Catalysts

Review

24 pages, 12197 KiB

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Chiral Porous Organic Frameworks: Synthesis, Chiroptical Properties, and Asymmetric Organocatalytic Applications

by Miguel Sanchez-Fuente, José Lorenzo Alonso-Gómez, Laura M. Salonen, Ruben Mas-Ballesté and Alicia Moya

Catalysts 2023, 13(7), 1042; https://doi.org/10.3390/catal13071042 - 27 Jun 2023

Cited by 4 | Viewed by 2739

Abstract

Chiral porous organic frameworks have emerged in the last decade as candidates for heterogeneous asymmetric organocatalysis. This review aims to provide a summary of the synthetic strategies towards the design of chiral organic materials, the characterization techniques used to evaluate their chirality, and [...] Read more.

Chiral porous organic frameworks have emerged in the last decade as candidates for heterogeneous asymmetric organocatalysis. This review aims to provide a summary of the synthetic strategies towards the design of chiral organic materials, the characterization techniques used to evaluate their chirality, and their applications in asymmetric organocatalysis. We briefly describe the types of porous organic frameworks, including crystalline (covalent organic frameworks, COFs) and amorphous (conjugated microporous polymers, CMPs; covalent triazine frameworks, CTFs and porous aromatic frameworks, PAFs) materials. Furthermore, the strategies reported to incorporate chirality in porous organic materials are presented. We finally focus on the applications of chiral porous organic frameworks in asymmetric organocatalytic reactions, summarizing and categorizing all the available literature in the field. Full article

(This article belongs to the Special Issue Exclusive Review Papers in Catalysis in Organic and Polymer Chemistry)

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19 pages, 3610 KiB

Open AccessFeature PaperReview

Use of Deep Eutectic Solvents in Plastic Depolymerization

by Andrea Nicola Paparella, Serena Perrone, Antonio Salomone, Francesco Messa, Luciana Cicco, Vito Capriati, Filippo Maria Perna and Paola Vitale

Catalysts 2023, 13(7), 1035; https://doi.org/10.3390/catal13071035 - 25 Jun 2023

Cited by 14 | Viewed by 5837

Abstract

Polymeric materials are widely used in every human endeavor (bottles, clothes, containers, toys, tools, etc.) due to their unique properties of chemical and mechanical resistance. They are, however, almost non-biodegradable, and their chemical recycling into monomers is difficult and costly, thereby allowing their [...] Read more.

Polymeric materials are widely used in every human endeavor (bottles, clothes, containers, toys, tools, etc.) due to their unique properties of chemical and mechanical resistance. They are, however, almost non-biodegradable, and their chemical recycling into monomers is difficult and costly, thereby allowing their accumulation into the environment. This review highlights recent advances in the use of deep eutectic solvents (DESs) as catalysts and/or green solvents in plastics degradation, with the aim of designing greener processes for polymers’ chemical recycling, by reusing their monomers. These greener processes, in combination with other catalytic approaches, are aimed at introducing plastics as feedstock into the synthesis of other materials, according to the circular economy principles. Full article

(This article belongs to the Special Issue Exclusive Review Papers in Catalysis in Organic and Polymer Chemistry)

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23 pages, 23164 KiB

Open AccessFeature PaperReview

An Overview of Catalytic Carbonylative Double Cyclization Reactions

by Bartolo Gabriele, Raffaella Mancuso, Nicola Della Ca’, Lucia Veltri and Ida Ziccarelli

Catalysts 2023, 13(6), 1025; https://doi.org/10.3390/catal13061025 - 20 Jun 2023

Cited by 7 | Viewed by 1702

Abstract

This short review is aimed at giving an overview of catalytic carbonylative double cyclization reactions, which are processes in which suitable organic substrates and carbon monoxide are sequentially activated by a promoting a catalyst to form two new cycles with the concomitant incorporation [...] Read more.

This short review is aimed at giving an overview of catalytic carbonylative double cyclization reactions, which are processes in which suitable organic substrates and carbon monoxide are sequentially activated by a promoting a catalyst to form two new cycles with the concomitant incorporation of carbon monoxide as a carbonyl function in the final product. Paradigmatic examples of this powerful synthetic methodology, which allows the one-step synthesis of complex molecular architectures from simple building blocks using the simplest and readily available C-1 unit (CO), are illustrated and discussed. The review is divided into five sections: (1) Introduction, (2) Functionalized Olefinic Substrates, (3) Functionalized Acetylenic Substrates, (4) Functionalized Halides, (5) Conclusions and Future Perspectives. Full article

(This article belongs to the Special Issue Exclusive Review Papers in Catalysis in Organic and Polymer Chemistry)

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20 pages, 3046 KiB

Open AccessFeature PaperReview

Metal-Catalyzed Cascade Reactions between Alkynoic Acids and Dinucleophiles: A Review

by María Teresa Herrero, Jokin Díaz de Sarralde, Nerea Conde, Aitor Herrán, Garazi Urgoitia and Raul SanMartin

Catalysts 2023, 13(3), 495; https://doi.org/10.3390/catal13030495 - 28 Feb 2023

Cited by 4 | Viewed by 2031

Abstract

Cascade reactions provide a straightforward access to many valuable compounds and reduce considerably the number of steps of a synthetic sequence. Among the domino and multicomponent processes that involve alkynes, the cascade reaction between alkynoic acids and C-, N-, O- and S-aminonucleophiles stands [...] Read more.

Cascade reactions provide a straightforward access to many valuable compounds and reduce considerably the number of steps of a synthetic sequence. Among the domino and multicomponent processes that involve alkynes, the cascade reaction between alkynoic acids and C-, N-, O- and S-aminonucleophiles stands out as a particularly powerful tool for the one-pot construction of libraries of nitrogen-containing heterocyclic compounds with scaffold diversity and molecular complexity. This reaction, based on an initial metal-catalyzed cycloisomerization that generates an alkylidene lactone intermediate, was originally catalyzed by gold(I) catalysts, along with silver salts or Brönsted acid additives, but other alternative metal catalysts have emerged in the last decade as well as different reaction media. This review examines the existing literature on the topic of metal-catalyzed cascade reactions of acetylenic acids and dinucleophiles and discusses aspects concerning substrate/catalyst ratio for every catalyst system, nature of the aminonucleophile involved and substrate scope. In addition, alternative solvents are also considered, and an insight into the pathway of the reaction and possible intermediates is also provided. Full article

(This article belongs to the Special Issue Exclusive Review Papers in Catalysis in Organic and Polymer Chemistry)

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28 pages, 6740 KiB

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Gold Complexes with Hydrophilic N-Heterocyclic Carbene Ligands and Their Contribution to Aqueous-Phase Catalysis

by Pascale Crochet and Victorio Cadierno

Catalysts 2023, 13(2), 436; https://doi.org/10.3390/catal13020436 - 17 Feb 2023

Cited by 3 | Viewed by 2343

Abstract

N-Heterocyclic carbenes (NHCs) are nowadays one of the most widely employed ligands in organometallic chemistry and homogeneous catalysis due to the inherent stability of the metal-carbene bond and the ease of modification of the backbone as well as the N-wingtips substituents [...] Read more.

N-Heterocyclic carbenes (NHCs) are nowadays one of the most widely employed ligands in organometallic chemistry and homogeneous catalysis due to the inherent stability of the metal-carbene bond and the ease of modification of the backbone as well as the N-wingtips substituents of these ligands. The functionalization of NHCs with hydrophilic groups offers the possibility of using NHC-metal complexes in aqueous catalysis, a hot topic within the Green Chemistry context due to the positive implications associated with the use of water as a reaction medium. In line with the enormous interest aroused by gold complexes in catalysis, significant efforts have been directed in the last years to the design and application of hydrophilic NHC-gold catalysts. This review is aimed to summarize the research in this area. The catalytic applications of water-soluble gold nanoparticles stabilized by hydrophilic NHCs are also covered. Full article

(This article belongs to the Special Issue Exclusive Review Papers in Catalysis in Organic and Polymer Chemistry)

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25 pages, 12011 KiB

Open AccessReview

Applications of Hantzsch Esters in Organocatalytic Enantioselective Synthesis

by Ana Maria Faisca Phillips and Armando J. L. Pombeiro

Catalysts 2023, 13(2), 419; https://doi.org/10.3390/catal13020419 - 16 Feb 2023

Cited by 14 | Viewed by 6534

Abstract

Hantzsch esters (1,4-dihydropyridine dicarboxylates) have become, in this century, very versatile reagents for enantioselective organic transformations. They can act as hydride transfer agents to reduce, regioselectively, a variety of multiple bonds, e.g., C=C and C=N, under mild reaction conditions. They are excellent reagents [...] Read more.

Hantzsch esters (1,4-dihydropyridine dicarboxylates) have become, in this century, very versatile reagents for enantioselective organic transformations. They can act as hydride transfer agents to reduce, regioselectively, a variety of multiple bonds, e.g., C=C and C=N, under mild reaction conditions. They are excellent reagents for the dearomatization of heteroaromatic substances, and participate readily in cascade processes. In the last few years, they have also become useful reagents for photoredox reactions. They can participate as sacrificial electron and hydrogen donors and when 4-alkyl or 4-acyl-substituted, they can act as alkyl or acyl radical transfer agents. These last reactions may take place in the presence or absence of a photocatalyst. This review surveys the literature published in this area in the last five years. Full article

(This article belongs to the Special Issue Exclusive Review Papers in Catalysis in Organic and Polymer Chemistry)

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30 pages, 9014 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Direct Catalytic Amidations from Carboxylic Acid and Ester Derivatives: A Review

by Armand Taussat, Renata Marcia de Figueiredo and Jean-Marc Campagne

Catalysts 2023, 13(2), 366; https://doi.org/10.3390/catal13020366 - 7 Feb 2023

Cited by 24 | Viewed by 11328

Abstract

The prevalence of amides in biological systems and chemical fields such as polymers, materials and natural products drives continuous research on novel procedures to obtain these ubiquitous functional groups. Currently, efforts to this purpose are mainly focused around the discovery of direct and [...] Read more.

The prevalence of amides in biological systems and chemical fields such as polymers, materials and natural products drives continuous research on novel procedures to obtain these ubiquitous functional groups. Currently, efforts to this purpose are mainly focused around the discovery of direct and catalytic methods that are more atom economic, safe and practical for diversified applications (e.g., organic, medicinal and peptide chemistries, material and polymer purposes, etc.), in accordance with green chemistry principles. The field of amide synthesis has attained such a level of significance that the number of reviews and articles addressing it grown exponentially in the last decade. Rather than providing a general overview of amidation methods, which have been described broadly and well in recent literature, the purpose of this review is to highlight recent efforts in the catalytic formation of amide bonds from amines and carboxylic acids or esters. The goal is to emphasize mechanistic and catalytic aspects, but also to discuss substrate tolerance and racemization issues (when applicable). Full article

(This article belongs to the Special Issue Exclusive Review Papers in Catalysis in Organic and Polymer Chemistry)

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64 pages, 21660 KiB

Open AccessReview

Palladium Supported on Bioinspired Materials as Catalysts for C–C Coupling Reactions

by Gianluigi Albano, Antonella Petri and Laura Antonella Aronica

Catalysts 2023, 13(1), 210; https://doi.org/10.3390/catal13010210 - 16 Jan 2023

Cited by 8 | Viewed by 2770

Abstract

In recent years, the immobilization of palladium nanoparticles on solid supports to prepare active and stable catalytic systems has been deeply investigated. Compared to inorganic materials, naturally occurring organic solids are inexpensive, available and abundant. Moreover, the surface of these solids is fully [...] Read more.

In recent years, the immobilization of palladium nanoparticles on solid supports to prepare active and stable catalytic systems has been deeply investigated. Compared to inorganic materials, naturally occurring organic solids are inexpensive, available and abundant. Moreover, the surface of these solids is fully covered by chelating groups which can stabilize the metal nanoparticles. In the present review, we have focused our attention on natural biomaterials-supported metal catalysts applied to the formation of C–C bonds by Mizoroki–Heck, Suzuki–Miyaura and Sonogashira reactions. A systematic approach based on the nature of the organic matrix will be followed: (i) metal catalysts supported on cellulose; (ii) metal catalysts supported on starch; (iii) metal catalysts supported on pectin; (iv) metal catalysts supported on agarose; (v) metal catalysts supported on chitosan; (vi) metal catalysts supported on proteins and enzymes. We will emphasize the effective heterogeneity and recyclability of each catalyst, specifying which studies were carried out to evaluate these aspects. Full article

(This article belongs to the Special Issue Exclusive Review Papers in Catalysis in Organic and Polymer Chemistry)

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19 pages, 4890 KiB

Open AccessReview

Morphology and Photocatalytic Activity of Zinc Oxide Reinforced Polymer Composites: A Mini Review

by Mokgaotsa Jonas Mochane, Mary Tholwana Motloung, Teboho Clement Mokhena and Tladi Gideon Mofokeng

Catalysts 2022, 12(11), 1439; https://doi.org/10.3390/catal12111439 - 15 Nov 2022

Cited by 12 | Viewed by 2716

Abstract

There is an approximately 3% of fresh water available globally for utilization, while the rest of the water is not available for usage, leaving billions of people with less water. Less water availability means that the majority of water consists of pollutants either [...] Read more.

There is an approximately 3% of fresh water available globally for utilization, while the rest of the water is not available for usage, leaving billions of people with less water. Less water availability means that the majority of water consists of pollutants either in ground water or drinking water, which in turn may have a negative impact on the environment and people. Various methods such as plasma technology, flocculation, neutralization, and disinfection have been utilized for wastewater treatment. The wastewater treatment methods have been found to be selective in terms of the removal of other pollutants, as a result, the majority of them are unable to remove pollutants such as antibiotics at a trace level. In order to ensure that there is a complete removal of pollutants from water, there is a need for the development of alternative wastewater treatment methods. The use of solar light by photocatalysis is an alternative method for the degradation of toxic pollutants. Different photocatalysts such as zinc oxide (ZnO), titanium dioxide (TiO₂), and silver (Ag) have been used in the process of photocatalysis. However, the above photocatalysts were found to have drawbacks such as agglomeration at higher contents and health problems during transportation. To solve the above problem, the nanoparticles were immobilized in various matrices such as polymers and ceramics, with polymers being preferred because of low cost, chemical inertness, and high durability. The current review discusses various methods for the preparation of ZnO and its synergy with other nanoparticles incorporated in various polymer matrices. Because it is known that the preparation method(s) affects the morphology, the morphology and the photocatalytic activity of various ZnO/polymer composites and hybrid systems of ZnO/other nanoparticles/polymer composites are discussed in depth. Full article

(This article belongs to the Special Issue Exclusive Review Papers in Catalysis in Organic and Polymer Chemistry)

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