Reversible Radical Addition Guides Selective Photocatalytic Intermolecular Thiol-Yne-Ene Molecular Assembly

Shlapakov N.S., Kobelev A.D., Burykina J.V., Kostyukovich A.Yu., König B., Ananikov V. P., Angew. Chem. Int. Ed., 2024, e202314208.
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In the realm of modern organic chemistry, harnessing the power of multicomponent radical reactions presents both significant challenges and extraordinary potential. This article delves into this scientific frontier by addressing the critical issue of controlling selectivity in such complex processes. We introduce a novel approach that revolves around the reversible addition of thiyl radicals to multiple bonds, reshaping the landscape of multicomponent radical reactions. The key to selectivity lies in the intricate interplay between reversibility and the energy landscapes governing C-C bond formation in thiol-yne-ene reactions. The developed approach not only allows to prioritize the thiol-yne-ene cascade, dominating over alternative reactions, but also extends the scope of coupling products obtained from alkenes and alkynes of various structures and electron density distributions, regardless of their relative polarity difference, opening doors to more versatile synthetic possibilities. In the present study, we provide a powerful tool for atom-economical C-S and C-C bond formation, paving the way for the efficient synthesis of complex molecules. Carrying out our experimental and computational studies, we elucidated the fundamental mechanisms underlying radical cascades, a knowledge that can be broadly applied in the field of organic chemistry.

4D Catalysis Concept Enabled by Multilevel Data Collection and Machine Learning Analysis

Galushko A.S., Ananikov V.P., ACS Catal., 2024, 14, 161-175.
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The influence of catalysis on the development of modern science and industry cannot be overestimated. Production of pharmaceutical substances and drugs, the oil industry, developments in the field of ecology and material science, and many other areas with a great impact on the world economy are progressing through the active use of catalysts. In the almost two hundred years that have passed since the description of the phenomenon of catalysis, the understanding of the principle of operation of catalysts has developed to a very high degree. Initially, it was assumed that the catalyst remains unchanged in the reaction in which it participates, while it is now well established that catalysis is a dynamic phenomenon in many systems. Catalytically active particles change as the catalyzed reaction proceeds and pass from one phase to another, which often leads to significant changes in catalytic activity and selectivity. In many cases, uncontrolled dynamic changes in the catalytic system lead to degradation and a loss of activity and selectivity. Understanding the mechanisms of the dynamic nature of active centers is very important for designing highly active catalysts, which in turn will have a positive impact on the environment, industry, economics, and numerous other areas.

Recent Trends in Supercapacitor Research: Sustainability in Energy and Materials

Chernysheva D., Smirnova N., Ananikov V.P. , ChemSusChem, 2024, 16, e202301367.
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Supercapacitors (SCs) have emerged as critical components in applications ranging from transport to wearable electronics due to their rapid charge-discharge cycles, high power density, and reliability. This review offers an analysis of recent strides in supercapacitor research, emphasizing pivotal developments in sustainability, electrode materials, electrolytes, and 'smart SCs' designed for modern microelectronics with attributes such as flexibility, stretchability, and biocompatibility. Central to this discourse are two dominant electrode materials: carbon materials (CMs), primarily in Electric Double Layer Capacitors (EDLCs), and pseudocapacitive materials, involving oxides/hydroxides, chalcogenides, metal-organic frameworks, conductive polymers and metal nitrides such as MXene. Despite EDLCs' historical use, challenges such as low energy density persist, with heteroatom introduction into the carbon lattice posed as a solution. Concurrently, pseudocapacitive materials dominate recent studies, with efficiency enhancement strategies, such as the creation of hybrids based on different types of materials, surface structural engineering and doping, under exploration. Emphasis is given to smart SCs with novel attributes such as self-charging, self-healing, biocompatibility, and environmentally conscious designs. In summary, the article underscores the drive in sustainable supercapacitor research to achieve high energy and power density, steering towards SCs that are efficient and versatile and involving bioderived/biocompatible SC materials.

Aerobic bacteria-supported biohybrid palladium catalysts for efficient cross-coupling reactions

Rybochkin P.V., Perchikov R.N., Karlinskii B.Ya., Kamanina O.A., Arlyapov V.A., Kashin A.S., Ananikov V.P. , J. Cat., 2024, 429, 115238.
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Boosting the generality of catalytic systems by the synergetic ligand effect in Pd-catalyzed C-N cross-coupling

Grebennikov N.O., Boiko D.A., Prima D.O., Madiyeva M., Minyaev M.E., Ananikov V.P., J. Cat., 2024, 429, 115240.
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In the areas of catalysis and organic chemistry, the development of versatile and efficient catalytic systems has long been a challenge, primarily due to the intricate relationship between ligands and transition metal centers. This study addresses this challenge by exploring the concept of ligand synergy to enhance the generality of catalytic systems, a crucial metric for their practical utility. By combining N-heterocyclic carbene (NHC) and phosphine ligands, we unveil a novel catalytic system that exhibits high level of generality in the Buchwald-Hartwig cross-coupling reaction. Our findings not only demonstrate the enhanced efficiency of this system, leading to the synthesis of valuable compounds with applications in organic electroluminescent devices and the pharmaceutical industry, but also shed light on the broader potential of ligand synergy in catalysis. Through machine learning analysis, we uncover the critical role of specific ligand properties, further paving the way for rational catalyst design.

Unraveling the transformative pathways of Au-NHC and Au-alkynyl complexes and bridging the gap between molecular and nanoscale gold systems

Grudova M.V., Galushko A.S., Ilyushenkova V.V., Minyaev M.E., Fakhrutdinov A.N., Prima D.O., Ananikov V.P., Inorg. Chem. Front., 2024, ASAP.
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The aim of the present study was to explore the transformations of heteroleptic and homoleptic Au( I) complexes in detail and to systematically map their chemical evolutionary pathways. The relationships between these Au(I) complexes and the formation of gold nanoparticles and between the leaching processes of Au species from nanoparticles by NHC carbenes were studied. Moreover, Au-based reaction systems exhibit a wide variety of gold complexes and metallic gold particles depending on the conditions. The evolutionary pathways and transformations of homoleptic and heteroleptic Au(I) complexes were mapped using NMR, ESI-HRMS and electron microscopy. Depending on the conditions, a diverse range of metallic gold nanoparticles was formed. Interestingly, the formation of an NHC-Au(I) complex during the leaching of Au species from metallic nanoparticles in the presence of NHC carbenes was also noted. Our findings illustrate that the composition of Au-based reaction systems can simultaneously include various gold complexes and gold particles, reinforcing the potential of gold complexes to activate and transform molecules in a variety of reactions. By studying and understanding the physical and chemical properties of NHC-Au(I) complexes and the transformations they undergo under various conditions, we provide new opportunities for future research using gold-based systems for the development of dynamic catalytic systems.

Base-Ionizable Anionic NHC Ligands in Pd-catalyzed Reactions of Aryl Chlorides

Chernenko A., Baydikova V., Kutyrev V., Astakhov A., Minyaev M., Chernyshev V., Ananikov V. P. , ChemCatChem, 2024, e202301471.
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Aryl chlorides, due to their affordability and accessibility, are preferred reagents in Pd-catalyzed arylation reactions. However, the reactivity of aryl chlorides is often reduced compared to aryl bromides and iodides due to the significantly higher barriers of the oxidative addition stage. This research introduces a novel design for NHC ligands, which notably enhances the efficiency of Pd/NHC catalytic systems in reactions where oxidative addition of aryl chloride is the rate-limiting step. This design leverages a synergy between specific steric characteristics and the anionic nature of the newly fashioned 1,2,4-triazol-5-ylidene ligands. These ligands, inspired by Nitron-type designs, can be ionized under basic conditions due to their NH-acidic aryl(alkyl)amino groups. Detailed experimental and DFT studies revealed that the deprotonation of these NHCs promotes electron donation to the metal center, promoting the oxidative addition of aryl chloride. The specially optimized ATPr ligand, featuring 2,6-diisopropylphenyl groups, displayed remarkable catalytic efficacy in the Suzuki-Miyaura reaction and improved outcomes in ketone α-arylation and Buchwald-Hartwig reactions with unactivated aryl chlorides. The insights and strategies established in this study provide rational considerations for further advancements in NHC designs and their applications in metal-catalyzed reactions.

Mechanistic Insight into Palladium-Catalyzed Asymmetric Alkylation of Indoles with Diazoesters Employing Bipyridine-N,N’-dioxides as Chiral Controllers

Fukazawa Ya., Vaganov V.Yu., Burykina J.V., Fakhrutdinov A.N., Safiullin R.I., Plasser F., Rubtsov A.E., Ananikov V.P., Malkov A.V. , Adv.Synth.Catal., 2024, 366, 121-133.
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Metal-catalyzed asymmetric alkylation of indoles with α-diazoesters is well-known, however, the underlying mechanisms of this reaction, particularly the origin of stereoselectivity, remain uncertain. For the Pd catalysis, we address this cutting-edge challenge from two complementary viewpoints – i) the molecular level regarding a single catalytically active Pd center; and ii) nano-level Pd species investigating the factors favoring the appearance of the preferred catalytic centers. The formation of the active catalytic species was monitored by structural methods (NMR and ESI-MS), and metal particles were characterized with electron microscopy (SEM, EDX). On the molecular level, chiral bipyridine-N,N'-dioxides proved to be competent chiral controllers. The kinetic and DFT computational data revealed a crucial role of water in the rate and selectivity determining steps and showed that the enantioselectivity of the process is controlled by the protodepalladation step. On the nano-scale, the important effect of catalyst precursor on the overall reaction performance was shown.

Comparative Study of Pd-Mediated Carbon−Carbon, Carbon−Heteroatom, and Heteroatom−Heteroatom Bond Formation/Breakage (C = Csp3, Csp2, Csp; X = B, N, O, Si, P, S, Se, Te)

Gordeev E.G., Musaev D.G., Ananikov V.P., Organometallics, 2024, 43, 1-13.
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Carbon–carbon and carbon–heteroatom bond formations via direct reductive elimination as one of the possible mechanisms of reductive elimination in Pd(II) complexes are the key stages of catalytic processes in fine organic synthesis. For the (R)2Pd(L)2, (X)2Pd(L)2 and (R)(X)Pd(L)2 complexes (where R = Me, Vin, Ph, or Eth; X = B, N, O, Si, P, S, Se, or Te; L = PPh3), the R–R, R–X, and X–X bond formation barriers and reaction energies were calculated. The reaction barriers for C–C and C–X coupling decrease in the series Csp3 > Csp > Csp2. The activity of coupling groups X containing a heteroatom decreases in the series of heteroatoms P, S, Se ≫ N ≫ O (for Csp2 and Csp types of carbon centers) and P > S, Se ≫ N ≫ O (for Csp3 type of carbon center). The relationship between the structural lability of the (R)2Pd(L)2 complexes and the probability of reductive elimination was determined by DFT molecular dynamics. An analysis of the calculated bond formation barriers and reaction energy showed that, in most cases, their values for unsymmetrical RX coupling are intermediate between the values for the reactions of symmetrical RR and XX coupling. The influence of the electronic properties of the coupling groups on the stabilization of the cis form of the complexes, which are suitable pre-reaction complexes for reductive elimination, was shown. The additivity of the energy difference between the cis and trans isomers was established: the cis–trans isomerization energies for the (R)(X)Pd(L)2 complexes are intermediate between the corresponding energies for the (R)2Pd(L)2 and (X)2Pd(L)2 complexes. A high degree of additivity of the QTAIM charge of the palladium atom in all of the considered complexes was analyzed. In the present detailed study, we establish a hierarchy in bond formation barriers, emphasizing the influence of carbon center types, and discern the impact of coupling groups containing heteroatoms, revealing distinct trends based on carbon center types.

Assembly of (2×C2+C`2)×n Molecular Complexity Using a Sequence of Pt‑ and Pd-Catalyzed Transformations with Calcium Carbide

Potorochenko A.N., Rodygin K.S., Ananikov V. P., Eur. J. Org. Chem., 2024, e202301012.
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Constructing molecular complexity from simple precursors stands as a cornerstone in contemporary organic synthesis. Systems harnessing easily accessible starting materials, which offer control over stereochemistry and support a modular assembly approach, are particularly in demand. In this research, we utilized calcium carbide, presenting a sustainable pathway to generate acetylene gas - a fundamental C2 building block. We performed a Pt-facilitated linkage of two C2-units sourced from two calcium carbide molecules to craft a conjugated C4 core with exceptional stereoselectivity. As a benchmark, we selected the synthesis of (E,E)-1,4-diiodobuta-1,3-diene, executing it in a two-chamber reactor. Compartmentalization of the reactions across these chambers resulted in the desired product in 85% yield. Furthermore, highenergy polymeric substances were derived by marrying the molecular intricacy between (E,E)-1,4-diiodobuta-1,3-diene and calcium carbide, underpinning a unique C4 + C2 assembly blueprint. The structure and morphology of the polymeric material were characterized by IR and NMR spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Overall, two complementary 2×C2-to-C4 and (2×C2+C`2)×n assembly schemes were developed using Pt and Pd catalysis.