Xenon Trioxide Research Articles

Taming XeO3 with Aza-Crowns: Computational Studies into σ-Hole Mediated Host-Guest Interactions.

Various aza-crowns with different sizes and substituents have been explored computationally as potential hosts for stabilizing the explosive guest xenon trioxide (XeO3) through σ-hole-mediated aerogen bonding interactions. Interestingly, aza-crowns demonstrate superior binding towards XeO3 compared to their oxygen and thio counterparts. However, unlike the latter cases, where the binding was found to be increasingly favorable with the increase in the size of the crowns, aza-crowns exhibit a variable size preference for XeO3, peaking with aza-15-crown-5, and reducing thereafter with increase in crown size.

Unveiling the Inverse Sandwich Complexes of XeO3: A Computational Exploration.

Our study introduces the design of inverse sandwich (iSw) complexes incorporating a noble gas compound: xenon trioxide (XeO3). Through comprehensive computational analyses, we have investigated the critical factors influencing their stability by employing a variety of state-of-the-art computational tools. We demonstrated that the coordination number of xenon in the iSw complex of XeO3 with 18-crown-6 is influenced by the presence of a rare, weakly stabilizing Xe···Xe interaction between the XeO3 molecules. Furthermore, we observed that the stability of iSw complexes of 1,3,5-triphenylbenzene (TPB) and its derivatives is not solely attributed to aerogen bonding, but also involves contributions from C-H···O interactions and back-donation from the lone pair of Xe to the antibonding C-C orbitals of TPB. Additionally, the significant contributions from orbital interactions and dispersion interactions in the TPB derivatives highlight the multifaceted amphoteric properties of XeO3 and reveal that the iSw complexes of TPB and derivatives are not predominantly governed by electrostatic interactions, contrary to conventional belief.

Structure property correlation study of energetic solid XeO3

In the realm of material science, xenon trioxide (XeO3) is characterized by an significant degree of shock sensitivity, resembling characteristics associated with primary explosives. To determine the underlying principles and quantify such behaviour we present a comprehensive computational study addressing the structural, vibrational, electronic and optical behaviour of energetic XeO3 by employing DFT calculations (Density Functional Theory). Our study demonstrates a good agreement between our computed structural parameters at equilibrium and experimental findings, particularly after incorporating vdW (van der Waals) interactions. Also, the mechanical stability of XeO3 is assessed by computing the Cij (elastic constants) and the B (bulk modulus). The evaluation of elastic constants in various directions indicates that (C33 > C22 > C11) XeO3 is highly shock sensitive along crystallographic a-axis. The computed (B) bulk modulus is determined to be 12.98 GPa, aligning closely with the values observed in other primary explosives. The phonon dispersion spectra computed within the harmonic approximation confirms the dynamical stability of XeO3 in P212121 structure. The spectra also reveal a notable interaction between the acoustic and optical branch, resulting in low thermal conductivity which is a trait for the energetic materials. The precise measurement of the energy band gap is crucial for establishing potential correlations with the photodecomposition process of energetic materials. To support this, we have conducted band structure calculations using the TB-mBJ (Tran-Blaha modified Becke-Johnson) potential, alongside the conventional GGA/LDA methods, generally known to underestimate band gaps. Our TB-mBJ based calculations yielded an energy band gap around 2.5 eV, which can also be compared with other energetic compounds. The rapid fluctuations of the optical constants suggest photodecomposition nature of XeO3 in the near UV region. The insights gained from our study would be of high interest for the study of other xenon (Xe) compounds and their oxides, delivering direction for potential applications across diverse fields.

Xenon Trioxide Adducts of O‐Donor Ligands; [(CH3)2CO]3XeO3, [(CH3)2SO]3(XeO3)2, (C5H5NO)3(XeO3)2, and [(C6H5)3PO]2XeO3

Xenon trioxide (XeO3 ) forms adducts with triphenylphosphine oxide, dimethylsulfoxide, pyridine-N-oxide, and acetone by coordination of the ligand oxygen atoms to the XeVI atom of XeO3 . The crystalline adducts were characterized by low-temperature, single-crystal X-ray diffraction, and Raman spectroscopy. Unlike solid XeO3 , which detonates when mechanically or thermally shocked, solid (C5 H5 NO)3 (XeO3 )2 , [(C6 H5 )3 PO]2 XeO3 , and [(CH3 )2 SO]3 (XeO3 )2 are insensitive to mechanical shock. The [(CH3 )2 SO]3 (XeO3 )2 adduct slowly decomposes over several days to (CH3 )2 SO2 , Xe, and O2 . All three complexes undergo rapid deflagration when ignited by a flame. Both [(C6 H5 )3 PO]2 XeO3 and (C5 H5 NO)3 (XeO3 )2 are room-temperature stable and the [(CH3 )2 CO]3 XeO3 complex dissociates at room temperature to form a stable solution of XeO3 in acetone. The xenon coordination sphere of [(C6 H5 )3 PO]2 XeO3 , a distorted square-pyramid, provides the first example of a five-coordinate XeO3 complex with only two Xe- - -O adduct bonds. The xenon coordination spheres of the remaining adducts are distorted octahedra, comprised of three Xe- - -O secondary bonds that are approximately trans to the primary Xe-O bonds of XeO3 . Quantum-chemical calculations were used to assess the nature of the Xe- - -O adduct bonds, which are described as predominantly electrostatic bonds between the nucleophilic oxygen atoms of the bases and the σ-holes of the electrophilic xenon atoms.

Oxidation of Np(V) with Xenon Trioxide in an HClO4 Solution

Oxidation of Np(V) to Np(VI) with xenon trioxide in a 0.5–1.4 M HClO4 solution was studied by spectrophotometry. The reaction rate is described by the equation–d[Np(V)]/dt = k[Np(V)][XeO3], where k = 4.6 × 10–3 L mol–1 s–1 in 1 M HClO4 at 92°С. The activation energy is close to 92 kJ mol–1. The activated complex is formed in contact of NpO 2 + and ХеО3 without participation of Н+ ions. The activated complex transforms into NpO 2 2+ and the products: ОН, Хе, and О2. The ОН radical oxidizes Np(V). Admixtures of Со2+ and especially Fe3+ accelerate the Np(V) oxidation.

A Stable Crown Ether Complex with a Noble‐Gas Compound

AbstractCrown ethers have been known for over 50 years, but no example of a complex between a noble‐gas compound and a crown ether or another polydentate ligand had previously been reported. Xenon trioxide is shown to react with 15‐crown‐5 to form the kinetically stable (CH2CH2O)5XeO3 adduct, which, in marked contrast with solid XeO3, does not detonate when mechanically shocked. The crystal structure shows that the five oxygen atoms of the crown ether are coordinated to the xenon atom of XeO3. The gas‐phase Wiberg bond valences and indices and the empirical bond valences indicate that the Xe‐ ‐ ‐Ocrown bonds are predominantly electrostatic and are consistent with σ‐hole bonding. Mappings of the electrostatic potential (EP) onto the Hirshfeld surfaces of XeO3 and 15‐crown‐5 in (CH2CH2O)5XeO3 and a detailed examination of the molecular electrostatic potential surface (MEPS) of XeO3 and (CH2CH2O)5 reveal regions of negative EP on the oxygen atoms of (CH2CH2O)5 and regions of high positive EP on the xenon atom, which are also in accordance with σ‐hole interactions.

A Stable Crown Ether Complex with a Noble-Gas Compound.

Crown ethers have been known for over 50 years, but no example of a complex between a noble-gas compound and a crown ether or another polydentate ligand had previously been reported. Xenon trioxide is shown to react with 15-crown-5 to form the kinetically stable (CH2 CH2 O)5 XeO3 adduct, which, in marked contrast with solid XeO3 , does not detonate when mechanically shocked. The crystal structure shows that the five oxygen atoms of the crown ether are coordinated to the xenon atom of XeO3 . The gas-phase Wiberg bond valences and indices and the empirical bond valences indicate that the Xe- - -Ocrown bonds are predominantly electrostatic and are consistent with σ-hole bonding. Mappings of the electrostatic potential (EP) onto the Hirshfeld surfaces of XeO3 and 15-crown-5 in (CH2 CH2 O)5 XeO3 and a detailed examination of the molecular electrostatic potential surface (MEPS) of XeO3 and (CH2 CH2 O)5 reveal regions of negative EP on the oxygen atoms of (CH2 CH2 O)5 and regions of high positive EP on the xenon atom, which are also in accordance with σ-hole interactions.

XeO3 adducts of pyridine, 4-dimethylaminopyridine, and their pyridinium salts

Xenon trioxide (XeO3), a highly shock-sensitive detonator, forms adducts with the N-bases, pyridine and 4-dimethylaminopyridine (4-DMAP). The reactions of pyridine and 4-DMAP with XeO3 in rigorously dried CH3CN and in CH3CN that had not been dried yielded (C5H5N)3XeO3(1) and (4-(CH3)2NC5H5N)3 XeO3·H2O (3), respectively, whereas their reactions in HF-acidified CH3CN yielded [C5H5NH]4[HF2]2[F]2(XeO3)2(2) and [4-(CH3)2NC5H4NH][HF2]XeO3(4). Crystalline (1), (2), and (4) failed to detonate when subjected to mechanical shock; however, (3) was significantly more sensitive to mechanical or thermal shock than XeO3. The adducts and their pyridinium salts were structurally characterized by low-temperature, single-crystal X-ray diffraction, and Raman spectroscopy. The crystal structures of (1) and (3) consist of XeO3 molecules that are N-coordinated to three pyridine and 4-DMAP ligands, respectively. A water molecule is also H-bonded to two oxygen atoms of two adjacent XeO3 molecules of (3). The pyridinium cations of (2) and (4) are H-bonded to [F]− and/or [HF2]− ions which are, in turn, F-coordinated to XeO3. Both [F]− ions of (2) bridge two XeO3 molecules to form Xe2F2-rings. Each [HF2]− anion of (4) bridges two cations and two XeO3 molecules by means of Xe⋯F secondary bonds and N(H)⋯F H-bonds. Quantum-chemical calculations for (1) and (2) provided energy-minimized geometries and calculated vibrational frequencies and intensities which were used to aid in the assignments of their Raman spectra. The NBO analyses showed the Xe⋯N, Xe⋯O, and Xe⋯F secondary bonding interactions are electrostatic in nature and may be described as σ-hole bonds.

Solid-State Structures of XeO3.

The solid-state structure of xenon trioxide, XeO3, was reinvestigated by low-temperature single-crystal X-ray diffraction and shown to exhibit polymorphism that is dependent on the crystallization conditions. The previously reported α-phase (orthorhombic, P212121) only forms upon evaporation of aqueous HF solutions of XeO3. In contrast, two new phases, β-XeO3 (rhombohedral, R3) and γ-XeO3 (rhombohedral, R3c), have been obtained by slow evaporation of aqueous solutions of XeO3. The extended structures of all three phases result from Xe═O---Xe bridge interactions among XeO3 molecules that arise from the amphoteric donor-acceptor nature of XeO3. The Xe atom of the trigonal-pyramidal XeO3 unit has three Xe---O secondary bonding interactions. The orthorhombic α-XeO3 displays the greatest degree of variation among the contact distances and has a significantly higher density than the rhombohedral phases. The ambient-temperature Raman spectra of solid α- and γ-XeO3 have also been obtained and assigned for the first time.

Syntheses and Structures of Xenon Trioxide Alkylnitrile Adducts

AbstractThe potent oxidizer and highly shock‐sensitive binary noble‐gas oxide XeO3 interacts with CH3CN and CH3CH2CN to form O3XeNCCH3, O3Xe(NCCH3)2, O3XeNCCH2CH3, and O3Xe(NCCH2CH3)2. Their low‐temperature single‐crystal X‐ray structures show that the xenon atoms are consistently coordinated to three donor atoms, which results in pseudo‐octahedral environments around the xenon atoms. The adduct series provides the first examples of a neutral xenon oxide bound to nitrogen bases. Raman frequency shifts and Xe−N bond lengths are consistent with complex formation. Energy‐minimized gas‐phase geometries and vibrational frequencies were obtained for the model compounds O3Xe(NCCH3)n (n=1–3) and O3Xe(NCCH3)n⋅[O3Xe(NCCH3)2]2 (n=1, 2). Natural bond orbital (NBO), quantum theory of atoms in molecules (QTAIM), electron localization function (ELF), and molecular electrostatic potential surface (MEPS) analyses were carried out to further probe the nature of the bonding in these adducts.

Syntheses and Structures of Xenon Trioxide Alkylnitrile Adducts.

The potent oxidizer and highly shock-sensitive binary noble-gas oxide XeO3 interacts with CH3 CN and CH3 CH2 CN to form O3 XeNCCH3 , O3 Xe(NCCH3 )2 , O3 XeNCCH2 CH3 , and O3 Xe(NCCH2 CH3 )2 . Their low-temperature single-crystal X-ray structures show that the xenon atoms are consistently coordinated to three donor atoms, which results in pseudo-octahedral environments around the xenon atoms. The adduct series provides the first examples of a neutral xenon oxide bound to nitrogen bases. Raman frequency shifts and Xe-N bond lengths are consistent with complex formation. Energy-minimized gas-phase geometries and vibrational frequencies were obtained for the model compounds O3 Xe(NCCH3 )n (n=1-3) and O3 Xe(NCCH3 )n ⋅[O3 Xe(NCCH3 )2 ]2 (n=1, 2). Natural bond orbital (NBO), quantum theory of atoms in molecules (QTAIM), electron localization function (ELF), and molecular electrostatic potential surface (MEPS) analyses were carried out to further probe the nature of the bonding in these adducts.

Autoacceleration of the free-radical chain luminescent oxidation of U(IV) with xenon trioxide in aqueous HClO4

Autoacceleration is observed in the chemiluminescent radical chain oxidation of U(IV) with xenon trioxide in aqueous perchloric acid in a Teflon (not conventional glass) reactor. The decay of chemiluminescence accompanying the reaction between U(IV) and XeO3 in the case of excess oxidizer obeys a first-order kinetic equation only at low U(IV) concentrations of 10−5–10−6 mol/l. Autoacceleration takes place at comparatively high reactant concentrations, when the contribution from the heterogeneous loss of radicals on the reactor walls into chain termination is comparatively small and the role of degenerate chain branching reactions is significant. It is inferred that a critical phenomenon rare for liquid-phase radical chain processes takes place in U(IV) oxidation with xenon trioxide: a comparative small increase in the reactant concentrations causes this chemiluminescent redox process to pass from the quasi-steady-state regime to autoacceleration.

Formation of excited uranyl ion in oxidation of U(IV) with xenon trioxide in aqueous H2SO4 and HClO4 solutions: III. Kinetic mode of self-accelerated reaction

Self-acceleration was revealed for chemiluminescent radical-chain oxidation of U(IV) with xenon trioxide in aqueous HClO4 solutions in a reactor made of Teflon (instead of conventionally used glass). In oxidant excess, U(IV) oxidation with XeO3 follows the first-order kinetics only at low (under 10−6 M) concentrations of U(IV) in solution. Self-acceleration is observed at relatively high concentrations of the reactants, when the contribution of the heterogeneous decay of the radicals to chain termination substantially decreases and that of the degenerate branching reactions to the U(IV) oxidation mechanism increases. Oxidation of U(IV) with XeO3 demonstrates a critical phenomenon, uncommon for liquid-phase radical-chain processes: a minor increase in the concentrations of the reactants is responsible for transition from a steady-state mode to self-acceleration of the redox process.

Formation of Excited Uranyl Ion in Oxidation of U(IV) with Xenon Trioxide in Aqueous Solutions of H2SO4and HClO4: II. Influence of H2O2on the Reaction Kinetics

The kinetics and mechanism of chemiluminescent oxidation of U(IV) with xenon trioxide [monoexponential decay of chemiluminescence (CL)] dramatically changes in the presence of H2O2. First the CL intensity slightly decreases (induction period), then increases by a factor of several units (autocatalytic oxidation), and finally sharply decreases by several orders of magnitude after reaching a maximum. Radical chain mechanism of the reaction was proposed. The elementary step of formation of CL emitter, electronically excited (UO22+)*, is electron transfer from the uranyl(V) ion (UO2+) to the oxidizing agent (OH radical). In the presence of H2O2 in the solution, OH radicals are formed non only by reaction of U(IV) with XeO3 but also by reaction of H2O2 with XeO3, which complicates the CL kinetics.

Formation of Excited Uranyl Ion in Oxidation of U(IV) with Xenon Trioxide in Aqueous Solutions of H2SO4and HClO4: I. Influence of Sulfate Anions

Kinetic and chemiluminescent parameters of U(IV) oxidation with xenon trioxide in 1 M H2SO4 were studied in relation to complexation of U(IV) with SO42- anions. The rate constant of oxidation of the sulfate complexes increases from ∼1 to 43 l mol-1 s-1 with increasing [Na2SO4] in the solution from 10-3 to 3×10-1 M. The equilibrium concentrations of aqua- and mono- and bisulfate complexes of U(IV) were calculated at different [Na2SO4] in the solution. The rate constant of reaction of U(SO4)2 with XeO3 [k = 72 l mol-1 s-1] is higher by an order of magnitude than the rate constant of oxidation of U(IV) monosulfate complex [k = 6.5 l mol-1 s-1]. The dependence of the lifetime of excited uranyl ions (τ) on the Na2SO4 concentration in 1 M HClO4 was measured. The chemiluminescence (CL) yield increases in the presence of sulfate anions owing to the growth of both the emission output of excited uranyl sulfate complexes and the yield of excitation of the CL emitter.

Chemihiminescence by the interaction of XeO3 and the products of photolysis of uranyl solutions in sulfuric acid

Using the chemiluminescence oxidation of U(IV) and H2O2 with xenon trioxide as a model, it has been found that during the photolysis of solutions of UO2SO4 in sulfuric acid in the absence of any organic compounds, the accumulation of U(SO4)2 and H2O2 takes place as a result of the reaction of the primary products of the photoreduction of uranyl ion,i.e., UO2+ and the OH radical.

Chemiluminescence in the oxidation of uranium(iv) by the products of the reaction of XeO3 and H2O2 in aqueous sulfuric acid solution

In previous work [i], we used a chemiluminescence method in the determination of small amounts of (down to 10 -9 mole/liter) uranium (IV) for a considerable (up to a i0 -z mole/liter) excess of uranyl ions in solution in a study of the radiolytic reduction of uranium(IV) in aqueous sulfuric acid solutions in the absence of organic OH-radical acceptors. The chemiluminescent oxidation of uranium(IV) by xenon trioxide was used as the model. This reaction has simple kinetics. In the case of excess oxidizing agent, the reaction rate decreases exponentially (Fig. i, curve i) with change in the uranium(IV) concentration by several orders of magnitude [2]. The kinetic curves for the chemiluminescence intensity measured after cessation of the x-ray irradiation of the solutions of XeO 3 and UOz2+ in 0.2 M H2SO 4 have a maximum or inflection point [I], which indicates the products of the radiolysis of water in the chemiluminescence reaction. We have shown that one of the reasons for the appearance of a maximum on the kinetic curve is the presence of H202 in the solution. Chemiluminescence was observed in the oxidation of U(IV) by the products of the reaction of H20 z and Xe03. The kinetics of this reaction is shown in Fig. I, curve 2. The time required for achieving the maximum after the simultaneous mixing of solutions of U(IV), XeO3, and H202, depends on the concentration of sulfuric acid in the solution, temperature (the time interval exponentially increases with decreasing temperature), concentration of the reagents, and reagent ratio. The sharp drop in the chemiluminescence intensity after reaching the maximum is related to consumption of U(IV). The unusual kinetic curve may be reproduced by the reintroduction of U(SO4) z to the solution.

ChemInform Abstract: Oxidation of Benzene (I) and Alkylbenzenes (III) with Xenon Trioxide Catalyzed by Cr(VI) Oxo Compounds or Porphyrin Complexes of Mn and Fe.

ChemInformVolume 20, Issue 26 Preparative Organic Chemistry ChemInform Abstract: Oxidation of Benzene (I) and Alkylbenzenes (III) with Xenon Trioxide Catalyzed by Cr(VI) Oxo Compounds or Porphyrin Complexes of Mn and Fe. G. B. SHUL'PIN, G. B. SHUL'PIN Inst. khim. fiz. AN SSSR, MoskvaSearch for more papers by this authorM. M. KATZ, M. M. KATZ Inst. khim. fiz. AN SSSR, MoskvaSearch for more papers by this authorYU. N. KOZLOV, YU. N. KOZLOV Inst. khim. fiz. AN SSSR, MoskvaSearch for more papers by this author G. B. SHUL'PIN, G. B. SHUL'PIN Inst. khim. fiz. AN SSSR, MoskvaSearch for more papers by this authorM. M. KATZ, M. M. KATZ Inst. khim. fiz. AN SSSR, MoskvaSearch for more papers by this authorYU. N. KOZLOV, YU. N. KOZLOV Inst. khim. fiz. AN SSSR, MoskvaSearch for more papers by this author First published: June 27, 1989 https://doi.org/10.1002/chin.198926100AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume20, Issue26June 27, 1989 RelatedInformation

Oxidation of benzene and alkylbenzenes by xenon trioxide catalyzed Cr(VI) oxo compounds or Mn and Fe porphyrin complexes

Oxidation of benzene and alkylbenzenes by xenon trioxide catalyzed Cr(VI) oxo compounds or Mn and Fe porphyrin complexes

Kinetics of the reactions of xenon trioxide. Communication 4. Mechanism of the decomposition of xenon trioxide in aqueous solution

1. The decomposition of xenon trioxide in aqueous solution proceeds via a chain mechanism over the range 1 < pH < 10 with the formation of hydrogen peroxide and XeO2 (XeO) as intermediate substances. 2. Over the range pH >10 the chain mechanism changes to an ionic mechanism involving the di-sproportionation of Xe(VI) with the formation of Xe(VIII) perxenates.