracted the attention of researchers over the past decade due to their properties and as less toxic forms of tellurium derivatives. However, the speciation of Te(VI) in aqueous ...solutions has not been comprehensively studied. We present a study of the equilibrium speciation of tellurates in aqueous solutions at a wide pH range, 2.5–15 by 17O, 123Te, and 125Te NMR spectroscopy. The coexistence of monomeric, dimeric, and trimeric oxidotellurate species in chemical equilibrium at a wide pH range has been shown. NMR spectroscopy, DFT computations, and single-crystal X-ray diffraction studies confirmed the formation and coexistence of trimeric tellurate anions with linear and triangular structures. Two cesium tellurates, Cs2Te4O8(OH)10 and Cs2Te2O4(OH)6, were isolated from the solution at pH 5.5 and 9.2, respectively, and studied by single-crystal X-ray diffractometry, revealing dimeric and tetrameric tellurate anions in corresponding crystal structures.
Peroxosolvates of 2‐aminonicotinic acid (I) and lidocaine N‐oxide (II) including the largest insular hydrogen peroxide clusters were isolated and their crystal structures were determined by ...single‐crystal X‐ray diffraction. An unprecedented dodecameric hydrogen peroxide insular cluster was found in I. An unusual cross‐like pentameric cluster was observed in the structure of II. The topology of the (H2O2)12 assembly was never observed for small‐molecule clusters. In I and II new double and triple cross‐orientational disorders of H2O2 were found. Cluster II is the first example of a peroxosolvate crystal structure containing H2O2 molecules with a homoleptic hydrogen peroxide environment. In II, a hydrogen bond between an H2O2 molecule and a peptide group ‐CONH⋅⋅⋅O2H2 was observed for the first time.
Peroxide bond: Peroxosolvates of 2‐aminonicotinic acid (I) and lidocaine N‐oxide (II) including unprecedented dodecameric and pentameric discrete hydrogen peroxide clusters were isolated and their structures were determined by single‐crystal X‐ray diffraction. In I and II new double and triple cross‐orientational disorders of H2O2 were found. In II, a hydrogen bond between an H2O2 molecule and a peptide group was observed for the first time.
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