Journal articles on the topic 'Alkenes – Synthesis; Metal catalysts; Complex compounds'
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1
Selvi, E. Thamarai, G. Kavinilavu, and A. Subramani. "Recent Advances Review on Iron Complexes as Catalyst in Oxidation Reactions of Organic Compounds." Asian Journal of Chemistry 34, no. 8 (2022): 1921–38. http://dx.doi.org/10.14233/ajchem.2022.23704.
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The complexes of iron are found to be too reactive and are too diverse in their reactivity, when compared to the other neighbouring metals in the group. Iron complexes are used in various catalytic reactions such as oxygenation of C–H bonds, the oxidation of alcohols to aldehydes, ketones (or) carboxylic acids, the epoxidation or dihydroxylation of alkenes and oxidative coupling reactions. Efforts are taken to avoid certain disadvantages taking place during enzymatic catalysis such as the temperature and solvent sensitivity, narrow substrate scope, restricted accessibility and so on observed while using other catalysts via iron enzymes. This helped in the various synthesis of complex molecules by increase in the number of iron catalyst systems for the oxidation reactions.
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Moskalik, Mikhail Y., and Vera V. Astakhova. "Triflamides and Triflimides: Synthesis and Applications." Molecules 27, no. 16 (August 15, 2022): 5201. http://dx.doi.org/10.3390/molecules27165201.
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Among the variety of sulfonamides, triflamides (CF3SO2NHR, TfNHR) occupy a special position in organic chemistry. Triflamides are widely used as reagents, efficient catalysts or additives in numerous reactions. The reasons for the widespread use of these compounds are their high NH-acidity, lipophilicity, catalytic activity and specific chemical properties. Their strong electron-withdrawing properties and low nucleophilicity, combined with their high NH-acidity, makes it possible to use triflamides in a vast variety of organic reactions. This review is devoted to the synthesis and use of N-trifluoromethanesulfonyl derivatives in organic chemistry, medicine, biochemistry, catalysis and agriculture. Part of the work is a review of areas and examples of the use of bis(trifluoromethanesulfonyl)imide (triflimide, (CF3SO2)2NH, Tf2NH). Being one of the strongest NH-acids, triflimide, and especially its salts, are widely used as catalysts in cycloaddition reactions, Friedel–Crafts reactions, condensation reactions, heterocyclization and many others. Triflamides act as a source of nitrogen in C-amination (sulfonamidation) reactions, the products of which are useful building blocks in organic synthesis, catalysts and ligands in metal complex catalysis, and have found applications in medicine. The addition reactions of triflamide in the presence of oxidizing agents to alkenes and dienes are considered separately.
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Su, Xiang, Panpan Wu, Wenfeng Liu, and Chao Chen. "A concise synthesis of indene-based polycyclic compounds via FeCl3-catalyzed cascade cyclization." Organic Chemistry Frontiers 5, no. 7 (2018): 1165–69. http://dx.doi.org/10.1039/c8qo00004b.
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An efficient and straightforward protocol to complex indene-based polycyclic compounds via the cascade cyclization of propargylic alcohols and alkenes was developed. The catalyst FeCl3, as an Earth-abundant and environment friendly transition metal salt, is attractive. This reaction proceeded through unusual C–C bond cleavage.
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Zykova, A. "Synthesis and Structure of Aryl Phosphorus Compounds." Bulletin of the South Ural State University series "Chemistry" 12, no. 4 (2020): 5–50. http://dx.doi.org/10.14529/chem200401.
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Based on an analysis of the literature published from the late 20th century to the beginning of the 21st century, methods for the synthesis of some complex tetraorganylphosphonium salts are systematized and described, along with the features of the chemical transformations of pentaphenylphosphorus, which was first obtained in 1953. The tetraorganylphosphonium salts were known much earlier, however, the features of the synthesis of transition metal complexes, which are usually obtained from tetraorganylphosphorus halides and metal halides, have not been sufficiently studied. The present review is devoted to the discussion of these topics, since the famous Wittig Reaction is associated with aryl phosphorus compounds, which allows synthesizing alkenes of a given structure, and derivatives of transition metals rightfully occupy a special place among catalysts of various chemical processes. The continuation of these classical studies in the field of chemistry of organoelemental compounds takes place at one of the leading universities in Russia - South Ural State University in the laboratory of chemistry of organoelemental compounds at the Faculty of Chemistry. This article aims at familiarizing the reader with the achievements of Professor V.V. Sharutin and his students in the field of organophosphorus compounds. The main attention is paid to the reactions of pentaphenylphosphorus and its derivatives, as well as methods for the synthesis of ionic complexes of silver, gold, copper, titanium, zirconium, hafnium, ruthenium, osmium, cobalt, rhodium, iridium, palladium and platinum with tetraorganylphosphonium cations. The structural features of the described compounds and the possibility of using transition metal complexes in some catalytic reactions are described.
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Lapshin, Ivan V., Alexander A. Kissel, and Alexander A. Trifonov. "Complexes of Rare- and Alkaline-Earth Elements in Catalytic Intermolecular Hydrophosphination of Multiple C—C Bonds." Vestnik RFFI, no. 2 (June 25, 2019): 58–73. http://dx.doi.org/10.22204/2410-4639-2019-102-02-58-73.
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In accordance with United Nations General Assembly resolution, the year 2019 was proclaimed the International Year of the Periodic Table of Chemical Elements. Rare-earth elements were discovered during the time of the Periodic System development. In the past few decades, their compounds have attracted great interest due to their unique reactivity. This review covers recent achievements in the field of intermolecular hydrophosphination of alkenes, dienes and alkynes, which is catalyzed by rare earth and alkaline-earth metal complexes. Catalytic hydrophosphination reaction is the addition of an P—H bond to С—С multiple bonds, and offers an efficient and elegant synthetic approach to production of the organophosphorus compounds widely used in industrial synthesis, pharmaceuticals, agrochemistry, and other areas. The high values of the ionic radii of rare earth and alkaline-earth metals in combination with the Lewis acidity provide their compounds with a pronounced tendency to complex formation and, accordingly, high coordination numbers. Due to high reactivity of M—E (E = C, H, N, P) bonds, ease of Ln—P ı-bond metathesis and multiple C—C bond insertions, these compounds offer new prospects for the catalysis of the alkenes and alkynes hydrophosphination. Therefore, complexes of non-toxic and relatively abundant in nature rare earth and alkaline earth metals can be a cheaper and more effective alternative to compounds of late transition metals in the catalysis of the C—P bond formation.
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Forchetta, Mattia, Francesca Valentini, Valeria Conte, Pierluca Galloni, and Federica Sabuzi. "Photocatalyzed Oxygenation Reactions with Organic Dyes: State of the Art and Future Perspectives." Catalysts 13, no. 2 (January 18, 2023): 220. http://dx.doi.org/10.3390/catal13020220.
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Oxygen atom incorporation into organic molecules is one of the most powerful strategies to increase their pharmacological activity and to obtain valuable intermediates in organic synthesis. Traditional oxidizing agents perform very well, but their environmental impact and their low selectivity constitute significant limitations. On the contrary, visible-light-promoted oxygenations represent a sustainable method for oxidizing organic compounds, since only molecular oxygen and a photocatalyst are required. Therefore, photocatalytic oxygenation reactions exhibit very high atom-economy and eco-compatibility. This mini-review collects and analyzes the most recent literature on organo-photocatalysis applications to promote the selective oxygenation of organic substrates. In particular, acridinium salts, Eosin Y, Rose Bengal, cyano-arenes, flavinium salts, and quinone-based dyes are widely used as photocatalysts in several organic transformations as the oxygenations of alkanes, alkenes, alkynes, aromatic compounds, amines, phosphines, silanes, and thioethers. In this context, organo-photocatalysts proved to be highly efficient in catalytic terms, showing similar or even superior performances with respect to their metal-based counterparts, while maintaining a low environmental impact. In addition, given the mild reaction conditions, visible-light-promoted photo-oxygenation processes often display remarkable selectivity, which is a striking feature for the late-stage functionalization of complex organic molecules.
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Daoust, Benoit, Nicolas Gilbert, Paméla Casault, François Ladouceur, and Simon Ricard. "1,2-Dihaloalkenes in Metal-Catalyzed Reactions." Synthesis 50, no. 16 (July 9, 2018): 3087–113. http://dx.doi.org/10.1055/s-0037-1610174.
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1,2-Dihaloalkenes readily undergo simultaneous or sequential difunctionalization through transition-metal-catalyzed reactions, which makes them attractive building blocks for complex unsaturated motifs. This review summarizes recent applications of such transformations in C–C and C–heteroatom bond forming processes. The facile synthesis of stereodefined alkene derivatives, as well as aromatic and heteroatomic compounds, from 1,2-dihaloalkenes is thus outlined.1 Introduction2 Synthesis of 1,2-Dihaloalkenes3 C–C Bond Forming Reactions4 C–Heteroatom Bond Forming Reactions5 Conclusion
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Aghahuseynova, Minira. "SYNTHESIS AND PROPERTIES OF METAL-COMPLEX CATALYSTS BASED ON OIL METALLOPORPHYRINS." EUREKA: Physics and Engineering 4 (July 31, 2020): 19–28. http://dx.doi.org/10.21303/2461-4262.2020.001356.
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The study of the properties and use of natural metalloporphyrins in the development of new highly selective methods for the oxygenation of hydrocarbons at moderate temperatures is an urgent problem. The present work is devoted to the extraction of metalloporphyrins from oil residues and the creation on their basis of effective catalytic systems for the oxidation of alkenes. The separation of metalloporphyrins from oil residues was carried out using new bifunctional organic extractants having the nature of keto-alcohols and providing a greater degree of extraction of porphyrins in comparison with the known traditionally used extractants. The results of a study of a number of new bifunctional organic reagents as extractants for the selective extraction of oil porphyrins from asphaltenes are presented, their spectral characteristics are studied, the dependence of the degree of extraction on the mass ratio of the extractant and the crude oil is revealed. The best results were obtained with a mass ratio of 1:30. The isolated mixture of metalloporphyrins is first subjected to demetallization with hydrochloric acid (pH=1–2), turning into a mixture of porphyrins, then, to obtain individual metal porphyrin complexes, the required transition metal ions are introduced into the porphyrin ring by treating the mixture with these metal salts. It was shown that the yield of synthesized oil porphyrins is 42–85 %, depending on the nature of the metal. The composition and structure of the synthesized oil metalloporphyrins containing iron, cobalt, nickel, manganese are established by modern methods of physico-chemical analysis. The catalytic properties of synthesized metalloporphyrins in the epoxidation of unsaturated alkenes have been investigated. Their dioxide adducts were obtained, and a mechanism was proposed for the oxidation of alkenes with the formation of oxinoid structures as a result of the decomposition of the oxygen complexes of metal porphyrins
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Yoshimura, Tomoyuki, Yuki Enami, and Jun-ichi Matsuo. "Asymmetric Synthesis of a Bicyclo[4.3.0]nonene Derivative Bearing a Quaternary Carbon Stereocenter: Desymmetrization of σ-Symmetrical Diketones through Intramolecular Addition of an Alkenyl Anion." Synthesis 52, no. 23 (August 20, 2020): 3667–74. http://dx.doi.org/10.1055/s-0040-1706421.
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The enantioselective synthesis of a bicyclo[4.3.0]nonene derivative bearing a quaternary carbon stereocenter is achieved by employing a desymmetrization strategy involving an intramolecular addition. The intramolecular nucleophilic addition of a highly reactive carbanion generated from an alkenyl iodide in the presence of a chiral ligand occurs with discrimination of two keto carbonyl groups to give the corresponding bicyclic compound in 81% yield and 39% ee. Asymmetric synthesis via an intramolecular desymmetrization strategy using a chiral ligand–carbanion complex represents a complementary approach to using chiral organocatalysts or chiral ligand–transition-metal complexes.
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Gyamfi, Abigail Owusuwaa, Martin Amponsah Yeboah, Richard Tia, and Evans Adei. "Computational study on the mechanism of transition metal-catalyzed formation of highly substituted furo [3,4-d] [1,2] oxazines." Journal of Theoretical and Computational Chemistry 17, no. 01 (February 2018): 1850011. http://dx.doi.org/10.1142/s0219633618500116.
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The mechanism of gold(III)-catalyzed 1,3-dipolar [[Formula: see text]] cycloaddition reactions of 2-(1-alkynyl)-2-alken-1-ones with nitrones to afford highly-substituted furo [3,4-d] [1,2] oxazines, which are useful as structural skeletons in biologically active compounds and as synthetic building blocks in organic synthesis, have been studied computationally. The results show that the reaction proceeds via the formation of a [Formula: see text]-complex in which the gold moiety coordinates to the triple bond of the 2-(1-alkynyl)-2-alken-1-ones, resulting in an intramolecular cyclization of the gold intermediate to generate a carbocation intermediate which is trapped by the nucleophilic oxygen of the nitrone to form a furanyl–gold complex, which upon subsequent cyclization affords the furo [3,4-d] [1,2] oxazine as well as regenerates the gold catalyst. The highest activation barrier in the entire cycle is 19.5[Formula: see text]kcal/mol which accompanies the intramolecular cyclization step. The activation barriers for the reactions of 2-(1-alkynyl)2-alken-1-ones with electron-donating and cyclic substituents are generally lower compared to those of the parent 2-(1-alkynyl)2-alken-1-one while the reactions of 2-(1-alkynyl)2-alken-1-ones with electron-withdrawing substituents have higher activation barriers. Preliminary exploratory calculations on the possibility of replacing gold, an expensive and rare metal, with a copper-based catalyst for the reaction, show that for the key elementary steps, the Cu (III) catalyst is at least as active as the Au (III) complex, thus providing a cheaper route to furo [3,4-d] [1,2] oxazine.
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Ding, Shengtao, and Weiwei Gao. "Progress on Iridium-Catalyzed Hydrosilylation of Alkenes and Alkynes." Synthesis 52, no. 23 (August 18, 2020): 3549–63. http://dx.doi.org/10.1055/s-0040-1707239.
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Hydrosilylation of multiple carbon–carbon bonds is a well-known process for the construction of organosilicon compounds. Nowadays, precious metal catalysts, especially platinum complexes, still occupy dominant positions in such processes. However, one important member of the precious metal family, iridium, is less used in this field. As early research mainly focused on developing stable and effective iridium catalysts, recent advances have disclosed the specific efficiency of simple iridium catalytic systems in the synthesis of functional organosilicon compounds. This short review summarizes the utilization of iridium complexes for the hydrosilylation of alkenes and alkynes, with an emphasis on the recent advances published in the last decade.1 Introduction2 Iridium-Catalyzed Hydrosilylation of Alkenes3 Iridium-Catalyzed Hydrosilylation of Alkynes4 Conclusions and Perspectives
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Dzhemilev, U. M., R. I. Khusnutdinov, and G. A. Tolstikov. "Synthesis of cyclobutane and cyclopentane compounds using homogeneous metal complex catalysts." Journal of Organometallic Chemistry 409, no. 1-2 (May 1991): 15–65. http://dx.doi.org/10.1016/0022-328x(91)86131-9.
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DZHEMILEV, U. M., R. I. KHUSNUTDINOV, and G. A. TOLSTIKOV. "ChemInform Abstract: Synthesis of Cyclobutane and Cyclopentane Compounds Using Homogeneous Metal Complex Catalysts." ChemInform 22, no. 34 (August 22, 2010): no. http://dx.doi.org/10.1002/chin.199134289.
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Mebs, Stefan, Sabrina Imke Kalläne, and Thomas Braun. "Hapticity of asymmetric rhodium-allyl compounds in the light of real-space bonding indicators." Zeitschrift für Kristallographie - Crystalline Materials 233, no. 9-10 (September 25, 2018): 615–26. http://dx.doi.org/10.1515/zkri-2017-2141.
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Abstract Rhodium boryl complexes are valuable catalysts for hydro- or diboration reactions of alkenes, but can also react with ketones (R2C=O) and imines (R2C=NR′) giving rise to insertion products having formally Rh–R2C–O/NR′–B linkages. The resulting molecular structures, however, may show complex metal–ligand and ligand–ligand interaction patterns with often unclear metal–ligand connectivities (hapticities, ηn). In order to assign the correct hapticity in a set of asymmetric rhodium-allyl compounds with molecular structures indicating η1−5 bonding, a comprehensive DFT study was conducted. The study comprises determination of a variety of real-space bonding indicators derived from computed electron and pair densities according to the AIM, ELI-D, NCI, and DORI topological and surface approaches, which uncover the metal–ligand connectivties and suggest an asymmetric ligand–metal donation/metal–ligand back-donation framework according to the Dewar–Chatt–Duncanson model.
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Arisawa, Mieko, and Masahiko Yamaguchi. "Rhodium-Catalyzed Synthesis of Organosulfur Compounds using Sulfur." Synlett 30, no. 14 (July 2, 2019): 1621–31. http://dx.doi.org/10.1055/s-0037-1611867.
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Sulfur is one of the few elements that occurs uncombined in nature. Sulfur atoms are found in natural amino acids and vitamins. In the chemical industry, organosulfur compounds are used for fabricating rubber, fibers, and dyes, pharmaceuticals, and pesticides. Although sulfur, which is cheap and easy to handle, is a useful source of sulfur atom in functional organosulfur compounds, it is rarely used in organic synthesis. Activation of sulfur by high temperature, light irradiation, treatment with nucleophiles and electrophiles, and redox conditions often results in the formation of various active sulfur species, which complicate reactions. The development of a method that mildly activates sulfur is therefore desired. The use of transition-metal catalysts is a new method of activating sulfur under mild conditions, and, in this article, we describe the rhodium-catalyzed synthesis of various organosulfur compounds by the insertion of sulfur atoms into single bonds and by the addition of sulfur to unsaturated bond in various organic compounds.1 Introduction2 Sulfur Activation without using Transition Metal3 Transition-Metal-Catalyzed Activation of Sulfur4 Rhodium-Catalyzed Reactions using Sulfur4.1 Rhodium-Catalyzed Sulfur Atom Exchange Reactions using Sulfur4.2 Synthesis of Diaryl Sulfides using Rhodium-Catalyzed Exchange Reaction of Aryl Fluorides and Sulfur/Organopolysulfides4.3 Rhodium-Catalyzed Synthesis of Isothiocyanate using Sulfur4.4 Rhodium-Catalyzed Sulfur Addition Reaction to Alkenes for Thiiranes Synthesis4.5 Rhodium-Catalyzed Sulfur Addition Reaction to Alkynes for 1,4-Dithiins Synthesis5 Conclusion
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Shul’pin, Georgiy B., and Lidia S. Shul’pina. "Oxidation of Organic Compounds with Peroxides Catalyzed by Polynuclear Metal Compounds." Catalysts 11, no. 2 (January 31, 2021): 186. http://dx.doi.org/10.3390/catal11020186.
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The review describes articles that provide data on the synthesis and study of the properties of catalysts for the oxidation of alkanes, olefins, and alcohols. These catalysts are polynuclear complexes of iron, copper, osmium, nickel, manganese, cobalt, vanadium. Such complexes for example are: [Fe2(HPTB)(m-OH)(NO3)2](NO3)2·CH3OH·2H2O, where HPTB-¼N,N,N0,N0-tetrakis(2-benzimidazolylmethyl)-2-hydroxo-1,3-diaminopropane; complex [(PhSiO1,5)6]2[CuO]4[NaO0.5]4[dppmO2]2, where dppm-1,1-bis(diphenylphosphino)methane; (2,3-η-1,4-diphenylbut-2-en-1,4-dione)undecacarbonyl triangulotriosmium; phenylsilsesquioxane [(PhSiO1.5)10(CoO)5(NaOH)]; bi- and tri-nuclear oxidovanadium(V) complexes [{VO(OEt)(EtOH)}2(L2)] and [{VO(OMe)(H2O)}3(L3)]·2H2O (L2 = bis(2-hydroxybenzylidene)terephthalohydrazide and L3 = tris(2-hydroxybenzylidene)benzene-1,3,5-tricarbohydrazide); [Mn2L2O3][PF6]2 (L = 1,4,7-trimethyl-1,4,7-triazacyclononane). For comparison, articles are introduced describing catalysts for the oxidation of alkanes and alcohols with peroxides, which are simple metal salts or mononuclear metal complexes. In many cases, polynuclear complexes exhibit higher activity compared to mononuclear complexes and exhibit increased regioselectivity, for example, in the oxidation of linear alkanes. The review contains a description of some of the mechanisms of catalytic reactions. Additionally presented are articles comparing the rates of oxidation of solvents and substrates under oxidizing conditions for various catalyst structures, which allows researchers to conclude about the nature of the oxidizing species. This review is focused on recent works, as well as review articles and own original studies of the authors.
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Hall, Dennis G., Jack C. H. Lee, and Jinyue Ding. "Catalytic enantioselective transformations of borylated substrates: Preparation and synthetic applications of chiral alkylboronates." Pure and Applied Chemistry 84, no. 11 (June 8, 2012): 2263–77. http://dx.doi.org/10.1351/pac-con-12-02-04.
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Organoboronic acid derivatives are well-established intermediates for the preparation of alcohols and amines, and in the formation of C–C bonds via different reactions, including homologations, carbonyl allylboration, or transition-metal-catalyzed cross-coupling chemistry. In the past decade, there has been great interest in the development of catalytic enantioselective methods for the preparation of chiral, optically enriched organoboronates as precursors of enantioenriched compounds. While the mainstream strategy remains the late-stage borylation of organic functional groups, our group has focused on an alternate strategy focused on modification of boron-containing substrates. In this way, acyclic and cyclic secondary alkyl- and allyl-boronates were prepared through catalytic enantioselective processes such as [4 + 2] cycloadditions, isomerizations, allylic substitutions, and conjugate additions. The resulting optically enriched boronates have been successfully utilized in the syntheses of complex natural products and drugs. One remaining challenge in the chemistry of secondary alkylboronate derivatives is their cross-coupling, especially with control of stereoselectivity. In this regard, our recent approach featured the conjugate asymmetric borylation of β-boronyl acrylates, providing the first enantioselective preparation of highly optically enriched 1,1-diboronyl derivatives. The chirality of these geminal diboron compounds is conferred through the use of two distinct boronate adducts, which can be coupled chemo- and stereoselectively with a variety of aryl and alkenyl halides under palladium catalysis.
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Mai, Juri, and Sascha Ott. "The Fascinating World of Phosphanylphosphonates: From Acetylenic Phosphaalkenes to Reductive Aldehyde Couplings." Synlett 30, no. 16 (August 13, 2019): 1867–85. http://dx.doi.org/10.1055/s-0039-1690129.
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This account highlights the versatility of phosphanylphosphonates, which can be used for the preparation of phosphorus-containing π-systems and as reagents for the reductive coupling of carbonyl compounds to alkenes. Phosphanylphosphonates with metal fragments coordinated to the P-lone pair have been known for a long time and they have been used for the synthesis of phosphaalkenes by means of the phospha-Horner–Wadsworth–Emmons reaction. With the original aim of incorporating phosphorus heteroatoms into classical all-carbon ethynylethene scaffolds, we entered the field of phosphanylphosphonates with the discovery that these compounds engage in complex cascade reactions with acetylenic ketones, forming 1,2-oxaphospholes, cumulenes, and bisphospholes. Later, we synthesized the first metal-free phosphanylphosphonate, which reacts with aldehydes to yield phosphaalkenes, but gives phospholones when diacetylenic ketones are used as substrates. In the final part of the account, we outline our discovery and the development of an unprecedented carbonyl–carbonyl cross-coupling reaction. This protocol offers a straightforward method for the synthesis of nonsymmetric 1,2-disubstituted alkenes directly from two dissimilar aldehydes.1 Combining Acetylenes with Phosphaalkenes2 Synthetic Examples of Acetylenic Phosphaalkenes3 The Phospha-Horner–Wadsworth–Emmons Approach to Phosphaalkenes3.1 Metal-Coordinated Phosphanylphosphonates3.2 Mechanism of the Phospha-Horner–Wadsworth–Emmons Reaction3.3 The First Metal-Free Phosphanylphosphonate and Its Reactivity with Aldehydes4 Reactions with Acetylenic Ketones4.1 Metal-Coordinated Phosphanylphosphonate and Monoacetylenic Ketones4.2 Metal-Coordinated Phosphanylphosphonate and Diacetylenic Ketones4.3 Metal-Free Phosphanylphosphonate and Diacetylenic Ketones5 Metal-Free Phosphanylphosphonate as a Coupling Reagent for Aldehydes6 E-Alkenes by the Reductive Coupling of Two Aldehydes7 Conclusions and Outlook
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Leigh, G. Jeffery, and John F. Nixon. "Michael Franz Lappert. 31 December 1928 — 28 March 2014." Biographical Memoirs of Fellows of the Royal Society 62 (January 2016): 277–98. http://dx.doi.org/10.1098/rsbm.2016.0014.
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Michael Lappert was one of the giants of twentieth-century organometallic chemistry. His research, carried out over six decades and leading to about 800 publications, had a profound and influential effect on the field, and his contributions covered almost every block of the Periodic Table. His early reputation was established by his extensive studies in boron chemistry exemplified by the reports of BCl 4 − , BN cyclobutadiene analogues, triborylamines, BCl 3 -catalysed ortho -Claisen rearrangements and evidence for restricted rotation about the B–N bond in aminoboranes. He had a lifelong interest in amides, including those of carbon, and especially electron-rich olefins, which remarkably were the ready source of numerous transition-metal carbene complexes. The last could also be obtained directly from the Vilsmeier reagent. He was the first to show that a carbene complex may act as an initiator of olefin metathesis. Later interests concerned the syntheses of new types of compound from all blocks of the Periodic Table driven by his imaginative use of new types of ligand (either sterically crowded or having no β-hydrogen atoms, often including SiMe 3 or Bu t substituents to confer lipophilicity). The use of CH n SiMe (3− n ) ( n = 0, 1 or 2) to stabilize transition-metal alkyl compounds was a major advance, because at the time stable homoleptic (a term he introduced) transition-metal alkyl compounds were unknown. He showed that the −CH(SiMe 3 ) 2 ligand could stabilize both low-coordinate transition metal and lanthanide compounds. Similarly, carbene analogues of the Main Group 14 elements germanium, tin and lead were obtained. Surprisingly in the solid state, these species were weakly dimerized (for example R 2 Sn=SnR 2 ), and unexpectedly exhibited a pyramidalized geometry at the heavy element. The latter had very significant bonding implications, because it differed fundamentally from the well-known planar structure of the corresponding alkenes. The first persistent or stable paramagnetic heavier Main Group element species MR 2 (M = P or As) and MR 3 (M = Ge or Sn) were also obtained while parallel work using −N(SiMe 3 ) 2 resulted in the corresponding Main Group amido derivatives. Other lipophilic ligands, such as β-diketiminates, were also widely used, as were bulky aryloxo and thiolato ligands, to obtain stable low-coordinate Main Group species. The first examples of d- and f-block species containing bridging alkyl groups were described. Those who worked with him cited his vast knowledge and supportive low-key advisory style, which ensured a contented and productive laboratory atmosphere. In addition to his scientific work, he was deeply interested in opera, literature and the theatre, about which he could talk knowledgeably.
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Malinowski, Jacek, Dominika Zych, Dagmara Jacewicz, Barbara Gawdzik, and Joanna Drzeżdżon. "Application of Coordination Compounds with Transition Metal Ions in the Chemical Industry—A Review." International Journal of Molecular Sciences 21, no. 15 (July 30, 2020): 5443. http://dx.doi.org/10.3390/ijms21155443.
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This publication presents the new trends and opportunities for further development of coordination compounds used in the chemical industry. The review describes the influence of various physicochemical factors regarding the coordination relationship (for example, steric hindrance, electron density, complex geometry, ligand), which condition technological processes. Coordination compounds are catalysts in technological processes used during organic synthesis, for example: Oxidation reactions, hydroformylation process, hydrogenation reaction, hydrocyanation process. In this article, we pointed out the possibilities of using complex compounds in catalysis, and we noticed what further research should be undertaken for this purpose.
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Trofimov, Boris, Nina Gusarova, and Nataliya Chernysheva. "Catalyst- and Solvent-Free Addition of the P–H Species to Alkenes and Alkynes: A Green Methodology for C–P Bond Formation." Synthesis 49, no. 21 (August 28, 2017): 4783–807. http://dx.doi.org/10.1055/s-0036-1588542.
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Traditional methods for C–P bond formation via direct addition of P–H species to unsaturated compounds are usually implemented in the presence of base and metal catalysts or radical initiators in various organic solvents. During the last five years, a novel efficient and general catalyst/initiator- and solvent-free version of the hydrophosphination and hydrophosphinylation of multiple C–C bonds with H-phosphines and their chalcogenides has begun to develop and it is attracting growing attention. This approach corresponds to the recently emerged pot-, atom-, and step-economy (PASE) green paradigm. This review covers the literature on the synthesis of useful and in-demand organophosphorus compounds via catalyst- and solvent-free addition of P–H species to alkenes and alkynes.1 Introduction2 Addition of Secondary Phosphines to Alkenes3 Hydrophosphinylation of Alkenes with Secondary Phosphine Chalcogenides3.1 Oxidative Addition of Phosphine Oxides to Vinyl Sulfides3.2 Addition of Secondary Phosphine Sulfides and Phosphine Selenides to Alkenes3.3 Addition of Secondary Phosphine Sulfides and Phosphine Selenides to Divinyl Chalcogenides3.4 Hydrophosphinylation of Alkenes with Secondary Phosphine/Chalcogen Pair (Three-Component Reactions)4 Addition of Secondary Phosphines to Alkynes5 Addition of Secondary Phosphine Chalcogenides to Alkynes6 Conclusion
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Hanf, Schirin, Carlos Lizandara-Pueyo, Timo Philipp Emmert, Ivana Jevtovikj, Roger Gläser, and Stephan Andreas Schunk. "Synthetic Routes to Crystalline Complex Metal Alkyl Carbonates and Hydroxycarbonates via Sol–Gel Chemistry—Perspectives for Advanced Materials in Catalysis." Catalysts 12, no. 5 (May 18, 2022): 554. http://dx.doi.org/10.3390/catal12050554.
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Metal alkoxides are easily available and versatile precursors for functional materials, such as solid catalysts. However, the poor solubility of metal alkoxides in organic solvents usually hinders their facile application in sol–gel processes and complicates access to complex carbonate or oxidic compounds after hydrolysis of the precursors. In our contribution we have therefore shown three different solubilization strategies for metal alkoxides, namely the derivatization, the hetero-metallization and CO2 insertion. The latter strategy leads to a stoichiometric insertion of CO2 into the metal–oxygen bond of the alkoxide and the subsequent formation of metal alkyl carbonates. These precursors can then be employed advantageously in sol–gel chemistry and, after controlled hydrolysis, result in chemically defined crystalline carbonates and hydroxycarbonates. Cu- and Zn-containing carbonates and hydroxycarbonates were used in an exemplary study for the synthesis of Cu/Zn-based bulk catalysts for methanol synthesis with a final comparable catalytic activity to commercial standard reference catalysts.
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Leszczyńska-Sejda, Katarzyna, Grzegorz Benke, Joanna Malarz, Mateusz Ciszewski, Dorota Kopyto, Jędrzej Piątek, Michał Drzazga, Patrycja Kowalik, Krzysztof Zemlak, and Bartłomiej Kula. "Rhenium(VII) Compounds as Inorganic Precursors for the Synthesis of Organic Reaction Catalysts." Molecules 24, no. 8 (April 12, 2019): 1451. http://dx.doi.org/10.3390/molecules24081451.
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Rhenium is an element that exhibits a broad range of oxidation states. Synthesis paths of selected rhenium compounds in its seventh oxidation state, which are common precursors for organic reaction catalysts, were presented in this paper. Production technologies for copper perrhenate, aluminum perrhenate as well as the ammonia complex of cobalt perrhenate, are thoroughly described. An ion exchange method, based on Al or Cu metal ion sorption and subsequent elution by aqueous perrhenic acid solutions, was used to obtain perrhenates. The produced solutions were neutralized to afford the targeted aluminum perrhenate and copper perrhenate products in high purity. The developed technologies allow one to manage the wastes from the production of these perrhenates as most streams were recycled. Hexaamminecobalt(III) perrhenate was produced by a newly developed method enabling us to produce a high purity compound in a reaction of spent hexaamminecobalt(III) chloride solution with a perrhenic acid. All prepared compounds are the basis for precursor preparation in organic catalysis.
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Bednářová, Eva, Štefan Malatinec, and Martin Kotora. "Applications of Bolm’s Ligand in Enantioselective Synthesis." Molecules 25, no. 4 (February 20, 2020): 958. http://dx.doi.org/10.3390/molecules25040958.
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One pathway for the preparation of enantiomerically pure compounds from prochiral substrates is the use of metal complex catalysis with chiral ligands. Compared to the other frequently used chiral ligands, chiral 2,2’-bipyridines have been underexploited, despite the data indicating that such ligands have considerable potential in synthetic chemistry. One of those is the so-called Bolm’s ligand, a compound possessing chiral alcohol moieties in the side chains attached to the 2,2’-bipyridine scaffold. Various metal salts have been used in combination with Bolm’s ligand as potent catalysts able to bring about enantioselective alkylations, allylations, conjugate additions, desymmetrization of meso-epoxides, aldol reactions, etc. This review aims to summarize Bolm’s ligand applications in the area of enantioselective synthesis over the last three decades since its preparation.
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Zeynalov, N. A., U. A. Mammadova, A. F. Isazade, N. T. Shikhverdiyeva, Ch M. Seidova, H. F. Aslanova, N. T. Rahimli, K. J. Hasanova, and E. H. Babayev. "SYNTHESIS AND STUDY OF THE STRUCTURE OF Pd AND Mn NANOPARTICLES IN THE PRESENCE OF POLYVINYLPYRROLIDONE." Chemical Problems 20, no. 2 (2022): 145–53. http://dx.doi.org/10.32737/2221-8688-2022-2-145-153.
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Poly-N-vinylpyrrolidone is widely used among synthetic polymers due to its non-toxicity and solubility in water and other organic solvents. Complex compounds with metals and non-metals find widespread application in various fields of industry and medicine. The purpose of this study is to synthesize metal-polymer complexes for obtaining a new type of catalyst. Poly-N-vinylpyrrolidone was first dissolved in water and then re-mixed with the addition of the PdCl2 salt. A reducing agent was added to the solution, and finally the resulting substance was established by means of a binder. The same process was typical for MnCl2 salt. Complexes obtained studied by various research methods (FTIR, XRD, SEM, UV-Vis). Proceeding from the results of the research methods, we can say that the construction process was successful and the metal nanoparticles settled on the surface and inside the polymer. The obtained complex compounds are intended to be used as catalysts
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Bibik, Y., D. Khomenko, R. Doroschuk, and R. Lampeka. "THE SYNTHESIS OF TRIAZOLE CONTAINING ANALOGUES OF SALEN AND VANEN." Bulletin of Taras Shevchenko National University of Kyiv. Chemistry, no. 2(54) (2017): 37–39. http://dx.doi.org/10.17721/1728-2209.2017.2(54).5.
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Facile methods of the preparation of heterocyclic analogues of Salen and Vanen are reported. The azamethine fragments of Schiff bases were replaced by 1,2,4-triazoles. The method of synthesis described may afford to prepare the series of ligand systems with different substituents with high overall yields relatively to the hydrazide. Unlike Schiff's bases, all synthesized compounds are chemically stable and resistant to oxidizing and reducing agents. The molecules are entirely conjugate to the π-systems, which is likely to be reflected in the electronic properties of coordination compounds. Obtained ligand systems could maintain great interest in the synthesis of various transition metal coordination compounds. These could be concluded from the fact that coordination behavior of synthesized ligands is expected to be similar to that is observed for Salen an Vanen type ligands respectively. The resulting compounds have the same donor centers from Salen and Vanen, having a similar planar structure and coordination behavior. All ligands are tetradentate, may leave vacant positions in the coordination sphere of transition metals and form five- and six-membered cycles. The Vanen analogues are capable of forming binuclear complex compounds, since they have internal N2O2 (for coordination with 3d metal ions) and external O2O2 (for exo-coordination of ions of lantanides) donor centers. The compounds obtained are capable of forming coordination compounds with antibacterial, antifungal, anticancer, antioxidant, anti-inflammatory, antimalarial, antiviral activities and also as homogeneous and heterogeneous catalysts in polymerization, epoxidation, hydrosilylation reactions, sensors etc. The analogues were analyzed by NMR and IR spectroscopy.
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Grau, Benedikt W., and Svetlana B. Tsogoeva. "Iron-Catalyzed Carbonyl–Alkyne and Carbonyl–Olefin Metathesis Reactions." Catalysts 10, no. 9 (September 21, 2020): 1092. http://dx.doi.org/10.3390/catal10091092.
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Construction of carbon–carbon bonds is one of the most important tools for the synthesis of complex organic molecules. Among multiple possibilities are the carbonyl–alkyne and carbonyl–olefin metathesis reactions, which are used to form new carbon–carbon bonds between carbonyl derivatives and unsaturated organic compounds. As many different approaches have already been established and offer reliable access to C=C bond formation via carbonyl–alkyne and carbonyl–olefin metathesis, focus is now shifting towards cost efficiency, sustainability and environmentally friendly metal catalysts. Iron, which is earth-abundant and considered as an eco-friendly and inexpensive option in comparison to traditional metal catalysts, fulfils these requirements. Hence, the focus of this review is on recent advances in the iron-catalyzed carbonyl–alkyne, carbonyl–olefin and related C–O/C–O metathesis reactions. The still large research potential for ecologically and economically attractive and sustainable iron-based catalysts is demonstrated.
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Ali, Siraj Z., Brenna G. Budaitis, Devon F. A. Fontaine, Andria L. Pace, Jacob A. Garwin, and M. Christina White. "Allylic C–H amination cross-coupling furnishes tertiary amines by electrophilic metal catalysis." Science 376, no. 6590 (April 15, 2022): 276–83. http://dx.doi.org/10.1126/science.abn8382.
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Intermolecular cross-coupling of terminal olefins with secondary amines to form complex tertiary amines—a common motif in pharmaceuticals—remains a major challenge in chemical synthesis. Basic amine nucleophiles in nondirected, electrophilic metal–catalyzed aminations tend to bind to and thereby inhibit metal catalysts. We reasoned that an autoregulatory mechanism coupling the release of amine nucleophiles with catalyst turnover could enable functionalization without inhibiting metal-mediated heterolytic carbon-hydrogen cleavage. Here, we report a palladium(II)-catalyzed allylic carbon-hydrogen amination cross-coupling using this strategy, featuring 48 cyclic and acyclic secondary amines (10 pharmaceutically relevant cores) and 34 terminal olefins (bearing electrophilic functionality) to furnish 81 tertiary allylic amines, including 12 drug compounds and 10 complex drug derivatives, with excellent regio- and stereoselectivity (>20:1 linear:branched, >20:1 E : Z ).
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Ratnasamy, Paul, Robert Raja, and Darbha Srinivas. "Novel, benign, solid catalysts for the oxidation of hydrocarbons." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 363, no. 1829 (April 15, 2005): 1001–12. http://dx.doi.org/10.1098/rsta.2004.1538.
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The catalytic properties of two classes of solid catalysts for the oxidation of hydrocarbons in the liquid phase are discussed: (i) microporous solids, encapsulating transition metal complexes in their cavities and (ii) titanosilicate molecular sieves. Copper acetate dimers encapsulated in molecular sieves Y, MCM-22 and VPI-5 use dioxygen to regioselectively ortho -hydroxylate l -tyrosine to l -dopa, phenol to catechol and cresols to the corresponding o -dihydroxy and o -quinone compounds. Monomeric copper phthalocyanine and salen complexes entrapped in zeolite-Y oxidize methane to methanol, toluene to cresols, naphthalene to naphthols, xylene to xylenols and phenol to diphenols. Trimeric μ 3 -oxo-bridged Co/Mn cluster complexes, encapsulated inside Y-zeolite, oxidize para -xylene, almost quantitatively, to terephthalic acid. In almost all cases, the intrinsic catalytic activity (turnover frequency) of the metal complex is enhanced very significantly, upon encapsulation in the porous solids. Spectroscopic and electrochemical studies suggest that the geometric distortions of the complex on encapsulation change the electron density at the metal ion site and its redox behaviour, thereby influencing its catalytic activity and selectivity in oxidation reactions. Titanosilicate molecular sieves can oxidize hydrocarbons using dioxygen when loaded with transition metals like Pd, Au or Ag. The structure of surface Ti ions and the type of oxo-Ti species generated on contact with oxidants depend on several factors including the method of zeolite synthesis, zeolite structure, solvent, temperature and oxidant. Although, similar oxo-Ti species are present on all the titanosilicates, their relative concentrations vary among different structures and determine the product selectivity.
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Pham Xuan Thao. "Study on the synthesis of thioamides from aldehyde N-tert-butylsulfinyl amide and sulfur in aqueous media." Journal of Military Science and Technology, no. 76 (December 12, 2021): 54–60. http://dx.doi.org/10.54939/1859-1043.j.mst.76.2021.54-60.
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Thioamides have been widely used in the fields of medicine and organic chemistry, some of which are essential bioactive compounds, plant protection agents, and drugs. It could also be used as a vulcanizing agent, an additive to lubricants and greases, and a ligand in organic synthesis. Usually, thioamide is synthesized at high temperatures or in the microwave using an expensive noble metal complex as catalysts. This paper presented a straightforward method for synthesizing thioamides by using N-tert-butylsulfinyl amide, aldehyde, and sulfur. The reaction was carried out in water, which is an environmentally friendly solvent. The reaction selectivity and yield were up to 89%.
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Najafpour, Mohammad Mahdi, Fahimeh Rahimi, Eva-Mari Aro, Choon-Hwan Lee, and Suleyman I. Allakhverdiev. "Nano-sized manganese oxides as biomimetic catalysts for water oxidation in artificial photosynthesis: a review." Journal of The Royal Society Interface 9, no. 75 (July 18, 2012): 2383–95. http://dx.doi.org/10.1098/rsif.2012.0412.
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There has been a tremendous surge in research on the synthesis of various metal compounds aimed at simulating the water-oxidizing complex (WOC) of photosystem II (PSII). This is crucial because the water oxidation half reaction is overwhelmingly rate-limiting and needs high over-voltage (approx. 1 V), which results in low conversion efficiencies when working at current densities required for hydrogen production via water splitting. Particular attention has been given to the manganese compounds not only because manganese has been used by nature to oxidize water but also because manganese is cheap and environmentally friendly. The manganese–calcium cluster in PSII has a dimension of about approximately 0.5 nm. Thus, nano-sized manganese compounds might be good structural and functional models for the cluster. As in the nanometre-size of the synthetic models, most of the active sites are at the surface, these compounds could be more efficient catalysts than micrometre (or bigger) particles. In this paper, we focus on nano-sized manganese oxides as functional and structural models of the WOC of PSII for hydrogen production via water splitting and review nano-sized manganese oxides used in water oxidation by some research groups.
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Nesterov, Dmytro S., and Oksana V. Nesterova. "Catalytic Oxidations with Meta-Chloroperoxybenzoic Acid (m-CPBA) and Mono- and Polynuclear Complexes of Nickel: A Mechanistic Outlook." Catalysts 11, no. 10 (September 25, 2021): 1148. http://dx.doi.org/10.3390/catal11101148.
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Selective catalytic functionalization of organic substrates using peroxides as terminal oxidants remains a challenge in modern chemistry. The high complexity of interactions between metal catalysts and organic peroxide compounds complicates the targeted construction of efficient catalytic systems. Among the members of the peroxide family, m-chloroperoxybenzoic acid (m-CPBA) exhibits quite complex behavior, where numerous reactive species could be formed upon reaction with a metal complex catalyst. Although m-CPBA finds plenty of applications in fine organic synthesis and catalysis, the factors that discriminate its decomposition routes under catalytic conditions are still poorly understood. The present review covers the advances in catalytic C–H oxidation and olefine epoxidation with m-CPBA catalyzed by mono- and polynuclear complexes of nickel, a cheap and abundant first-row transition metal. The reaction mechanisms are critically discussed, with special attention to the O–O bond splitting route. Selectivity parameters using recognized model hydrocarbon substrates are summarized and important factors that could improve further catalytic studies are outlined.
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Walley, Jacob E., Yuen-Onn Wong, Lucas A. Freeman, Diane A. Dickie, and Robert J. Gilliard. "N-Heterocyclic Carbene-Supported Aryl- and Alk- oxides of Beryllium and Magnesium." Catalysts 9, no. 11 (November 8, 2019): 934. http://dx.doi.org/10.3390/catal9110934.
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Recently, we have witnessed significant progress with regard to the synthesis of molecular alkaline earth metal reagents and catalysts. To provide new precursors for light alkaline earth metal chemistry, molecular aryloxide and alkoxide complexes of beryllium and magnesium are reported. The reaction of beryllium chloride dietherate with two equivalents of 1,3-diisopropyl-4,5-dimethylimidizol-2-ylidine (sIPr) results in the formation of a bis(N-heterocyclic carbene) (NHC) beryllium dichloride complex, (sIPr)2BeCl2 (1). Compound 1 reacts with lithium diisopropylphenoxide (LiODipp) or sodium ethoxide (NaOEt) to form the terminal aryloxide (sIPr)Be(ODipp)2 (2) and alkoxide dimer [(sIPr)Be(OEt)Cl]2 (3), respectively. Compounds 2 and 3 represent the first beryllium alkoxide and aryloxide species supported by NHCs. Structurally related dimers of magnesium, [(sIPr)Mg(OEt)Brl]2 (4) and [(sIPr)Mg(OEt)Me]2 (5), were also prepared. Compounds 1-5 were characterized by single crystal X-ray diffraction studies, 1H, 13C, and 9Be NMR spectroscopy where applicable.
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Kholodniak, Olena, and Sergiy Kovalenko. "Substituted acyl thioureas and acyl thiosemicarbazides: synthesis and biological activity (minireview)." ScienceRise: Pharmaceutical Science, no. 2(36) (April 29, 2022): 56–71. http://dx.doi.org/10.15587/2519-4852.2022.255738.
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Acyl isothiocyanates and their functional derivatives (acyl thioureas and acyl thiosemicarbazides) are an important group of organic compounds that are widely used in the synthesis of heterocycles and in chemistry as catalysts, ligands, colorimetric hemosensors, etc. In recent years, there has been an increased interest towards this class of compounds as promising biologically active compounds, especially since the latest advances in medicinal chemistry for them are not sufficiently studied.
The aim. To summarize and systematize information for the last 10 years on methods of synthesis and biological activity of substituted acyl thioureas and acyl thiosemicarbazides.
Materials and methods. Web-tools for finding scientific information (Reaxys, Scopus, Google Scholar, ScienceResearch, SciFinder, Web of Science, etc.).
Results and discussion. Literature sources related to the methods of synthesis of substituted acyl thioureas and acyl thiosemicarbazides were systematized and analyzed. The main approaches for the formation of these compounds are revealed: stepwise formation from carboxylic acids, through acyl chlorides and acyl isothiocyanates followed by nucleophilic addition of amines or hydrazides of carboxylic acids ("one-pot synthesis"), nucleophilic addition of amines or hydrazides of carboxylic acids directly to acyl isothiocyanates and parallel microwave synthesis using acyl isothiocyanates and amines as reagents. The possibility of their use as ligands for the formation of complex compounds with transition metal ions was discussed. In the review biological activity of these structures, namely antimicrobial, fungicidal, antitumor, antiviral, antifungal and other activities was detailazed.
Conclusions. The basic approaches to the synthesis of substituted acylthuoureas and acyl thiosemicarbazides which include the application of carboxylic acids, their derivatives (acyl halides and isothiocyanates) and N-nucleophiles as initial compounds were discussed. It was shown that aforementioned class of the compounds reveals the versatile biological activity and are promising for further structural modification aimed to the search of novel drugs
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Bravo Fuchineco, Daiana A., Angélica C. Heredia, Sandra M. Mendoza, Enrique Rodríguez-Castellón, and Mónica E. Crivello. "Esterification of Levulinic Acid to Methyl Levulinate over Zr-MOFs Catalysts." ChemEngineering 6, no. 2 (March 25, 2022): 26. http://dx.doi.org/10.3390/chemengineering6020026.
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At present, the trend towards partial replacement of petroleum-derived fuels by those from the revaluation of biomass has become of great importance. An effective strategy for processing complex biomass feedstocks involves prior conversion to simpler compounds (platform molecules) that are more easily transformed in subsequent reactions. This study analyzes the metal–organic frameworks (MOFs) that contain Zr metal clusters formed by ligands of terephthalic acid (UiO-66) and aminoterephthalic acid (UiO-66-NH2), as active and stable catalysts for the esterification of levulinic acid with methanol. An alternative synthesis is presented by means of ultrasonic stirring at room temperature and 60 °C, in order to improve the structural properties of the catalysts. They were analyzed by X-ray diffraction, scanning electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, microwave plasma atomic emission spectroscopy, acidity measurement, and N2 adsorption. The catalytic reaction was carried out in a batch system and under pressure in an autoclave. Its progress was followed by gas chromatography and mass spectrometry. Parameters such as temperature, catalyst mass, and molar ratio of reactants were optimized to improve the catalytic performance. The MOF that presented the highest activity and selectivity to the desired product was obtained by synthesis with ultrasound and 60 °C with aminoterephthalic acid. The methyl levulinate yield was 67.77% in batch at 5 h and 85.89% in an autoclave at 1 h. An analysis of the kinetic parameters of the reaction is presented. The spent material can be activated by ethanol washing allowing the catalytic activity to be maintained in the recycles.
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Richter, Ferdinand, Nicholas Birchall, Christoph M. Feil, Martin Nieger, and Dietrich Gudat. "Annellated 1,3,4,2-Triazaphospholenes-Simple Modular Synthesis and a First Exploration of Ligand Properties." Molecules 27, no. 15 (July 25, 2022): 4747. http://dx.doi.org/10.3390/molecules27154747.
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The successful use of 1,3,4,2-triazaphospholenes (TAPs) as organo-catalysts stresses the need for efficient synthetic routes to these molecules. In this study, we establish the [1 + 4]-cycloaddition of PBr3 to azo-pyridines as a new approach to preparing pyrido-annellated TAPs in a single step from easily available precursors. The modular assembly of the azo-component via condensation of primary amines and nitroso compounds along with the feasibility of post-functionalization at the P–Br bond under conservation of the heterocyclic structure allows, in principle, to address a wide range of target molecules, which is illustrated by prototypical examples. The successful synthesis of a transition metal complex confirms for the first time the ability of a TAP to act as a P-donor ligand. Crystallographic studies suggest that hyperconjugation effects and intermolecular interactions induce a qualitatively similar ionic polarization of the P–Br bonds in TAPs as in better known isoelectronic diazaphospholenes.
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Oborina, E. N., A. M. Nalibayeva, V. G. Fedoseeva, I. A. Ushakov, I. B. Rozentsveig, and S. N. Adamovich. "Synthesis, Sorption and Metallochromy Properties of Organosilicon Derivatives of 1-Acetylguanidine." Bulletin of the South Ural State University series "Chemistry" 13, no. 1 (2021): 78–87. http://dx.doi.org/10.14529/chem210108.
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Increased interest in carbofunctional organosilicon monomers (silanes) and polymers (silsesquioxanes) is associated with the fact that these compounds are promising reagents and building blocks, materials for micro-electronics, agriculture and medicine, complexones, catalysts, and efficient sorbents. Thus, functional polysilsesquioxanes surpass mineral and organic sorbents in sorption properties. Moreover, they have the highest chemical and thermal stability. Along with sorption activity carbofunctional organosilicon compounds of both monomeric and polymeric structures can possess metallochromic properties. All this paves the way for the large-scale development of analytical systems for the creation of new complex test methods for the determination, concentration and separation of metals from solutions. In the present study the functional monomer N-[3-(triethoxysilyl)propyl]acetylguanidine 1 was synthesized by the condensation reaction of 1-acetylguanidine and 3-triethoxysilyl-propylamine. Poly-N-[3-silsesquioxanyl) propyl]acetylguanidine 2 was obtained by hydrolytic polycondensation of compound 1. The composition and structure of compounds 1 and 2 were confirmed by IR and 1H NMR spectroscopy, as well as by elemental analysis. Polymer 2 was studied as a sorbent for ions of heavy metals, such as Hg (II), and noble metals Ag (I), Au (III), Rh (II), Pd (II), Pt (IV) from solutions of their salts in hydrochloric or nitric acid. For polymer 2, the values of static sorption capacities have been calculated. The latter depend on the nature of the metal and have values from 78 mg/g (for platinum) to 366 mg/g for rhodium. The graphs of the degree of metal extraction depending on the sorption time and acid concentration have been plotted. A sorption mechanism is proposed, which is realized due to the chelate interaction of the metal cation (M+) with the amide groups of compounds 1 and 2. The interaction of monomer 1, in the form of indicator paper, and polymer 2, in the powder form, with salts of the studied metals is accompanied by intense specific coloration (metallochromy). Color tables of the samples after their contact with the Ag (I), Au (III), Pd (II), Pt (IV), Rh (III), Hg (II) salts are given.
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Simões, Mário M. Q., Cláudia M. B. Neves, Sónia M. G. Pires, M. Graça P. M. S. Neves, and José A. S. Cavaleiro. "Mimicking P450 processes and the use of metalloporphyrins." Pure and Applied Chemistry 85, no. 8 (June 30, 2013): 1671–81. http://dx.doi.org/10.1351/pac-con-12-11-15.
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Metalloporphyrins (MPs) are known to catalyze in vitro a broad range of cytochrome P450-mediated reactions occurring in vivo. Most of the biomimetic research using MPs in oxidative catalysis has been directed towards the oxidation of organic compounds presenting significant reactivity features in one functional group. Much less effort has been made to imitate the oxidation of more complex molecules, with a range of functionalities, such as drugs or other xenobiotics. By varying the structure of the porphyrin, the metal ion, the oxidant, and the reaction conditions, it is possible to modulate the regioselectivity of the oxidation reactions. Recently, and along with studies on the synthesis and reactivity of porphyrins, chlorins, and phthalocyanines, our group was able to develop an interesting line of research in the field of biomimetic oxidation of organic compounds using environmentally benign hydrogen peroxide as oxidant and Mn(III) or Fe(III) porphyrin complexes as catalysts. The more up to date results obtained in such work are reviewed here.
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Pyne, Stephen. "Preface." Pure and Applied Chemistry 80, no. 4 (January 1, 2008): iv. http://dx.doi.org/10.1351/pac20088004iv.
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This issue of Pure and Applied Chemistry comprises 12 papers from some of the speakers at the 21st International Congress for Heterocyclic Chemistry, which was held at the University of New South Wales, Sydney, Australia from 15-20 July 2007. The topics of these papers cover some of the major themes of the conference, including natural products synthesis (as highlighted by the presentation of K. C. Nicolaou during his ISHC Senior Award in Heterocyclic Chemistry lecture on the synthesis of complex natural products and further demonstrated by contributions by Profs. Banwell, Bates, Sodeoka, Naito, Vogel, and Pyne); new methods for the synthesis of heterocycles based on metal-catalyzed reactions (Profs. Ma and Mase); and new catalysts for asymmetric synthesis based on chiral heterocyclic ligands (Prof. Nishiyama). Papers on the synthesis of heterocyclic compounds using the borono-Mannich reaction (Prof. Hutton) and green chemistry methods (Prof. Varma) are also included.I would like to thank all contributors for their timely efforts and the editorial staff for their help.Stephen PyneConference Editor
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Gao, Xiuyun, Lulu He, Juntong Xu, Xueying Chen, and Heyong He. "Facile Synthesis of P25@Pd Core-Shell Catalyst with Ultrathin Pd Shell and Improved Catalytic Performance in Heterogeneous Enantioselective Hydrogenation of Acetophenone." Catalysts 9, no. 6 (June 9, 2019): 513. http://dx.doi.org/10.3390/catal9060513.
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Heterogeneous enantioselective hydrogenation is an ideal method for synthesizing important chiral compounds in pesticides and pharmaceuticals. Up to the present, supported noble-metal catalysts are most widely studied in heterogeneous enantioselective hydrogenations. However, it is found that the weak interactions existing on the surface of support may have negative effects on the enantioselectivity. Herein, a new category of TiO2 (Aeroxide® P25) supported Pd catalyst with ultrathin Pd shell was successfully prepared via a simple strategy based on the reduction of PdI carbonyl complex. Characterization results show that a well-dispersed ultrathin Pd shell with an average thickness of ~1.0 nm and a Pd loading of 36 wt.% was formed over the surface of P25 support. By excluding the negative weak interactions from the support, the P25@Pd core-shell catalyst with unique electronic properties of Pd exhibits higher activity and enantioselectivity than that of Pd/P25 catalyst prepared by the impregnation method and unsupported Pd black catalyst in the enantioselective hydrogenation of acetophenone.
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Cesari, Cristiana, Riccardo Conti, Andrea Cingolani, Valerio Zanotti, Maria Cristina Cassani, Luca Rigamonti, and Rita Mazzoni. "Synthesis and Reactivity of Poly(propyleneimine) Dendrimers Functionalized with Cyclopentadienone N-Heterocyclic-Carbene Ruthenium(0) Complexes." Catalysts 10, no. 2 (February 22, 2020): 264. http://dx.doi.org/10.3390/catal10020264.
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Ligand design in metal chemistry is a fundamental step when pursuing compounds with specific reactivity. In this paper, the functionalization of the OH group in the lateral chain of the N-heterocyclic-carbene (NHC) ligand bound to a bis-carbonyl cyclopentadienone NHC ruthenium(0) complex allowed the decoration of five generations of poly(propyleneimine) (PPIs) dendrimers with up to 64 organometallic moieties. The coupling was achieved by employing carbonyldiimidazole and the formation of carbamate linkages between dendritic peripheral NH2 and lateral OH groups on ruthenium complexes. The synthetic procedure, chemical purification, and spectroscopic characterization of the five generations of dendrimers (3g1–5) are here described. The ruthenium-modified dendrimers were activated as catalysts in the transfer hydrogenation of the model compound 4-fluoroacetophenone in the presence of cerium ammonium nitrate as their mononuclear congeners. The catalytic activity, being similar for the five generations, shows a decrease if compared to mononuclear complexes. This detrimental effect might be ascribed to the –CH2NH– functionalization, largely present in dendrimer skeleton and that can compete with the hydrogen transfer mechanism, but also partially to a dendritic effect caused by steric encumbrance.
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Зломанов, Владимир Павлович, Родион Сергеевич Эшмаков, and Игорь Владиславович Пролубщиков. "Formation of a solvate of manganese(III) acetylacetonate with chloroform." Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 24, no. 1 (March 15, 2022): 29–32. http://dx.doi.org/10.17308/kcmf.2022.24/9052.
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Metal acetylacetonates are coordination compounds consisting of the acetylacetonate anion (CH3COCHCOCH3, indicated as acac) and metal ions. Typically, both oxygen atoms of the anion bind with the metal and form a six-membered chelate ring. The simplest complexes have the formulas M(acac)3 and M(acac)2. Many complexes are soluble in organic solvents, and such solutions are used for the synthesis of catalysts. The processes of formation of solvates of acetylacetonates of various metals have not been studied properly. It should be noted that the determination of the composition and properties of solvates is important for understanding the peculiarities of the extraction processes of metal acetylacetonates.Manganese(III) acetylacetonate Mn(acac)3, for example, is also widely used. The recrystallisation of the complex is most commonly conducted from solutions in chloroform, and in this case, the corresponding solvates may be formed, which can affect the structure and properties of Mn(acac)3. There are no data on the synthesis conditions and the composition of the solvates of manganese(III) acetylacetonate with chloroform. Therefore, the purpose of this work is to study the possibilities of its formation and to establish the composition of such solvates. The formation of the solvate in solution was established using Fourier IR spectroscopy by the shift of the absorption band of the C-H chloroform bond. The composition of the Mn(acac)3· 2CHCl3 solvate was determined using gravimetric analysis.
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Kinzel, Niklas Werner, Derya Demirbas, Eckhard Bill, Thomas Weyhermüller, Christophe Werlé, Nicolas Kaeffer, and Walter Leitner. "Systematic Variation of 3d Metals in a Redox-Innocent Ligand Environment: Structures, Electrochemical Properties and CO2 Activation." ECS Meeting Abstracts MA2022-01, no. 49 (July 7, 2022): 2078. http://dx.doi.org/10.1149/ma2022-01492078mtgabs.
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In the endeavor to close the anthropogenic carbon cycle and produce goods in a de-fossilized future, electrochemical carbon dioxide reduction constitutes a powerful tool.[1] Herein,3d transition metal complexes range among the most effective catalysts to overcome the kinetic barriers for CO2 activation.[2] In a recent literature review, we analyzed the main reaction pathways of homogeneously catalyzed CO2 electroreduction from an organometallic perspective and classified them into two mechanisms: (1) direct coordination of carbon dioxide to the metal center prior to activation and (2) formation of a metal hydride as the intermediate reactive to CO2.[3] Although properties of the metal center such as hydricity, or substrate (CO2) and product (CO, HCO2H...) binding affinity, are crucial regarding the mechanism and the ability of the complex to mediate CO2 reduction, systematic variations of the metal within an identical, redox-innocent ligand backbone remain scarcely investigated. In this study,[4] we report on the synthesis, structures, and electrochemistry of 3d transition metal complexes (M = Mn(I), Fe(II), Co(II), Ni(II), Cu(I) and Zn(II)) coordinated by a new redox-innocent PNP pincer ligand system (Figure 1). The ligand combines a large steric demand, partially shielding the metal center, with a high degree of aromaticity. With these features, the ligand only marginally interferes in the redox processes but still takes sufficient π-backbonding to stabilize low-valent metals. The coordination compounds derived thereof were analyzed by spectroscopic methods (e.g., NMR, EPR, and Mössbauer) as well as crystal X-Ray diffraction to determine their spatial and electronic structures. These findings served as the starting point for a further exploration of the electrochemical reduction of the complexes via cyclic voltammetry. While the Mn, Cu, and Zn complexes solely exhibit ligand reduction or decomposition processes, the distinct electrochemical waves found for the Fe, Co and Ni coordination compounds could be assigned to metal-centered reduction events from M(II) down to M(0). For both cobalt and nickel, the reductions appear to be accompanied by their chloride ligands being lost or exchanged with the acetonitrile solvent, a fact that we currently investigate[5] as these phenomena remain misjudged across many (CO2) electroreduction catalysts. In contrast to Co and Ni, Fe undergoes a more complex reduction pattern likely yielding a dimeric species. Despite their unequal reduction pathways, the evolution of the voltammograms of the complexes under CO2 atmosphere indicates an interaction of each of the complexes with the substrate molecule in their reduced metal states. The d10 Ni(0) species putatively forms an Aresta-type Ni-η2-CO2 complex, in which the electron transfer to the substrate through backbonding is insufficient to enable electrocatalytic activity. At contrast, CO2 binding at the d9 Co(0) intermediate likely leads to additional electron uptake and formation of a formal Co(I) metallacarboxylate complex able to promote turnover (Figure 2). Eventually, we related our findings to the few literature precedents that incorporate redox-innocent ligands. This assessment shows that beneficial characteristics in the electrochemical activation of CO2 by complexes based on redox-innocent ligands are an unsaturated coordination sphere (coordination number = 4 or 5) as well as a d7 to d9 configuration in the reduced oxidation state (+I or 0). The on-purpose design of complexes that simultaneously meet these three characteristics hence provides a promising strategy for catalyst development. In particular, dynamic structural and electronic changes under electrochemical conditions, such as the exchange of chlorido ligands with acetonitrile as faced in this study, must be controlled to ensure the primary operation of the metal centers in the desired catalytic manifold. References [1] P. De Luna, C. Hahn, D. Higgins, S. A. Jaffer, T. F. Jaramillo, E. H. Sargent, Science 2019, 364, eaav3506. [2] R. Francke, B. Schille, M. Roemelt, Chem. Rev. 2018, 118, 4631. [3] N. W. Kinzel, C. Werlé, W. Leitner, Angew. Chem. Int. Ed. 2021, 60, 11628. [4] N. W. Kinzel,D. Demirbas, E. Bill, T. Weyhermüller, C. Werlé,N. Kaeffer, W. Leitner, Inorg. Chem. 2021, doi: 10.1021/acs.inorgchem.1c02909. [5] N. W. Kinzel, N. Kaeffer, W. Leitner in preparation. Figure 1
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Kowalska, Marta, Dominik Popiel, Martyna Walter, Remigiusz Bąchor, Monika Biernat, Marek Cebrat, Monika Kijewska, Mariola Kuczer, Maciej Modzel, and Alicja Kluczyk. "Veni, Vidi, Vici: Immobilized Peptide-Based Conjugates as Tools for Capture, Analysis, and Transformation." Chemosensors 10, no. 1 (January 12, 2022): 31. http://dx.doi.org/10.3390/chemosensors10010031.
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Analysis of peptide biomarkers of pathological states of the organism is often a serious challenge, due to a very complex composition of the cell and insufficient sensitivity of the current analytical methods (including mass spectrometry). One of the possible ways to overcome this problem is sample enrichment by capturing the selected components using a specific solid support. Another option is increasing the detectability of the desired compound by its selective tagging. Appropriately modified and immobilized peptides can be used for these purposes. In addition, they find application in studying the specificity and activity of proteolytic enzymes. Immobilized heterocyclic peptide conjugates may serve as metal ligands, to form complexes used as catalysts or analytical markers. In this review, we describe various applications of immobilized peptides, including selective capturing of cysteine-containing peptides, tagging of the carbonyl compounds to increase the sensitivity of their detection, enrichment of biological samples in deoxyfructosylated peptides, and fishing out of tyrosine–containing peptides by the formation of azo bond. Moreover, the use of the one-bead-one-compound peptide library for the analysis of substrate specificity and activity of caspases is described. Furthermore, the evolution of immobilization from the solid support used in peptide synthesis to nanocarriers is presented. Taken together, the examples presented here demonstrate immobilized peptides as a multifunctional tool, which can be successfully used to solve multiple analytical problems.
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Pires, Marina, Sara Purificação, A. Santos, and M. Marques. "The Role of PEG on Pd- and Cu-Catalyzed Cross-Coupling Reactions." Synthesis 49, no. 11 (April 26, 2017): 2337–50. http://dx.doi.org/10.1055/s-0036-1589498.
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Carbon–carbon and carbon–heteroatom coupling reactions are among the most important transformations in organic synthesis as they enable complex structures to be formed from readily available compounds under different routes and conditions. Several metal-catalyzed cross-coupling reactions have been developed creating many efficient methods accessible for the direct formation of new bonds between differently hybridized carbon atoms.During the last decade, much effort has been devoted towards improvement of the sustainability of these reactions, such as catalyst recovery and atom efficiency. Polyethylene glycol (PEG) can be used as a medium, as solid-liquid phase transfer catalyst, or even as a polymer support. PEG has been investigated in a wide variety of cross-coupling reactions either as an alternative solvent to the common organic solvents or as a support for catalyst, substrate, and ligand. In this review we will summarize the different roles of PEG in palladium- and copper-catalyzed cross-coupling reactions, with the focus on Heck, Suzuki–Miyaura, Sonogashira, Buchwald–Hartwig, Stille, Fukuyama, and homocoupling reactions. We will highlight the role of PEG, the preparation of PEGylated catalysts and substrates, and the importance for the reaction outcome and applicability.1 Introduction2 PEG in Heck Reactions3 PEG in Homocoupling Reactions4 PEG in Suzuki–Miyaura Reactions5 PEG in Sonogashira Reactions6 PEG in Buchwald–Hartwig Reactions7 PEG in Stille Reactions8 PEG in Fukuyama Reactions9 PEG in Miscellaneous Cross-Coupling Routes10 Conclusions
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Polimbetova, G. S., M. M. Aleshkova, G. O. Bugubaeva, Zh U. Ibraimova, and A. K. Borangazieva. "Oxidation of Sodium Hypophosphite by Oxygen in Alcoholic Solutions of Ferrum (III)." Eurasian Chemico-Technological Journal 7, no. 1 (September 21, 2016): 33. http://dx.doi.org/10.18321/ectj410.
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<p>Hypophosphites are widely used as reducers in the metal protection coating, as reagents in the synthesis of various organophosphorus compounds, in analytical chemistry, and in many other fields. NaH<sub>2</sub>PO<sub>2</sub> difficultly reacts with many oxidizers without catalysts despite of the significant reduction potential. The kinetics and the mechanism of hypophosphite oxidation in aqueous acid solution of the metal and nonmetal salts are studied in detail. The reactivity of hypophosphite in the organic solvents was not almost studied. In this work the basic possibility of synthesis dialkylphosphites from cheap, accessible and harmless NaH<sub>2</sub>PO<sub>2</sub> and alcohols is shown. Sodium hypophosphite is oxidized by oxygen in alcoholic solutions of FeCl<sub>3</sub> at 50-80 °С to dialkylphosphites. Kinetic and mechanism of the reaction are investigated by methods of volumetry, redox-potentiometry, GC, IR-, UV-, EPR-, Mössbauer- and NMR <sup>31</sup>Р-spectroscopy and X-ray powder diffraction analysis, optimum conditions are found, kinetic and activation parameters of the reaction are calculated. It is shown, that the process follows redox-mechanism and consists of two key stages: reduction of Fe (III) by hypophosphite with formation of dialkylphosphite and reoxidation of Fe (II) by oxygen. The coordination mechanism of reduction reaction of Fe (III) by hypophosphite is proposed. According to this mechanism the dialkylphosphite forms through innersphere redox-decomposition of intermediate alcoxyhypophosphite complex of Fe (III). The coordination mechanism of the process is confirmed by low values of Е<sup>≠</sup> and negative activation entropies ∆S<sup>≠</sup>. The availability in an inner sphere of Fe (III) bromide, low-molecular alcohols, water, characterized by high acidity, increases the reaction rate of oxidative alcoxylation of hypophosphite and promotes the further transformation of dialkylphosphite to di- and trialkylphosphate.</p>
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Alizade, Shahla, IbragimovHikmet Jamal, AmirovFariz Ali, and AliyevFariz Ramik. "INVESTIGATION THE OLIGOMERIZATION PROCESS OF HEXENE-1." JOURNAL OF ADVANCES IN CHEMISTRY 14, no. 1 (December 12, 2017): 6041–45. http://dx.doi.org/10.24297/jac.v14i1.6455.
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In article for oligomerization and alkylation processes, to obtain a useful and highly stable active catalyst, New Catalytic Complex (NCC) synthesized which is based on aluminum metal using C2H4Cl2 and this complex has shown high stability in alkylation, oligomerization processes compared to other aluminum-containing catalysts. It is difficult to regulate the molecular mass distribution of received products during oligomerization, either Intensificate the oligomerization process of olefins that is why this process take place in presence of obtaining of bimetal catalytic complex with a highly stable activity from the modification of the New Catalytic Complex(NCC) with transition metal chloride. Comparatively studied oligomerization of Hexen-1 in present of new bimetallic catalytic complex which was modified by NCC and chromium salt (NCC/CrCl3), effect of temperature, reaction time, concentration of the catalyst and the proportion of catalyst components (Al:Cr) in the process was investigated.It was determined that at the initial time (10 min) conversion hexene-1 and the yield of purposeful oil fraction were low. Increasing time, conversion rate of Hexen-1 increases and the optimal time for the process is considered as 60 minutes. In low concentrations of catalyst (0,1-0,3) oligomerization of hexene-1 is low but in high concentrations(>1%) reaction goes with high rate, at optimal concentration 0,5% mass both the yield of oil fraction and its chemical-physical properties were high.In oligomerization process investigated ratio effect of catalyst components Al: Cr that was used Al: Cr=(4-32):1 mol.It has been revealed that oligomerization of Hexen-1, at low mol ratio of components (4:1), received yield of oligomer fraction decreases while mol ratio increases (16:1, 32:1).Studies determined that bimetallic complex at 8:1 mole has shown the maximal activity in oligomerization process of Hexen-1.The effect of the temperature on the oligomerization process was studied in the range of 30-60ºC, increasing the temperature up to 50 °C has a positive effect on the course of the process and despite providing complete oligomerization of hexene-1 its also providing increasing the amount of oil fractions with high viscosity. According to the researches, the optimal conditions for the oligomerization process of hexene-1 with the participation of the bimetallic catalytic complex: reaction time – 60 min., concentration of catalyst – 0,5 % by wt., mol ration of components Al:Cr = 8:1, temperature – 50 °C. In known optimal condition its possible to obtain oligomers with physical indications, characterized by narrow molecular mass distribution, by new catalytic complex that was modified by chromium salt.Such products have special importance, as low-freezing, high viscosity index qualitative engine oils.Synthesis of bimetallic catalytic complexes, with their presence in oligomerization of olefins and fractions, opens wide range perspectives in synthesis of different high-molecular compounds in industry
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Böhm, Andreas, Kurt Polborn, Karlheinz Sünkel, and Wolfgang Beck. "Metallkomplexe mit biologisch wichtigen Liganden, CIV [1]. ortho-Palladierte Komplexe von N,N-Dimethyl-C-phenyl-glycinmethylester. Synthese von α-Aminosäure-Derivaten durch Insertion von Isocyaniden, CO, Alkenen und Alkinen in die Pd-C-Bindung / Metal Complexes of Biologically Important Ligands, CIV [ 1]. ortho-Palladated Complexes of N,N-Dimethyl-C-phenylglycine-methylester. Synthesis of α-Amino Acid Derivatives by Insertion of Isocyanides, CO, Alkenes, and Alkynes into the Pd-C Bond." Zeitschrift für Naturforschung B 53, no. 4 (April 1, 1998): 448–58. http://dx.doi.org/10.1515/znb-1998-0411.
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Abstract N,N-Dimethyl-C-phenylglycinemethylester reacts with Pd(OAc)2 in acetic acid to give the orthopalladated, acetato bridged complex 1. Treatment of 1 with sodium halide affords the chloro, bromo, and iodo bridged compounds [Me2NC(H)(CO2Me)C6H4PdX]2 (2a -c) (X = halide). From 2a and 1,1′-bis(diphenylphosphino)ferrocene the phosphine bridged trinuclear complex 3 is obtained. Substitution of the amine ligand of 2a by the phosphino group is observed for the reaction of 2a with Ph2PC(Me)C(Me)PPh2. Insertion of 2,6-dimethyl-phenylisocyanide, CO, alkyl-vinyl-ketones, and diphenylacetylene into the Pd-C bond o f 2a -c provides the orthosubstituted organic and organometallic derivatives of phenylglycine 6a -c, 7, 8a -b and 9a -c. The crystal structures of 1, 4a, 6a, 7 and 9a were determined by X-ray diffraction.
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Shalmagambetov, K. M., G. J. Zhaksylykova, F. M. Kanapieva, N. J. Kudaibergenov, and G. M. Abyzbekova. "ETHOXYCARBONYLATION OF PENTENE-1 IN THE PRESENCE OF PdCl2(PPh3)2-PPh3-AlCl3SYSTEM." Chemical Journal of Kazakhstan 79, no. 3 (September 15, 2022): 110–19. http://dx.doi.org/10.51580/2022-3/2710-1185.84.
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Reactions based on CO allow the synthesis of almost all oxygen-containing organic compounds, which are important raw materials for obtaining practically valuable products of wide consumption. Alkoxycarbonylation of olefins with CO and various alcohols in the presence of metal complex catalysts synthesizes esters of carboxylic acids in one step. The purpose:In accordance with previously synthesized ethyl esters of enanthic and 2-methylcapronic acids in the reaction of ethoxycarbonylation of hexene-1 with СОin the presence of the catalytic system PdCl2(PPh3)2-PPh3-AlCl3in this work we planned to synthesize ethyl esters of capronic and 2-methylvalerian acids by hydroethoxycarbonylation of pentene-1 with CO in the presence of the same catalytic system. Methodology: The autoclave was sealedand then filled with CO to 1.5 MPa pressure. The pressure of CO was brought to 2.0 MPa, the temperature was raised to 1000C for 1 hour and at this pressure and temperature the reaction mixture was stirred for 5 h. Results and discussion: Experimental results show that the reaction proceeds with the formation of two isomeric products of linear (EECA) and branched structure (EE-2-MVA). Optimal reaction conditions have been found, at which the yield of the target products (sum of isomeric esters of EECA and EE-2-MVA) reaches 74.72 %. Conclusion:The catalytic activity of the three-component system PdCl2(PPh3)2-PPh3-AlCl3 containing AlCl3as a promoter in the reaction of ethoxycarbonylation of pentene-1 has been established. The reaction proceeds with the formation of two isomeric products of linear (EECA) and branched structure (EE-2-MVA).
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Zheleznyak, А. R., О. М. Bakalinska, А. V. Brichka, G. O. Kalenyuk, and М. Т. Каrtel. "Properties, production methods and use of tin nanoxide." Surface 12(27) (December 30, 2020): 193–230. http://dx.doi.org/10.15407/surface.2020.12.193.
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The prevalence of tin compounds, economic affordability and non-toxicity determine its wide range of applications. Modern scientific literature on the properties, methods of preparation and application of tin nanooxide is analyzes in review. Its main characteristics and structural features are described. The ability of tin cations to be in two oxidation states, the ease of reduction of Sn+4 to Sn+2 and reverse oxidation, determines the redox properties of the SnO2 surface. In addition to stable oxides Sn4+ and Sn2,+ the existence of a homologous series of Snn+1O2n metastable compounds is assumed. It is proved that four-coordinated Sn+2 cations on the SnO2 surface can coexist only with oxygen vacancies in the immediate environment. Such cationic sites have the properties of strong Lewis acids and are highly reactive. Computer simulation of the SnO2 crystal surface allows us to propose a number of catalytic activity of SnO2 surfaces: (110) < (001) < (100) < (101). Preparation methods and synthesis parameters (nature and type of precursor, stabilizing agent and solvent, duration and temperature of the reaction, pH of the reaction mixture, etc.) determine the physicochemical properties of nanoparticles (shape, size, morphology and degree of crystallinity). The main (sol-gel, precipitation and coprecipitation, CVD, spray pyrolysis, hydrothermal, “green”) and less common (detonation, electric discharge) methods of nano-SnO2 obtaining are analyzed in the work. A variety of methods of synthesis and conditions makes it possible to obtain SnO2 nanoparticles with desired properties, which determine the activity of tin oxide in redox reactions, namely: nanosize and morphology of particles with prevalence of the most reactive faces - (100) і (101). Among the methods that do not require complex hardware design, one can dwell on the methods of sol-gel, "green" and coprecipitation. Tin oxide is traditionally used as an abrasive for polishing metal, glass and ceramic products. The transition to nanosized particles allows this material to reversibly absorb and release oxygen, which has determined its use in the design of gas-sensitive and biosensors, the creation of solar cells, fuel cells, lithium-ion batteries, oxidation catalysts, transparent and photoconductors. The multivalence and the presence of oxygen vacancies on the surface of tin oxide nanoparticles, the ease and speed of penetration into the cell membrane give nano-SnO2 properties of medicinal preparations, which makes it possible to use it in biomedical technologies for the treatment of diseases associated with oxidative stress lesions. The size, concentration of nanoparticles and modification of their surface are the key factors of influence, which usually intensify the antimicrobial, antibacterial, antitumor and antioxidant activity of the material.