Crystal structure of (Z)-N-benzylidene-1-phenylmethanamine oxide hydrogen peroxide monosolvate

The title adduct, C14H13NO·H2O2, consists of (Z)-N-benzylidene-1-phenylmethanamine oxide and hydrogen peroxide molecules in a 1:1 ratio. The organic coformer adopts a skew geometry with an inter-aryl-ring dihedral angle of 81.9 (2)°. In the crystal, the organic and peroxide molecules are linked through both peroxide O—H donor groups to oxide O-atom acceptors, giving one-dimensional chains extending along the b axis. Present also are weak intermolecular C—H...O hydrogen-bonding interactions

Crystalline Peroxosolvates: Nature of the Coformer, Hydrogen-Bonded Networks and Clusters, Intermolecular Interactions

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. H2O2 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 H2O2 compared to water and the conformational mobility of H2O2. 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 H2O2 molecules, H2O2 and water molecules, and H2O2 and halogen anions. H2O2 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 H2O2/H2O 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

Ammonium and caesium carbonate peroxosolvates: supramolecular networks formed by hydrogen bonds

Diammonium carbonate hydrogen peroxide monosolvate, 2NH4+·CO32-·H2O2, (I), and dicaesium carbonate hydrogen peroxide tris­olvate, 2Cs+·CO32-·3H2O2, (II), were crystallized from 98% hydrogen peroxide. In (I), the carbonate anions and peroxide solvent mol­ecules are arranged on twofold axes. The peroxide mol­ecules act as donors in only two hydrogen bonds with carbonate groups, forming chains along the a and c axes. In the structure of (II), there are three independent Cs+ ions, two of them residing on twofold axes, as are two of the four peroxide mol­ecules, one of which is disordered. Both structures comprise complicated three-dimensional hydro­gen-bonded networks.Published versio

Fast Quantum Approach for Evaluating the Energy of Non-Covalent Interactions in Molecular Crystals: The Case Study of Intermolecular H-Bonds in Crystalline Peroxosolvates

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

Speciation of Tellurium(VI) in Aqueous Solutions: Identification of Trinuclear Tellurates by 17O, 123Te, and 125Te NMR Spectroscopy

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, Cs2[Te4O8(OH)10] and Cs2[Te2O4(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

Synthesis of high volumetric capacity graphene oxide-supported tellurantimony Na- and Li-ion battery anodes by hydrogen peroxide sol gel processing

High-charge-capacity sodium-ion battery anodes made of Sb2Te3@reduced graphene oxide are reported for the first time. Uniform nano-coating of graphene oxide is carried out from common sol of peroxotellurate and peroxoantimonate under room temperature processing. Reduction by hydrazine under glycerol reflux yields Sb2Te3@reduced graphene oxide. The electrodes exhibit exceptionally high volumetric charge capacity, above 2300mAhcm-3 at 100mAg-1 current density, showing very good rate capabilities and retaining 60% of this capacity even at 2000mAg-1. A comparison of sodiation and lithiation shows that lithiation exhibits better volumetric charge capacity, but surprisingly only marginally better relative rate capability retention at 2000mAg-1. Tellurium-based electrodes are attractive due to the high volumetric charge capacity of Te, its very high electric conductivity, and the low relative expansion upon lithiation/sodiation

Graphene oxide organogel electrolyte for quasi solid dye sensitized solar cells

Low concentration, as low as 0.4 wt.% graphene oxide organogels is reported for different organic solvents. The gelation of organic solvents at exceedingly low concentrations opens the door for the implementation of graphene oxides based electrolytes in various electrochemical applications. Here we demonstrate the use of acetonitrile–graphene oxide (GO) gel containing iodide/triiodide as a quasi-solid electrolyte for dye sensitized solar cells (DSCs). Electrochemical impedance studies reveal that the mass transfer barrier is not adversely affected by the presence of the minute amount of GO gel former. The achieved energy conversion efficiency (η) for the device without GO and with 1% GO gel electrolytes is 6.9% and 7.5% respectively under one sun illumination

Zinc Dioxide Nanoparticulates: A Hydrogen Peroxide Source at Moderate pH

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, Zn²⁺, 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

Peroxosolvates: Formation Criteria, H₂O₂ Hydrogen Bonding, and Isomorphism with the Corresponding Hydrates

The Cambridge Structural Database has been used to investigate the detailed environment of H₂O₂ molecules and hydrogen-bond patterns within “true” peroxosolvates in which the H₂O₂ molecules do not interact directly with the metal atoms. A study of 65 crystal structures and over 260 hydrogen bonds reveals that H₂O₂ always forms two H-bonds as proton donors and up to four H-bonds as a proton acceptor, but the latter can be absent altogether. The necessary features of peroxosolvate coformers are clarified. (1) Coformers should not participate in redox reactions with H₂O₂ and should not catalyze its decomposition. (2) Coformers should be Brønsted bases or exhibit amphoteric properties. The efficiency of the proposed criteria for peroxosolvate formation is illustrated by the synthesis and characterization of several new crystals. Conditions preventing the H₂O₂/H₂O isomorphous substitution are essential for peroxosolvate stability: (1) Every H₂O₂ in the peroxosolvate has to participate in five or six hydrogen bonds. (2) The distance between the two proton acceptors forming H-bonds with the H₂O₂ molecule should be longer than the distance defined by the nature of the acceptor atoms

Nanocrystalline SnS2 coated onto reduced graphene oxide: demonstrating the feasibility of a non-graphitic anode with sulfide chemistry for potassium-ion batteries

An anode material incorporating a sulfide is reported. SnS2 nanoparticles anchored onto reduced graphene oxide are produced via a chemical route and demonstrate an impressive capacity of 350 mA h g-1, exceeding the capacity of graphite. These results open the door for a new class of high capacity anode materials (based on sulfide chemistry) for potassium-ion batteries