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The development of lithium sulfur (Li-S) batteries has provided a popular alternative to the current state-of-art battery technologies because of their low cost as well as high theoretical specific energy. However, it is still challenging to develop sulfur cathodes with high Coulombic efficiency due to the polysulfide dissolution problem. Herein, we present a new strategy to improve the Coulombic efficiency by using nitryl grafted sulfur cathode, which is confirmed by in-situ XRD measurement and XPS analysis. The formed SEI layer on the nitryl grafted sulfur cathode could effectively trap the soluble polysulfide and avoid polysulfide migration from cathode into electrolyte, which allows significant improvement in the capacity retention of 80.6% after 450 cycles. In addition, a Coulombic efficiency of ~ 100% is achieved for the nitryl grafted sulfur (Nitryl-S) cathode, which is superior to the value of bare S cathode. The excellent performance is owing to the significantly reduced concentration of soluble polysulfide as evidenced by in-situ UV/Vis spectroscopy analysis. Thus this strategy might open up a new avenue for practical application of Li-S batteries.

Solvent effects in liquid-phase hydrodechlorination (HDC) of chlorinated organic compounds (COCs) over Pd/C catalyst were systematically studied. For the HDC of 4-chlorobiphenyl (4-CBP) with triethylamine (Et3N), Pd/C exhibited much higher catalytic activity in protic solvents than that in aprotic polar and non-polar solvents, and a clear correlation between the HDC rate and polarity of protic solvents was observed. Moreover, water promoted Pd/C-catalyzed HDC of 4-CBP in homogeneous alcohol-water solvents and biphasic organic-water solvents with Et3N, and the HDC rate of 4-CBP increased with the increase of water content in the above solvent systems. Catalyst characterization (FT-IR and XRD) combined with solvent parameters and isotope labelling analysis were introduced to explain in-depth the solvent effects in the HDC of 4-CBP with Et3N. It was found that protic solvents would transfer active hydrogen atom (H*) via hydrogen bonding network or exchange their hydroxyl hydrogen with H*, which was beneficial to the stabilization of H* and interface HDC reaction. Thus, the higher HDC rate was achieved in solvent systems contained protic solvents with higher hydrogen-bond donor capability (α) values. On the other hand, non-polar and polar aprotic solvents had a negative effect on H* and mass transfer, and thus suppressed interface HDC reaction. Similar solvent effects were observed in Pd/C-catalyzed hydrogenation of unsaturated bonds-containing groups (nitryl group, carbonyl group, and carbon-carbon double bond). The results presented here would provide vital guidance for the rational selection of solvent systems for Pd/C-catalyzed HDC of COCs and hydrogenation of unsaturated bonds-containing groups.

Photocatalytic reduction can be an effective and promising technology for the selective reduction of aromatic nitro organics. In this paper, a novel Z-scheme CdS/SnS2 photocatalyst was well-designed and fabricated via simple in-site reaction process containing thioacetamide as a sulfur sources and cubic CdSnO3 as template. The resulting CdS/SnS2 composite has well-constructed cubic nanostructure of strong adhesion between CdS and SnS2, presenting high absorption to visible light. Importantly, strong charge transfer between the contacting regions of CdS and SnS2 through the intermediate sulfur atoms combined with both metals was generated, which speeds up separation of photogenerated electron and hole. The advantageous combination of high light-harvesting and effective charge transfer is responsible for the excellent photocatalytic activity at the CdS/SnS2 heterointerface. Resultantly, the prepared CdS/SnS2 composites exhibit high conversion efficiency and selectivity on 4-nitroaniline (4-NA) reduction in the aqueous solution containing ammonium formate under visible light irradiation, which can reduce almost all 4-NA within 12 min. Trapping experiments and ESR analysis demonstrated that ammonium formate not only can effectively decrease recombination of photogenerated charge carriers but also react with holes to generate CO2− radicals possessing strong reduction ability. The 4-NA are effectively photo-reduced by the synergistic effect of electrons and CO2− radicals. According to the experimental results, a possible Z-scheme charge transfer mechanism was proposed. Besides, the photo-reduction of aromatic nitro organics possessed different para-groups (p-nitrophenol, nitrobenzene, and p-nitrobenzaldehyde) was also investigated. It is found that the electron-drawing group can decrease the electron density of its para-position nitryl, which quickens the nitro reduction.

In this study, an easy and facile route is followed to synthesize carbon dots (CDs) from candle soot (CS) for efficient and selective detection of mercury (Hg (II)) and iron (Fe (III)) toxic metals ions. These CDs were obtained via oxidation process are furthermore doped with nitrogen (N) to make them more competent towards the target applications. N-doped CDs (N-CDs) are synthesized by ethylene diamine (N source) and sodium lauryl sulphate (favorable for synthesis of smaller N-CDs). The average size of synthesized N-CDs is found in between 2.0 nm to 5.0 nm and they efficaciously have emitted blue FL under UV lamp exposure (∼290-365 nm). Zeta potential shows the net surface charge of N-CDs is negative (−10.4 mV) and plays an important role for the sensitivity of sensor and its binding efficiency towards metal ions. Functional groups (amine, hydroxyl, carbonyl, nitryl and alkenes) present on N-CDs are favorable for quenching and binding probability. Optimum pH was found 4–5 for getting better FL intensity of N-CDs. This FL is disappeared during quenching of certain concentrations of Hg(II) and Fe(III) ions due to the selective quenching of N-CDs with these metal ions. The linear range and optical detection limit of Hg (II) ions are 20–50 μM and 50 nM respectively, while for Fe (III) ions these values are 20–50 μM and 10.0 nM respectively. The fabricated N-CDs are inexpensive colorimetriC–Optical detector, selective and sensitive towards the detection of Hg (II) and Fe (III) ions contaminations and could be used as FL sensor probe for the detection of toxic metals sensing applications.

The metabolic mechanisms for imidazolidine oxidation of imidacloprid (IMI) by cytochrome P450 3A4 (CYP3A4) have been investigated using quantum mechanical/molecular mechanical (QM/MM) calculations. The binding mode of CYP3A4 with IMI is examined by molecular docking in collaboration with molecular dynamics (MD) simulations. The results show that there are six amino acid residues, involving Arg192, Phe195, Ile349, Ala285, Phe284 and Phe88, closely distributed around the IMI. The binding free energy analysis exhibits that the CYP3A4-IMI binding structure is stabilized by electrostatic interaction and van der Waals interaction. Arg192 plays a major role in the binding of CYP3A4 with IMI based on its polarity and the hydrogen bond between the H atom in Arg192 side chain and the nitryl O atom of IMI. Two possible pathways, pathway 1 and pathway 2, are evaluated. Two spin states of the Fe (III) center, quartet and doublet, are considered. The free energy calculations are done using QM/MM steered molecular dynamics (SMD) simulation at the B3LYP/6–31 + G(d):ff14SB level for two pathways. The ONIOM QM/MM single-point calculations at the B3LYP/6–311 + G(2d,2p):ff99SB//B3LYP/6–31 + G(d): ff14SB and M06-2X/6–311 + G(2d,2p):ff99SB//B3LYP/6–31 + G(d):ff14SB levels are carried out to obtain more credible energy information. The results indicate that for both pathways, the free energy barriers on the low-spin doublet state are lower than those on the high-spin quartet state. Both pathways are the stepwise processes. Pathway 1 has higher possibility to occur with the free energy barriers being lower by 10–15 kcal·mol−1 compared with pathway 2, which gives rise to trans-5′-hydroxyl-IMI as the final product. The first proton-transfer is the rate-limiting step and the calculated activation free energy is consistent with the experimental conclusion.

Quantum interference (QI) in single molecular junctions shows a promising perspective for realizing conceptual nanoelectronics. However, controlling and modulating the QI remains a big challenge. Herein, two-type substituents at different positions of meta-linked benzene, namely electron-donating methoxy (–OMe) and electron-withdrawing nitryl (–NO2), are designed and synthesized to investigate the substituent effects on QI. The calculated transmission coefficients T(E) indicates that –OMe and –NO2 could remove the antiresonance and destructive quantum interference (DQI)-induced transmission dips at position 2. –OMe could raise the antiresonance energy at position 4 while –NO2 groups removes the DQI features. For substituents at position 5, both of them are nonactive for tuning QI. The conductance measurements by scanning tunneling microscopy break junction show a good agreement with the theoretical prediction. More than two order of magnitude single-molecule conductance on/off ratio could be achieved at the different positions of –NO2 substituent groups at room temperature. The present work proves chemical substituents can be used for tuning QI features in single molecular junctions, which provides a feasible way toward realization of high-performance molecular devices.

A series of Ce–MnO x /TiO2 catalysts were prepared using a novel sol–gel template method and investigated for low-temperature selective catalytic reduction (SCR) of NO with NH3 at temperatures ranging from 353 to 473 K. The 0.07Ce–MnO x /TiO2 catalyst showed the highest activity and best resistance to SO2 poisoning. The structure and properties of the catalysts were characterized using X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), thermogravimetry (TG)–differential scanning calorimetry (DSC)–mass spectroscopy (MS), high-resolution transmission electron microscopy (HRTEM), Brunauer–Emmett–Teller (BET) measurements, H2-temperature-programmed reduction (TPR), and NH3-temperature-programmed desorption (TPD). The superior catalytic activity of the 0.07Ce–MnO x /TiO2 catalyst was probably due to a change in the active components, an increase in surface active oxygen and surface acid sites, and lower crystallinity and larger surface area with Ce doping. Furthermore, the reduction ability also became stronger. The SO2 poisoning resistance of the 0.07Ce–MnO x /TiO2 catalyst improved because doping with Ce can effectively decrease the formation of ammonium salt on the catalyst surface and the sulfation of MnO x . In situ diffuse-reflectance infrared Fourier-transform (DRIFT) spectroscopy experiments indicated that addition of Ce could promote adsorption of NH3 and inhibit generation of some nitryl species. The SCR reactions over the catalysts mainly followed the Eley–Rideal mechanism accompanied with a partial Langmuir–Hinshelwood mechanism.

This research demonstrated that, in a colorimetric sensor array, 2,4,6-trinitrotoluene (TNT), 2,6-dinitrotoluene (2,6-DNT), 2,4-dinitrotoluene (2,4-DNT) and 4-nitrotoluene (4-MNT) were identifiable through a unique pattern in a qualitative and semi-quantitative manner. The adsorption capacity of the molecularly imprinted colloidal particles (MICs) for their corresponding templates was 0.27mmol TNT/g, 0.22mmol 2,6-DNT/g, 0.31mmol 2,4-DNT/g and 0.16mmol 4-MNT/g, respectively. Every optical sensor utilized in the arrays contained three-dimensional molecularly imprinted photonic crystal (MIPC) sensor with different imprinted templates. The intelligent materials can display different colors from green to red to 20mM corresponding nitroaromatics with varying diffraction red shifts of 84nm (TNT), 46nm (2,6-DNT), 54nm (2,4-DNT) and 35nm (4-MNT), respectively. With the assistance of principal component analysis (PCA) and rational design, the sensor array can illustrate the influence of the nitryl quantity and generate a separate response region of nitroaromatics for pattern recognition with 95.25% of variance explained in the measurements by the first three principal components (PCs). The statistical analysis endowed the cross-reactive array with better classification and identification ability and this novel detection platform provided a wider applied range among other harmful chemicals in a simple sensor array with customized functionality.

The dependence of discrete crystal density (dc) of a series of cubane and its nitro derivatives on the nitro group amount was understood via analogically analyzing their crystal packing. It was found that dc does not successively increase with the increase in the hydrogen atoms replacement by nitro groups because the intermolecular interactions that strongly influence the crystal packing vary from H⋯H to H⋯O and O⋯O interactions, with weak to strong and weak strength, respectively. The relatively low dc of octanitrocubane (less than that of 1,2,3,4,5,6,8-heptanitrocubane) is thought to be clearly due to the replacement of all the hydrogen atoms by nitro groups, rendering O⋯O interactions to be completely predominant and unfavorable for closer packing, i.e., they have a lower packing coefficient. This deduction from the crystal packing of a series of analogues of nitrocubane derivatives to understand the observed dc can be seen as a prototype to understand the crystal packing and provide a foundation for designing new CHNO explosives, in which H⋯O and O⋯O interactions are usually prevalent. Moreover, it was proposed that a specific quantity of hydrogen atoms is usually indispensable to achieve a high dc value for CHNO energetic crystals.

A process for quinoline synthesis through palladium-catalyzed oxidative cyclization of aryl allyl alcohols and anilines is described. This process works in the absence of acid, base and any other additive and has a broad substrate scope, tolerating electron-withdrawing groups such as nitryl, trifluoromethyl and so on. A series of quinolines are prepared in satisfactory yields.

Excess-electron compounds can be considered as novel candidates for nonlinear optical (NLO) materials because of their large static first hyperpolarizabilities (β0 ). A room-temperature-stable, excess-electron compound, that is, the organic electride Na@(TriPip222), was successfully synthesized by the Dye group (J. Am. Chem. Soc. 2005, 127, 12416). In this work, the β0 of this electride was first evaluated to be 1.13×106 au, which revealed its potential as a high-performance NLO material. In particular, the substituent effects of different substituents on the structure, electride character, and NLO response of this electride were systemically studied for the first time by density functional theory calculations. The results revealed that the β0 of Na@(TriPip222) could be further increased to 8.30×106 au by introducing a fluoro substituent, whereas its NLO response completely disappeared if one nitryl group was introduced because the nitro-group substitution deprived the material of its electride identity. Moreover, herein the dependence of the NLO properties on the number of substituents and their relative positions was also detected in multifluoro-substituted Na@(TriPip222) compounds.

Nitryl surface functionalized TiO2 hollow spheres (TiO2-NO2 HSs) composite material was successfully fabricated by a simple sol-gel combined with solvothermal and concentrated HNO3 treatment strategy using carbon microspheres obtained from hydrothermal carbonization of waste Camellia oleifera shells as a template. The microstructure, surface property, compositional and structural information, and optical and electronic property of as-prepared TiO2-NO2 HSs were well characterized. Compare with conventional g-C3N4 and TiO2 photocatalysts, the as-prepared TiO2-NO2 HSs exhibited excellent simulated sunlight photocatalytic activity toward aqueous organic pollutants degradation and hydrogen evolution from water-splitting, which can be attributed to their unique hollow spherical microstructure and the introduction of -NO2 groups.

A theoretical study of nitryl halide heterodimers has been carried out using SCS-RI-MP2 and CCSD(T) at the complete basis set (CBS) calculations. For this purpose, 66 heterodimers have been characterized as minima and arranged in six groups depending on the interactions involved and their geometrical arrangements. The CCSD(T)/CBS interaction energies vary between −0.6 and −11.1 kJ mol−1. The heavier the halogen atoms, the larger the interaction energies. Natural bond orbital (NBO) and “atoms-in-molecules” (AIM) theories were then used to analyze the complexes, confirming the presence of halogen, chalcogen, and π-hole interaction bonds. The largest charge-transfer energy contributions were found for halogen bonded complexes (up to 29.1 kJ mol−1). Furthermore, the physical nature of the interactions was studied using symmetry-adapted perturbation theory (SAPT) calculations, and it was concluded that dispersion was the major source of attraction, although electrostatics is important in halogen bonded complexes.

Five twisted donor–π–acceptor cyanostilbene derivatives containing carbazole have been designed and synthesized with high yields. Their emission could be tuned from blue to orange by simply altering electron acceptors (donors). It was found that larger molecular dipole and the Stokes shifts of the donor–π–acceptor dyes could result in bathochromic shifts of absorption and emission. The density functional theory calculations further demonstrated that with the increase of the electron-donating or accepting abilities of the substituents, the energy gaps of the fluorophores gradually decreased, which elucidated the substituent effect of the organic fluorophores on their photophysical properties. Moreover, they exhibit typical intramolecular charge transfer (ICT), aggregation-induced emission (AIE), and crystallization-induced emission enhancement (CIEE) characteristics. Furthermore, the hydrogen- (2a), methyl- (2d) and chlorine-substituted (2e) derivatives exhibit remarkable reversible mechanochromic features (with emission wavelength changes up to 119 nm), while the methoxyl- (2b) and nitryl- substituted (2c) derivatives have no mechanochromic characteristics owing to the fact that they have strong crystallizability. The analysis of the X-ray crystal structure proved that the AIE-, CIEE-active and mechanochromic behavior was associated with the stator–rotor structures, twisted conformations and crystal packing modes. More importantly, the substitution effect of cyanostilbene derivatives would provide an effective way to obtain full-color optoelectronic materials with AIE and mechanochromic properties.

In this study, carbon spheres (CS) with ideal particle sizes (~700 nm) and regular morphology were prepared by extending the Stober method followed by oxidative modification of nitric acid to obtain carbon spheres (MCS) with abundant carboxyl and nitryl functional groups. Characterisation by SEM, BET, XRD, Raman spectroscopy, FTIR, XPS, and elemental analysis confirmed that these materials possessed regular morphology, large specific surface area (636 m2/g for CS and 339 m2/g for MCS), a good degree of graphitisation and many carboxyl groups. Because of abundant functional groups, MCS showed excellent adsorption properties for cationic targets (paraquat (PQ), chrysoidine G (CG) and malachite green (MG)), where the maximum adsorption capacities for PQ, CG and MG were 134.63, 299.44 and 326.93 mg/g, respectively. Compared with the linearity of Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models and the pseudo-first-order, pseudo-second-order, Elovich and intra-particle diffusion kinetics models, the adsorption models for PQ, CG and MG were best represented by the Temkin, Langmuir, and Freundlich isotherms, respectively, and the adsorption kinetics all fitted well with the Elovich model. Moreover, the good regeneration demonstrated in this study (the adsorption capacity remained at more than 80% after five cycles) makes MCS an outstanding candidate for water purification.

A one-pot universal approach for transforming arylamines to aryl halides via reaction with sodium nitrite (NaNO2 ) and N-halosuccinimide (NXS) in DMF at room temperature under metal- and acid-free condition is described. This new protocol that is complementary to the Sandmeyer reaction, is suggested to involve the in situ generation of nitryl halide induce nitrosylation of aryl amine to form the diazo intermediate which is halogenated to furnish the aryl halide.

Biological liquefaction of nitric-acid-oxidized low-rank coal is well-documented in the literature. However, few studies focused on the macromolecular structure of nitric-acid-oxidized low-rank coal. In this paper, Fushun nitric-acid-oxidized coal was first analyzed by Fourier transform infrared spectroscopy (FTIR) and 13C nuclear magnetic resonance (NMR) spectra to investigate its elemental composition and organic functional groups. Then, the coal macromolecular structural parameters were calculated, and its structural unit was constructed. The results showed that the Fushun nitric-acid-oxidized coal structural unit had a molecular formula of C192H161N9O39. Carbon existed in the form of carboxyl and alkyl with 1–3 carbon atoms, besides aryl. Oxygen existed in the form of carboxyl, carbonyl, and phenolic groups, ether bond, etc. Nitrogen existed in the form of nitryl, amide, etc. The hydrogen aromaticity, length of the side chain, ratio of aromatic carbon, and ratio of phenolic carbon were 0.086, 0.567, 0...

The transfer enthalpies and entropies of hydroxyl and nitryl in different mobile phase systems were compared by van’t Hoff curve. Results suggest that the presence of acetonitrile and methanol in the mobile phase may decrease the interaction of solute and stationary phase with respect to subcritical water, thereby reducing the contribution of enthalpy to the retention. Retention mechanisms of phenolic compound appear to be more similar in subcritical water and water/methanol systems on the PRP-1 column. Hydrogen bond in subcritical water system plays a very important role in the retention of the phenols.

Besides their fundamental importance, compounds containing C, N and O have great potential as so-called “high-energy density materials” (HEDMs). Due to their explosive nature, HEDMs usually have great difficulty in laboratory synthesis and characterization. Thus, reliably finding a HEDM candidate with good kinetic stability (i.e., rate-determining barrier is above 20 kcal mol−1) in computation has proven to be a key base for the subsequent experimental study, as well as being documented by two recent examples, i.e., diazirinone ([C,N2,O]-A, Angew. Chem., Int. Ed., 2011, 50, 1720) and nitryl cyanide ([C,N2,O2]-B, Angew. Chem., Int. Ed., 2014, 53, 6893). What is the next synthetic target for molecular HEDMs? Having been predicted to possess both large exothermicity (190 kcal mol−1) and a large decomposition barrier to N2 + CO2 (29 kcal mol−1) at the CCSD(T)/TZ2P//MP2/6-31G(d) level (J. Phys. Chem., 1996, 100, 19840), C with a bicyclic [C,N2,O2] structure appears to well deserve a synthetic trial for HEDMs. In this work, by re-evaluating the stability of C, we located a new rate-determining transition state for decomposition (TS2). With TS2, a significantly reduced decomposition barrier was arrived at, i.e., 11.6–13.0 kcal mol−1 at the G3B3, CBS-QB3, G4, W1BD and CCSD(T)_CBS//B3LYP/aug-cc-pVTZ composite energy calculated levels using a restricted wave function. Strikingly, TS2 possesses a significant open-shell feature and the barrier was further reduced to be 6.9 kcal mol−1 at the UCCSD(T)_CBS//UB3LYP/aug-cc-pVTZ level. Thus, the bicyclic isomer C is unlikely to be a molecular HEDM, though its spectroscopic detection could still be feasible. Finally, the ring-opening stability of the c-CO2 moiety in the present [C,N2,O2]-C largely contrasts with that in the well-known methyldioxirane, demonstrating a different influence on the complexation to c-CO2.

In this study, the optimal synthetic route for 2,4,6-trinitro-1,3,5-triazine (TNTA) was investigated. The synthesis of TNTA was performed using cyanamide (H2NCN) as a starting material. In the first stage, a radical addition reaction was used to generate melamine, which is the precursor of TNTA. In addition, a gaseous nitration reaction using nitrogen dioxide radicals (•NO2) as the nitration agent was used to gradually induce radical substitutions to convert dicyandiamide (H2NCN)2 to melamine (H2NCN)3. Additional nitration steps lead to triaminocyanide and, ultimately, TNTA. In addition, nitryl cyanide (O2NCN) was also tested as a starting material for radical addition to generate dinitryl cyanide (O2NCN)2, trinitryl cyanide (O2NCN)3, and, finally, TNTA. The activation energy barrier in each of the reaction steps as well as the various synthetic routes were compared to provide insight into the design of more feasible routes for the synthesis of TNTA. © 2014 Wiley Periodicals, Inc.

The elusive nitryl cyanide, NCNO2, has been synthesized and characterized. It was prepared in good yield, isolated by fractional condensation, characterized by NMR and vibrational spectroscopy, and studied by theoretical calculations. Nitryl cyanide holds promise as a high energy density material (HEDM) and might also prove useful as a HEDM building block. The simplicity and inherent stability of nitryl cyanide, together with the known multitude of nitriles in interstellar space, suggest that the compound might also be a potential candidate for observations in atmospheric and interstellar chemistry.

Quantum calculations at the DFT-D3/def2-TZVPD level of theory have been used to examine complexes between O2YBr (Y═N, P, and As) molecules and several Lewis bases, that is, NH3, H2O, and HF. The interactions of the lone pair of the ammonia, water, and hydrogen fluoride with the σ-hole and π-hole of O2YBr molecules have been considered. In general, the complexes where the Lewis base lone pair interacts with the π-hole are more favorable than those with σ-hole. The nature of the interactions has been characterized with the Bader theory of atoms in molecules (AIM). We have also studied the ability of trifluoronitromethane and nitromethane to interact with anions using their π-hole along with an analysis the Cambridge Structural Database. We have found a large number of hits that provide strong experimental support for ability of the nitryl (-NO2) group to interact with anions and Lewis bases. In some X-ray structures, the π-hole interaction is crucial in the crystal packing and has a strong influence in the solid state architecture of the complexes. Finally, due to the relevance in atmospheric chemistry, we have studied noncovalent σ/π-hole complexes of nitryl bromide with ozone.

a b s t r a c t An ultra-thin passive film on electroless nickel phosphorus coating (ENPC) was obtained by treated in a passivation bath. The antitarnish and corrosion properties of the film were studied by acid exposure and potentiodynamic polarization. XPS was utilized to analyze the chemical composition and formation process of the film. The acid exposure test indicated the antitarnish property of the coating was obviously improved by passivation treatment. The potentiodynamic polarization test showed that the corrosion current for the passivated Ni-P coating was lower than that of untreated coating. By XPS measurement, the thickness of film was evaluated as a few nanometers and the film was made up of Cr, C, O and N. The N and C elements in the film suggested the nitryl aromatic compound should take part in the formation of film. The XPS spectra fitting results indicated that Cr was in the form of Cr2O3 and Cr(OH)3, while O was originated to Cr2O3, Cr(OH)3 and–NO2 in aromatic compound. And the XPS results were used to justify the formation mechanism of the passive film. © 2014 Elsevier Ltd. All rights reserved.

In this work, three new organic donor–acceptor small-molecules, in which bicarbazole served as the electron donor, and benzothiazole, nitryl or 1,1′-dicyanovinyl were used as the electron acceptor, were designed and synthesized in order to fabricate sandwiched memory devices. Acceptors with a variable electron-delocalized extent and electron-withdrawing strength were attached to the molecular backbone in order to investigate the effect on the devices switching behavior. The bi-n-butylcarbazole benzothiazole (BCZ-BT) based memory device exhibited volatile static random access memory (SRAM) switching behaviour, while the devices based on bi-n-butylcarbazole nitryl (BCZ-NO2) was found to exhibit stable nonvolatile write-once-read-many-times (WORM) data storage characteristics and the bi-n-butylcarbazole dicyanovinyl (BCZ-CN) device acted as rewritable flash memory with a higher ON/OFF current ratio of about 104. Therefore, tunable data storage devices synthesized by adjusting the terminal acceptor groups offer feasible guidance for the rational design of organic molecules to achieve superior memory performance.

Density functional theory calculations have proven the polar nature of the crossed intermolecular radical anion cycloadditions of various enones. The substituent effects on the chemo- and stereoselectivity of the cycloadditions have been elucidated. The electronic structures of the substituents strongly influence the formation of the radical anion and the reactivity of cycloaddition. The amino and nitryl substituents are both unfavorable for the cycloaddition. The cycloaddition is sensitive to the substituents on the C atoms which form a σ bond in the first cycloaddition step by both steric hindrance and electronic effect. To improve the chemoselectivity, one of these C atoms should be unsubstituted. The stereoselectivity mainly caused by the difference in steric interaction between the trans and cis transition states is benefited by the bulky substituents on the carbonyl.

3,5-Dinitrobenzoic acid of 3,5-diamino-1,2,4-triazole (DAT) salt (DAT·DNBA) was synthesized and its structure was characterized by element analysis, IR and single-crystal X-ray diffraction analysis. The thermal behavior was investigated with the methods of differential scanning calorimetry (DSC) and rapid scan Fourier transform infrared spectroscopy (in situ thermolysis/RSFTIR), and the thermal decomposition reaction kinetics was obtained by means of DSC technique at the different heating rate. The results show that there are two mass loss stages at the thermal decomposition process, and the apparent activation energy and pre-exponential factor of the exothermic decomposition reaction of DAT·DNBA obtained by five integral methods (General integral, MacCallum–Tanner, Satava–Sestak, Agrawal, Flynn–Wall–Ozawa) and one differential method (Kissinger) are 226.37 kJ mol−1 and 1014.51 s−1 in the second decomposition stage. According to the change of the bond intensities, it can be deduced that hydronitrogen, oxynitride, and carbonitride should appear in the gaseous products breaking away from the condensed phase of DAT·DNBA. The groups of nitryl, amido and carboxyl have main contribution to some properties of the compound from the result of the quantum chemical calculation. The self-accelerating decomposition temperature (TSADT), thermal ignition temperature (TTIT) and the critical temperatures of thermal explosion (Tb) and the adiabatic time-to-explosion (tTIAD) is obtained as 660.25 K, 677.16 K, 691.70 K and 236 s, respectively. The detonation velocity (D) and pressure (p) were also estimated as 8358.86 m s−1 and 30.19 GPa. The above-mentioned information is quite useful for analysis and evaluating the stability and thermal safety of DAT·DNBA.

International audience; In the nitrosyl halides series (XNO, where X = F, Cl, Br, I), INO is the only chemical species whose rotational spectrum has not been reported. Nitrosyl iodide, together with the nitryl (INO2), nitrite (IONO) and nitrate (IONO2) iodides, are believed to impact tropospheric ozone levels. Guided by our quantum chemical calculations, we report the detection of INO in the gas phase by high-resolution spectroscopy for the first time. INO was generated by mixing continuously I2 and NO. The measurement and least-squares analysis of 173 a-type rotational transitions resulted in the accurate determination of molecular parameters.

Quantum calculations at the MP2/cc-pVTZ have been used to examine 1:1 and 1:2 complexes between O2NX (X = Cl, Br) with HCN and HNC moieties. The interaction of the lone pair of the HCN(HNC) with the σ-hole and π-hole of O2NX molecules and hydrogen bonding between lone pairs of X and O of O2NX with H of HCN and HNC have been considered in 1:1 complexes. The 1:1 complexes can easily be differentiated using the stretching frequency of the N–X bond. Thus, those complexes with σ-hole and H···O2NX interactions show a blue shift of the N-X bond stretching while a red shift is observed in the complexes along the π-hole and H···XNO2 interactions. In the 1:2 complexes, the cooperative and diminutive energetic effects have been analyzed using the many-body interaction energies. The nature of the interactions has been characterized with the Atoms in Molecules (AIM) and Natural Bond Orbital (NBO) methodologies. Stabilization energies of 1:1 and 1:2 complexes including the variation of the zero-point vibrational energy (ΔZPVE) are in the range 3–9 kJ mol−1 and 21–40 kJ mol−1, respectively.

Study on the thermal instability of N,N'-Dinitrourea (DNU) is very important for its use as an energetic precursor. Thermal decomposition mechanism of DNU is studied by an in situ pyrolytic Fourier transform infrared spectroscopy with the temperature program and density functional theory calculations at B3LYP level. The experimental results have shown that the nitryl group of DNU molecule is initially broken, followed by the rearrangement or reaction simultaneously. All the decomposition reactions are nearly complete prior to 100 degrees C resulting in the formation of N2O, NO2, CON, CONH and NO2NH2. Theoretical calculations confirmed that the syn, anti conformation play a key role in the decomposition process and the N-N bonds were broken firstly with the increase of temperature. The plotted potential energy curve via the corresponding bond length showed that the cleavage of N-N bond in the condensed-phase of DNU was a highly reversible process and a typical radical recombination reaction with zero barriers in the initial step. Finally, the possible decomposition pathways of the N2-N5 bond homolysis and its following reactions were proposed. The final products of N2O, NO2, CONH and NO2NH2, detected in the experiments, were formed by alpha-cleavage or hydrogen atom rearrangement of the radicals that were formed in the initial step. (C) 2011 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

In this study, an enhanced ultrasensitive and selective sensor for detection of Cr(III) was constructed based on gold nanoparticles (AuNPs) dually labeled with 5-thio-2-nitrobenzoic acid (TNBA) and horseradish peroxidase (HRP). TNBA was used as an affinity tag for Cr(III) binding and HRP as optical signal amplifier. Following the addition of Cr(III), the aggregation of AuNPs labeled with TNBA occurred, because the nitryl groups of TNBA selectively interacted with Cr(III). After the addition of TMB solution to the aggregation, the optical signals would be generated. The density of the signal is correlated with the concentration of Cr(III), which can be easily discerned by the naked eye or be measured spectrophotometrically. The application results indicated that the dually labeled sensor (TNBA–AuNPs–HRP) was highly sensitive to Cr(III) in the concentration of 0.04 to 210 μM. The limit of detection (LOD) was 0.04 μM, which is 45 times lower than that of the sensor without HRP enhancement.

The removal of 2,4-dinitrotoluene (2,4-DNT) by simultaneous UV-photo(cata)lysis and biodegradation was explored using intimately coupled photolysis/photocatalysis and biodegradation (ICPB) with two novel porous carriers. First, a porous ceramic carrier was used to attach the photocatalyst (TiO2) on its exterior and accumulate biomass in its interior. UV irradiation alone decomposed 71% of the 2,4-DNT in 60 h, and TiO2 catalyst improved the photolysis to 77%. Second, a macroporous sponge carrier was used to strongly adsorb 2,4-DNT and protect microorganisms from 2,4-DNT inhibition and UV irradiation. The main photolytic reactions were reduction of the nitryl to amino and hydrolysis of the amino to release NH 4 + . The main biodegradation reactions were oxidative release of NO 3 − and accelerated reductive release of NH 4 + . ICPB more thoroughly released inorganic N, with nearly equal amounts being oxidized to nitrate and reduced to ammonium. The genera Burkholderia and Bacillus were found inside the sponge carriers, and they are associated with biodegradation of DNT and its photolysis intermediates. Therefore, using an adsorbent and macroporous biofilm carrier enabled the effective removal of 2,4-DNT by ICPB.

In a previous paper, we have reported that dilute nitric acid in reversed micelle systems can oxidize the Br − ion to Br 2 and proposed that the nitryl (or nitronium) ion NO 2 + should be the active species in the oxidation process. Nitration of phenol in reversed micelle systems with dilute nitric acid, CHCl 3 /CTAC/H 2 O (2.0 mol dm − 3 HNO 3 in the 1.0% (v/v) H 2 O phase), was performed at 35 °C to obtain 2- and 4-nitrophenols, where CTAC represents cetyltrimethylammonium chloride. In similar CTAC and AOT reversed micelle (CHCl 3 or heptane/AOT) systems, 4-methylphenol was converted to 2-nitro-4-methylphenol, where AOT stands for sodium bis(2-ethylhexyl) sulfosuccinate. In aqueous 2.0 mol dm − 3 HNO 3 solution accompanied by 4.0 mol dm − 3 LiCl (and a small amount of LiBr as the bromide resource), trans -1,4-dibromo-2-butene was successfully brominated to 1,2,3,4-tetrabromobutane. This result is a good evidence that the Br − ion can be oxidized to Br 2 in dilute nitric acid (2.0 mol dm − 3 ) provided that it contains concentrated salts. At 20–40 °C, the apparent oxidation-reaction rate constants ( k /s − 1 ) of Br − to Br 2 were evaluated in 0.1–2.0 mol dm − 3 HNO 3 solution accompanied by concentrated LiCl (3.5–9.0 mol dm − 3 ). For chloride salts, the cation effects increased as Et 4 N + ≪ Na + + 2+ 2+ . Even the evolution of Cl 2 was demonstrated from − 3 HNO 3 solution containing concentrated LiCl, MgCl 2 , and CaCl 2 as well as AlCl 3 , therefore, an indirect oxidation mechanism of the Br − ion through Cl 2 was proposed as follows: 2Cl − + NO 2 + → Cl 2 + NO 2 − ; 2Br − + Cl 2 → Br 2 + 2Cl − .

Trumpet-shaped carbon nanocone (CNC) is used as a π-conjugated bridge to design high-performance nonlinear optical (NLO) material. Owing to the attractive trumpet-shaped structure, O2N–CNC–NH2 exhibits nonlinear optical behavior that is both surprisingly and qualitatively distinct from conventional π-conjugated organic species. It has been shown that the electron-acceptor nitryl (−NO2) at the apex of the trumpet and the electron-donor amino (−NH2) at the bottom edge of the trumpet to form O2N–CNC–NH2 is beneficial to improve the NLO response of CNC. Significantly, the first hyperpolarizabilities (βtot) of O2N–CNC–NH2 show an arc-shaped change as −NH2 substituting different H atoms along the arc-shaped bottom edge of CNC. Interestingly, the βtot values of H–CNC–NH2 also show an arc-shaped change. By comparison of the βtot values of O2N–CNC–NH2 and H–CNC–NH2, it has been found that no matter which bottom H of H–CNC–H is substituted by NH2, the βtot value of H–CNC–NH2 will be increased about 1.6 times after ...

Two new ferrocene–porphyrin derivatives, namely 5,15-bis(ferrocenyl)-10,20-bis(4-nitrophenyl)porphyrin (1) and its nickel congener 5,15-bis(ferrocenyl)-10,20-bis(4-nitrophenyl)porphyrinatonickel (2) have been designed, synthesized, and characterized. Their self-assembly properties have been comparatively studied by electronic absorption and FTIR spectroscopy, TEM, SEM, XRD, and X-ray photoelectron spectroscopy (XPS). Metal-free 1 self-assembles into nanospheres with diameters in the range of 30–50 nm, depending mainly on intermolecular π–π interactions. In contrast, the coordination of nickel to 1 introduces an additional Ni–O coordination bond between the nitryl group of one molecule of 2 and the nickel center of the neighboring 2 unit, which, in cooperation with the intermolecular π–π interaction, induces the formation of nanobelts (ca. 50–300 μm length, 10–50 nm width) during the self-assembly process of 2.

We systematically investigate the linear optical properties and the static second-order nonlinear optical (NLO) properties on a series of two-dimensional (2D) D-π-A-π-D/A-π-D-π-A sandwich metallocarborane-containing molecules with density functional theory (DFT). It can be found that the substitution effect has an influence on the electronic absorption and NLO responses of the 2D molecules. For example, the β v e c value is sensitive to the substitution from amino (–NH2) to nitryl (–NO2); the angle between the two A–D branches significantly affects the dipole moment and β v e c value. In addition, time-dependent DFT calculations and the analysis of major molecular orbitals predict that the sandwich metallocarborane acts as an electron donor better than electron acceptor. Furthermore, the two strong synchronized charge transfer (CT) coming from the two branches and p–π (B2p–C≡C) conjugation contributes to the second-order polarizabilities in our studied systems.

Poly(silanylenediethynylanthracene) (PSDEA) exhibits a hole-transporting ability experimentally. In order to simulate the property of PSDEA, a series of silanylenediethynylanthracene oligomers were designed. The structures of these oligomers were optimized by using density function theory at B3LYP/6-31G(d) level. The energy gaps of the oligomers decrease with the increase in the chain length. The energy gaps of the oligomers also decrease in the presence of the electron-withdrawing group on the anthracene ring. The 13C chemical shifts and nucleus independent chemical shifts (NICS) at the anthracene ring center in the oligomers were calculated at B3LYP/6–31G level. The chemical shifts of the carbon atoms connected with the nitryl group changed upfield, compared with those of the carbon atoms without the nitryl group. The aromaticity at the anthracene ring center decreases in the presence of the electron-withdrawing group, whereas increases with the increase in the number of the silanylene units. The most sensitive location for calculating the NICS values is 0.1 nm above the anthracene plane.

The article focus on the isomerization of nitrous acid HONO to hydrogen nitryl HNO2. Density functional (B3LYP) and MP2 methods, and a wide variety of basis sets, have been chosen to investigate the mechanism of this reaction. The results clearly show that there are two possible paths: 1) Uncatalysed isomerisation, trans-HONO → HNO2, involving 1,2-hydrogen shift and characterized by a large energetic barrier 49.7 ÷ 58.9 kcal/mol, 2) Catalysed double hydrogen transfer process, trans-HONO + cis-HONO → HNO2 + cis-HONO, which displays a significantly lower energetic barrier in a range of 11.6 ÷ 18.9 kcal/mol. Topological analysis of the Electron Localization Function (ELF) shows that the hydrogen transfer for both studied reactions takes place through the formation of a ‘dressed’ proton along the reaction path.1 Use of a wide variety of basis sets demonstrates a clear basis set dependence on the ELF topology of HNO2. Less saturated basis sets yield two lone pair basins, V1(N), V2(N), whereas more saturated ones (for example aug-cc-pVTZ and aug-cc-pVQZ) do not indicate a lone pair on the nitrogen atom. Topological analysis of the Electron Localizability Indication (ELI-D) at the CASSCF (12,10) confirms these findings, showing the existence of the lone pair basins but with decreasing populations as the basis set becomes more saturated (0.35e for the cc-pVDZ basis set to 0.06e for the aug-cc-pVTZ). This confirms that the choice of basis set not only can influence the value of the electron population at the particular atom, but can also lead to different ELF topology. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010

DFT (U)B3LYP/6-31G(d,p), (U)B3LYP/6-31+G(d,p), and (U)B3LYP/6-311+G(d,p) calculations were carried out to investigate the ring opening reactions of the cyclopropylcarbinyl radical (leading to the 3-butenyl radical) and its mono-substituted analogues containing the methyl, ethyl, propyl, isopropyl, isobutyl, fluorine, chlorine, bromine, hydroxyl, methoxy, cyanogen, nitryl, vinyl, and phenyl substituents on the ring (leading to the pseudo-secondary and primary radicals, respectively). The enthalpies of activation, rate constants, and reaction enthalpies for all ring opening reactions were calculated. The predicted enthalpy of activation, rate constant, and reaction enthalpy of the cyclopropylcarbinyl radical ring opening reaction are in excellent agreement with the corresponding experimental values. For the alkyl (methyl, ethyl, propyl, isopropyl, and isobutyl) substitutions, steric effects are found to be the dominating factor to affect the ring opening reactions, while for the rest substitutions, the stereoelectronic effects play the most important roles. Our calculations indicate that the cyanogen, nitryl, vinyl, and phenyl substituents, which contain π bonds, have much larger effects on the ring opening reactions than the other substituents.

The thermal decomposition mechanism of hydrazine 3-nitro-1,2,4-triazol-5-one (HNTO) compound was studied by means of differential scanning calorimetry (DSC), thermogravimetry and derivative thermogravimetry (TG-DTG), and the coupled simultaneous techniques of in situ thermolysis cell with rapid scan Fourier transform infrared spectroscopy (in situ thermolysis/RSFTIR). The thermal decomposition mechanism is proposed. The quantum chemical calculation on HNTO was carried out at B3LYP level with 6-31G+(d) basis set. The results show that HNTO has two exothermic decomposition reaction stages: nitryl group break first away from HNTO molecule, then hydrazine group break almost simultaneously away with carbonyl group, accompanying azole ring breaking in the first stage, and the reciprocity of fragments generated from the decomposition reaction is appeared in the second one. The C–N bond strength sequence in the pentabasic ring (shown in Scheme 1) can be obtained from the quantum chemical calculation as: C3–N4 > N2–C3 > N4–C5 > N1–C5. The weakest bond in NTO− is N7–C3. N11–N4 bond strength is almost equal to N4–C5. The theoretic calculation is in agreement with that of the thermal decomposition experiment.

The fabrication of honeycomb-patterned films from nitryl poly(ether ether ketone)s (PEEK-NO2) in a high-humidity atmosphere was reported in this article. PEEK-NO2 was prepared through acid (nitric acid and sulfuric acid) nitration from poly(ether ether ketone)s (PEEK). The obtained polymer, which was characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) showed excellent solubility and thermal stability. Some influence factors on the pattern formation and the fabrication of the porous structure, such as the solution concentration, the solvent, and the atmosphere humidity, were investigated. The results showed that with the increase of the solution concentration, the aperture of the film diminished gradually; the lower the solvents´ boiling point were, the smaller the films´ apertures were and the more regular the pores´ arrange; only under high-humidity circumstances could obvious and ordered honeycomb films be formed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

A Pt/TiO 2 photocatalyst was used in the photocatalytic degradation of 2,4,6-trinitrotoluene (TNT) under the irradiation of the simulated sunlight. The results show that the destruction of TNT is faster and more complete with the photocatalyst. The photocatalytic degradation of TNT follows first order kinetics. The transformation of nitryl groups of TNT molecules into nitrite and nitrate ions may be accelerated in the presence of the Pt/TiO 2 photocatalyst. Compared with that without the catalyst, the concentration of nitrate ions was improved 32.3 times within 2.5 h.

Rotational constants B and C, centrifugal distortion constants ΔJ and ΔJK, and nuclear hyperfine coupling constants are determined for four isotopomers of nitryl bromide from their rotational spectra. Experimental nuclear quadrupole coupling constants are interpreted to provide information about the N–Br bond and are compared with those from electronic structure calculations.

The reaction mechanism between HNO2 and C6H5Br in aqueous solution in the presence or absence of O2 was studied using laser flash photolysis transient absorption spectrum technique under irradiation at 355 nm. The experimental results suggested the generation of ·OH radical through the photolysis of HNO2. The addition of ·OH radical to bromobenzene to form an OH-adduct, C6H5Br···OH, involved a second-order rate constant of (8.1±0.7)× 109 L·mol−1·s−1. C6H5Br···OH could be oxidized by O2 or HNO2. The second-order rate constant (3.0±0.5)× 107 L·mol−1·s−1 for the reaction of C6H5Br···OH with HNO2 was much lower than (4.0±0.6)× 108 L·mol−1·s−1 for the reaction of C6H5Br···OH with O2. The decay constant of C6H5Br···OHO2 produced by the reaction of C6H5Br···OH with O2 was (2.4± 0.1)× 104 s−1. Gas chromatographic and mass spectrometric (GC-MS) analysis suggested the formation of multiple compounds containing nitryl or quinone formed by the reaction of C6H5Br···OH with HNO2 or O2.

Gaseous nitryl azide N 4 O 2 is generated by the heterogeneous reaction of gaseous ClNO 2 with freshly prepared AgN 3 at −50 °C. The geometric and electronic structure of the molecule in the gas phase has been characterized by in situ photoelectron spectroscopy (PES) and quantum chemical calculations. The experimental first vertical ionization energy of N 4 O 2 is 11.39 eV, corresponding to the ionization of an electron on the highest occupied molecular orbital (HOMO) {4a″(π nb(N4–N5–N6) )} −1 . An apparent vibrational spacing of 1600 ± 60 cm −1 (ν as O1N2O3) on the second band at 12.52 eV (π nb(O1–N2–O3) ) further confirms the preference of energetically stable chain structure in the gas phase. To complement the experimental results, the potential-energy surface of this structurally novel transient molecule is discussed. Both calculations and spectroscopic results suggest that the molecule adopts a trans -planar chain structure, and a five-membered ring decomposition pathway is more favorable.

A series of europium complexes were synthesized and their electroluminescent (EL) characteristics were studied. It was found by comparison that the different substituted groups, such as methyl, chlorine, and nitryl, on ligand 1,10-phenanthroline affect significantly the EL performance of devices based on these complexes. The more methyl-substituted groups on ligand 1,10-phenanthroline led to higher device efficiency. A chlorine-substituted group showed the approximate EL performance as two methyl-substituted groups, whereas a nitryl substituent reduced significantly the EL luminous efficiency. However, β-diketonate ligand TTA and DBM exhibited similar EL performance. The improved EL luminous efficiency by proper substituted groups on the 1,10-phenanthroline was attributed to the reduction of the energy loss caused by light hydrogen atom vibration, as well as concentration quenching caused by intermolecular interaction, and the match of energy level between the ligand and Eu 3+ .

The thermal decomposition of Ni(NO3)2·6H2O (1), Ca(NO3)2·4H2O (2) and nitryl/nitrosyl nitrato nickelate(II), NO2/NO[Ni(NO3)3] (3), was investigated by thermogravimetric measurements with quasi-isothermal conditions and compared to Co(NO3)2·6H2O. The respective decomposition processes of 1 and 2 differ from each other showing that at one hand anhydrous Ca(NO3)2 was obtained whereas anhydrous nickel dinitrate has not be formed due to redox and condensation reactions. Instead basic nickel compounds have been formed. In reducing atmosphere nickel metal can be obtained. Anhydrous Ni(NO3)2 results by the thermal degradation of nitryl/nitrosyl nitrato nickelate. FT-Raman spectra have been of help in the judgement of the decomposition processes.

By using a strategy of introducing hydrophobic groups to the linkers, a hydrostable MOF was constructed based on 5-nitroisophthalate and 2,2′-dimethyl-4,4′-bipyridine coligands, revealing a 3D dia topology structure with a 1D channel parallel to the c axis. TGA, PXRD, and water vapor sorption results show high thermal and water stability for the framework. The framework is very porous and possesses not only high busulfan payloads with an encapsulation efficiency up to 21.5% (17.2 wt %) but also very high CO2 selective capture compared with that of other small gases (i.e., CH4, N2, O2, CO, and H2) at 298 K based on molecular simulations due to the pore surface being populated by methyl and nitryl groups. Furthermore, in vitro MTT assays were conducted on four different cells lines with increasing concentrations of the framework, and the results showed that the framework was nontoxic (cell viability >80%) in spite of the concentrations up to 500 μg/mL.

In this manuscript we report the synthesis and X-ray characterization of several complexes of Cu(II), Co(II) and Ni(II) with 2-(N-benzimidazolyl)-pyrimidine (L) and nitrate co-ligands. Complexes 1 and 2 are trans and cis isomers, respectively, with formula [CuL2(NO3)(2)]. Furthermore, complexes 2, [CuL2(NO3)(2)] (3) and [NiL2(NO3)(2)] (4) are essentially isostructural with a cis-disposition of the nitrate ligands. In compounds 1-4, the coordination mode of nitrate is terminal bidentate. Finally, during the synthesis of compound 1, a few crystals of a different complex were found and separated manually from the bulk sample and characterized by X-ray diffraction. In this compound (5), the benzimidazole ring of the ligand is oxidized to benzimidazolone (L') and the formula of this unexpected compound is [CuL'(2)(H2O)(2)](NO3)(2). Complexes 1 and 5 are characterized by the presence of anion-pi interactions that are relevant to the final 3D architecture and packing. In the crystal structures of the five compounds, C-H center dot center dot center dot O hydrogen bonds, anion-pi and pi-stacking interactions are described and analysed by means of density functional theory (DFT) calculations since they play an important role in the construction of three-dimensional supramolecular frameworks. Moreover, some unconventional interactions have been characterized using Bader's theory of atoms-in-molecules.

The reaction IO + NO → I + NO 2 has been studied theoretically using DFT and ab initio methods. Six transition state configurations have been characterized in total. Four of them correspond to the conformational and isomerization barriers among the reaction intermediates, namely between cis -and trans -iodine nitrites, IONO c , IONO t and nitryl iodide, INO 2 . Interesting features identified in the potential energy surface are the two distinct iodine abstraction transition states that lead to I + NO 2 through each nitrite conformer. The heats of formation for the three bound intermediates are evaluated based on the calculated dissociation energies and are compared to the corresponding properties of the Cl and Br derivatives.