General cross-coupling reactions with adaptive dynamic homogeneous catalysis

Ghosh I., Shlapakov N., Karl T.A., Düker J., Nikitin M., Burykina J.V., Ananikov V.P. and König B., Nature, 2023.
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Cross-coupling reactions are among the most important transformations in modern organic synthesis. Although the range of reported (het)aryl halides and nucleophile coupling partners is very large considering various protocols, the reaction conditions vary considerably between compound classes, necessitating renewed case-by-case optimization of the reaction conditions. Here we introduce adaptive dynamic homogeneous catalysis (AD-HoC) with nickel under visible-light-driven redox reaction conditions for general C(sp2)–(hetero)atom coupling reactions. The self-adjustive nature of the catalytic system allowed the simple classification of dozens of various classes of nucleophiles in cross-coupling reactions. This is synthetically demonstrated in nine different bond-forming reactions (in this case, C(sp2)–S, Se, N, P, B, O, C(sp3, sp2, sp), Si, Cl) with hundreds of synthetic examples under predictable reaction conditions. The catalytic reaction centre(s) and conditions differ from one another by the added nucleophile, or if required, a commercially available inexpensive amine base.

Time-Resolved Formation and Operation Maps of Pd Catalysts Suggest a Key Role of Single Atom Centers in Cross-Coupling

Galushko A.S., Boiko D.A., Pentsak E.O., Eremin D.B., Ananikov V.P., J. Am. Chem. Soc., 2023, ASAP.
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An approach to the spatially localized characterization of supported catalysts over a reaction course is proposed. It consists of a combination of scanning, transmission, and high-resolution scanning transmission electron microscopy to determine metal particles from arrays of surface nanoparticles to individual nanoparticles and individual atoms. The study of the evolution of specific metal catalyst particles at different scale levels over time, particularly before and after the cross-coupling catalytic reaction, made it possible to approach the concept of 4D catalysis–tracking the positions of catalytic centers in space (3D) over time (+1D). The dynamic behavior of individual palladium atoms and nanoparticles in cross-coupling reactions was recorded with nanometer accuracy via the precise localization of catalytic centers. Single atoms of palladium leach out into solution from the support under the action of the catalytic system, where they exhibit extremely high catalytic activity compared to surface metal nanoparticles. Monoatomic centers, which make up only approximately 1% of palladium in the Pd/C system, provide more than 99% of the catalytic activity. The remaining palladium nanoparticles changed their shape and could move over the surface of the support, which was recorded by processing images of the array of nanoparticles with a neural network and aligning them using automatically detected keypoints. The study reveals a novel opportunity for single-atom catalysis─easier detachment (capture) from (on) the carbon support surface is the origin of superior catalytic activity, rather than the operation of single atomic catalytic centers on the surface of the support, as is typically assumed.

“3-in-1” Hybrid Biocatalysts: Association of Yeast Cells Immobilized in a Sol–Gel Matrix for Determining Sewage Pollution

Kamanina O.A., Lantsova E.A., Rybochkin P.V., Arlyapov V.A., Saverina E.A., Kulikovskaya N.S., Perepukhov A.M., Vereshchagin A.N., Ananikov V. P., ACS Appl. Mater. Interfaces, 2023, ASAP.
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Recent advances in the development of green furan ring-containing polymeric materials based on renewable plant biomass

Karlinskii B.Ya., Ananikov V.P., Chem. Soc. Rev., 2023, 52, 836-862.
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Fossil resources are rapidly depleting, forcing researchers in various fields of chemistry and materials science to switch to the use of renewable sources and the development of corresponding technologies. In this regard, the field of sustainable materials science is experiencing an extraordinary surge of interest in recent times due to the significant advances made in the development of new polymers with desired and controllable properties. This review summarizes important scientific reports in recent times dedicated to the synthesis, construction and computational studies of novel sustainable polymeric materials containing unchanged (pseudo)aromatic furan cores in their structure. Linear polymers for thermoplastics, branched polymers for thermosets and other crosslinked materials are emerging materials to highlight. Various polymer blends and composites based on sustainable polyfurans are also considered as pathways to achieve high-value-added products.

An unusual Microdomain Factor Controls Interaction of Organic Halides with the Palladium Phase and Influences Catalytic Activity in the Mizoroki-Heck Reaction

Kashin A.S., Prima D.O., Arkhipova D.M., Ananikov V.P., Small, 2023.
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In this work, using a combination of scanning and transmission electron microscopy (SEM and TEM), the transformations of palladium-containing species in imidazolium ionic liquids in reaction mixtures of the Mizoroki-Heck reaction and in related organic media are studied to understand a challenging question of the relative reactivity of organic halides as key substrates in modern catalytic technologies. The microscopy technique detects the formation of a stable nanosized palladium phase under the action of an aryl (Ar) halide capable of forming microcompartments in an ionic liquid. For the first time, the correlation between the reactivity of the aryl halide and the microdomain structure is observed: Ar-I (well-developed microdomains) > Ar-Br (microphase present) > Ar-Cl (minor amount of microphase). Previously, it is assumed that molecular level factors, namely, carbon-halogen bond strength and the ease of bond breakage, are the sole factors determining the reactivity of aryl halides in catalytic transformations. The present work reports a new factor connected with the nature of the organic substrates used and their ability to form a microdomain structure and concentrate metallic species, highlighting the importance of considering both the molecular and microscale properties of the reaction mixtures.

Expanding the Role of Dimeric Species: On-Cycle Involvement, Improved Stability, and Control of Stereo-Specificity. A Case Study of Atom-Economic Catalytic Hydrothiolation

Sahharova L.T., Burykina Ju.V., Kostyukovich A.Yu., Eremin D.B., Boiko D.A., Fakhrutdinov A.N. and Ananikov V.P., ACS Catal., 2023, 13, 3591-3604.
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A common assumption that dimeric metal complexes in many catalytic systems represent a resting state and are not directly involved in catalytic processes was revised in a combined experimental and theoretical study. On-cycle participation of dimeric metal complexes, rather than typically assumed off-cycle involvement, was revealed, and advantageous performance in terms of improved selectivity was observed. The conceptual rationalization for the participation of dimeric species in the catalytic cycle was developed. The Pd-catalyzed hydrothiolation process (where strong Pd–S binding is well established and a persistent opinion for the inactive/poisoning role of dimeric species is presumed) was evaluated as a challenging system to test the concept. Activation of an (NHC)Pd(Cl)(acac) precatalyst (NHC─N-heterocyclic carbene and acac─acetylacetonate) under the reaction conditions produced monomeric (NHC)Pd(SPh) 2 or dimeric (NHC)2Pd2(SPh)4 species depending on the steric bulkiness of the NHC ligand. Dimeric complexes possessed higher selectivity and tolerated disulfide impurities in contrast to monomeric complexes. Quantum chemical modeling suggested that dimeric catalysis proceeds through the opening of only one (μ-SPh)–Pd bridging bond with retention of the dimeric structure. The second bridging bond is maintained, which prevents the monomerization of the complex. Catalytically active species were detected in a hydrothiolation reaction by high-resolution mass spectrometry and NMR spectroscopy. Proving the opportunity for productive homogeneous catalysis via strongly coordinated dimeric metal species opens new opportunities for catalyst design in the increased nuclearity dimension.

Rapid access to molecular complexity from bioderived 5-HMF derivatives via cascade cycloadditions

Averochkin G.M., Gordeev E.G., Kucherov F.A. and Ananikov V.P., Green Chem., 2023, 25, 1045–1055.
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For the first time, the transformation of biobased 5-HMF derivatives succeeded in a 2 × [4 + 2] cascade cycloaddition reaction, leading to a drastic (3–5-fold) increase in molecular complexity as a result of one synthetic step. A new approach to the use of plant biomass in organic synthesis using a cascade Diels–Alder reaction of 5-HMF dimer derivatives with alkynes has been developed. This reaction proceeds under thermodynamic control, diastereoselectively and regioselectively, providing rapid access to compounds of high molecular complexity with the same synthetic availability as previously obtained regular cycloadducts. As a concept illustration, under conditions of kinetic control, cycloadditions of two molecules of dienophiles are realized, and the resulting products, when heated, rearrange into thermodynamically more favorable cascade products. Reaction pathways were studied in detail using quantum chemical calculations to reveal major factors influencing the selectivity of the process. Discovery of a new sustainability pathway should be noted – to date, oligomeric derivatives are considered a waste of 5-HMF degradation, while the present study highlights them as a valuable material for the synthesis of nonplanar scaffolds.

”Liquid-to-solid” conversion of biomass wastes enhanced by nitrogen doping for the preparation of high-value-added carbon materials for energy storage with superior characteristics

Chernysheva D., Sidash E., Konstantinov M., Klushin V., Tokarev D., Andreeva V., Kolesnikov E., Kaichev V., Smirnova N., Ananikov V.P. , ChemSusChem, 2023, ASAP.
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Sustainable development of mankind urgently recalls for decreasing the cost of energy storage. Continuous massive consumption of dedicated carbon electrode materials with complex internal molecular architecture calls for re-thinking both the source of materials and the process of their production. Finding an efficient sustainable solution is focused on the reuse and development of waste processing into corresponding high-value-added carbon materials. The processing of solid wastes into solid value-added carbon materials ("solid-to-solid") is relatively well developed but can be a two-stage process involving carbon architecture rearrangement and heteroatom doping. Processing liquid wastes into high-value-added solid material ("liquid-to-solid") is typically much more challenging with the need for different production equipment. In the present study, a new approach is developed to bypass the difficulty in the "liquid-to-solid" conversion and simultaneously built in the ability for heteroatom doping within one production stage. Polycondensation of liquid humins waste with melamine (as a nitrogen-containing cross-linking component) results in solidification with preferential C and N atomic arrangements. For subsequent thermochemical conversion of the obtained solidified wastes, complicated equipment is no longer required, and under simple process conditions, carbon materials for energy storage with superior characteristics were obtained. A complete sequence is reported in the present study, including liquid waste processing, nitrogen incorporation, carbon material production, structural study of the obtained materials, detailed electrochemical evaluation and real supercapacitor device manufacture and testing.

The phenomenon of “dead” metal in heterogeneous catalysis: opportunities for increasing the efficiency of carbon-supported metal catalysts

Mironenko R.M., Eremin D.B., Ananikov V.P., Chem. Sci., 2023.
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This review addresses the largely overlooked yet critical issue of "dead" metal in heterogeneous metal catalysts. "Dead" metal refers to the fraction of metal in a catalyst that remains inaccessible to reactants, significantly reducing the overall catalyst performance. As a representative example considered in detail here, this challenge is particularly relevant for carbon-supported metal catalysts, extensively employed in research and industrial settings. We explore key factors contributing to the formation of "dead" metal, including the morphology of the support, metal atom intercalation within the support layers, encapsulation of metal nanoparticles, interference by organic molecules during catalyst preparation, and dynamic behavior under microwave irradiation. Notably, the review outlines a series of strategic approaches to mitigate the occurrence of "dead" metal during catalyst preparation, thus boosting the catalyst efficiency. The knowledge gathered is important for enhancing the preparation of catalysts, especially those containing precious metals. Beyond the practical implications for catalyst design, this study introduces a novel perspective for understanding and optimizing the catalyst performance. The insights are expected to broadly impact different scientific disciplines, empowered with heterogeneous catalysis and driving innovation in energy, environmental science, and materials chemistry, among others. Exploring the "dead" metal phenomenon and potential mitigation strategies brings the field closer to the ultimate goal of high-efficiency, low-cost catalysis

Fast evaluation of the safety of chemical reactions using cytotoxicity potentials and bio-Strips

Egorova K.S., Posvyatenko A.V., Galushko A.S., Ananikov V.P., Chemosphere, 2023, ASAP.
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We introduce new quantitative environmental metrics - "cytotoxicity potentials" – which can be used for the preliminary evaluation of the safety of chemical reactions from the viewpoint of the cytotoxicity of their components. We also elaborate the concept of bio-Profiles to be employed for fast estimation of the potential environmental dangers of chemical processes by (1) including the common cytotoxicity scale for all routes of synthesis of a particular product and (2) proposing a novel, more compact representation of the bio-Profiles themselves in the form of bio-Strips. These improvements allow direct comparisons of various synthetic routes for a particular target product, thus providing faster assessment of the reactions in question from the viewpoint of their "overall cytotoxicity". The advantages of these developments are illustrated by 36 routes of synthesizing 1,1′-biphenyl and 72 routes of synthesizing 4-methoxy-1,1′-biphenyl. The effect of incomplete conversion on bio-Strips and their metrics is also discussed. In addition, we address the impact of the selection of a particular cell line on the evaluation of the reaction safety by comparing the results obtained in three cell lines of various origins.

Selective Buchwald–Hartwig arylation of C-amino-1,2,4-triazoles and other coordinating aminoheterocycles enabled by bulky NHC ligands and TPEDO activator

Astakhov A.V., Chernenko A.Yu., Kutyrev V.V., Ranny G.S., Minyaev M.E., Chernyshev V.M., Ananikov V.P. , Inorg. Chem. Front., 2023, 10, 218-239.
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C-Amino-1,2,4-triazoles are challenging polynitrogen substrates for metal-catalyzed arylation due to their multidentate character, enhanced coordinating ability and decreased nucleophilicity of the amino group. In the present study, the Buchwald–Hartwig cross-coupling of diverse 3(5)-amino-1,2,4-triazoles with aryl chlorides and bromides delivering (hetero)arylamino-1,2,4-triazoles in good-to-excellent yields under Pd/NHC catalysis was developed. The use of Pd complexes with bulky NHC ligands such as IPr*OMe and TPEDO (1,1,2,2-tetraphenylethane-1,2-diol) as an in situ Pd(II) to Pd(0) reductant enabled the selective arylation of the NH2 group even in acidic NH unprotected substrates and deactivated 1-substituted 5-amino- and 4-substituted 3-amino-1,2,4-triazoles. The reaction mechanism and structure–activity relationships were studied with DFT calculations. A significant effect of the position of the N-substituent in the 1,2,4-triazole ring on the favorable reaction pathways was revealed.

Анализ, классификация и предотвращение образования дефектов в экструзионной 3D-печати

Ерохин К.С., Наумов С.А., Анаников В.П., Успехи химии, 2023, 92, RCR5103.
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Additive manufacturing technologies (or 3D printing) have emerged as powerful tools for creating a diverse array of objects, promising a paradigm shift in production methodologies across industries. In chemistry, it allows the manufacturing of reactors with complex topology. However, the benefits of these technologies can be diminished by the use of suboptimal parameters or inferior materials, leading to defects that significantly degrade the quality and functionality of the resulting products. The formulation of effective preventive strategies remains hampered by an incomplete understanding of defect formation. Given this, our review provides a comprehensive exploration of defects that arise during the Fused Filament Fabrication (FFF) — one of the most prevalent 3D printing methods. The defects are systematically classified according to several key characteristics, including size, type, mode of occurrence, and location. Each common defect is discussed in detail, describing its external manifestation, root causes, the impact on the properties of printed parts, and potential preventive measures. Our findings unveil the complex interplay between material properties, printing parameters, and cooling dynamics in the defect formation process. This classification has significant practical relevance, providing a solid basis for the development of strategies to minimize defects and improve the quality of 3D printed products. It provides valuable insights for a wide audience, including researchers investigating chemical processes and additive manufacturing technologies, 3D printing engineers, 3D printer operators, and quality assurance engineers involved in production quality control. In addition, our review points the way forward for future research in this area. There is a crucial need for the development of advanced machine learning and artificial intelligence models that can predict defect formation based on given printing parameters and material properties. Future investigations should also focus on the discovery of novel materials and refining of printing parameters to achieve superior quality of FFF 3D printed products. This is the first review on defect analysis, classification, and prevention methods in 3D printing. This review serves as a cornerstone for these future advances, promoting a deeper understanding of defect formation and prevention in additive manufacturing.

Digital biology approach for macroscale studies of biofilm growth and biocide effects with electron microscopy

Kozlov K.S., Boiko D.A., Detusheva E.V., Detushev K.V., Pentsak E.O., Vereshchagin A.N., Ananikov V.P., Dig. Discov., 2023, ASAP.
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Microbial interactions are one of the major topics of current research due to their great societal relevance. It is now established that biofilms—associations of microorganisms, exchanging various chemical compounds, including proteins and nucleic acids—are capable of promoting horizontal transfer of resistance genes. However, our understanding of the processes occurring in biofilms is rather limited. A possible method to partly overcome this problem is the implementation of highly efficient imaging and mapping of these structures. This work proposes a combination of automated scanning electron microscopy (SEM) and a comprehensive software system that uses deep neural networks to perform an in-depth analysis of biofilms. Time-dependent, high-throughput mapping of biofilm electron microscopy images was achieved using deep learning and allowed microscale data analysis of visible to the eye biofilm-covered area ( i.e., at the macroscale). For this study, to the best of our knowledge, the first matrix and cell-annotated biofilm segmentation dataset was prepared. We show that the presented approach can be used to process statistical data investigation of biofilm samples in a volume, where automation is essential (>70 000 separate bacterial cells studied; >1000 times faster than regular manual analysis). To evaluate the approach, multiple time steps of biofilm development were analyzed by first-to-date kinetic modeling of biofilms with SEM, revealing the complex dynamics of biofilm formation. Moreover, it was shown that the described procedure is capable of capturing differences between antibiotics and antimicrobial compounds applied to studied biofilms.

Analyzing ionic liquid systems using real-time electron microscopy and a computational framework combining deep learning and classic computer vision techniques

Boiko D.A., Kashin A.S., Sorokin V.R., Agaev Yu.V., Zaytsev R.G., Ananikov V.P., J. Mol. Liq., 2023, 376, 121407.
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Electron microscopy (EM) is one of the most important methods for characterizing various systems, and it is traditionally applied to static solid structures. Remarkable recent developments have opened multiple possibilities for in situ observation of different phenomena, including liquid phase processes. In contrast to routine solid-state EM measurements with static images, electron microscopy in liquids often deals with ubiquitous dynamics, which can be recorded as video streams. Providing much information about the sample, real-time EM increases the complexity of data analysis, challenging researchers to develop new, highly efficient systems for data processing. The present work proposes a framework for data anal- ysis in real-time electron microscopy. Multiple algorithm choices are compared, and efficient solutions are described. Using the best algorithm, combining classical computer vision methods and deep learning-based denoising, the unique anisotropic effect of the electron beam in microstructured ionic liquid-based systems was discovered. The developed method provides an efficient approach for studying the structure and transformation of soft micro-scale domains in molecular liquids. The corresponding software was made publicly available, and detailed instructions to reapply it to other problems were provided.

The influence of superbasic conditions and solvent effects on NMR spectra and structural parameters of acetylene in solution

Shahkhatuni A.G., Harutyunyan A.S., Shahkhatuni A.A., Kostyukovich A.Yu., Ananikov V.P., J. Mol. Liq., 2023, 122381.
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Acetylene is a key industrial building block with a reach functionalization chemistry under strong basis (i.e., so called, superbasic) conditions in solution. In spite of significance of such acetylene transformations, mechanistic understanding of liquid-phase processes at molecular level under superbasic conditions remains a challenge. In the present study, a detailed comparative analysis of several factors influencing acetylene in solution was performed using NMR spectroscopy. Solvent effects, deuterium isotope effects, and temperature effects were estimated on experimental JCH spin-spin coupling constants and the chemical shift difference of ΔδC, and their possible outcome on acetylene bond length were assessed. Acetylene was studied under superbasic conditions in DMSO/KOH mixtures, and chemical exchange processes were observed, manifesting themselves as a coalescence of JCH. Possible exchange reactions are validated by quantum chemical calculations. The studied phenomenon may shed light on the mechanism of acetylene activation under superbasic conditions and contribute to understanding functionalization chemistry in the liquid phase.

Bio-Derived Furanic Compounds with Natural Metabolism: New Sustainable Possibilities for Selective Organic Synthesis

Romashov L.V., Kucherov F.A., Kozlov K.S., Ananikov V.P., Int. J. Mol. Sci., 2023, 24, 3997.
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Biomass-derived C6-furanic compounds have become the cornerstone of sustainable technologies. The key feature of this field of chemistry is the involvement of the natural process only in the first step, i.e., the production of biomass by photosynthesis. Biomass-to-HMF (5-hydroxymethylfurfural) conversion and further transformations are carried out externally with the involvement of processes with poor environmental factors (E-factors) and the generation of chemical wastes. Due to widespread interest, the chemical conversion of biomass to furanic platform chemicals and related transformations are thoroughly studied and well-reviewed in the current literature. In contrast, a novel opportunity is based on an alternative approach to consider the synthesis of C6-furanics inside living cells using natural metabolism, as well as further transformations to a variety of functionalized products. In the present article, we review naturally occurring substances containing C6-furanic cores and focus on the diversity of C6-furanic derivatives, occurrence, properties and synthesis. From the practical point of view, organic synthesis involving natural metabolism is advantageous in terms of sustainability (sunlight-driven as the only energy source) and green nature (no eco-persisted chemical wastes).

From Antibacterial to Antibiofilm Targeting: An Emerging Paradigm Shift in the Development of Quaternary Ammonium Compounds (QACs)

Saverina E.A., Frolov N.A., Kamanina O.A., Arlyapov V.A., Vereshchagin A.N., Ananikov V.P., ACS Infect. Dis., 2023, ASAP.
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Multicationic Quaternary Ammonium Compounds: A Framework for Combating Bacterial Resistance

Seferyan M.A., Saverina E.A., Frolov N.A., Detusheva E.V., Kamanina O.A., Arlyapov V.A., Ostashevskaya I.I., Ananikov V.P. and Vereshchagin A.N., ACS Infect. Dis., 2023, ASAP.
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During previous stages of research, high biocidal activity toward microorganism archival strains has been used as the main indicator in the development of new antiseptic formulations. Although this factor remains one of the most important characteristics of biocide efficiency, the scale of antimicrobial resistance spread causes serious concern. Therefore, focus shifts toward the development of formulations with a stable effect even in the case of prolonged contact with pathogens. Here, we introduce an original isocyanuric acid alkylation method with the use of available alkyl dichlorides, which opened access to a wide panel of multi-QACs with alkyl chains of various lengths between the nitrogen atoms of triazine and pyridine cycles. We used a complex approach for the resulting series of 17 compounds, including their antibiofilm properties, bacterial tolerance development, and antimicrobial activity toward multiresistant pathogenic strains. As a result of these efforts, available compounds have shown higher levels of antibacterial activity against ESKAPE pathogens than widely used commercial QACs. Hit compounds possessed high activity toward clinical bacterial strains and have also demonstrated a long-term biocidal effect without significant development of microorganism tolerance. The overall results indicated a high level of antibacterial activity and the broad application prospects of multi-QACs based on isocyanuric acid against multiresistant bacterial strains.

Examination of Pt2dba3 as a “cocktail”-type catalytic system for alkene and alkyne hydrosilylation reactions

Ondar E.E., Kostyukovich A.Yu., Burykina J.V., Galushko A.S., Ananikov V.P., Catal. Sci. Technol., 2023, ASAP.
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Recent developments have underpinned that the creation of a potent catalytic system does not always necessitate the assembly of complex and costly organic ligands with transition metal compounds. Aligned with the principles of dynamic catalysis, a simpler methodology involving the use of regular complexes as catalyst precursors under carefully selected reaction conditions is feasible. The dynamic transformations that these metal compounds undergo can generate a catalyst system with acceptable selectivity and impressive performance characteristics. In our study, we utilized this approach for the hydrosilylation reaction, where we employed a readily available and stable tris(dibenzylideneacetone)diplatinum(0) complex (Pt 2dba3) as a catalyst. Dynamic transformations of Pt2dba3 create a mixture of platinum-bearing compounds within the reaction system, forming a "cocktail"-type catalyst system with performance levels comparable to Karstedt's catalyst (Pt2dvtms3), a popular choice for hydrosilylation reactions. This "cocktail"-type catalyst was examined using a suite of methods, such as decomposition tests, monitoring of platinum nanoparticle formation via electron microscopy, and X-ray absorption fine structure analysis. The gathered data suggest that the reaction system contains both platinum molecular complexes and nanoparticles ranging between 1.6 and 2.6 nm in size. Furthermore, a mechanistic study scrutinizing the selectivity of the alkyne hydrosilylation reaction was conducted using DFT calculations. Molecular dynamics modeling of the key intermediate demonstrated the reversibility of the oxidative addition stage in the catalytic cycle and revealed possible mechanistic pathways for the external-ligand-free catalytic system.

A Simple Protocol for the C-N Cross-Coupling of Aryl Chlorides with Amines Applying Ni/NHC Catalysis

Khazipov O., Pyatachenko A., Chernyshev V.M. and Ananikov V.P., ChemCatChem, 2023, e202300466.
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An efficient protocol for the C-N cross-coupling of aryl chlorides with (hetero)aryl- and alkyl amines under nickel catalysis has been developed. The main advantage of the protocol is the use of a self-activated Ni/NHC catalytic system generated in situ from readily available bench-stable air-tolerant precursors: NiCl2Py2, IPrHCl, and sodium tert-butoxide. A mass spectrometry mechanistic study of the reaction system revealed the dynamics of competitive processes of Ni/NHC active species formation and degradation involving NHC reductive elimination reactions and tert-butoxide base. Optimization of the NiCl2Py2/IPrHCl/tBuONa ratio and the reaction temperature allowed efficient catalysis to be achieved. The developed simple protocol represents a simple alternative for methods relying on the use of air-sensitive and unstable Ni(cod)2 or expensive well-defined Ni/NHC precatalysts.

Atom-economical synthesis of 1,2-bis(phosphine oxide)ethanes from calcium carbide with straightforward access to deuterium- and 13C-labeled bidentate phosphorus ligands and metal complexes

Lotsman K.A., Rodygin K.S., Skvortsova I., Kutskaya A.M., Minyaev M.E. and Ananikov V.P., Org. Chem. Front., 2023, ASAP.
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Stable and easily detectable isotopic labels provide advanced opportunities in a wide range of chemical applications. Highly specific information can be retrieved upon analysis of isotopic label movement from one position to another. The incorporation of isotopic labels into organic molecules is in high demand; however, it may often be rather challenging. The introduction of D and 13C labels is of particular interest due to authentic signals in NMR spectra and the reliable identification of isotopic label positions in target molecules. In this work, a convenient methodology for the introduction of D and 13C labels was developed using calcium carbide as a source of D- and 13C-labeled acetylene and phosphine oxides as substrates. As a result, d4- and 13C2-1,2-bis(phosphine oxide)ethanes were isolated in yields and isotopic purities up to 99%. The resulting phosphine oxides were reduced to the corresponding phosphines, which were used as ligands for the preparation of D-labeled Ni and Pd complexes in 80–96% yields with further characterization by NMR spectroscopy, X-ray and HRMS. The incorporation of D and 13C labels using calcium carbide and acetylene is of key importance since atom-economical addition reactions can be involved with intrinsic opportunity for saving valuable isotopic labels.

CO2-free Calcium Carbide Manufacturing: Demanded Strategy in the Carbon-neutral Chemical Industry

Samoylenko D.E., Samoylenko K.S., Ananikov V.P. , Chin. J. Chem., 2023, ASAP.
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Calcium carbide is considered a possible key component in the sustainable carbon cycle, including convenient recycling of carbon wastes to industrial uptake. However, currently employed CaC2 manufacturing process produces significant amounts of CO2. One of the main factors of its appearance is the formation of carbon oxide during the reaction. The reaction of lime ore with coal inevitably results in the formation of CO and the loss of one carbon atom. CO is usually burnt, forming CO2 to maintain the required high temperature during synthesis – 2200 °C. In the present study, we discuss that the use of calcium metal instead of lime represents a good opportunity to prevent CO2 emission since the reaction of Ca with carbon occurs in an atom-efficient manner and results in only CaC2 at a much lower temperature of 1100 °C. Here, the reaction of Ca with carbon was successfully tested to synthesize CaC2. The desired product was isolated in gram-scale amounts in 97.2% yield and 99% purity. The environmental friendliness of the proposed method originates from the calculations of the E-factor and much lower reaction temperature. Rationalization is provided concerning the cost factor of Ca within the considered process.

Photochemically induced formation of adhesive hydrogels from sodium alginate, acrylamide, and iron sandwich complexes

Sokolov A.S., Korabelnikova V.A., Ananikov V.P., Michurov D.A., Lozinskya V.I., Perekalin D.S., Chem. Commun., 2023, 10532-10535.
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Visible light irradiation of an aqueous solution of sodium alginate and organometallic complex [(C 5H5)Fe(toluene)]BF4 transforms it into a rigid hydrogel due to crosslinking of the carboxylate groups by the iron ions. Irradiation of the same iron complex together with K2S2O8 initiates the polymerization of acrylamide, which provides an efficient method for light-controlled one-step preparation of alginate-polyacrylamide double network hydrogels, which are capable of gluing wet glass with 100–200 kPa shear strength.

Systematic study of FFF materials for digitalizing chemical reactors with 3D printing: superior performance of carbon-filled polyamide

Korabelnikova V.A., Gordeev E.G., Ananikov V.P. , React. Chem. Eng., 2023, ASAP.
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The discovery of high-performance thermoplastics for additive technologies has opened new areas of science and industry with the paramount application of fused filament fabrication 3D printing (FFF). Indeed, it is the emergence of new materials that the further development of FFF technology is associated with. Such materials must combine several high performance characteristics. For use in chemical laboratory practice, FFF materials must possess a challenging combination of properties – chemical resistance, heat stability and mechanical strength. In this work, a systematic study of these characteristics was carried out for general purpose plastics (PLA+, TPU and PC+), plastics with high chemical resistance (PP, PP-GF) and plastics with increased chemical and heat resistance based on polyamides (PA, PA6-CF). It is shown that, in terms of the combination of advantageous practical properties, carbon-filled polyamide-6 (PA6-CF) is a superior material for digital design of chemical reactors in laboratory practice. In this work, a new methodology for complex testing of FFF parts has been developed, which provides the possibility to examine simultaneous effects on several external factors. Tests of chemical reactors made of PA6-CF in the catalytic hydrogenation of alkynes showed the high efficiency of this material for the manufacturing of chemical equipment. The test reactions were performed with high conversion both in batch mode and in continuous flow mode at elevated temperature in a short time using a small amount of palladium catalyst.

Overclocking nitronyl nitroxide gold derivatives in cross-coupling reactions

Zayakin I.A., Tretyakov E.V., Akyeva A.Ya., Syroeshkin M.A., Burykina J.V., Dmitrenok A.S., Korlyukov A.A., Nasyrova D.I., Bagryanskaya I., Stass D., Ananikov V.P., Chem. Eur. J., 2023, 29, e2022031.
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Nitronyl nitroxides are functional building blocks in cutting-edge research fields, such as the design of molecular magnets, the development of redox and photoswitchable molecular systems and the creation of redox-active components for organic and hybrid batteries. The key importance of the nitronyl nitroxide function is to translate molecular-level-optimized structures into nano-scale devices and new technologies. In spite of great importance, efficient and versatile synthetic approaches to these compounds still represent a challenge. Particularly, methods for the direct introduction of a nitronyl nitroxide moiety into aromatic systems possess many limitations. Here, we report gold derivatives of nitronyl nitroxide that can enter Pd(0)-catalysed cross-coupling reactions with various aryl bromides, affording the corresponding functionalized nitronyl nitroxides. Based on the high thermal stability and enhanced reactivity in catalytic transformation, a new reagent is suggested for the synthesis of radical systems via a universal cross-coupling approach.

Sustainable application of calcium carbide residue as a filler for 3D printing materials

Samoylenko D.E., Rodygin K.S., Ananikov V.P. , Sci. Rep., 2023, 13, 4465.
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Industrial activity results in ton-scale production of calcium carbide and generation of a significant amount of calcium carbide residue (CCR), which is often disposed of in the environment as waste. CCR is an active chemical, and rain washes away alkali from sludge, changing the pH of soils and water and damaging the environment. In this work, we explored new opportunities for the utilization of CCR in view of the coming industrial uptake of digital design and additive technologies. Amazingly, CCR can be successfully used as a filler for the modification of 3D printed materials towards the introduction of hybrid organic/inorganic frameworks. A series of commercially available plastics (PLA, ABS, Nylon, PETG, SBS) were successfully used as matrices for CCR-based composite production with high CCR contents up to 28%. Tensile analyses showed increases in tensile strength and Young's modulus of 9% and 60%, respectively. Moreover, in comparison with the pure plastics, the CCR-based materials better maintained the digitally designed shape (lower shrinkage). Importantly, CCR-filled materials are 3D printable, making them very promising components in the building sector. Considering the amount of already available CCR stored in the environment, this material is available in large quantities in the near future for hybrid materials, and anticipated opportunities exist in the additive manufacturing sector. The involvement of CCR in practical composite materials is equally important for environmental protection and reuse of already available multiple-ton wastes.

Synthesis and a combined experimental/theoretical structural study of a comprehensive set of Pd/NHC complexes with o-, m-, and p-halogen- substituted aryl groups (X = F, Cl, Br, CF3)

Pankov R.O., Prima D.O., Kostyukovich A.Yu., Minyaev M.E. and Ananikov V.P., Dalton Trans., 2023, ASAP.
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Pd/NHC complexes (NHCs – N-heterocyclic carbenes) with electron-withdrawing halogen groups were prepared by developing an optimized synthetic procedure to access imidazolium salts and the corresponding metal complexes. Structural X-ray analysis and computational studies have been carried out to evaluate the effect of halogen and CF3 substituents on the Pd–NHC bond and have provided insight into the possible electronic effects on the molecular structure. The introduction of electron-withdrawing substituents changes the ratio of σ-/π-contributions to the Pd–NHC bond but does not affect the Pd–NHC bond energy. Here, we report the first optimized synthetic approach to access a comprehensive range of o-, m-, and p-XC6H4-substituted NHC ligands, including incorporation into Pd complexes (X = F, Cl, Br, CF3). The catalytic activity of the obtained Pd/NHC complexes was compared in the Mizoroki–Heck reaction. For substitution with halogen atoms, the following relative trend was observed: X = Br > F > Cl, and for all halogen atoms, the catalytic activity changed in the following order: m-X, p-X > o-X. Evaluation of the relative catalytic activity showed a significant increase in the catalyst performance in the case of Br and CF3 substituents compared to the unsubstituted Pd/NHC complex.

New class of RSO2-NHC ligands and Pd/RSO2-NHC complexes with tailored electronic properties and high performance in catalytic C-C and C-N bonds formation

Pasyukov ​D.V., Shevchenko M.A., Astakhov A.V., Minyaev M.E., Zhang Y., Chernyshev V.M., Ananikov​ V.P., Dalton Trans., 2023.
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Imidazolium salts have received ubiquitous applications as N-heterocyclic carbene precursors and metal nanoparticle stabilizers in catalysis and metallodrug research. Substituents directly attached to the imidazole ring can have a significant influence on the electronic, steric, and other properties of NHC-proligands as well as their metal complexes. In the present study, for the first time, a new type of Pd/NHC complexes with the RSO2 group directly attached to the imidazol-2-ylidene ligand core was designed and synthesized. Electronic properties as well as structural features of new ligands were evaluated by means of experimental and computational methods. Interestingly, the introduction of a 4-aryl(alkyl)sulfonyl group only slightly decreased electron donation, but it significantly increased π-acceptance and slightly enhanced the buried volume (%Vbur) of new imidazol-2-ylidenes. New Pd/NHC complexes were obtained through selective C(2)H-palladation of some of the synthesized 4-RSO2-functionalized imidazolium salts under mild conditions. Several complexes demonstrated good activity in the catalysis of model cross-coupling reactions, outperforming the activity of similar complexes with non-substituted NHC ligands.

Tuning Sugar Biomass Waste Conversion for the Preparation of Carbon Materials for Supercapacitors and Catalysts for Oxygen Reduction

Chernysheva D.V., Konstantinov M.S., Sidash E.A., Klushin V.A., Tokarev D.V., Andreeva V.E., Butova V.V., Kaichev V.V., Smirnova N.V., Ananikov V.P. , Energy Technol., 2023, 11, 2201145.
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Agriculture is the most massive material circulation activity of humans, with significant annual volumes of production as well as substantial amounts of waste. Transforming agricultural wastes into high-value-added products is the key to sustainable development with efficient usage of renewable resources. The present study demonstrates the fine-tuning of the sugar beet pulp processing to access two types of materials for cutting edge applications—supercapacitors and fuel cells. Alkaline fine-tuning results in N,O-doped carbon material (CM) with an advantageous combination of surface area and morphology that allows to achieve high specific capacitance (308 F g −1), and excellent stability (>10 000 charge/discharge cycles). Not limited to the CM preparation and characterization, a real device is created in the present study to demonstrate the efficient usage of the carbon electrode in the form of the assembled coin cell. Acidic fine-tuning, in contrast, yields a methodology for P,N,O-doped material and optimizes to form active sites with electrocatalytic activity in the oxygen reduction reaction that is used for electricity production in proton-exchange membrane fuel cells. The developed approach demonstrates the tuning of functional properties and morphology of CMs under experimentally simple conditions using conventional reagents (KOH and H 3PO4) and opens up new directions in the circular biomass usage projects.

Densely Packed Chemical Synthesis Equipment by 3D Spatial Design and Additive Manufacturing: Acetylene Generation Cartridge

Erokhin K.S., Ananikov V.P., Org. Process Res. Dev., 2023, ASAP.
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Preparation of and carrying out chemical reactions often require considerable laboratory space. Miniaturization of chemical equipment and reducing laboratory space requirements are an essential task to improve cost-efficiency, as well as increase safety and decrease potential risks. In this work, we discuss the miniaturization of laboratory equipment through the spatial optimization of functional parts. To demonstrate this, we have optimized the size of one of the most cumbersome processes in the lab, the generation of gases from solid sources. We have developed a ready-to-use acetylene generation cartridge with a high degree of functional filling of the internal space, which significantly compacts its dimensions. The cartridge was sealed upon three-dimensional (3D) printing, prepacked with the reagent, and found suitable for long-term storage. In addition to acetylene generation, built-in water trap channels and a drying compartment made it possible to obtain dried gas on the output of the cartridge. The cartridge showed high efficiency in the reactions for the synthesis of bis(arylthio)-substituted ethenes and butadienes. To expand the range of products based on acetylene, a procedure for the synthesis of 1,2-bis(alkylthio)ethenes was developed. The use of the cartridge allowed us to obtain target Z-ethenes with good yields and stereoselectivity.

Dynamic behavior of metal nanoparticles in MOF materials: analysis with electron microscopy and deep learning

Erokhin K.S., Pentsak E.O., Sorokin V.R., Agaev Yu.V., Zaytsev R.G., Isaeva V.I. and Ananikov V.P., Phys. Chem. Chem. Phys., 2023, ASAP.
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Electron microscopy is a key characterization technique for nanoscale systems, and electron microscopy images are typically recorded and analyzed in terms of the morphology of the objects under study in static mode. The emerging current trend is to analyze the dynamic behavior at the nanoscale observed during electron microscopy measurements. In this work, the study of the stability of MOF structures with different compositions and topologies under conditions of an electron microscope experiment revealed an unusual dynamic behavior of M NPs formed due to the electron-beam-induced transformation of specific frameworks. The transition to the liquid phase led to spatial movement, rapid sintering, and an increase in the M NPs size within seconds. In the case of copper nanoparticles, instantaneous sublimation was observed. The dynamic behavior of Co NPs was analyzed with a computational framework combining deep learning and classic computer vision techniques. The present study for the first time revealed unique information about the stability of a variety of MOFs under an electron beam and the dynamic behavior of the formed M NPs. The formation of Fe, Ni, Cu, and Co NPs was observed from a molecular framework with a specific subsequent behavior – a stable form for Fe, excessive dynamics for Co, and sublimation/condensation for Cu. Two important outcomes of the present study should be mentioned: (i) electron microscopy investigations of MOF samples should be made with care, as decomposition under an electron beam may lead to incorrect results and the appearance of "phantom" nanoparticles; and (ii) MOFs represent an excellent model for fundamental studies of molecular-to-nano transitions in situ in video mode, including a number of dynamic transformations.

Studying photochemical transformations using ESI-MS

Burykina Yu.V., Ananikov V.P., ChemPhotoChem, 2023, 7, e202200175.
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The investigation of photochemical reaction mechanisms by electrospray ionization mass spectrometry (ESI-MS) is a rapidly growing field. Herein, we point out that the approach is user-friendly and easy to implement. Commonly used ESI-MS research devices are reviewed, and some applications are highlighted to facilitate the discovery of new photochemical transformations.

This concept article reviews application-oriented possibilities in the mechanistic investigation of photochemical reactions by electrospray ionization mass spectrometry (Photo-Chem-ESI-MS). A brief review of essential techniques for coupling photochemical reactions with ESI-MS online monitoring is presented. Representative customized advanced tools for "light on/light off" mechanistic studies of photochemical reactions aimed at the detection of specific intermediates are discussed. The design of dedicated Photo-Chem-ESI-MS setups is the focus of modern research and will enable more profound insight into the field.

Predicting 195Pt NMR Chemical Shifts in Water-Soluble Inorganic/Organometallic Complexes with a Fast and Simple Protocol Combining Semiempirical Modeling and Machine Learning

Ondar E.O., Polynski M.V., Ananikov V.P., ChemPhysChem, 2023, e202200940.
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Water-soluble Pt complexes are the key components in medicinal chemistry and catalysis. The well-known cisplatin family of anticancer drugs and industrial hydrosylilation catalysts are two leading examples. On the molecular level, the activity mechanisms of such complexes mostly involve changes in the Pt coordination sphere. Using 195Pt NMR spectroscopy for operando monitoring would be a valuable tool for uncovering the activity mechanisms; however, reliable approaches for the rapid correlation of Pt complex structure with 195Pt chemical shifts are very challenging and not available for everyday research practice. While NMR shielding is a response property, molecular 3D structure determines NMR spectra, as widely known, which allows us to build up 3D structure to 195Pt chemical shift correlations. Accordingly, we present a new workflow for the determination of lowest-energy configurational/conformational isomers based on the GFN2-xTB semiempirical method and prediction of corresponding chemical shifts with a Machine Learning (ML) model tuned for Pt complexes. The workflow was designed for the prediction of 195Pt chemical shifts of water-soluble Pt(II) and Pt(IV) anionic, neutral, and cationic complexes with halide, NO2−, (di)amino, and (di)carboxylate ligands with chemical shift values ranging from −6293 to 7090 ppm. The model offered an accuracy (normalized root-mean-square deviation / RMSD) of 0.98 % / 131.25 ppm on the held-out test set.

Reductive Elimination or C–C bond Activation with Model Ni, Pd, Pt Complexes? A High-Accuracy Comparative Computational Analysis of Reactivity

Polynski M.V., Ananikov V.P., Eur. J. Inorg. Chem., 2023, 26, e202200572.
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The development of Pd- and Ni-catalyzed reactions for C–C bond formation is one of the primary driving forces in modern organic synthesis and the fine chemical industry. However, understanding the role of conformational mobility in reaction mechanisms is a long-standing challenge. We highlight the effect of a multirotamer (multiconformer) system on the effective Gibbs free energy of activation in the key C–C coupling process and promote the use of a simplified version of multiconformer transition state theory that is straightforward to apply. Multivariate regression helped to quantitatively map the effect of coupled organic substituents (their structural and electronic parameters), as well as to determine the relative activity of metals. We provide computational evidence for solvent control of the equilibrium in RE/C–C-bond activation for some model complexes. We also demonstrate that Ni complexes, being unique in the catalysis of sp3-sp3couplings, can be more challenging for machine learning and computational chemistry. The modeling was performed at an exceptionally high level, DLPNO-CCSD(T)/CBS//RIJCOSX-PBE0-D4/def2-TZVP. The Conclusions section contains an infographic summarizing the key findings related to the fields of cross-coupling catalysis, machine learning in catalysis, and computational chemistry.

The Fast Formation of a Highly Active Homogeneous Catalytic System upon the Soft Leaching of Pd Species from a Heterogeneous Pd/C Precursor

Galushko A.S., Ilyushenkova V.V., Burykina J.V., Shaydullin R.R., Pentsak E.O., Ananikov V. P. , Inorganics, 2023, 260.
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Understanding the interface between soluble metal complexes and supported metal particles is important in order to reveal reaction mechanisms in a new generation of highly active homogeneous transition metal catalysts. In this study, we show that, in the case of palladium forming on a carbon (Pd/C) catalyst from a soluble Pd(0) complex Pd2dba3, the nature of deposited particles on a carbon surface turns out to be much richer than previously assumed, even if a very simple experimental procedure is utilized without the use of additional reagents and procedures. In the process of obtaining a heterogeneous Pd/C catalyst, highly active "hidden" metal centers are formed on the carbon surface, which are leached out by the solvent and demonstrate diverse reactivity in the solution phase. The results indicate that heterogeneous catalysts may naturally contain trace amounts of molecular monometallic centers of a different nature by easily transforming them to the homogeneous catalytic system. In line with a modern concept, a heterogenized homogeneous catalyst precursor was found to leach first, leaving metal nanoparticles mostly intact on the surface. In this study, we point out that the previously neglected soft leaching process contributes to high catalyst activity. The results we obtained demand for leaching to be reconsidered as a flexible tool for catalyst construction and for the rational design of highly active and selective homogeneous catalytic systems, starting from easily available heterogeneous catalyst precursors.

Calcium carbide residue - a key inorganic component of the sustainable carbon cycle

Rodygin K.S., Gyrdymova Yu.V., Ananikov V.P., Russ. Chem. Rev., 2023, 91, RCR5048.
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The transfer of waste materials from the chemical industry to the building sector is an emerging area of sustainable development. Leftovers, by-products, tails and sludge from chemical processes may be valuable components of building mixtures. Feeding the construction industry by chemical wastes is a profitable chain for both sectors. In fact, calcium carbide residue (CCR) can be considered a link between the chemical industry and construction materials. Carbide sludge is the main waste product of acetylene gas production from calcium carbide. The released acetylene is actively used in the modern chemical industry. An alternative method of acetylene production — the cracking of oil and gas — is beyond sustainability; thus, the carbide route is more promising in the hydrocarbon-free future. However, the carbide route is accompanied by a significant amount of the side-product carbide sludge, which is currently used as a CO 2 capture agent, binder, building material, in inorganic synthesis, etc. In this review, the potential of carbide sludge in the construction industry and other areas is highlighted.

Metadynamics simulations of R–NHC reductive elimination in intermediate palladium complexes of cross-coupling and Mizoroki–Heck reactions

Kostyukovich A.Yu., Gordeev E.G., Ananikov V.P., Mendeleev Commun., 2023, ASAP.
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Exploring the free energy surface of the R–NHC coupling reaction in the key intermediates of the Mizoroki–Heck and cross-coupling catalytic cycles has been conducted by the methods of biased and unbiased molecular dynamics. Molecular dynamics simulations were carried out both in vacuum and in a polar solvent, with the following main observations on the influence of the media: (1) the solvent prevents the dissociation of the solvate ligand, so the R–NHC coupling proceeds in a four-coordination complex (rather than in a three-coordination one, as in the case of a gas-phase reaction); (2) in the condensed phase, the potential barrier of the reaction is significantly higher compared to the same process in vacuum (17.7 vs. 21.8 kcal mol-1); (3) polar solvent stabilizes the R–NHC coupling product. The reaction in a polar medium is exergonic (ΔG = −3.9 kcal mol-1), in contrast to the in vacuum modeling, where the process is endergonic (ΔG = 0.4 kcal mol-1).

Transformations of Pd/(N-Heterocyclic Carbene) Molecular Complexes into a Nanosized Catalyst System in the Mizoroki–Heck Reaction

Kostyukovich A.Yu., Patil E.D., Burykinа J.V., Ananikov V.P. , Kinet. Catal., 2023.
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