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This minireview presents the results that show the potential of molecular nitrogen fixation by carbonyl cluster compounds of platinum metals at room temperature and atmospheric pressure to produce ammonia or its derivatives. Although the main attention is given to processes with the participation of derivatives of platinum and palladium, it was demonstrated that molecular nitrogen fixation is characteristic of all the platinum metals, except osmium.

Cutting-edge research on graphite-like carbon nitride-based (g-C3N4) photocatalytic systems for molecular nitrogen fixation is summarized. The properties of modified g-C3N4 with grafted functional groups, structural defects (nitrogen or carbon vacancies), doped with nonmetals and metals, as well as g-C3N4-based binary and ternary composites with the participation of metals, their oxides, metalates, carbonates, hydrocarbons, and sulfides are discussed. The most promising areas of further research are outlined.

Chromism from phosphomolybdate – malachite green dye moiety through hydrogen bonding interaction with water molecules is reported. Interestingly, the substance with bound di-nitrogen or di-oxygen together with water molecules also exhibits color change. N2 or O2 binding vis-a-vis chromism is a new insight.

Novel processes for the sustainable production of fertilizers are highly sought after to combat climate change. Herein, we demonstrate that by irradiating with strong UVA-light, TiO2 is able to photocatalytically oxidize molecular nitrogen in the gas phase under ambient conditions to NOx and nitrate. The reaction produces predominantly nitrogen dioxide with a high selectivity of up to 93% which could be captured afterwards to produce nitric acid or nitrates and used as sustainable (solar) fertilizer.

Denitrification and anaerobic ammonium oxidation (anammox) are important biological processes of the nitrogen cycle that help to preserve the global ecosystem. However, indiscriminate development and global population growth result in the discharge of large amounts of nitrogen species (e.g., via the Haber–Bosch process), particularly nitrogen oxides and ammonia, which cannot be fully digested by microorganisms and therefore accumulate in soil and water. Photocatalysts can promote the conversion of nitrogen oxides and ammonia to molecular nitrogen under the action of photogenerated electrons and holes, thus mimicking denitrifying and anammox bacteria, respectively. Herein, we review the biomimetic photocatalysts and photoelectrochemical cells used to convert aqueous and airborne nitrogen species to molecular nitrogen and shed light on the charge transfer mechanism that should be selectively controlled to favor the formation of molecular nitrogen over that of nitrogen-containing intermediates and by-products. Last but not least, we discuss the outlooks and perspectives of solar-powered molecular nitrogen recovery and suggest guidelines for the design of high-performance denitrification/anammox bacteria-like photocatalysts.

A combined experimental and computational study is reported on a hitherto unrecognised single lanthanide catalyst for the breaking of molecular nitrogen and formation of ammonia at ambient temperature and low pressure. We combine in situ electrical conductance and electron diffraction measurements to track the conversion from the lanthanide metals to the insulating lanthanide nitrides. The efficiency of the conversion is then interpreted using $\mathrm{DFT}+U$ calculations, suggesting a molecular nitrogen dissociation pathway separate from that well established for transition metals. Finally, we show that exposure of the lanthanide surfaces to both molecular nitrogen and hydrogen results in the formation of ammonia.

Analysis of the distribution and genesis of nitrogen in salts and subsalt formation fluids in the Volga-Ural Basin makes it possible to distinguish two genetically distinct groups of subsalt fluids and corresponding two distinct sources of nitrogen. One of them includes calcium chloride bridnes, nitrogen-saturated oils, and nitrogen-bearing formation gases. The fluids of this group have δ15N > 0‰ and occur closer to the surface in the platform part of the basin. The other group comprises only oils saturated with CH4 and methane formation gases, and the fluids of the latter group likely have δ15N < 0‰ and were found near the margin of the platform, in the Ural Foredeep and near the Caspian depression. The first group with isotopically heavy nitrogen is supposedly formed by fluids remaining after the loss of volatile components during ancient metamorphism of the rocks, whereas the second group was likely generated by the volatiles released during the degassing of the same rocks.

Nitric acid is manufactured by oxidizing ammonia where the ammonia comes from an energy demanding and non-eco-friendly, Haber–Bosch process. Electrochemical oxidation of N2 to nitric acid using renewable electricity could be a promising alternative to bypass the ammonia route. In this work, we discuss the plausible reaction mechanisms of electrochemical N2 oxidation (N2OR) at the molecular level and its competition with the parasitic oxygen evolution reaction (OER). We suggest the design strategies for N2 oxidation electro-catalysts by first comparing the performance of two catalysts – TiO2(110) (poor OER catalyst) and IrO2(110) (good OER catalyst), towards dinitrogen oxidation and then establish trends/scaling relations to correlate OER and N2OR activities. The challenges associated with electrochemical N2OR are highlighted., Electrochemical oxidation of N2 to HNO3 (N2OR) is explored in conjunction with parasitic oxygen evolution reaction (OER) on a poor and a good OER catalyst, TiO2 and IrO2. We develop scaling relations to correlate OER and N2OR activities on oxides.

Replacement of a part of malt with unmalted materials is a common practice in beer production. These materials may differ in chemical composition than barley malt, which in turn can contribute to changes in the final composition of the wort. Consequently, it may affect yeast metabolism and final parameters of the obtained products. In this research, two unmalted pseudocereals were used: quinoa (Chenopodium quinoa Willd.) and amaranth (Amaranthus cruentus L.). Maltose syrup was tested as a reference material due to its commercial usage as a substitute of malt in production of worts. Replacement of a part of the malt with quinoa or amaranth favorably influenced the profiles of amino and fatty acids. Due to the fact that the type and concentration of individual amino acids and fatty acids in the fermented wort significantly affect the flavor compounds synthesized by yeast, differences in the profiles of esters and higher alcohol have been noted in beers produced with pseudocereals.

Although molecular dinitrogen (N2) is widely used as a carrier or inert gas for many catalytic reactions, it is rarely considered as a catalytic promoter. Here, we report that N2 could be used to reduce the activation energy for catalytic hydrodeoxygenation over ruthenium-based catalysts. Specifically, we report a 4.3-fold activity increase in the catalytic hydrodeoxygenation of p-cresol to toluene over a titanium oxide supported ruthenium catalyst (Ru/TiO2) by simply introducing 6 bar N2 under batch conditions at 160 °C and 1 bar hydrogen. Detailed investigations indicate that N2 can be adsorbed and activated on the metallic ruthenium surface to form hydrogenated nitrogen species, which offer protic hydrogen to lower the activation energy of direct carbonaromatic–oxygen bond scission and the hydrogenation of hydroxy groups. Thus, by employing different ruthenium catalysts, including Ru/TiO2, Ru/Al2O3, Ru/ZrO2 and Ru/C, we demonstrate that N2 promotion of hydrodeoxygenation can be regarded as a general strategy. Due to its stability nitrogen is often employed as an inert gas during catalytic reactions. Now, a study shows that N2 can act as promoter for the catalytic hydrodeoxygenation of p-cresol on supported ruthenium catalysts through the formation of hydrogenated nitrogen species acting as a source of protic hydrogen.

Fifteen natural gas samples were collected from the autochthonous Miocene strata between Debica and Przemyśl towns in the eastern sector of the Polish Carpathian Foredeep. The samples were analysed for the molecular and stable isotope compositions of carbon (δ13C in CH4, C2H6, C3H8, i-C4H10, n-C4H10 and CO2), hydrogen (δ2H in CH4, C2H6 and C3H8), nitrogen (δ15N in N2), and all stable isotopes of noble gases (He, Ne, Ar, Kr and Xe) in order to reveal the origin and migration pathway of these gases. Methane concentrations usually exceeded 90 vol%. Methane was mainly generated by microbial carbon dioxide reduction. The rhythmic and cyclic deposition of clays, muds and sands in the Miocene marine basin facilitated and intensified microbial processes. Microbial ethane can be produced by methanogenic Archaea from acetate via reduction. Ethane partly contains a minor component generated from early mature thermogenic process. Propane and butanes were also generated thermogenically. The hydrocarbon gases in the Miocene horizons IIA and IIIA of the Gora Ropczycka field were generated at higher maturity thermogenic process than the rest of the analysed Miocene gases probably from the Middle Jurassic type III kerogen. They migrated to the Miocene horizons from the underlying Upper Jurassic horizon IV of the same field along a fault. Carbon dioxide of the analysed Miocene gases was mainly generated by primary microbial processes. Moreover, the total carbon constrained in the analysed Miocene gases from 0.1 to 6 wt% contained mantle-derived carbon, and thus carbon dioxide mantle component. Molecular nitrogen was mainly generated during low-temperature thermal transformation of organic matter. It might also involve a relatively insignificant component released from NH4-rich illites of the clayey facies of Miocene strata and an atmospheric component delivered by recharge of air-saturated seawater to the reservoir. Inorganic fluid supply from greater lithospheric depth would not be responsible for the promotion of thermal transformation of organic matter. Molecular nitrogen from Miocene horizons in the Gora Ropczycka field was generated during the thermal transformation of organic matter of higher maturity than the rest of Miocene gases, and migrated from the Upper Jurassic horizon along a fault. Helium is dominated by its radiogenic component, with a minor contribution from the mantle. The almost constant mixing ratios of the two helium components in the natural gases from Miocene horizons of various depths suggest that He migrated from a common inorganic deep-seated source in the lithosphere. The other noble gases are dominated by atmospheric components delivered to the hydrocarbon reservoirs by recharge of air-saturated seawater, with minor nucleogenic 21Ne, radiogenic 40Ar, and sedimentary Kr and Xe contributions. The atmospheric component is isotopically fractionated for Ne, and elementally fractionated with various degrees. The ratios of radiogenic 4He to nucleogenic 21Ne or radiogenic 40Ar are higher than the crustal production ratios, suggesting fractionation during thermal release from their host minerals and/or phase related fractionation during their transport to the gas reservoirs. The striking similarity in noble gas isotopic/elemental ratios of the Gora Ropczycka gas from the Miocene horizon IIIA to the nearby reservoir in Mesozoic strata is consistent with gas migration along a fault system.

High content of molecular nitrogen (N2) is one of the natural gas exploration risks in petroliferous basins where black shales act as source rocks of either hydrocarbon gas or molecular nitrogen. In this study, two overmature and one low-maturity shale samples and their kerogens were investigated to determine the generation characteristics of molecular nitrogen as well as methane and the differences in the release processes of inorganic nitrogen fixed in ammonium-bearing minerals and organic nitrogen bound in kerogen. The results illustrate that with increasing pyrolysis temperature, the yield of methane first increases and then decreases with an inflection temperature of 650 °C (EqVRo = 3.4%), whereas the yield of molecular nitrogen shows a continuous increase throughout the pyrolysis experiment. The molecular nitrogen during the stage of methane generation (i.e., EqVRo 3.4%). The results also reveal that at the experimental maxima of thermal maturity (EqVRo = 4.9%), the generation potential of inorganic molecular nitrogen (mg/g Ninorg) is much lower than that of organic molecular nitrogen (mg/g Norg), indicating that in our experiments the organic nitrogen in kerogen is more easily to be converted into molecular nitrogen than the inorganic nitrogen in ammonium-bearing minerals. All these results indicate that molecular nitrogen content in shale gas may change dramatically during thermal evolution, and source rocks with exceptionally high maturity and high abundance of organic nitrogen likely lead to a high molecular nitrogen risk, particularly in regions of poor preservation conditions of shale gas, which may be the main reasons for the high molecular nitrogen content in the Lower Cambrian shale gas in South China.

The paper describes remarkable reactions of the direct synthesis of aromatic amines from molecular nitrogen. Two types of systems capable of inducing such reactions are considered in detail. The first type involves systems based on titanium compounds (Cp2TiCl2, Cp2TiPh2, CpTiCl3, TiCl4, Ti(OBu)4) and excess aryllithium reagents (PhLi, p-, m- and o-MeC6H4Li, α-C10H8Li, oPhC6H4Li) in ether. The second type is obtained by treating diaryltitanocenes Cp2TiAr2 (Ar = Ph, p- and m-MeC6H4) with metals of groups I and II (Li, Na, Mg) in ethereal media. In both cases the interaction with dinitrogen proceeds at room temperature and results in the formation of aromatic amines and ammonia after hydrolysis. The highest activity in amine production is displayed by the systems Cp2TiCl2 + PhLi in ether and Cp2TiPh2 + Li in THF. The mechanism of the reactions found is discussed.

The number of separations and analyses of molecular species using traveling wave ion-mobility spectrometry-mass spectrometry (TWIMS-MS) is increasing, including those extending the technique to analytes containing metal atoms. A critical aspect of such applications of TWIMS-MS is the validity of the collisional cross sections (CCSs) measured and whether they can be accurately calibrated against other ion-mobility spectrometry (IMS) techniques. Many metal containing species have potential reactivity toward molecular nitrogen, which is present in high concentration in the typical Synapt-G2 TWIMS cell. Here, we analyze the effect of nitrogen on the drift time of a series of cationic 1,10-phenanthroline complexes of the late transition metals, [(phen)M](+), (M = Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, and Hg) in order to understand potential deviations from expected drift time behaviors. These metal complexes were chosen for their metal open-coordination site and lack of rotameric species. The target species were generated via electrospray ionization (ESI), analyzed using TWIMS in N2 drift gas, and the observed drift time trends compared. Theoretically derived CCSs for all species (via both the projection approximation and trajectory method) were also compared. The results show that, indeed, for metal containing species in this size regime, reaction with molecular nitrogen has a dramatic effect on measured drift times and must not be ignored when comparing and interpreting TWIMS arrival time distributions. Density-functional theory (DFT) calculations are employed to analyze the periodic differences due to the metal's interaction with nitrogen (and background water) in detail.

Resonance structures corresponding to the (3sσ) 2 2 Σ + state in carbon monoxide at 10.044 eV and the (3sσ g ) 2 2 Σ g + state in nitrogen at 11.499 eV have been studied in elastic electron scattering over the range of scattering angle from 95° to 180°. A new magnetic angle-changing technique has been used in the measurements, which has enabled the first observation of these resonance structures at and close to 180°. The width of the 2 Σ + resonance in carbon monoxide has been determined to be 42±3 meV.

A kinetic model for the catalytic wet air oxidation of aqueous ammonia over Ru/TiO2 catalyst was developed considering the consecutive reaction steps as follows: (i) formation of active oxygen sites O* by the dissociative adsorption of aqueous O2 on the catalyst, (ii) oxidation of aqueous NH3 by the reaction with three O* sites to produce HNO2, (iii) aqueous phase dissociation of HNO2 into H+ and NO2−, (iv) formation of NH4+ by the association of NH3 with the HNO2-dissociated H+, (v) formation of N2 by the aqueous phase reaction between NO2− and NH4+, (vi) formation of NO3 by the reaction of NO2− with an O* site. For each reaction step, a rate equation was derived and its kinetic parameters were optimized by experimental data fitting. Activation energies for the reactions (ii), (v), and (vi) were 123.1, 76.7, and 54.5 kJ/mol, respectively, suggesting that the oxidation reaction of aqueous NH3 to HNO2 was a ratedetermining step. From the simulation using the kinetic parameters determined, the initial pH adjustment of the ammonia solution proved to be critical for determining the oxidation product selectivity between desirable N2 and undesirable NO3− as well as the degree of oxidation conversion of ammonia.

Rate constants for the reactions of N 2 + Fe(CO) 3 , N 2 + Fe(CO) 4 , CO + Fe(CO) 3 (N 2 ), N(C 2 H 5 ) 3 + Fe(CO) 3 , and N(C 2 H 5 ) 3 + Fe(CO) 4 are reported. The magnitudes of these rate constants are compared to rate constants for other reactions of Fe(CO) 3 and Fe(CO) 4 in the gas phase. The aforementioned reactions involving Fe(CO) 4 and Fe(CO) 3 (N 2 ) are anticipated to be formally spin disallowed. Factors that could influence the magnitude of the rate constants in these systems are discussed.

A radiation-catalytic experiment of the fixation and reduction of molecular nitrogen has been carried out. The [WH 4 (dtpe) 2 ] complex was applied to fix molecular nitrogen in a γ-radiation field. Plots of the dependence of either the number of molecules of ammonia or hydrazine vs dose are presented. A mechanism for the radiation-catalytic fixation and reduction of molecular nitrogen using the [WH 4 (dtpe) 2 ] complex is suggested. The unusually high radiation yields of ammonia and hydrazine are explained as due to a cyclic process.

The two molybdenum(IV) hydride complexes [MoH4(dppe)2][dppe = (C6H5)2 PCH2CH2P(C6H52] and [MoH4(dtpe)2] [dtpe =(o-CH3C6H4)2PCH2CH2P(o-CH3C6H4)2] were applied in a process of radiation-catalytic reduction of molecular nitrogen. The yields of ammonia and hydrazine were determined for different concentrations of these complexes in cyclohexane solutions. The mechanism of the reduction of molecular nitrogen by γ-radiation is suggested. It has also been discovered that the [MoH4(LL)2] complexes are useful in the process of radiation-catalytic fixation and reduction of nitrogen.

Hydride complexes of W(IV) with dpep (diphenylethylphosphine) and dpmp (diphenylmethylphosphine) were irradiated in thf+C6H12(1∶1) solutions, saturated with N2+H2(1∶3). Radiation yields of hydrazine, ammonia and amines were evaluated. The mechanism of reduction of molecular nitrogen is discussed.

The sections in this article are Molecular Nitrogen Nitrogen Hydrides: Ammonia and Hydrazine Dinitrogen Complexes of the Transition Metals

Molecular nitrogen is intrinsically unreactive, so much so that it has confounded chemists for decades in attempts to functionalize this abundant diatomic molecule. While biological systems and industrial processes can fix nitrogen to form ammonia, the challenge is to discover a process that involves a homogeneous catalyst that can utilize N(2) as a feedstock to generate higher value organonitrogen materials. In this review, the activation of molecular nitrogen by transition metal complexes is reviewed with the view to present new kinds of transformations for coordinated dinitrogen. Moreover, some reaction types that are as yet unknown are outlined to try and stimulate further research in this area.

The authors have studied the reactions of a number of metastable nitrogen species with silane in a discharge-flow reactor. By monitoring the decays in the metastable number densities both as a function of time and as a function of silane number density, they have determined reaction rate coefficients, in units of 10{sup {minus}11} cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}, for the following species: N{sub 2}(A{sup 3}{Sigma}{sub u}{sup +}, {nu}{prime} = 0), 0.84 {plus minus} 0.16; N{sub 2}(A{sup 3}{Sigma}{sub u}{sup +}, {nu}{prime} = 1), 1.23 {plus minus} 0.24; N{sub 2}(a{prime}{sup 1}{Sigma}{sub u}{sup {minus}},{nu}{prime} = 0), 20.7 {plus minus} 5.0; N({sup 2}D), 5.9 {plus minus} 1.3; N({sup 2}P), 0.09 {plus minus} 0.03; and N({sup 4}S), < 0.008. When silane is added to a flow containing only N{sub 2}(A{sup 3}{Sigma}{sub u}{sup +}), they observe no spectral features of any kind between 220 and 850 nm. Adding silane to a flow of atomic nitrogen excites several atomic lines of silicon, the SiN and SiH bands between 400 and 430 nm, and a continuum extending between 270 and 450 nm, all very weakly.

Enol lactones 7, which are readily prepared from o-haloacetophenone derivatives 15 by palladium-catalyzed carbonylation, react with the titaniumisocyanate complex [3THF·Mg2Cl2OTiNCO] (1) generated by fixation of CO2 with titaniumnitrogen complex [TiNMg2Cl2·THF] to give the isoindolinone derivatives 8 in good yields.

Quantum chemical calculations on the mechanism of the gas-phase reaction between dicarbene C2(X 1Σ + ) and the nitrogen molecule have been carried out within the Moller-Plesset perturbation theory (MP2/aug-cc-pVDZ) for the linear, perpendicular, and parallel orientations of the reacting molecules in the collision complex. The last orientation is of greatest interest, since in this case the system passes, with a threshold energy of 37.2 kcal/mol, through a transition state shaped as a distorted tetrahedron, which then turns into vibrationally strongly excited cyanogen. The latter decomposes into two CN radicals in 10−13–10−14s.

A ReV hydrido complex with bis-1,2-(diphenylphosphine)ethane and triphenylphosphine was employed for the photochemically induced fixation and reduction of dinitrogen. Tetrahydrofuran/cyclohexane (1 : 1) solutions, acidified and non-acidified, were examined in the UV radiation field.

Nitrogen and sulfur release from eleven coals during pyrolysis at high temperatures (≥1000 °C) was studied in both fixed-bed and free-fall quartz reactors. Yields of N2, char-N and H2S were found to depend strongly on the pyrolysis conditions, such that N2 and H2S yields increased with increasing pyrolysis temperature and coal particle residence time, whereas char-N decreased. There was also a strong inverse correlation between N2 and char-N yields, suggesting that the majority of N2 is produced from char-N through solid-phase reactions. H2S formation had no clear relationship with the carbon and sulfur contents of the parent coal. Demineralization with HCl washing was observed to remove primarily Ca2+ cations from four low rank coals examined and to increase the char-N and H2S yields but decrease N2 generation. In contrast, the addition of 3 wt% Ca to the four coals drastically enhanced N2 formation and suppressed the formation of char-N and H2S. The X-ray diffraction analysis of the chars derived from Ca-loaded coals revealed that the Ca was present primarily as CaO with an average crystallite size of 15–45 nm, and that the presence of the Ca promoted carbon crystallization. Small diffraction peaks due to CaS were also observed. Fine particles of CaO may not only promote N2 formation through solid phase reactions of char-N but undergo sulfur capture reactions. A mechanism for the Ca-catalyzed N2 formation was discussed in terms of solid–solid reactions between CaO particles and char-N. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.

Sixteen natural gas samples were collected from Devonian, Pennsylvanian and Miocene strata of the Polish Lublin and Ukrainian Lviv basins, from the southern area of the Upper Silesian Coal Basin (USCB) and western part of the Carpathian Foredeep (CF) in Poland. The samples were analysed for the molecular composition and stable isotope compositions of gaseous hydrocarbons (CH4, C2H6 and C3H8) and CO2,N2, and noble gases (He, Ne, Ar, Kr, and Xe) in order to reveal the origin and migration pathways of these gases. Hydrocarbon gases and the majority of the of CO2 were generated during two stages of thermogenic processes from Type-II and II/III kerogens in the Lublin Basin, and during both thermogenic and microbial processes in the Lviv Basin. The thermogenic component was generated from Type-II kerogen. Coal-bed hydrocarbon gases accumulated in the Pennsylvanian strata of the southern part of the USCB, originated from both thermogenic and microbial processes. Isotopically light microbial methane may have migrated from Miocene (Upper Badenian) Skawina Formation of the CF to Carboniferous coal-bearing strata and/or might result from diffusion and adsorption-desorption processes during the migration of thermogenic gases from deeper lying coal seams through the microporous coal structure. Hydrocarbon gases and carbon dioxide which accumulated in the sandstone reservoirs of Upper Badenian Skawina Formation of the western part of the CF, most probably were generated from dispersed organic matter within the claystones and mudstones of these strata and at least partly migrated from the Carboniferous coal-bearing strata of the USCB. N2 could have been produced as a result of various biogenic and abiogenic processes, and contributed to the atmospheric component. Characteristic radiogenic 4He composition of the analysed gases suggest the accumulation of α-particles formed from U and Th radioactive decay in the crustal gas reservoirs. Radiogenic 40Ar and nucleogenic 21Ne with abundance ratios characteristic of crustal reservoirs were also observed. Addition of mantle-derived He to the gases from Miocene strata is evident from elevated 3He/4He ratios ranging between 0.2 and 1.6 × 10−6. A small contribution of Ne from the mantle along with He is also suggested by the slightly elevated 20Ne/22Ne ratios relative to atmosphere. The mantle component is most likely to have migrated from the upper mantle to the gas reservoirs through the deep-seated Bzie-Czechowice Fault Zone.

Recent developments in the activation and reactivity of coordinated dinitrogen are reviewed. Examples of weakly activated dinitrogen metal complexes, strongly reduced nitrogen-nitrogen bonds and N2 cleavage reactions are discussed. Protonation reactions to form ammonia or hydrazido derivatives are covered along with processes in which nitrogen-boron, nitrogen-silicon or nitrogen-carbon bonds can form. Although this review builds on previous publications, a general introduction to this field is included.

Destruction of isotopicaliy enriched nitric oxide (

An accurate new representation for the potential energy surface for the N2–N2 dimer has been obtained from the analysis of scattering experiments from our laboratory, and of available second virial coefficient data. A harmonic expansion functional form describes the salient geometries of the dimer and accounts for the relative contributions to the intermolecular interaction from components of different nature. The equilibrium geometry is a T conformation with well depth 13.3 meV (107.14 cm−1) and at a distance of 4.03 A. In order to assist in the analysis of spectra, we calculated the bound rotovibrational states for the (N2)2 system for J⩽6 by solving a secular problem over the exact Hamiltonian, considering the N2 monomers as rigid rotors, and where the Coriolis coupling is included.

Nitrogen-containing multi-wall carbon nanotubes (N-MWCNTs) were synthesized using aerosol assisted chemical vapor deposition (CVD) techniques in conjunction with benzylamine:ferrocene or acetonitrile:ferrocene mixtures. Different amounts of toluene were added to these mixtures in order to change the N/C ratio of the feedstock. X-ray photoelectron and near-edge X-ray absorption fine structure spectroscopy detected pyridinic, pyrrolic, graphitic, and molecular nitrogen forms in the N-MWCNT samples. Analysis of the spectral data indicated that whilst the nature of the nitrogen-containing precursor has little effect on the concentrations of the different forms of nitrogen in N-MWCNTs, the N/C ratio in the feedstock appeared to be the determining factor. When the N/C ratio was lower than ca. 0.01, all four forms existed in equal concentrations, for N/C ratios above 0.01, graphitic and molecular nitrogen were dominant. Furthermore, higher concentrations of pyridinic nitrogen in the outer shells and N2 molecules in the core of the as-produced N-MWCNTs suggest that the precursors were decomposed into individual atoms, which interacted with the catalyst surface to form CN and NH species or in fact diffused through the bulk of the catalyst particles. These findings are important for a better understanding of possible growth mechanisms for heteroatom-containing carbon nanotubes (CNTs) and therefore paving the way for controlling the spatial distribution of foreign elements in the CNTs using CVD processes.

Diamonds originating from the transition zone or lower mantle were previously identified based on the chemistry of their silicate or oxide mineral inclusions. Here we present data for such a super-deep origin based on the internal pressure of nitrogen in sub-micrometer inclusions in diamonds from Juina, Brazil. Infrared spectroscopy of four diamonds, rich in such inclusions revealed high concentrations of fully aggregated nitrogen (average of 900 ppm, all in B centers) and almost no platelets. Raman spectroscopy indicated the presence of solid, cubic δ - N 2 at 10.9 ± 0.2 GPa (corresponding to a density of 1900 kg/m3). Transmission electron microscopy of two diamonds found two generations of octahedral inclusions: microinclusions (average size: 150 nm, average concentration: 100 ppm) and nanoinclusions (20–30 nm, 350 ppm). EELS detected nitrogen and a diffraction pattern of one nanoinclusion yielded a tetragonal phase, which resembles γ - N 2 with a density of 1400 kg/m3 (internal pressure = 2.7 GPa). We also observed up-warping of small areas (∼150 nm in size) on the polished surface of one diamond. The ∼2 nm rise can be explained by a shallow subsurface microinclusion, pressurized internally to more than 10 GPa. Using available equations of state for nitrogen and diamond, we calculated the pressures and temperatures of mechanical equilibrium of the inclusions and their diamond host at the mantle geotherm. The inclusions originated at the deepest part of the transition zone at pressures of ∼22 GPa (630 km) and temperatures of ∼1640 °C. We suggest that both generations are the result of exsolution of nitrogen from B centers and that growth took a few million years in a subducting mantle current. The microinclusions nucleated first, followed by the nanoinclusions. Shortly after the exsolution events, the diamonds were trapped in a plume or an ascending melt and were transported to the base of the lithosphere and later to the surface.

The kinetic model of toluene decomposition in nonequilibrium low-temperature plasma generated by a pulse-periodic discharge operating in a mixture of nitrogen and oxygen is developed. The results of numerical simulation of plasma-chemical conversion of toluene are presented; the main processes responsible for C6H5CH3 decomposition are identified; the contribution of each process to total removal of toluene is determined; and the intermediate and final products of C6H5CH3 decomposition are identified. It was shown that toluene in pure nitrogen is mostly decomposed in its reactions with metastable N2(A3Σu+) and N2(a′1Σu−) molecules. In the presence of oxygen, in the N2 : O2 gas mixture, the largest contribution to C6H5CH3 removal is made by the hydroxyl radical OH which is generated in this mixture exclusively due to plasma-chemical reactions between toluene and oxygen decomposition products. Numerical simulation showed the existence of an optimum oxygen concentration in the mixture, at which toluene removal is maximum at a fixed energy deposition.

According to the B3LYP calculations, nitrous oxide, the product of N2 oxidation by peroxo vanadium complexes, easily adds to the V=O bond to form hyponitrite, which undergoes further oxidation.

Open-system non-isothermal pyrolysis up to 1,200°C in combination with elemental analysis was used to study the thermal liberation of molecular nitrogen (N2) from sedimentary rocks and kerogen concentrates of Palaeozoic age from the Central European Basin system and an Eocene shale (Liaohe Basin, China) with a high content (36%) of ammonium feldspar (buddingtonite). The N/Corg (atomic) ratios of the kerogen concentrates ranged from 0.005 to 0.014, which represents the range commonly observed for coals. Bulk N/Corg ratios of the Palaeozoic shales extended from 0.035 to 0.108, indicating the presence of significant amounts of inorganic nitrogen. Namurian A and A-B (CnA; CnA-B) samples typically exhibited the earliest onset of N2 generation with intense, characteristic peaks around 600°C. N2 liberation from the buddingtonite-rich sample occurred at higher temperatures, with a broad peak around 700°C. Pyrograms of the kerogen concentrates showed no or strongly reduced N2 generation in the 500–700°C range. On-line isotope-specific analysis of the pyrolytically liberated N2 on one sample revealed a variability of ∼10‰ in the δ15N values and a steady increase in δ15N with temperature during the main phase of N2 generation.

The nitridation processes of thin V films in molecular nitrogen at atmospheric pressure in a RTP-system, a conventional tube furnace and a high temperature in situ X-ray diffraction (XRD) reaction chamber with a Pt heating stage were compared. The main differences of these three techniques result from their strongly differing heating rates (RTP 50 K/s, in situ chamber 3 K/s, furnace 0.4 K/s) in combination with effects of traces of oxygen in the N 2 process gas: In the furnace, oxide formation on top of the V film takes place at moderate temperatures during the long heating up period. This oxide layer acts as diffusion barrier for nitrogen and prevents nitride formation at higher temperatures. In RTP, due to the fast ramp up to the process temperature no substantial V oxide layer is formed and nitridation of the entire V film proceeds rapidly. In the in situ XRD chamber, strong VN peaks show up above 800°C and only a few weak peaks indicate the presence of some oxide too. According to special RTP experiments, UV radiation emitted from the tungsten halogen lamps in the RTP system does not play a crucial role for the activation and dissociation of the molecular nitrogen in RTP.

We have studied the pyrolysis of trimethylaluminum (TMA) in a nitrogen-containing atmosphere of a vapor phase epitaxy reactor. It is established that, in the presence of gallium nitride coatings in the reactor, the main product of TMA pyrolysis in a nitrogen-hydrogen atmosphere is aluminum nitride. Using this process (without introducing ammonia), we obtained perfect epitaxial aluminum nitride layers.

The properties of reversible, room-temperature, chiral, ionic liquids (L-A-C) are reported. They are easily prepared by passing CO2 gas through equimolar mixtures of a simple amidine (L) and a chiral amino alcohol (A), L/A, derived from a naturally occurring amino acid, and they can be returned to their L/A states by passing a displacing gas, N2, through the ionic liquid; the process of passing from uncharged to charged states can be repeated several times without discernible degradation of each phase. All of the 40 L/A combinations examined form room-temperature ionic liquids (most to ca. 50 °C under 1 atm of CO2) and they remain liquids to at least −20 °C. The L-A-C phases are more viscous than their corresponding L/A phases, the conductivities are much higher in the L-A-C phases than in the L/A phases, and the solubility characteristics of the liquids can be modulated significantly by exposing them to either CO2 or N2 gas. The spectroscopic characteristics of the L/A and L-A-C phases have been compared...

4-Phenylbut-3-enamide could be synthesized from corresponding 3-chloroprop-2-enylbenzene, carbon monoxide (1 atm), and titanium–nitrogen complexes, prepared from Ti(O i Pr) 4 , Li, TMSCl, and molecular nitrogen (1 atm), using a palladium catalyst. The reaction proceeds via transmetalation of the titanium–nitrogen complex to an acylpalladium complex. P t Bu 3 as a ligand of the palladium catalyst, afforded a good result, and the amounts of Li and TMSCl affected the yield of amide. When the reaction was carried out using a bidentate ligand on the palladium complex under an atmosphere of argon instead of carbon monoxide, an allylamine derivative was obtained.

Multiwall CN x nanotubes have been grown in the result of acetonitrile decomposition over Fe catalyst (CVD method). The random nanotubes samples have been produced by classical technique using catalyst nanoparticles formed by iron bimaleate thermolysis. The aligned nanotubes have been synthesized by aerosol assisted CVD method where ferrocene was used as a catalyst source. X-ray photoelectron spectroscopy (XPS) showed the random sample contains two kinds of nitrogen, while additional high-energy peak was detected in the N Is-spectrum of the aligned CN x nanotubes. X-ray absorption spectra measured near the N K-edge (NEXAFS) of the samples exhibited three peaks for both type of CN x nanotubes. The relative intensity of the high-energy peak was found to be much higher in the spectrum of aligned nanotubes. Assignment of the NEXAFS peaks was made using results of quantum-chemical calculations on carbon tube model incorporating pyridinic, three-fold coordinated and molecule nitrogen. The high-energy peak was shown to correspond to N 2 molecules and its absence in the XPS spectrum of random CN x nanotubes indicates the gaseous nitrogen is mainly concentrated in the interior region of nanotubes. The larger encapsulation of molecules in the aligned CN x nanotubes could be due to the higher diffusion of nitrogen atoms trough the catalytic particles formed directly in the CVD process.