Search

The lakes has an enormous sediment carbon storage potential. This study aims to estimate sediment organic carbon stock in the of Middle Kaban lake, Republic of Tatarstan. The study revealed that the in the surface layer of lake sediments carbon stocks amount to 1134 tons. Total organic carbon stocks in the bottom sediments of Middle Kaban lake amount to 5986 tons. In CO2 equivalent, 21949 tons of greenhouse gases are accumulated in the lake bottom sediments.

Understanding the mechanisms and controlling the possibilities of surface nanostructuring is of crucial interest for both fundamental science and application perspectives. Here, we report a direct experimental observation of laser-induced periodic surface structures (LIPSS) formed near a predesigned gold step edge following single-pulse femtosecond laser irradiation. Simulation results based on a hybrid atomistic-continuum model fully support the experimental observations. We experimentally detect nanosized surface features with a periodicity of ∼300 nm and heights of a few tens of nanometers. We identify two key components of single-pulse LIPSS formation: excitation of surface plasmon polaritons and material reorganization. Our results lay a solid foundation toward simple and efficient usage of light for innovative material processing technologies.

Significant innovations in the regulatory framework of the construction industry of the Russian Federation force construction organizations to change their attitude to digital technology in general and automation in particular. The existing objective differences of construction companies, carrying out their activities at different stages of the life cycle of construction products, put them in different initial conditions on the way to solving the problem. In the present study, the authors analyze the level of elaboration of a number of issues that arise at different stages of the construction project life cycle (CPLC). As a result of the analysis, the authors conclude that there is a lack of attention to digitalization at the stage “construction”. In particular, it is noted that little attention is paid to the automation of the management activities of companies at this stage of CPLC lifecycle. The authors analyze possible approaches to the automation of management tasks of a construction organization that directly erects buildings and structures. As a result, key features of approaches to the formation of task complexes for automation for two different groups of departments of the management apparatus of a construction organization are formulated. Based on the results of the study, the authors conclude that in order to ensure the effective functioning of construction companies and organizations the use of digitalization technologies at all stages is mandatory.

The assessment of caesium-137 accumulation in parts of fungi fruiting bodies of Leccinum aurantiacum (Bull.) Gray in a mixed spruce-aspen forest on sod-podzolic soil was carried out. Average specific activity of cesium-137 for caps is 1814±112 Bq/kg and for stems 873±73 Bq/kg. It was found that the specific activity of cesium-137 does not exceed the permissible values, but significantly differs between the cap and stem of fruit bodies. The coefficients of cesium-137 accumulation from soil vary for caps from 4.6 to 6.1 and for stems from 1.7 to 2.8. High specific activity of cesium-137 in aspen leaf fall 289±27 Bq/kg and litter 339±23 Bq/kg compared to the underlying soil horizons was noted.

The Telescope Array (TA) experiment, the largest observatory studying ultra-high energy cosmic rays in the northern hemisphere, has reported evidence for two medium-scale anisotropies. The first, known as the TA hotspot, is an excess in the arrival direction distribution for events with energies greater than 5.7 × 1019 eV. More recently, an additional excess of events with energies greater than 1019.4 eV appearing in the direction of the Perseus-Pisces supercluster has been named the PPSC excess. In this presentation, we will update the status of the TA hotspot and the PPSC excess results using the most recent data measured by the TA surface detector array.

Located in the west desert of Utah, USA, the Telescope Array experiment is the largest ultra-high energy cosmic ray observatory in the northern hemisphere. It consists of two types of detectors: scintillator surface detectors (SDs) and air fluorescence detectors (FDs). A total of 507 SDs consisting of two-layer plastic scintillation counters is deployed with 1.2 km spacing, making measurements over an area of approximately 700 km2. There are 3 FD stations, having 38 fluorescence telescopes viewing 3°–31°in elevation, overlooking the SD array. In this work, we update the Telescope Array energy spectrum as measured by the SD array for 14 years. We verify the linearity in TA SD energy reconstruction using three different energy comparisons: Monte Carlo comparison, FD/SD comparison, and Constant Intensity Cut method. The spectral features of ankle, softening, and GZK cutoff are seen in 14 years of TA SD data. Also, we consistently observe that the cutoff energy depends on declination.

The new aluminium alloy for drill pipes is one of the 6xxx-series alloys. The alloy has high strength properties at room and elevated temperatures, as well as high corrosion resistance and workability. Semi-finished extruded products from the new alloy have the following properties: UTS = 420 MPa, YTS = 380 MPa, elongation = 10% and YTS150 = 345 MPa, corrosion rate in solution (pH 11) = 0.09 g/m2 h. Based on the obtained properties, the new alloy can be used as a replacement for D16 alloy.

Violation of the symmetrical mode of operation of the electric network causes a deterioration in the quality of electric energy and significantly reduces the reliability of the functioning of electrical equipment and elements of the electric network. A mathematical model of an electrical network with a grounded neutral is proposed аnd a software package that allows us to evaluate the level of voltage asymmetry of a three-phase system depending on the changing unbalanced load was created. The simulation and calculation of the studied parameters for various combinations of loads and the technical means of balancing the operating mode of the electric network (the balancing device – BD) is carried out. Programs for the Matlab graphic editor are compiled and diagrams of changes in electricity quality indicators are constructed. A numerical analysis is carried out and recommendations are given to determine the most appropriate place for connecting the BD in the electrical network to improve the quality of electricity based on the calculation made.

Modern manufacturers of multipurpose machining centers design and manufacture equipment according to the criterion of maximum rigidity and productivity to ensure processing of the maximum range of materials at high accelerated cutting modes. As a result, in most machine-building tasks, the support structure of the machine is unnecessarily rigid due to the production of excessively massive frames and body elements of the machine. These structural elements have high weight and size characteristics, which leads to an increase in inertial loads on the drive feed mechanisms. In serial and mass production, heavy elements of the support structure significantly increase the energy consumption of the machine, while reducing labor productivity. Modern methods of design optimization, together with finite element methods, allow solving the problem of energy efficiency and productivity by modifying the support structures according to the criterion of minimum rigidity in accordance with the boundary conditions of the cutting forces when processing the selected product range.

Analysis of the specific activity of cesium-137 in the fruiting bodies of representatives of the genus Leccinum collected during mass fruiting in the vicinity of the Seytesyavr Lake (Khibiny) showed that it does not exceed the permissible values. The data obtained can be used as reference data for comparison with the results of accumulation of cesium-137 by fruiting bodies of species of the genus Leccinum collected in other regions.

Based on the research of the main causes of dielectric elements premature aging and electrical destruction of primary dielectric elements in high voltage electrical equipment the complex method for remote monitoring of said electrical equipment has been developed. The developed mobile diagnostic device is allowing detection and periodic control of the most dangerous defects. The set of diagnostic parameters of defects was experimentally obtained by using three physical methods (electromagnetic, optical, and acoustic), and allows to inspect the origin and development of defects, and to determine residual life of dielectric elements with a sufficient degree of reliability. The researched characteristics of the kinetics of reduction in operating parameters of polymer insulators permitted the development of the detection of accelerated increase in defects under the influence of ultra-large partial discharges.

The article discusses distribution electrical networks 0.38 kV operating modes, feeding individual residential buildings. The electrical energy parameters measurement were certified RESURS-UF2M device carried out. The currents and voltages time diagrams based on the measurements made and using Matlab technologies were constructed. It is established that the level of phase currents unbalance is quite high and causes significant three-phase power supply system unbalance voltage accordingly. The power of quality indicators - calculations, characterizing voltage unbalance were made, which were based on the measurements and the computer program “Asymmetry” was used. As well as the additional power losses coefficient determining by the phase currents unbalance, were calculations. Time diagrams these indicators are constructed and their analysis were made. As a result, the power of quality is significantly reduced by unbalance power consumption in the studied electrical network were founded. At the same time, the additional power losses are significant increases. Specific recommendations for the normalization electrical network-operating mode are given.

The article is devoted to the study of the role of the regional component in implementation of the Agenda for Sustainable Development until 2030. Achievement of the 17 Goals and 169 targets in the field of sustainable development indicated in it can hardly be conditioned only by the successful and effective policy of each of the UN member states in this direction. This is explained, first of all, by the fact that the implementation of the Agenda envisages both the interaction of countries at a universal level and largely depends on their regional cooperation, including through integration associations. Wherein, the study of the relevant experience of the Eurasian Economic Union as one of the largest regional associations of economic integration is of considerable interest in this matter. The authors consider practical achievement of the mentioned Goals, primarily Goal 8, through the prism of ensuring freedom of movement of labor within the Union and the effective functioning of its common labor market.

In the present article the authors discuss the possibility of increasing of the suitability of milk as a raw material for cheese production through preservation of native properties of milk proteins, in the first place biologically complete whey proteins as well as the weight ratio of total and ionic calcium. For thermodynamic evaluation of the biosystem we used activation energy (Ea), chemical, physical and organoleptic characteristics. As a result: a methodology has been developed for determination of foodstuffs activation energy; it was determined that with increase in the proportion of the pectin introduced the activation energy and structuredness of the biosystem also increases, when the proportion of pectin is 0.5% the activation energy is 1.788 kJ/mol, when the proportion of pectin is 3% the activation energy is 2.241 kJ/mol, which means the increase by 25%; in the studied pasteurization standard, the maximum content of calcium is observed at 85oC and is equal to 133.8 mg%., in the control sample of milk the content of calcium is 130 mg%; addition of a complex food additive as a protector makes it possible to preserve native properties of the biosystem and guarantees formation of a denser protein coagulum which allows producing high-quality fermented milk products and cheeses.

Complex remote monitoring and the developed non-contact diagnostic device (NDD) allow monitoring the technical condition and revealing the residual life of high-voltage dielectric elements. It is based on non-contact remote periodic measurement of a set of diagnostic parameters (characteristics of electrical discharges emitted by insulators during operation) necessary for a reliable assessment of the operating state of high-voltage dielectric equipment at the moment of operation and determination of its residual life. NDDs are installed on each phase conductor and used to measure diagnostic parameters, followed by computer processing of the accumulated information signals. An analysis of the set of necessary diagnostic parameters makes it possible to form a conclusion on the degree of performance of dielectric elements. The paper considers a method for detecting defective high-voltage insulators using the developed non-contact diagnostic devices by the radio frequency method and assessing the difference in time of arrival of a partial discharge signal.

The article substantiates the relevance of the inspection of overhead power lines by determining the mechanical loads of the conductors. The conductor sways under the action of external loads and variable internal mechanical loads. The conductor behaves in span like a pendulum. A model of the harmonic oscillations of the conductor in flight is derived to assess the mechanical loads of the conductor overhead power lines. This mathematical model is based on mathematical models of a flexible thread and a model of a physical pendulum. A conductor is a physical pendulum, where the conductor acts as the body, and in the role of the fixed axis of rotation, a straight line passing through the suspension points of the conductor. The article briefly describes an algorithm for calculating the conductor sag for the case when the conductor suspension points are at the same height. The results obtained using the developed model for calculating the sag of the conductor by its period are compared with the available experimental data. Experimental equipment is described. The error of the method is estimated.

The length of overhead power transmission lines in the Russian Federation is over 2.8 million kilometers. Power grids are rapidly becoming obsolete. The level of deterioration of the equipment achieves 70% [1]. This leads to breakdowns on overhead power transmission lines and reduce the quality of electricity supply. One of the focus areas towards improving the situation is a deep modernization of the power grid with an orientation on energy efficiency. The purpose of this work is the creation a system for operative monitoring of the technical condition of high-voltage power-transmission lines based on modular devices. The modular device is configured depending on the issues at hand: control of ice formation; control of ice melting; localization of the place of short circuit, breakage, lightning strike; determination of electrical loads on the wire or control of the load of overhead power transmission lines; determination of mechanical loads at the wire suspension point; determination of conditions for the occurrence of ice formation, determination of defects in insulators. This will equip the overhead line diagnostic systems without serious financial costs by simple installation on the wire of the developed device which design allows to change the configuration of the equipment and solve a wide range of tasks.

To solve the problem of adaptive correction for dispersion distortions of the characteristics of a wideband transionospheric channel, we developed a method of diagnosing frequency dispersion parameters using satellite data on the total electron content (TEC) of the ionosphere developed. It also considers TEC measurement stochastic error. For this reason, we performed an analysis of the limitation of the communication signal bandwidth for the case of dispersion correction with an error. It was found that the TEC measurement error that typically exists in practice allows us to spread signal bandwidth by up to three times.

Paper presents the outcomes of the studies into the adaptive wideband equalization for frequency dispersion correction in HF band considering variations in interference characteristics and ionosphere parameters. The subject matter of the research were megahertz-bandwidth channels with single-hop F layer propagation mode. There are presented data on variations in the channel amplitude frequency response that are caused by the interference of magneto-ionic components (intramodal multipath). Test facility for carrying out full-scale experiments was developed with the use of Universal Software Radio Peripheral platform supported by the groundbreaking software-defined radio technology. Verification of the developed methods and algorithms was performed in the experiments on oblique sounding over the Cyprus-to-Yoshkar-Ola propagation path by the linearly frequency modulated continuous wave signal.

The energy spectrum of ultra-high energy cosmic rays is the most emblematic observable for describing these particles. Beyond a few tens of EeV, the Pierre Auger Observatory and the Telescope Array, currently being exploited, provide the largest exposures ever accumulated in the Southern and Northern hemispheres to measure independently a suppression of the intensity, in a complementary way in terms of the coverage of the sky. However, the comparison of the spectra shows differences that are not reducible to an overall uncertainty on the calibration of the energy scale used to reconstruct the extensive air showers. In line with the previous editions of the UHECR workshops, a working group common to both experiments examined these differences by focusing this time on quantification of these differences in the region of the sky commonly observed, where the spectra should be in agreement within uncertainties when directional-exposure effects are taken into account. These differences are compared with the systematic uncertainties of each experiment. We have also revisited the methods of determining cosmic-ray energies and deriving the energy spectrum. We describe the surface detector (SD) spectrum obtained adopting an energy calibration based on the constant intensity cut method (CIC), a Monte Carlo-based attenuation correction, and an energy-dependent CIC attenuation correction.

The Telescope Array (TA) experiment is measuring cosmic rays of energies from PeV to 100 EeV and higher in the Northern hemisphere. TA has two parts: main TA and the TA low energy extension (TALE). Main TA is a hybrid detector that consists of 507 plastic scintillation counters on a 1200m - spaced square grid that are overlooked by three fluorescence detector stations. TALE is also a hybrid detector that consists of additional fluorescence telescopes arranged to view higher elevations and an infill array of 103 plastic scintillation counters. In this work, we describe the combined TA surface detector (SD) and TALE fluorescence detector spectrum, check the calculation of the TA SD spectrum at the highest energies using an alternative, Constant Intensity Cut, method and discuss the declination dependence of the TA SD spectrum at the highest energies. Details of the TALE spectrum calculation have been presented in a separate work at this conference.

The article shows the advantages of plasma hardening in comparison with other methods of surface hardening of steel products. Appropriate schemes of hardening of various products are considered and experimental data characterizing the possibility of obtaining a hardened layer of various thickness during the realization of various methods of plasma heating are presented.

Protection of important energy facilities from direct lightning impact requires the creation of special devices for lightning protection in particular multi-chamber arresters. To improve the efficiency of multi-chamber arrester operation it is necessary to perform mathematical simulation of the physical processes that take place inside such devices. To develop a mathematical model of arc discharge it is necessary to know the thermodynamic and transport properties of the plasma depending on temperature and pressure. In the article the dependences of the thermodynamic and transport properties of plasma in a multi-chamber arrester were obtained for the two-temperature plasma model for the electron temperature range Te = 300–30 000 K, the nonequilibrium degree range is 1–5, and the pressure range p = 0.3–1 atm.

One of several working groups established for this workshop was charged with examining results and methods associated with the UHECR energy spectrum. We summarize the results of our discussions, which include a better understanding of the analysis choices made by groups and their motivation. We find that the energy spectra determined by the larger experiments are consistent in normalization and shape after energy scaling factors are applied. Those scaling factors are within systematic uncertainties in the energy scale, and we discuss future work aimed at reducing these systematics.

Abstract Background Optic neuritis is an acute, demyelinating neuropathy of the optic nerve often representing the first appreciable symptom of multiple sclerosis. Wallerian degeneration of irreversibly damaged optic nerve axons leads to death of retinal ganglion cells, which is the cause of permanent visual impairment. Although the specific mechanisms responsible for triggering these events are unknown, it has been suggested that a key pathological factor is the activation of immune-inflammatory processes secondary to leukocyte infiltration. However, to date, there is no conclusive evidence to support such a causal role for infiltrating peripheral immune cells in the etiopathology of optic neuritis. Methods To dissect the contribution of the peripheral immune-inflammatory response versus the CNS-specific inflammatory response in the development of optic neuritis, we analyzed optic nerve and retinal ganglion cells pathology in wild-type and GFAP-IκBα-dn transgenic mice, where NF-κB is selectively inactivated in astrocytes, following induction of EAE. Results We found that, in wild-type mice, axonal demyelination in the optic nerve occurred as early as 8 days post induction of EAE, prior to the earliest signs of leukocyte infiltration (20 days post induction). On the contrary, GFAP-IκBα-dn mice were significantly protected and showed a nearly complete prevention of axonal demyelination, as well as a drastic attenuation in retinal ganglion cell death. This correlated with a decrease in the expression of pro-inflammatory cytokines, chemokines, adhesion molecules, as well as a prevention of NAD(P)H oxidase subunit upregulation. Conclusions Our results provide evidence that astrocytes, not infiltrating immune cells, play a key role in the development of optic neuritis and that astrocyte-mediated neurotoxicity is dependent on activation of a transcriptional program regulated by NF-κB. Hence, interventions targeting the NF-κB transcription factor in astroglia may be of therapeutic value in the treatment of optic neuritis associated with multiple sclerosis.

Cocrystallizations of trans -[PtX' 2 (NCNR 2 ) 2 ] (R 2 = Me 2 , X' = Cl 1a , Br 1b , I 1c ; R 2 = (CH 2 ) 5 , X' = I 2c ) with SbX 3 (X = Cl, Br, I) gave 1:2 cocrystals 1a ·2SbCl 3 , 1b ·2SbBr 3 , 1c ·2SbCl 3 , 1c ·2SbBr 3 , 1c ·2SbI 3 , and 2c ·2SbI 3 . In all six X-ray structures, the association of the molecular coformers is achieved mainly by Sb III ···d z 2 [Pt II ] metal-involving intermolecular pnictogen bonding. Density functional theory (DFT) calculations (based on experimentally determined geometries) using both gas-phase and solid-state approximations revealed that a σ-(Sb)-hole interacts with an area of negative potential associated with the d z 2 -orbital of the positively charged platinum(II) sites, thus forming a pnictogen bond whose energy falls in the range between -7.3 and -16.9 kcal/mol.

The structure-directing "key-to-lock" interaction of double σ-(I III )-hole donating iodonium cations with the O-flanked pseudo-lacune rims of [β-Mo 8 O 26 ] 4- gives halogen-bonded iodonium-beta-octamolybate supramolecular associates. In the occurrence of their tetragonal pyramidal motifs, deep and broad σ-(I III )-holes of a cation recognize the molybdate backbone, which provides an electronic pool localized around the two lacunae. The halogen-bonded I⋯O linkages in the structures were thoroughly studied computationally and classified as two-center, three-center bifurcated, and unconventional "orthogonal" I⋯O halogen bonds. In the latter, the O-atom approaches orthogonally the C-I III -C plane of an iodonium cation and this geometry diverge from the IUPAC criteria for the identification of the halogen bond., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

We designed 0D, 1D, and 2D supramolecular assemblies made of diaryliodonium salts (functioning as double σ-hole donors) and carboxylates (as σ-hole acceptors). The association was based on two charge-supported halogen bonds (XB), which occurred between I III sites of the iodonium cations and the carboxylate anions. The sequential introduction of the carboxylic groups in the aryl ring of the benzoic acid added a dimension to the 0D supramolecular organization of the benzoate, which furnished 1D-chained and 2D-layered structures when terephthalate and trimesate anions, correspondingly, were applied as XB acceptors. The structure-directing XB were studied using DFT calculations under periodic boundary conditions and were followed by the one-electron-potential analysis and the Bader atoms-in-molecules topological analysis of electron density. These theoretical methods confirmed the existence of the XB and verified the philicities of the interaction partners in the designed solid-state structures.

We developed an atom- and reaction mass efficient strategy for the preparation of diarylselenides using iodonium salts as reactants. The developed approach allows the obtaining of diarylselenides from the corresponding trimethoxyphenyl-substituted iodonium salts via a two-step one-pot reaction sequence. The proposed metal-free methodology is based on the involvement of both iodonium aryl groups for diarylation.

Five new copper(I) complexes─composed of the paired dibenzohalolium and [CuL 2 ] - (L = 1,2,4-oxadiazolate) counterions in which O,O-atoms of the anion are simultaneously linked to the halogen atom─were generated and isolated as the solid via the three-component reaction between [Cu(MeCN) 4 ](BF 4 ), sodium 1,2,4-oxadiazolates, and dibenzohalolium triflates (or trifluoroacetates). This reaction is different from the previously reported Cu I -catalyzed arylation of 1,2,4-oxadiazolones by diaryliodonium salts. Inspection of the solid-state X-ray structures of the complexes revealed the strong three-center X···O,O (X = Br, I) halogen bonding occurred between the oxadiazolate moieties and dibenzohalolium cation. According to performed theoretical calculations, this noncovalent interaction (or noncovalent chelation) was recognized as the main force in the stabilization of the copper(I) complexes. An explanation for the different behavior of complexes, which provide either chelate or nonchelate binding, is based on the occurrence of additional -CH 3 ···π interactions, which were also quantified.

The co-crystallization of tetracyanobenzene (TCB) with haloarenes ArX provided six new co-crystals TCB ⋅ ArX (ArX=PhCl, PhBr, 4-MeC 6 H 4 Cl, 4-MeC 6 H 4 Br, 4-MeOC 6 H 4 Cl, 1,2-Br 2 C 6 H 4 ) which were studied by X-ray diffraction. In these systems, the strong collective effect of π⋅⋅⋅π stacking interactions and lone pair-(X)⋅⋅⋅π-hole-(C) bondings between TCB and ArX promote the strength of X⋅⋅⋅N cyano halogen bonding (HaB). Theoretical studies showed that the stacking interactions affect the σ-hole depth of the haloarenes, thus significantly boosting their ability to function as HaB donors. According to the molecular electrostatic potential calculations, the σ- hole-(Cl) value (1.5 kcal/mol) in the haloarene 4-MeOC 6 H 4 Cl (featuring an electron-rich arene moiety and exhibiting very poor σ-hole-(Cl) ability) increases significantly in the stacked trimer (TCB) 2  ⋅ 4-MeOC 6 H 4 Cl (12.5 kcal/mol). Theoretical DFT calculations demonstrate the dramatic increase of X⋅⋅⋅N cyano HaB strength for stacked trimers in comparison with parent unstacked haloarenes., (© 2022 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

The co-crystallization of the lead(II) complex [Pb(S 2 CNEt 2 ) 2 ] with tetraiodoethylene (C 2 I 4 ) gave the co-crystal, [Pb(S 2 CNEt 2 ) 2 ]∙½C 2 I 4 , whose X-ray structure exhibits only a small change of the crystal parameters than those in the parent [Pb(S 2 CNEt 2 ) 2 ]. The supramolecular organization of the co-crystal is largely determined by an interplay between Pb⋯S tetrel bonding (TeB) and I⋯S halogen bonding (HaB) with comparable contributions from these non-covalent contacts; the TeBs observed in the parent complex, [Pb(S 2 CNEt 2 ) 2 ], remain unchanged in the co-crystal. An analysis of the theoretical calculation data, performed for the crystal and cluster models of [Pb(S 2 CNEt 2 ) 2 ]∙½C 2 I 4 , revealed the non-covalent nature of the Pb⋯S TeB (-5.41 and -7.78 kcal/mol) and I⋯S HaB (-7.26 and -11.37 kcal/mol) interactions and indicate that in the co-crystal these non-covalent forces are similar in energy.

A single-crystal X-ray diffraction (XRD) study of diaryliodonium tetrachloroaurates (or, in the recent terminology, tetrachloridoaurates), [( p -XC 6 H 4 ) 2 I][AuCl 4 ] (X = Cl, 1 ; Br, 2 ), was performed for 1 (the structure is denoted as 1a to show similarity with the isomorphic structure 2a ) and two polymorphs─ 2a (obtained from MeOH) and 2b (from 1,2-C 2 H 4 Cl 2 ). Examination of the XRD data for these three structures revealed 2-center C-X···Au III (X = Cl and Br) and 3-center bifurcated C-Br···( Cl - Au ) halogen bonding (abbreviated as XB) between the p -Cl or p -Br atoms of the diaryliodonium cations and the gold(III) atom of [AuCl 4 ] - . The noncovalent nature of Au III -involving interactions, the nucleophilicity of the gold(III) atoms, and the electrophilic role of p -X atoms of the diaryliodonium cations in the XBs were studied by a set of complementary computational methods. Combined experimental and theoretical studies allowed the recognition of the d-nucleophilicity of the [d 8 Au III ] atom which, regardless of its rather substantial formal 3+ charge, can function as a d-nucleophilic partner of XB. This conclusion was also supported by theoretical calculations performed for the structures' refcodes BINXOM and ICSD 62511; the obtained data verified the nucleophilicity of Au III toward a K + ions or a σ-(Cl)-hole, respectively. All our results, together with consideration of relevant literature, indicate that gold atoms in the three oxidation states (0, I, and even III) exhibit nucleophilicity in XBs.

Cyclometalated platinum(II) complexes [Pt(ppy)Cl(CNAr)] (ppy = 2-phenylpyridinato-C 2 , N ; Ar = C 6 H 4 -2-I 1 , C 6 H 4 -4-I 2 , C 6 H 3 -2-F-4-I 3 , and C 6 H 3 -2,4-I 2 4 ) bearing ancillary isocyanide ligands were obtained by the bridge-splitting reaction between the dimer [Pt(ppy)(μ-Cl)] 2 and 2 equiv any one of the corresponding CNAr. Complex 2 was crystallized in two polymorphic forms, namely, 2 I and 2 II , exhibiting green (emission quantum yield of 0.5%) and orange (emission quantum yield of 12%) phosphorescence, respectively. Structure-directing non-covalent contacts in these polymorphs were verified by a combination of experimental (X-ray diffraction) and theoretical methods (NCIplot analysis, combined electron localization function (ELF), and Bader quantum theory of atoms in molecules (QTAIM analysis)). A noticeable difference in the spectrum of non-covalent interactions of 2 I and 2 II is seen in the Pt···Pt interactions in 2 II and absence of these metallophilic contacts in 2 I . The other solid luminophores, namely, 1 , 3 I-II , 4 , and 4 ·CHCl 3 , exhibit green luminescence; their structures include intermolecular C-I···Cl-Pt halogen bonds as the structure-directing interactions. Crystals of 1 , 2 I , 3 I , 3 II , 4 , and 4 ·CHCl 3 demonstrated a reversible mechanochromic color change achieved by mechanical grinding (green to orange) and solvent adsorption (orange to green)., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

In this study, we present results of a detailed topological analysis of electron density (ED) of 145 halogen-bonded complexes formed by various fluorine-, chlorine-, bromine-, and iodine-containing compounds with trimethylphosphine oxide, Me 3 PO. To characterize the halogen bond (XB) strength, we used the complexation enthalpy, the interatomic distance between oxygen and halogen, as well as the typical set of electron density properties at the bond critical points calculated at B3LYP/jorge-ATZP level of theory. We show for the first time that it is possible to predict the XB strength based on the distance between the minima of ED and molecular electrostatic potential (ESP) along the XB path. The gap between ED and ESP minima exponentially depends on local electronic kinetic energy density at the bond critical point and tends to be a common limiting value for the strongest halogen bond.

Porous architectures characterized by parallel channels arranged in honeycomb or rectangular patterns are identified in two polymorphic crystals of a zwitterionic 4-(aryliodonio)-benzenesulfonate. The channels are filled with disordered water molecules which can be reversibly removed on heating. Consistent with the remarkable strength and directionality of the halogen bonds (XBs) driving the crystal packing formation, the porous structure is stable and fully preserved on almost quantitative removal and readsorption of water. The porous systems described here are the first reported cases of one-component 3D organic frameworks whose assembly is driven by XB only (XOFs). These systems are a proof of concept for the ability of zwitterionic aryliodonium tectons in affording robust one-component 3D XOFs. The high directionality and strength of the XBs formed by these zwitterions and the geometrical constraints resulting from the tendency of their hypervalent iodine atoms to act as bidentate XB donors might be key factors in determining this ability., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Three isomorphic cocrystals were obtained via the crystallization of [PPN][AuCl 2 ] ( 1 ) from CHBr 3 ( 1 ·CHBr 3 ), or CHCl 3 /1,2-C 2 F 4 Br 2 ( 1 ·CHCl 3 ) and CH 2 Cl 2 /Et 2 O ( 1 ·CH 2 Cl 2 ) mixtures. Analysis of the single-crystal X-ray diffraction data for these cocrystals revealed a gold(I)-involving two-center C-X···Au halogen bond (abbreviated as XB; X = Cl, Br) and a three-center bifurcated C-Br···( Cl - Au ) XB; in the latter, the gold(I)-chloride linkage functions as an integrated XB acceptor. The noncovalent nature and energies [spanning from -1.58 to -5.52 kcal/mol for C-X···Au and -6.37 kcal/mol for C-Br···( Cl - Au ) XBs] of these noncovalent interactions were studied by density functional theory calculations and topological analysis of the electron density distribution in the framework of the quantum theory of atoms-in-molecules (QTAIM) followed by noncovalent interaction (NCI) analysis at the B3LYP-D3/jorge-TZP-DKH level of theory. The nucleophilicity of the gold(I) centers toward halogens of halomethanes was verified by a set of independent methods including electrostatic potential surfaces, electron localization function projection, natural bond orbital charge transfer, electron density/electrostatic potential profile, Wiberg bond indexes, natural population analysis, and atoms-in-molecules charge analyses.

This review highlights recent studies discovering unconventional halogen bonding (HaB) that involves positively charged metal centers. These centers provide their filled d-orbitals for HaB, and thus behave as nucleophilic components toward the noncovalent interaction. This role of some electron-rich transition metal centers can be considered an oxymoron in the sense that the metal is, in most cases, formally cationic; consequently, its electron donor function is unexpected. The importance of Ha⋅⋅⋅d-[M] (Ha=halogen; M is Group 9 (Rh, Ir), 10 (Ni, Pd, Pt), or 11 (Cu, Au)) interactions in crystal engineering is emphasized by showing remarkable examples (reported and uncovered by our processing of the Cambridge Structural Database), where this Ha⋅⋅⋅d-[M] directional interaction guides the formation of solid supramolecular assemblies of different dimensionalities., (© 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Two isostructural trans -[MI 2 (CNXyl) 2 ]·I 2 (M = Pd or Pt; CNXyl = 2,6-dimethylphenyl isocyanide) metallopolymeric cocrystals containing uncommon bifurcated iodine···(metal-iodide) contact were obtained. In addition to classical halogen bonding, single-crystal X-ray diffraction analysis revealed a rare type of metal-involved stabilizing contact in both cocrystals. The nature of the noncovalent contact was studied computationally (via DFT, electrostatic surface potential, electron localization function, quantum theory of atoms in molecules, and noncovalent interactions plot methods). Studies confirmed that the I···I halogen bond is the strongest noncovalent interaction in the systems, followed by weaker I···M interaction. The electrophilic and nucleophilic nature of atoms participating in I···M interaction was studied with ED/ESP minima analysis. In trans -[PtI 2 (CNXyl) 2 ]·I 2 cocrystal, Pt atoms act as weak nucleophiles in I···Pt interaction. In the case of trans -[PdI 2 (CNXyl) 2 ]·I 2 cocrystal, electrophilic/nucleophilic roles of Pd and I are not clear, and thus the quasimetallophilic nature of the I···Pd interaction was suggested.

An interplay between 4-bromo- and 4-iodo-5-nitrophthalonitriles (XNPN, X=Br or I) and any one of the azines (pyridine 1, 4-dimethylaminopyridine 2, isoquinoline 3, 4-cyanopyridine 4, 2-methylpyridine 5, 2-aminopyridine 6, quinoline 7, 1-methylisoquinoline 8, and 2,2'-bipyridine 9) proceeds differently depending on steric and electronic effects of the heterocycles. Sterically unhindered azines 1-3 underwent N-arylation to give the corresponding azinium salts (characterized by 1 H and 13 C{H} NMR and high-resolution ESI-MS). In contrast, azines 4-9 with sterically hindered N atoms or bearing an electron-withdrawing substituent, form stable co-crystals with XNPN, where two interacting molecules are bound by halogen bonding. In all obtained co-crystals, X⋅⋅⋅N structure-directed halogen bonds were recognized and theoretically evaluated including DFT calculations (PBE0-D3/def2-TZVP level of theory), QTAIM analysis, molecular electrostatic potential surfaces, and noncovalent interaction plot index. Estimated energies of halogen bonding vary from -7.6 kcal/mol (for 6 ⋅ INPN) to -11.4 kcal/mol (5 ⋅ INPN)., (© 2021 Wiley-VCH GmbH.)

The complexes [RhX(COD)] 2 (X = Cl, Br; COD = 1,5-cyclooctadiene) form cocrystals with σ-hole iodine donors. X-ray diffraction studies and extensive theoretical considerations indicate that the d z 2 -orbitals of two positively charged rhodium(I) centers provide sufficient nucleophilicity to form a three-center halogen bond (XB) with the σ-hole donors. The two metal centers function as an integrated XB acceptor, providing assembly via a metal-involving XB., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

An extensive series of 128 halogen-bonded complexes formed by trimethylphosphine oxide and various F-, Cl-, Br-, I- and At-containing molecules, ranging in energy from 0 to 124 kJ/mol, is studied by DFT calculations in vacuum. The results reveal correlations between R-X⋅⋅⋅O=PMe 3 halogen bond energy Δ E , X⋅⋅⋅O distance r , halogen's σ-hole size, QTAIM parameters at halogen bond critical point and changes of spectroscopic parameters of phosphine oxide upon complexation, such as 31 P NMR chemical shift, Δ δ P, and P=O stretching frequency, Δν. Some of the correlations are halogen-specific, i.e., different for F, Cl, Br, I and At, such as Δ E ( r ), while others are general, i.e., fulfilled for the whole set of complexes at once, such as Δ E (Δ δ P). The proposed correlations could be used to estimate the halogen bond properties in disordered media (liquids, solutions, polymers, glasses) from the corresponding NMR and IR spectra.

Reinvestigation of ( o -benzoquinonedioximate) 2 Ni/I 2 systems demonstrated that the reaction itself and also the crystallization conditions dramatically affect the identity of generated species. Crystallization (CHCl 3 , 20-25 °C) of the nickel(II) dioximate complex [Ni(bqoxH) 2 ] (bqoxH 2 = o -benzoquinonedioxime) with I 2 in the 1:(1-10) molar ratios of the reactants led to several ( o -benzoquinonedioximate) 2 Ni derivatives and/or iodine adducts [Ni(I)(bqoxH)(bqoxH 2 )]· 3 / 2 I 2 , [Ni(I 3 )(bqoxH)(bqoxH 2 )]·[Ni(bqoxH) 2 ], and [Ni(I 3 )(bqox •- )(bqoxH 2 )]·I 2 ; the latter one, featuring the anion-radical bqox •- ligand, is derived from the formal (-2H + /1 e - )-oxidation of bqoxH 2 . In these three adducts, various types of noncovalent interactions were identified experimentally and their existence was supported theoretically. The [Ni(I 3 )(bqox •- )(bqoxH 2 )]·I 2 adduct exhibits simultaneous semicoordination and coordination patterns of the triiodide ligand; this is the first recognition of the semicoordination of any polyiodide ligand to a metal center. The semicoordination noncovalent contact Ni···I 3 (3.7011(10) Å) is substantially longer that the Ni-I 3 coordination bond (2.8476(9) Å), and the difference in energies between these two types of linkages is 8-12 kcal/mol.

Hexaiododiplatinates(ii) bearing ammonium and phosphonium cations, [R4N]2[Pt2(μ-I)2I4] {R = Et (1) and n-Bu (2)} and [R3PR1]2[Pt2(μ-I)2I4] {R = n-Bu and R1 = n-Bu (3); R = Ph and R1 = Ph (4); R = Ph and R1 = CH2Ph (5)}, were synthesized and characterized by high resolution ESI-MS, 1H, 13C{1H}, 31P{1H}, and 195Pt NMR spectroscopy, Fourier transform infrared and Raman spectroscopy, X-ray diffraction (XRD), X-ray powder diffraction, and also electrostatic surface potential calculations. Complexes 1-3 were cocrystallized with halogen bond (XB) donors based on organic iodides featuring electron withdrawing groups {REWGIs: 1,3,5-triiodotrifluorobenzene (1,3,5-FIB), iodopentafluorobenzene (IPFB), 1,4-diiodotetrafluorobenzene (1,4-FIB), and tetraiodoethylene (C2I4)} to give crystalline adducts 1·2(1,3,5-FIB), 1·2IPFB, 2·2(1,4-FIB), and 3·C2I4. Inspection of the XRD data of the obtained adducts revealed the presence, in all four structures, of intermolecular REWGII-Pt XBs between the iodine centers of REWGIs and the terminal iodide ligands of [Pt2(μ-I)2I4]2- anions, where the latter act as rectangular XB-accepting synthons forming XBs with two, three, and even four Pt-Iterminal ligands. The results of Hirshfeld molecular surface analysis and density functional theory (DFT) calculations (the M06/DZP-DKH level of theory) followed by topological analysis of the electron density distribution within the framework of Bader's approach (QTAIM) confirmed the existence of the detected XBs, and their estimated energies vary from 2.2 to 4.7 kcal mol-1.

The dihalomethanes CH 2 X 2 (X=Cl, Br, I) were co-crystallized with the isocyanide complexes trans-[MX M 2 (CNC 6 H 4 -4-X C ) 2 ] (M=Pd, Pt; X M =Br, I; X C =F, Cl, Br) to give an extended series comprising 15 X-ray structures of isostructural adducts featuring 1D metal-involving hexagon-like arrays. In these structures, CH 2 X 2 behave as bent bifunctional XB/XB-donating building blocks, whereas trans-[MX M 2 (CNC 6 H 4 -4-X C ) 2 ] act as a linear XB/XB acceptors. Results of DFT calculations indicate that all XCH 2 -X⋅⋅⋅X M -M contacts are typical noncovalent interactions with estimated strengths in the range of 1.3-3.2 kcal mol -1 . A CCDC search reveals that hexagon-like arrays are rather common but previously overlooked structural motives for adducts of trans-bis(halide) complexes and halomethanes., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The isocyanide trans-[PdBr 2 (CNC 6 H 4 -4-X') 2 ] (X'=Br, I) and nitrile trans-[PtX 2 (NCC 6 H 4 -4-X') 2 ] (X/X'=Cl/Cl, Cl/Br, Br/Cl, Br/Br) complexes exhibit similar structural motif in the solid state, which is determined by hitherto unreported four-center nodes formed by cyclic halogen bonding. Each node is built up by four Type II C-X'⋅⋅⋅X-M halogen-bonding contacts and include one Type I M-X⋅⋅⋅X-M interaction, thus giving the rhombic-like structure. These nodes serve as supramolecular synthons to form 2D layers or double chains of molecules linked by a halogen bond. Results of DFT calculations indicate that all contacts within the nodes are typical noncovalent interactions with the estimated strengths in the range 0.6-2.9 kcal mol -1 ., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The complexes [Pt(tpp)] (H 2 tpp=tetraphenylporphyrin), [M(acac) 2 ] (M=Pd, Pt, Hacac=acetylacetone), and [Pd(ba) 2 ] (Hba=benzoylacetone) were co-crystallized with highly electron-deficient arene systems to form reverse arene sandwich structures built by π-hole⋅⋅⋅[M II ] (d 8 M=Pt, Pd) interactions. The adduct [Pt(tpp)]⋅2 C 6 F 6 is monomeric, whereas the diketonate 1:1 adducts form columnar infinity 1D-stack assembled by simultaneous action of both π-hole⋅⋅⋅[M II ] and C⋅⋅⋅F interactions. The reverse sandwiches are based on noncovalent interactions and calculated ESP distributions indicate that in π-hole⋅⋅⋅[M II ] contacts, [M II ] plays the role of a nucleophile., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In the current study, we evaluated the solubility of a number of organometallic species and showed that it is noticeably improved in diiodomethane when compared to other haloalkane solvents. The better solvation properties of CH 2 I 2 were associated with the substantially better σ-hole-donating ability of this solvent, which results in the formation of uniquely strong solvent-(metal complex) halogen bonding. The strength of the halogen bonding is attenuated by the introduction of additional halogen atoms in the organometallic species owing to the competitive formation of more favourable intermolecular complex-complex halogen bonding. The exceptional solvation properties of diiodomethane and its inertness towards organometallic species make this solvent a good candidate for NMR studies, in particular, for the acquisition of spectra of insensitive spins., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The nitrosoguanidinate complex [Ni{NH═C(NMe 2 )NN(O)} 2 ] (1) was cocrystallized with I 2 and sym-trifluorotriiodobenzene (FIB) to give associates 1·2I 2 and 1·2FIB. Structures of these solid species were studied by XRD followed by topological analysis of the electron density distribution within the framework of Bader's approach (QTAIM) at the M06/DZP-DKH level of theory and Hirshfeld surface analysis. Our results along with inspection of XRD (CCDC) data, accompanied by the theoretical calculations, allowed the identification of three types of Ni···I contacts. The Ni···I semicoordination of the electrophilic nickel(II) center with electron belt of I 2 was observed in 1·2I 2 , the metal-involving halogen bonding between the nucleophilic nickel(II)-d z 2 center and σ-hole of iodine center was recognized and confirmed theoretically in the structure of [FeNi(CN) 4 (IPz)(H 2 O)] n (IPz = 4-N-coordinated 2-I-pyrazine), whereas the arrangement of FIB in 1·2FIB provides a boundary case between the semicoordination and the halogen Ni···I bondings. In 1·2I 2 and 1·2FIB, noncovalent interactions were studied by variable temperature XRD detecting the expansion of noncovalent contacts with preservation of covalent bond lengths upon the temperature increase from 100 to 300 K. The nature and energies of all identified types of the Ni···I noncovalent interactions in the obtained (1·2I 2 and 1·2FIB) and in the previously reported ([FeNi(CN) 4 (IPz)(H 2 O)] n , [NiL 2 ](I 3 ) 2 ·2I 2 (L = o-phenylene-bis(dimethylphosphine), [NiL]I 2 (L = 1,4,8,11-tetra-azacyclotetradecane), Ni(en) 2 ] n [AgI 2 ] 2n (en = ethylenediamine), and [NiL](ClO 4 ) (L = 4-iodo-2-((2-(2-(2-pyridyl)ethylsulfanyl)ethylimino)methyl)-phenolate)) structures were studied theoretically. The estimated strengths of these Ni···I noncovalent contacts vary from 1.6 to 4.1 kcal/mol and, as expected, become weaker on heating. This work is the first emphasizing electrophilic-nucleophilic dualism of any metal center toward noncovalent interactions.

Metal-involving halogen bonding was detected in a series of associates of CHI3 with trans-[PtX2(NCNAlk2)2] (X = Cl, Br). The HI2C-Iη(1)(Pt) halogen bonding and the bifurcated HI2C-Iη(2)(Pt-Cl) halogen bonding - the latter undergoes the thermally induced reversible HI2C-I∙∙∙η(2)(Pt-Cl) ⇄ HI2C-I∙∙∙η(1)(Pt) transformation - were observed and confirmed theoretically.