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18 pages, 5022 KiB

Open AccessReview

Searching for New Gold(I)-Based Complexes as Anticancer and/or Antiviral Agents

by Paola Checconi, Annaluisa Mariconda, Alessia Catalano, Jessica Ceramella, Michele Pellegrino, Stefano Aquaro, Maria Stefania Sinicropi and Pasquale Longo

Molecules 2025, 30(8), 1726; https://doi.org/10.3390/molecules30081726 - 11 Apr 2025

Viewed by 848

Abstract

Approaches capable of simultaneously treating cancer and protecting susceptible patients from lethal infections are highly desirable, although they prove challenging. Taking inspiration from the well-known anticancer platinum complexes, successive studies about the complexation of organic compounds with other late transition metals, such as [...] Read more.

Approaches capable of simultaneously treating cancer and protecting susceptible patients from lethal infections are highly desirable, although they prove challenging. Taking inspiration from the well-known anticancer platinum complexes, successive studies about the complexation of organic compounds with other late transition metals, such as silver, gold, palladium, rhodium, ruthenium, iridium, and osmium, have led to remarkable anticancer activities. Among the numerous chemical moieties studied, N-heterocyclic carbenes (NHCs) have revealed very attractive activities due to their favorable chemical properties. Specifically, gold–NHC complexes emerged as some of the most active complexes acting as antitumor agents. On the other hand, some recent studies have highlighted the involvement of these complexes in antiviral research as well. The well-known gold-based, orally available complex auranofin approved by the Food and Drug Administration (FDA) for the treatment of rheumatoid arthritis has been suggested as a repositioned drug for both cancer and viral infections. In the era of the COVID-19 pandemic, the most interesting goal could be the discovery of gold–NHC complexes as dual antiviral and anticancer agents. In this review, the most recent studies regarding the anticancer and antiviral activities of gold(I)–NHC complexes will be analyzed and discussed, offering an interesting insight into the research in this field. Full article

(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 3rd Edition)

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5 pages, 552 KiB

Open AccessShort Note

Chloro(η²,η²-cycloocta-1,5-diene){1-benzyl-3-[(S)-2-hydroxy-1-methylethyl]benzimidazol-2-ylidene}rhodium(I)

by Satoshi Sakaguchi and Shogo Matsuo

Molbank 2024, 2024(2), M1811; https://doi.org/10.3390/M1811 - 19 Apr 2024

Viewed by 1187

Abstract

Previously, we demonstrated the synthesis of a well-defined hydroxyalkyl-functionalized N-heterocyclic carbene (NHC)/Ru(II) complex through the transmetalation reaction between [RuCl₂(p-cymene)]₂ and the corresponding NHC/Ag(I) complex derived from a chiral benzimidazolium salt using the Ag₂O method. In [...] Read more.

Previously, we demonstrated the synthesis of a well-defined hydroxyalkyl-functionalized N-heterocyclic carbene (NHC)/Ru(II) complex through the transmetalation reaction between [RuCl₂(p-cymene)]₂ and the corresponding NHC/Ag(I) complex derived from a chiral benzimidazolium salt using the Ag₂O method. In this study, we successfully synthesized [RhX(cod)(NHC)] complexes through a one-pot deprotonation route. The hydroxyalkyl-substituted benzimidazolium salt reacted with [Rh(OH)(cod)]₂ in THF at room temperature, affording the corresponding monodentate NHC/Rh(I) complex in nearly quantitative yield. The rhodium complex was characterized using NMR, HRMS measurement, and elemental analysis. Full article

(This article belongs to the Topic Heterocyclic Carbene Catalysis)

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5 pages, 640 KiB

Open AccessShort Note

Chloro(η²,η²-cycloocta-1,5-diene){1-[(2-[(S)-1-(hydroxymethyl)-3-methylbutyl]amino)-2-oxoethyl]-3-(1-naphthalenylmethyl)benzimidazol-2-ylidene}rhodium(I)

by Satoshi Sakaguchi and Shogo Matsuo

Molbank 2024, 2024(2), M1810; https://doi.org/10.3390/M1810 - 19 Apr 2024

Viewed by 1381

Abstract

Commercially available and air- and moisture-stable rhodium complex [Rh(OH)(cod)]₂ (2) was utilized in the synthesis of [RhX(cod)(NHC)] (3). The presence of an OH group in complex 2 serves as an internal base, facilitating the deprotonation of the C–H [...] Read more.

Commercially available and air- and moisture-stable rhodium complex [Rh(OH)(cod)]₂ (2) was utilized in the synthesis of [RhX(cod)(NHC)] (3). The presence of an OH group in complex 2 serves as an internal base, facilitating the deprotonation of the C–H bond of the azolium ring in the hydroxyamide-substituted benzimidazolium salt 1. This reaction between 1 and 2 proceeded in THF at room temperature without temperature control, affording the desired NHC/Rh complex 3 in excellent yield. The characterization of complex 3 was accomplished through NMR and HRMS analyses, revealing its existence as a diastereomeric mixture of two NHC/Rh complexes. Furthermore, its catalytic performance was briefly evaluated in the reaction between 2-naphthaldehyde (5) and phenylboronic acid (6). Full article

(This article belongs to the Topic Heterocyclic Carbene Catalysis)

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16 pages, 1642 KiB

Open AccessArticle

Substituent-Controllable Cascade Regioselective Annulation of β-Enaminones with N-Sulfonyl Triazoles for Modular Access to Imidazoles and Pyrroles

by Hua Wang, Tongtong Zhou, Mengdi Wu, Qingqing Ye and Xinwei He

Molecules 2023, 28(11), 4416; https://doi.org/10.3390/molecules28114416 - 29 May 2023

Cited by 4 | Viewed by 1724

Abstract

A controllable synthesis of trisubstituted imidazoles and pyrroles has been developed through rhodium(II)-catalyzed regioselective annulation of N-sulfonyl-1,2,3-trizaoles with β-enaminones. The imidazole ring was formed through a 1,1-insertion of the N-H bond to α-imino rhodium carbene, followed by a subsequent intramolecular 1,4-conjugate [...] Read more.

A controllable synthesis of trisubstituted imidazoles and pyrroles has been developed through rhodium(II)-catalyzed regioselective annulation of N-sulfonyl-1,2,3-trizaoles with β-enaminones. The imidazole ring was formed through a 1,1-insertion of the N-H bond to α-imino rhodium carbene, followed by a subsequent intramolecular 1,4-conjugate addition. This occurred when the α-carbon atom of the amino group was bearing a methyl group. Additionally, the pyrrole ring was constructed by utilizing a phenyl substituent and undergoing intramolecular nucleophilic addition. The mild conditions, good tolerance towards functional groups, gram-scale synthesis capability, and ability to undergo valuable transformations of the products qualify this unique protocol as an efficient tool for the synthesis of N-heterocycles. Full article

(This article belongs to the Special Issue Novel Organic Synthetic Route to Heterocyclic Compounds)

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12 pages, 2806 KiB

Open AccessArticle

Catalyst Loading Controls Chemoselectivity: Unusual Effect in Rhodium(II) Carbene Insertion Reactions with Tetrahydrofuran

by Alexander Kazantsev, Ivan A. Rodionov, Olga Bakulina, Grigory Kantin, Dmitry Dar’in and Mikhail Krasavin

Catalysts 2023, 13(2), 428; https://doi.org/10.3390/catal13020428 - 16 Feb 2023

Cited by 1 | Viewed by 2258

Abstract

(E)-3-Arylidene-4-diazopyrrolidine-2,5-diones previously shown to yield two products in reactions with tetrahydrofuran mediated by rhodium carbenes—tetrahydrofur-2-yl-substituted product of C-H insertion and spirocyclic product of formal C-O insertion. Accidentally, it was noted that the ratio of the two products depends on the catalyst loading, [...] Read more.

(E)-3-Arylidene-4-diazopyrrolidine-2,5-diones previously shown to yield two products in reactions with tetrahydrofuran mediated by rhodium carbenes—tetrahydrofur-2-yl-substituted product of C-H insertion and spirocyclic product of formal C-O insertion. Accidentally, it was noted that the ratio of the two products depends on the catalyst loading, and the phenomenon was investigated in detail. It was found to be of preparative significance: by solely changing the catalyst loading from 0.01 mol% to 10 mol%, one can obtain sound yields of either of the two products. Mechanistic and kinetic interpretation of this new phenomenon has been proposed. Full article

(This article belongs to the Special Issue Catalysts in Energy Applications II)

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12 pages, 2467 KiB

Open AccessArticle

X-H Bond Insertion Promoted by Heterogeneous Dirhodium Metal–Organic Cage with Alkynes as Safe Carbene Precursors

by Lianfen Chen, Chaoyi Zhao, Weixian Mo, Chunsheng Li and Xiaoming Lin

Molecules 2023, 28(2), 608; https://doi.org/10.3390/molecules28020608 - 6 Jan 2023

Cited by 3 | Viewed by 1974

Abstract

A facile and efficient methodology for the generation of the C-X (X = Si, B) bond through a carbene insertion process was demonstrated using a dirhodium metal–organic cage, MOC-Rh-1, as a heterogeneous catalyst. A series of functionalized alkynes were utilized as [...] Read more.

A facile and efficient methodology for the generation of the C-X (X = Si, B) bond through a carbene insertion process was demonstrated using a dirhodium metal–organic cage, MOC-Rh-1, as a heterogeneous catalyst. A series of functionalized alkynes were utilized as safe carbene precursors to furnish Si-H and B-H insertion products in moderate to excellent yields. These reactions featured a high atom-economy, a broad substrate scope, and mild reaction conditions. Moreover, the as-prepared MOC-Rh-1 catalyst was recovered easily from the reaction system by simple centrifugation and reused for ten runs without a significant loss in activity, which made good use of the valuable precious metal rhodium. Full article

(This article belongs to the Special Issue Molecule-Based Crystalline Materials)

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15 pages, 1968 KiB

Open AccessArticle

Preparation of Mixed Bis-N-Heterocyclic Carbene Rhodium(I) Complexes

by Ramón Azpíroz, Mert Olgun Karataş, Vincenzo Passarelli, Ismail Özdemir, Jesús J. Pérez-Torrente and Ricardo Castarlenas

Molecules 2022, 27(20), 7002; https://doi.org/10.3390/molecules27207002 - 18 Oct 2022

Viewed by 2071

Abstract

A series of mixed bis-NHC rhodium(I) complexes of type RhCl(η²-olefin)(NHC)(NHC’) have been synthesized by a stepwise reaction of [Rh(μ-Cl)(η²-olefin)₂]₂ with two different NHCs (NHC = N-heterocyclic carbene), in which the steric hindrance of both [...] Read more.

A series of mixed bis-NHC rhodium(I) complexes of type RhCl(η²-olefin)(NHC)(NHC’) have been synthesized by a stepwise reaction of [Rh(μ-Cl)(η²-olefin)₂]₂ with two different NHCs (NHC = N-heterocyclic carbene), in which the steric hindrance of both NHC ligands and the η²-olefin is critical. Similarly, new mixed coumarin-functionalized bis-NHC rhodium complexes have been prepared by a reaction of mono NHC complexes of type RhCl(NHC-coumarin)(η²,η²-cod) with the corresponding azolium salt in the presence of an external base. Both synthetic procedures proceed selectively and allow the preparation of mixed bis-NHC rhodium complexes in good yields. Full article

(This article belongs to the Special Issue Organometallic Complexes: Fundamentals and Applications)

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12 pages, 2767 KiB

Open AccessArticle

Enantiopure Cyclometalated Rh(III) and Ir(III) Complexes Displaying Rigid Configuration at Metal Center: Design, Structures, Chiroptical Properties and Role of the Iodide Ligand

by Antoine Groué, Jean-Philippe Tranchier, Geoffrey Gontard, Marion Jean, Nicolas Vanthuyne and Hani Amouri

Chemistry 2022, 4(1), 156-167; https://doi.org/10.3390/chemistry4010014 - 12 Mar 2022

Viewed by 2838

Abstract

Enantiopure N-heterocyclic carbene half-sandwich metal complexes of the general formula [Cp*M(C^C:)I] (M = Rh, Ir; C^C: = NI-NHC; NI-H = Naphthalimide; NHC = N-heterocyclic carbene) are reported. The rhodium compound was obtained as a single isomer displaying six membered metallacycle and [...] Read more.

Enantiopure N-heterocyclic carbene half-sandwich metal complexes of the general formula [Cp*M(C^C:)I] (M = Rh, Ir; C^C: = NI-NHC; NI-H = Naphthalimide; NHC = N-heterocyclic carbene) are reported. The rhodium compound was obtained as a single isomer displaying six membered metallacycle and was resolved on chiral column chromatography to the corresponding enantiomers (S)-[Cp*Rh(C^C:)I] (S)-2 and (R)-[Cp*Rh(C^C:)I] (R)-2. The iridium congener, however, furnishes a pair of regioisomers, which were resolved into (S)-[Cp*Ir(C^C:)I] (S)-3 and (R)-[Cp*Ir(C^C:)I] (R)-3 and (S)-[Cp*Ir(C^C:)I] (S)-4 and (R)-[Cp*Ir(C^C:)I] (R)-4. These regioisomers differ from each other, only by the size of the metallacycle; five-membered for 3 and six-membered for 4. The molecular structures of (S)-2 and (S)-4 are reported. Moreover, the chiroptical properties of these compounds are presented and discussed. These compounds display exceptional stable configurations at the metal center in solution with enantiomerization barrier ΔG^≠ up to 124 kJ/mol. This is because the nature of the naphthalimide-NHC clamp ligand and the iodide ligand contribute to their configuration’s robustness. In contrast to related complexes reported in the literature, which are often labile in solution. Full article

(This article belongs to the Special Issue Special Issue to Celebrate the Life and Work of Alexander von Zelewsky (1936–2021))

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15 pages, 2261 KiB

Open AccessArticle

General Method to Increase Carboxylic Acid Content on Nanodiamonds

by Ganesh Shenoy, Jessica Ettedgui, Chandrasekhar Mushti, Jennifer Hong, Kelly Lane, Burchelle Blackman, Hak-Sung Jung, Yasuharu Takagi, Yeonee Seol, Martin Brechbiel, Rolf E. Swenson and Keir C. Neuman

Molecules 2022, 27(3), 736; https://doi.org/10.3390/molecules27030736 - 23 Jan 2022

Cited by 9 | Viewed by 4510

Abstract

Carboxylic acid is a commonly utilized functional group for covalent surface conjugation of carbon nanoparticles that is typically generated by acid oxidation. However, acid oxidation generates additional oxygen containing groups, including epoxides, ketones, aldehydes, lactones, and alcohols. We present a method to specifically [...] Read more.

Carboxylic acid is a commonly utilized functional group for covalent surface conjugation of carbon nanoparticles that is typically generated by acid oxidation. However, acid oxidation generates additional oxygen containing groups, including epoxides, ketones, aldehydes, lactones, and alcohols. We present a method to specifically enrich the carboxylic acid content on fluorescent nanodiamond (FND) surfaces. Lithium aluminum hydride is used to reduce oxygen containing surface groups to alcohols. The alcohols are then converted to carboxylic acids through a rhodium (II) acetate catalyzed carbene insertion reaction with tert–butyl diazoacetate and subsequent ester cleavage with trifluoroacetic acid. This carboxylic acid enrichment process significantly enhanced nanodiamond homogeneity and improved the efficiency of functionalizing the FND surface. Biotin functionalized fluorescent nanodiamonds were demonstrated to be robust and stable single-molecule fluorescence and optical trapping probes. Full article

(This article belongs to the Section Nanochemistry)

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25 pages, 31428 KiB

Open AccessReview

Electrocyclizations of Conjugated Azapolyenes Produced in Reactions of Azaheterocycles with Metal Carbenes

by Nikolai V. Rostovskii, Mikhail S. Novikov and Alexander F. Khlebnikov

Organics 2021, 2(3), 313-336; https://doi.org/10.3390/org2030017 - 14 Sep 2021

Cited by 6 | Viewed by 4173

Abstract

Conjugated azapolyenes (azabuta-1,3-dienes, aza-/diaza-/oxaza-/oxadiazahexa-1,3,5-trienes) are highly reactive in electrocyclization reactions, which makes them convenient precursors for the synthesis of a wide range of four-, five-, and six-membered nitrogen heterocycles that are of relevance for medicinal chemistry. Ring opening reactions of 2H-azirines [...] Read more.

Conjugated azapolyenes (azabuta-1,3-dienes, aza-/diaza-/oxaza-/oxadiazahexa-1,3,5-trienes) are highly reactive in electrocyclization reactions, which makes them convenient precursors for the synthesis of a wide range of four-, five-, and six-membered nitrogen heterocycles that are of relevance for medicinal chemistry. Ring opening reactions of 2H-azirines and azoles containing an N–N or N–O bond, initiated by a transition metal carbene, have become increasingly important in recent years, since they easily allow the generation of azapolyenes with different numbers of double bonds and heteroatoms in various positions. This review summarizes the literature, published mainly in the last decade, on the synthetic and mechanistic aspects of electrocyclizations of azapolyenes generated by the carbene method. Full article

(This article belongs to the Special Issue Pericyclic Reactions in Organic Synthesis)

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9 pages, 1412 KiB

Open AccessFeature PaperArticle

Unprecedented Use of NHC Gold (I) Complexes as Catalysts for the Selective Oxidation of Ethane to Acetic Acid

by Ana P. C. Ribeiro, Inês A. S. Matias, Poorya Zargaran, A. Stephen K. Hashmi and Luísa M. D. R. S. Martins

Materials 2021, 14(15), 4294; https://doi.org/10.3390/ma14154294 - 31 Jul 2021

Cited by 6 | Viewed by 2748

Abstract

The highly efficient eco-friendly synthesis of acetic acid (40% yield) directly from ethane is achieved by the unprecedented use of N-heterocyclic carbene (NHC) and N-heterocyclic oxo-carbene (NHOC) gold(I) catalysts in mild conditions. This is a selective and promising protocol to generate directly acetic [...] Read more.

The highly efficient eco-friendly synthesis of acetic acid (40% yield) directly from ethane is achieved by the unprecedented use of N-heterocyclic carbene (NHC) and N-heterocyclic oxo-carbene (NHOC) gold(I) catalysts in mild conditions. This is a selective and promising protocol to generate directly acetic acid from ethane, in comparison with the two most used methods: (i) the three-step, capital- and energy-intensive process based on the high-temperature conversion of methane to acetic acid; (ii) the current industrial methanol carbonylation processes, based in iridium and expensive rhodium catalysts. Green metrics determinations highlight the environmental advantages of the new ethane oxidation procedure. Comparison with previous reported published catalysts is performed to highlight the features of this remarkable protocol. Full article

(This article belongs to the Special Issue Transition Metal Complexes and Their Applications)

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17 pages, 31063 KiB

Open AccessArticle

Facile N9-Alkylation of Xanthine Derivatives and Their Use as Precursors for N-Heterocyclic Carbene Complexes

by Moloud Mokfi, Jörg Rust, Christian W. Lehmann and Fabian Mohr

Molecules 2021, 26(12), 3705; https://doi.org/10.3390/molecules26123705 - 17 Jun 2021

Cited by 6 | Viewed by 3090

Abstract

The xanthine-derivatives 1,3,7-trimethylxanthine, 1,3-dimethyl-7-benzylxanthine and 1,3-dimethyl-7-(4-chlorobenzyl)xanthine are readily ethylated at N9 using the cheap alkylating agents ethyl tosylate or diethyl sulfate. The resulting xanthinium tosylate or ethyl sulfate salts can be converted into the corresponding PF₆⁻ and chloride salts. The reaction [...] Read more.

The xanthine-derivatives 1,3,7-trimethylxanthine, 1,3-dimethyl-7-benzylxanthine and 1,3-dimethyl-7-(4-chlorobenzyl)xanthine are readily ethylated at N9 using the cheap alkylating agents ethyl tosylate or diethyl sulfate. The resulting xanthinium tosylate or ethyl sulfate salts can be converted into the corresponding PF₆⁻ and chloride salts. The reaction of these xanthinium salts with silver(I) oxide results in the formation of different silver(I) carbene-complexes. In the presence of ammonia, ammine complexes [Ag(NHC)(NH₃)]PF₆ are formed, whilst with Et₂NH, the bis(carbene) salts [Ag(NHC)₂]PF₆ were isolated. Using the xanthinium chloride salts neutral silver(I) carbenes [Ag(NHC)Cl] were prepared. These silver complexes were used in a variety of transmetallation reactions to give the corresponding gold(I), ruthenium(II) as well as rhodium(I) and rhodium(III) complexes. The compounds were characterized by various spectroscopic methods as well as X-ray diffraction. Full article

(This article belongs to the Special Issue Advances in Organometallic Chemistry—Papers of the Editorial Board Members (EBMs))

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24 pages, 5206 KiB

Open AccessReview

Rh(I) Complexes in Catalysis: A Five-Year Trend

by Serenella Medici, Massimiliano Peana, Alessio Pelucelli and Maria Antonietta Zoroddu

Molecules 2021, 26(9), 2553; https://doi.org/10.3390/molecules26092553 - 27 Apr 2021

Cited by 15 | Viewed by 5216

Abstract

Rhodium is one of the most used metals in catalysis both in laboratory reactions and industrial processes. Despite the extensive exploration on “classical” ligands carried out during the past decades in the field of rhodium-catalyzed reactions, such as phosphines, and other common types [...] Read more.

Rhodium is one of the most used metals in catalysis both in laboratory reactions and industrial processes. Despite the extensive exploration on “classical” ligands carried out during the past decades in the field of rhodium-catalyzed reactions, such as phosphines, and other common types of ligands including N-heterocyclic carbenes, ferrocenes, cyclopentadienyl anion and pentamethylcyclopentadienyl derivatives, etc., there is still lively research activity on this topic, with considerable efforts being made toward the synthesis of new preformed rhodium catalysts that can be both efficient and selective. Although the “golden age” of homogeneous catalysis might seem over, there is still plenty of room for improvement, especially from the point of view of a more sustainable chemistry. In this review, temporally restricted to the analysis of literature during the past five years (2015–2020), the latest findings and trends in the synthesis and applications of Rh(I) complexes to catalysis will be presented. From the analysis of the most recent literature, it seems clear that rhodium-catalyzed processes still represent a stimulating challenge for the metalloorganic chemist that is far from being over. Full article

(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry)

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18 pages, 2447 KiB

Open AccessArticle

Redox Isomerization of Allylic Alcohols Catalyzed by New Water-Soluble Rh(I)-N-Heterocyclic Carbene Complexes

by Csilla Enikő Czégéni, Marianna Fekete, Eszter Tóbiás, Antal Udvardy, Henrietta Horváth, Gábor Papp and Ferenc Joó

Catalysts 2020, 10(11), 1361; https://doi.org/10.3390/catal10111361 - 23 Nov 2020

Cited by 9 | Viewed by 3680

Abstract

New water-soluble, N-heterocyclic carbene (NHC) or mixed NHC/tertiary phosphine complexes [RhCl(cod)(sSIMes)], Na₂[Rh(bmim)(cod)(mtppts)], and [Rh(bmim)(cod)(pta)]BF₄ were synthetized and applied for the first time as catalysts in redox isomerization of allylic alcohols in aqueous media. [RhCl(cod)(sSIMes)] (with added sulfonated [...] Read more.

New water-soluble, N-heterocyclic carbene (NHC) or mixed NHC/tertiary phosphine complexes [RhCl(cod)(sSIMes)], Na₂[Rh(bmim)(cod)(mtppts)], and [Rh(bmim)(cod)(pta)]BF₄ were synthetized and applied for the first time as catalysts in redox isomerization of allylic alcohols in aqueous media. [RhCl(cod)(sSIMes)] (with added sulfonated triphenylphosphine) and [Rh(bmim)(cod)(pta)]BF₄ catalyzed selectively the transformation of allylic alcohols to the corresponding ketones. The highest catalytic activity, TOF = 152 h⁻¹ (TOF = (mol reacted substrate) × (mol catalyst × time)⁻¹) was observed in redox isomerization of hept-1-en-3-ol ([S]/[cat] = 100). The catalysts were reused in the aqueous phase at least three times, with only modest loss of the catalytic activity and selectivity. Full article

(This article belongs to the Special Issue Catalysis in Heterocyclic and Organometallic Synthesis)

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16 pages, 1889 KiB

Open AccessArticle

Selective Hydration of Nitriles to Corresponding Amides in Air with Rh(I)-N-Heterocyclic Complex Catalysts

by Csilla Enikő Czégéni, Sourav De, Antal Udvardy, Nóra Judit Derzsi, Gergely Papp, Gábor Papp and Ferenc Joó

Catalysts 2020, 10(1), 125; https://doi.org/10.3390/catal10010125 - 16 Jan 2020

Cited by 21 | Viewed by 5649

Abstract

A new synthetic method for obtaining [RhCl(cod)(NHC)] complexes (1–4) (cod = η⁴-1,5-cyclooctadiene, NHC = N-heterocyclic carbene: IMes, SIMes, IPr, and SIPr, respectively) is reported together with the catalytic properties of 1–4 in nitrile hydration. [...] Read more.

A new synthetic method for obtaining [RhCl(cod)(NHC)] complexes (1–4) (cod = η⁴-1,5-cyclooctadiene, NHC = N-heterocyclic carbene: IMes, SIMes, IPr, and SIPr, respectively) is reported together with the catalytic properties of 1–4 in nitrile hydration. In addition to the characterization of 1–4 in solution by ¹³C NMR spectroscopy, the structures of complexes 3, and 4 have been established also in the solid state with single-crystal X-ray diffraction analysis. The Rh(I)-NHC complexes displayed excellent catalytic activity in hydration of aromatic nitriles (up to TOF = 276 h⁻¹) in water/2-propanol (1/1 v/v) mixtures in air. Full article

(This article belongs to the Special Issue Catalysis in Heterocyclic and Organometallic Synthesis)

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