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Interaction of Nitrite Ions with Hydrated Portlandite Surfaces: Atomistic Computer Simulation Study
Materials. 2023. Vol. 16. No. 14. Article 5026.
The nitrite admixtures in cement and concrete are used as corrosion inhibitors for steel reinforcement and also as anti-freezing agents. The characterization of the protective properties should account for the decrease in the concentration of free NO2− ions in the pores of cement concretes due to their adsorption. Here we applied the classical molecular dynamics computer simulation approach to quantitatively study the molecular scale mechanisms of nitrite adsorption from NaNO2 aqueous solution on a portlandite surface. We used a new parameterization to model the hydrated NO2− ions in combination with the recently upgraded ClayFF force field (ClayFF-MOH) for the structure of portlandite. The new NO2− parameterization makes it possible to reproduce the properties of hydrated NO2− ions in good agreement with experimental data. In addition, the ClayFF-MOH model improves the description of the portlandite structure by explicitly taking into account the bending of Ca-O-H angles in the crystal and on its surface. The simulations showed that despite the formation of a well-structured water layer on the portlandite (001) crystal surface, NO2− ions can be strongly adsorbed. The nitrite adsorption is primarily due to the formation of hydrogen bonds between the structural hydroxyls on the portlandite surface and both the nitrogen and oxygen atoms of the NO2− ions. Due to that, the ions do not form surface adsorption complexes with a single well-defined structure but can assume various local coordinations. However, in all cases, the adsorbed ions did not show significant surface diffusional mobility. Moreover, we demonstrated that the nitrite ions can be adsorbed both near the previously-adsorbed hydrated Na+ ions as surface ion pairs, but also separately from the cations.
Publication based on the results of:
sobov P., Yakushev I., Shestakov A. et al., Organometallics 2025 Vol. 44 No. 24 P. 2873–2881
Interaction of {Cryptand(K+)}(C60•–) with CpCo(CO)2 yields the air-sensitive crystalline salt {Cryptand(K+)}{CpCo(CO)-η2-C60•–} (1), in which C60•– replaces carbonyl group in CpCo(CO)2. Two Co–C bonds of 2.028(9) and 2.057(8)Å are formed. The magnetic moment of 1 is 1.72 μB, indicating a doublet S = 1/2 spin state of {CpCo(CO)-η2-C60•–} at 300 K. The compound shows a broad ...
Added: September 20, 2026
Копьев А., JETP Letters 2026 Vol. 123 No. 5 P. 310–316
The incompressible three-dimensional Euler equations develop very thin pancake-like regions of exponen tially increasing vorticity. The characteristic thickness of such regions decreases exponentially with time, while the other two dimensions do not change considerably, making the flow near each pancake strongly anisotropic. The pancakes emerge in increasing number with time, which may enhance the anisotropy ...
Added: September 18, 2026
Захаров А. В., Düven H., Capar M. I., Physics Letters A 2026 No. 576 Article 131388
Molecular dynamics simulations were carried out to study the structural properties of nematic pentyl
cyanobiphenyl (5CB) and pentyloxy cyanobiphenyl (5OCB) liquid crystals (LCs) doped with gold nanoparti
cles (GNPs) of different numbers, shapes and sizes. The spherical GNPs of two different radii and rod-like have
been doped in 5CB and 5OCB cyanobiphenyl liquid crystals. In order to describe ...
Added: September 17, 2026
Andreev D. V., Kornev S. A., Bondarenko G.G. et al., Inorganic Materials: Applied Research 2026 Vol. 17 No. 5 P. 1226–1230
Comparative studies are carried out to investigate high-field charge degradation effects in the gate
dielectric of metal—insulator—semiconductor (MIS) structures with aluminum and polysilicon gates.
Charging phenomena in MIS structures are explored using high-field electron injection into the dielectric
under conditions of gradually increasing voltage current density, with periodic short-term switching to a measurement
mode at a constant low injection ...
Added: September 15, 2026
Poddiakov A., / Series Social Science Research Network "Social Science Research Network". 2026. No. 7437658.
Clarity of knowledge and reasoning is necessary in many cases. Yet vagueness in scientific thinking related to surprise, curiosity, "ability to engage with not-knowing" (de Freitas) and abductive reasoning is also a crucially important source of scientific creativity which supplements combinatorial logic when dealing with the already known. Starting from studies by C. S. Peirce ...
Added: September 15, 2026
Water confined in heterogeneous clay–quartz pores: Structure and dynamics from atomistic simulations
Glushak A., Tararushkin E., Smirnov G., Colloids and Surfaces A: Physicochemical and Engineering Aspects 2027 Vol. 752 Article 141756
The molecular-scale behavior of water in heterogeneous clay–quartz systems is critical for understanding cementation processes in natural soils and compacted bentonite, which is crucial for oil recovery and nuclear waste disposal barriers construction. Here we investigate how heterogeneity of mixed Na-montmorillonite and α-quartz surfaces affect water structure and dynamics in nanopores of 2.5 to 60 Å ...
Added: September 15, 2026
Bochkin G., Doronin S., Fel’dman E. et al., Lobachevskii Journal of Mathematics 2024 Vol. 45 No. 3 P. 1188–1207
We consider the remote state restoring and perfect transfer of the zero-order coherence matrix (PTZ) in a spin system governed by the XXZ-Hamiltonian conserving the excitation number. The restoring tool is represented by several nonzero Larmor frequencies in the Hamiltonian. To simplify the analysis we use two approximating models including either step-wise or pulse-type time-dependence ...
Added: September 14, 2026
Fel’dman E. B., Lazarev I., Pechen A. N. et al., Quantum Information Processing 2026 Vol. 25 Article 121
We consider the state-restoring protocol based on the controlled interaction of a linear chain with environment through incoherent control by the specially adjusted step-wise time-dependent Lindblad operators. We show that the best restoring result (maximal scale factors in the restored state) corresponds to the symmetrical Lindblad equation. (0, 1)-excitation dynamics is considered numerically, and restoring ...
Added: September 14, 2026
Li S., Hu J., Lazarev I. et al., Annals of Physics 2026 Vol. 494 Article 170618
The distribution of entanglement is a crucial task for quantum communication towards realizing a globe-spanning quantum internet. Recently, a protocol for deterministic long-distance distribution of macroscopic entanglement over a network of ensembles of qubits was introduced (Pyrkov et al., 2025). It was shown that this protocol allows for the propagation of macroscopic amounts of entanglement ...
Added: September 14, 2026
Pyrkov A., Lazarev I., Byrnes T., Advanced Quantum Technologies 2025 Article 2400524
Distributing long-distance entanglement is a fundamental goal that is necessary for a variety of tasks such as quantum communication, distributed quantum computing, and quantum metrology. Currently quantum repeater schemes typically aim to distribute one ebit at a time, the equivalent of one Bell pair's worth of entanglement. Here, a scheme is presented to distribute a ...
Added: September 14, 2026
I. D. Lazarev, Narozniak M., Byrnes T. et al., Physical Review A: Atomic, Molecular, and Optical physics 2025 Vol. 111 No. 012416 Article 012416
Unsupervised machine learning is one of the main techniques employed in artificial intelligence. We introduce an algorithm for quantum-assisted unsupervised data clustering using the self-organizing feature map, a type of artificial neural network. The complexity of our algorithm scales as 𝑂(𝐿𝑁), in comparison to the classical case which scales as 𝑂(𝐿𝑀𝑁), where 𝑁 is the ...
Added: September 14, 2026
Kolin N., Nazarov D., Krivenko K. et al., Dyes and Pigments 2026 Vol. 254 Article 113957
Interaction of thioindigo dianions with metal phthalocyanines, MPc, where M = MgII, MnII, AlIIICl and SiIVCl2, in the presence of cryptand[2.2.2] produces anionic and neutral complexes: {Crypt(K+)}2{(trans-thioindigo2−)⋅(MgIIPc)2}2−⋅2C6H4Cl2 (1); {Crypt(Cs+)}2{(trans-thioindigo2−)⋅(MnIIPc)2}2− (2), {Crypt(K+)}{(cis-Hthioindigo−)2⋅(AlIIIPc)}− (3) and {(cis-Hthioindigo−)2⋅(SiIVPc)} (4). Bidentate thioindigo2− ligand forms symmetric binuclear dimers in 1 and 2 with short M-O(thioindigo2−) bonds of 1.899(2) and 1.984(6) Å length for ...
Added: September 14, 2026
Faraonov M., Romanenko N., Ivanov T. et al., Dalton Transactions 2026 Vol. 55 No. 24 P. 9428–9438
Doubly reduced phthalocyanine complexes remain largely unexplored despite their potential relevance for molecular spin-based applications. Herein, we report the synthesis of a series of crystalline complexes, {cryptand(Cs + )} 2 [M(Pc) 4– ] 2–. ...
Added: September 14, 2026
Mikhailenko M., Astakhova T., Timokhina E. N. et al., Inorganic Chemistry Frontiers 2026 Vol. 13 No. 14 P. 6145–6156
series of anionic bi- and trinuclear complexes of Co II , Fe II , and Mn II with hexaazatrinaphthylene (HATNA) and hexaazatriphenylenehexacarbonitrile (HAT(CN) 6 ), incorporating paramagnetic Cp* 2 Fe + cations ( S = 1/2), were obtained and investigated. ...
Added: September 14, 2026
Nazarov D., Yakushev I. A., Kuzmin A. V. et al., Inorganic Chemistry Frontiers 2026 Vol. 13 No. 11 P. 5039–5050
Reduced tetra(4-pyridyl)porphyrins (H 2 TPyP and Cu II TPyP) form polymers with M III (TMHD) 3 (M = Dy, Tb and Gd). Folded zigzag 2D and linear 1D polymers are obtained. Their structure, optical and magnetic properties are investigated. ...
Added: September 14, 2026
Sobov P. A., Yakushev I. A., Shestakov A. et al., Inorganic Chemistry 2026 Vol. 65 No. 16 P. 9107–9115
Interaction of fullerene C60 with Cs2Fe(CO)4 in the presence of two equivalents of tetrabutylammonium iodide (TBAI) yields the first dianionic coordination complex of fullerene: (TBA+)2{[Fe2(CO)6]-η2,η2-C60}2– (1). According to magnetic data and DFT calculations, complex 1 has a diamagnetic ground (S = 0) and a triplet excited state (S = 1) populated above 80 K. As ...
Added: September 14, 2026
Faraonov M., Romanenko N., Ivanov T. et al., Crystal Growth & Design 2026 Vol. 26 No. 7 P. 2792–2801
A redox-active tetrapyrazinoporphyrazine ligand was used as a platform for the design of multimetallic coordination complexes. The first paramagnetic homo- and heterotrimetallic complexes have been obtained as crystals through the reaction of iron(II) octaethyltetrapyrazinoporphyrazine, FeII(Et8TPyzPz), with 3d- (FeII, CoII) and 4f-metal (DyIII) iodides. In these conditions, tetrapyrazinoporphyrazine can coordinate to metals to form exo- and ...
Added: September 14, 2026
Sobov P. A., Khasanov S., Kuzmin A. V. et al., Inorganic Chemistry Communications 2026 Vol. 185 Article 116055
New complex {(dppf)CpFe(CO)}(C60)⋅C6H4Cl2 (1) was obtained when stoichiometric mixture of C60 and CoII(dppf)Cl2 is reduced by two equivalents of (Cs+){CpFe(CO)2−} (dppf: 1,1`-bis(diphenylphosphino)ferrocene). CpFe(CO)2− anion reduces CoII(dppf)Cl2 and CpFe(CO)2 abstracts the dppf ligand from Co(dppf) forming (dppf)CpFeI(CO). Electron transfer from (dppf)CpFeI(CO) to C60 is observed. As a result, the state of {(dppf)CpFe(CO)}δ+(C60)δ−⋅C6H4Cl2 (δ = 0.54–0.86) is intermediate between ...
Added: September 14, 2026
Krivenko K., Kuzmin A. V., Mikhailenko M. et al., Dyes and Pigments 2026 Vol. 246 Article 113342
Mono- and binuclear complexes of FeII and CoII with deprotonated trans-indigo were obtained. Reduction of indigo by metallic iron in the presence of crystal violet (CV) yields (CV+)[(FeCl2)HIndigo]−⋅C6H4Cl2 (1). The reaction of FeI2 and CoI2 with one equivalent of decamethylchromocene (Cp∗2Cr) and one or half equivalent of indigo yields mononuclear (Cp∗2Cr+)[(CoI2)HIndigo]−⋅C6H4Cl2 (2), (Cp∗2Cr+)[(FeI2)HIndigo]−⋅ xC6H4Cl2, where ...
Added: September 14, 2026
Sosunov E., Skabitsky I. V., Churakov A. et al., Crystal Growth & Design 2026 Vol. 26 No. 4 P. 1775–1782
Polynuclear 5d–3d assemblies represent a promising class of systems for exploring the interplay among electronic structure, magnetism, and self-assembly. Here, we report the synthesis and structural characterization of the first heterometallic wheel-shaped Pt–Mn cluster, [PtIV12PtII6Mn18(OAc)72(μ3-O)12]·43C6H6(1), which incorporates 36 metal centers. The giant ring is constructed from alternating PtIIMnII paddlewheel fragments and PtIV2Mn2 oxo-acetate units, bridged ...
Added: September 14, 2026
Nikitiuk B., Nikolay Kondratyuk, Pisarev V., Journal of Molecular Liquids 2025 Vol. 440 Article 128894
Understanding how liquids transition into glassy states under varying thermodynamic conditions remains a fundamental challenge in condensed matter physics. While temperature-driven vitrification has been extensively studied, the effects of high pressure on glass formation are comparatively underexplored -- particularly in molecular liquids. In this work, we employ molecular dynamics simulations to investigate the behaviour of ...
Added: November 12, 2025
Lenev D. Y., Zakharov S. A., V. V. Pisarev, Russian Journal of Physical Chemistry A 2024 Vol. 98 No. 12 P. 2816–2822
Molecular dynamics is used to calculate the vapor–liquid equilibrium and liquid–vapor surface
tension for a methane–ethane system. Good agreement of the parachor value for ethane between the molecular
model and experimental data is shown for the 203–253 K range of temperatures and pressures up to
60 atm. The dependence of the surface tension of the mixture on pressure ...
Added: November 15, 2024
Полянский А. А., Efremov R., Биологические мембраны 2024 Т. 41 № 4 С. 403–421
The paper overviews the results of computational studies of the molecular mechanisms underlying
the adaptation of model cell membranes taking place during their interaction with proteins and peptides. We
discuss changes in the structural and dynamic parameters of the water–lipid environment, the hydrophobic/
hydrophilic organization of the lipid bilayer surface (the so-called “mosaicity”), etc. Taken together,
these effects are ...
Added: September 19, 2024
Pavlova T., Shevlyuga V. M., Journal of Chemical Physics 2024 Vol. 160 No. 5 Article 054701
For the most precise incorporation of single impurities in silicon, which is utilized to create quantum devices, a monolayer of adatoms on the Si(100) surface and a dopant-containing molecule are used. Here we studied the interaction of a phosphorus tribromide with a chlorine monolayer with mono- and bivacancies in a scanning tunneling microscope (STM) at ...
Added: July 2, 2024