The interaction of xenon with n-alkane solvents Comparison between different cavity models

A recently proposed model for calculating the energetics of cavity formation in liquids is used to study the interaction of rare gases in n-alkane solvents. It is observed that the energy and the entropy of interaction of a given solute with different n-alkane solvents are very similar and show a monotonic variation with the n-alkane carbon number. This behaviour, which is not observed when other methods are used to calculate the energetics of cavity formation, reinforces the idea of the similarity of the contact energies of the different n-alkane molecules.     

The interaction of iron pyrite with oxygen, nitrogen and nitrogen oxides: a first-principles study

Sulphide materials, in particular MoS(2), have recently received great attention from the surface science community due to their extraordinary catalytic properties. Interestingly, the chemical activity of iron pyrite (FeS(2)) (the most common sulphide mineral on Earth), and in particular its potential for catalytic applications, has not been investigated so thoroughly. In this study, we use density functional theory (DFT) to investigate the surface interactions of fundamental atmospheric components such as oxygen and nitrogen, and we have explored the adsorption and dissociation of nitrogen monoxide (NO) and nitrogen dioxide (NO(2)) on the FeS(2)(100) surface. Our results show that both those environmentally important NO(x) species chemisorb on the surface Fe sites, while the S sites are basically unreactive for all the molecular species considered in this study and even prevent NO(2) adsorption onto one of the non-equivalent Fe-Fe bridge sites of the (1 × 1)-FeS(2)(100) surface. From the calculated high barrier for NO and NO(2) direct dissociation on this surface, we can deduce that both nitrogen oxides species are adsorbed molecularly on pyrite surfaces.     

FT-IR study of the interaction of oxygen,argon, helium,nitrogen and xenon with hydroxyl groups in H-Y zeolite at low temperatures

Adsorptions of O₂, Ar, He, N₂ and Xe on H-Y zeolite at low temperatures were studied by transmission Fouriertransform infrared spectroscopy. For the O₂ adsorption, a weak v(OO) band was observed at 1550 cm⁻¹. The formation of a weak hydrogen-bonding of O₂ and Ar with the bridging OH-groups in the supercage was observed, while these molecules did not interact chemically nor physically with the bridging OH-groups in the small cavities. These results indicate that O₂ and Ar can approach the acid sites in the supercages, but cannot approach those in the small cavities. However, a slight physical interaction (not the H-bonding) of He with the OH groups in the small cavities was observed, suggesting that He would be able to approach near the sites. N₂ adsorption gave two v(NN) bands at 2353 and 2338 cm⁻¹, which have been attributed to the N2 species adsorbed on Lewis acid sites and on Br0nsted acid sites, respectively. It was observed that N₂ and Xe interact strongly with the bridging OH-groups in the supercages as well as weakly with the silanol groups. On the basis of the IR-spectroscopic data on the strength of the interaction with the small and nonpolar gases, the acidic properties of H-Y was compared with those of H-MOR and H-ZSM-5.     

The interaction of nitrogen and carbon monoxide with certain ions and neutral species

MNDO method is used to study the interaction of nitrogen and carbon monoxide molecules with a proton, hydrogen atom, hydride ion, hydrogen molecule ion and hydrogen molecule. Predicted geometries and heats of reaction of different complexes are presented. The wave functions are analyzed in terms of ground state charge distributions and overlap populations. Electronic effects accompanying complexation are also discussed.     

The interaction of hyperthermal nitrogen with N-covered Ag(111)

A mixed beam of hyperthermal N atoms and N(2) molecules was scattered from the N-covered Ag(111) surface held at 300 K. The angular distribution of scattered N atoms is very broad. In contrast, N(2) molecules exhibit a sharp angular distribution. Taking into account the relative mass ratio, N loses more energy at the surface than N(2). In terms of energy loss, the atoms approximately follow the binary collision model while the molecules do not. Instead, the energy curves of scattered N(2) are more comparable to the parallel momentum conservation model for near specular outgoing angles (40°-65°). For both atoms and molecules the angle-resolved intensity and final energy curves are very similar to those from the bare surface. However, the N-covered surface yields non-negligible N(2) intensity for a broad range of outgoing angles, including along the surface normal. This was not the case from the clean surface, where the measured intensity distribution was confined to the narrower angular range indicated above. Backscattering and direct abstraction reactions are evaluated as possible origins of this additional N(2) signal. Of these, an abstraction mechanism appears to be the most consistent with the measured data.     

Chemiluminescence accompanying solid-phase interaction of terbium(III) sulfate with xenon difluoride

It has been found that solid-phase interaction of anhydrous terbium(III) sulfate powder with xenon difluoride at room temperature is accompanied by chemiluminescence (CL). The formation of terbium( IV) and ozone in the course of the reaction has been observed spectrophotometrically. Two CL emitters, xenon in the Xe(I)* oxidation state (540, 580 nm) and Tb(III)* (490, 545, 590 nm), have been revealed. Emission by the former is observed at the beginning of the reaction. After the consumption of xenon difluoride, the emission is due to excited Tb(III) generated as a result of reduction of the Tb(IV) intermediate.     

The interaction of formohydroxamic acid with nitrogen: FTIR matrix isolation and ab initio studies

Argon matrix infrared spectra of the complexes formed between formohydroxamic acid, HCONHOH (FHA) and nitrogen have been recorded. The experimental results indicate formation of two isomeric complexes in which the nitrogen atom of the N₂ molecule is attached to the NH or OH groups of FHA. Theoretical studies of the structure and spectral characteristics of the complexes were carried out on the MP2 level with the 6-311++G(2d,2p) basis set. The calculated vibrational frequencies for the complexes present in the matrices are in good agreement with the experimental data.     

Study of the interaction of atomic oxygen and nitrogen with ruthenium by the bond interaction method

The heats of atomically adsorbed oxygen and nitrogen on Ru(0001) and Ru(1010) planes have been calculated by the semiempirical bond interaction method. The calculations show that oxygen is strongly adsorbed on ruthenium, while molecular nitrogen cannot be chemisorbed on ruthenium.

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Protons solvated in noble-gas matrices: interaction with nitrogen

The interaction of a (NgHNg)(+) cation (Ng = Ar and Kr) with a nitrogen molecule is studied. The structure, energetics, and vibrational properties of these complexed systems are computationally studied at the MP2/6-311++G(2d,2p) level of theory. The computations reveal two stable structures, linear and T-shaped configurations, with BSSE corrected interaction energies of the order of -1000 cm(-1). The (NgHNg)(+)[dot dot dot]N(2) complexes are characterized experimentally by IR absorption spectroscopy in solid Ar and Kr matrices. The spectra show that only one complex structure is present, as evidenced by the single nitrogen-induced nu(3) band. According to the computational results, the linear structure is more probable in the experiments. However, our results show that the one-to-one complex at the present computational level does not accurately agree with the matrix-isolation experiments, the differences originating possibly from the influence of the surrounding matrix. Based on the current data, the mechanism of cation decay in noble-gas matrices is discussed. The observed similar decay of (NgHNg)(+) and its N(2) complex indicates that the solvated proton is unable to tunnel and is therefore immobile in noble-gas matrices. The observations for the cation decay are consistent with the electron neutralization mechanism.     

The vaporization properties of krypton and xenon

The vaporization properties of krypton and xenon are reassessed from the experimental results published in the literature, more sparsely since the 1970s. The measured vapour pressure and the saturated liquid density of both substances are adjusted to empirical, reliable equations. Results are presented for the calculated vapour pressures and the orthobaric densities of the two substances. The coordinates of the triple point, the normal boiling temperature, and the critical point are discussed as well as the corresponding values of the enthalpies of vaporization. Argon, for which recent experimental, accurate work has been published, was kept out of the present review.     

Liquid mixtures of xenon with fluorinated species: xenon + sulfur hexafluoride

The vapor-liquid equilibrium of binary mixtures of xenon + SF6 has been measured at nine temperatures from 235.34 to 295.79 K and pressures up to 6.5 MPa. The mixture critical line is found to be continuous between the critical points of the pure components, and hence, the system can be classified as type I phase behavior in the scheme of van Konynenburg and Scott. The excess Gibbs free energies have been calculated, and the experimental results have been interpreted using the statistical associating fluid theory for potentials of variable range (SAFT-VR). Additionally, the SAFT-VR equation has been used to model other systems involving SF6 and alkanes, illustrating the predictability of the approach and further demonstrating the transferability of parameters between binary mixtures involving alkanes and xenon.     

dπ-pπ interaction in bonds of silicon with nitrogen and phosphorus

Conclusions The stretching vibration frequencies of the Si-H bond in substituted silanes containing an Si-N bond depend both on the inductive effect of the substituents and the d-p, p,- and , -conjugation effects.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2609–2611, November, 1970.     

Some reactions of ammonium or hydrazinium fluorides with xenon difluoride or xenon hexafluoride

The reactions between ammonium fluoride, hydrazinium(1+) fluoride, hydrazinium(2+) fluoride and XeF₂ or XeF₆ were studied. It was found that Xe, HF, N₂ were formed in these reactions. Interestingly enough, beside of these gases nitrogen fluorides in different quantities were formed also. The courses and the products of the above reactions are compared with analogous reactions with KrF₂.     

The sublimation of argon, krypton, and xenon

In this paper, the sublimation pressure of Ar, Kr, and Xe are obtained as functions of temperature from an exactly integrated form of the Clapeyron equation. No fitting to experimental data of the equilibrium pressure has been necessary. The deviation plots of the sublimation pressure show that the results are satisfactory. The derived enthalpy of sublimation of the three rare gases from T = 0 K up to their respective triple point temperatures are asymmetric, distorted parabolas showing maxima for . The , which is a measure of the cohesion energy of the solid crystals, is easily calculated. A general equation has been obtained for as a function of temperature which also gives the enthalpies of sublimation of neon and radon. The (s + ? + g) triple point coordinates of Rn are reassessed.     

Some reactions with krypton difluoride and xenon fluorides

The VF₅XeF_x (x being 2,4 and 6) system was sistematically investigated. Besides XeF_2^·.VF₅ (1) and 2XeF_6^·.VF₅ (2), new adducts XeF_6^·.VF₅ and XeF_6^·.2VF₅ were also isolated. The obtained adducts were characterized by following mass balance throughout the experiment, by Raman and IR spectroscopy, by recording the melting point - composition diagram, etc.The results of reactions in a system with some binary fluorides (e.g. TiF₄, MnF₂, CrF₃) and KrF₂ are also discussed.     

Synthesis and characterization of glycosylated nitrogen mustard derivatives and their interaction with bovine serum albumin

To improve the specificity of nitrogen mustards towards tumor cells, glucose-nitrogen mustard, fructose-nitrogen mustard, and lactose-nitrogen mustard were prepared as three novel glycosylated nitrogen mustard derivatives by esterification of bis(2-chloroethyl)carbamic chloride (BCC) with glucose, fructose, and lactose, respectively. BCC was synthesized from bis(2-chloroethyl)amine hydrochloride and triphosgene. The topic products were characterized by infrared (IR) and mass spectrometry (MS), and their interaction with bovine serum albumin was investigated by measuring fluorescence spectra in tris(hydroxymethyl)aminomethane hydrochloride (Tris–HCl) buffer solution at physiological conditions.