Robby Vroemans

Nature Synthesis, Published online: 15 June 2023; doi:10.1038/s44160-023-00341-3

Publication date: 12 October 2023

Source: Chem, Volume 9, Issue 10

Author(s): Jieran Ma, Duy Le, Ning Yan

Nature, Published online: 14 June 2023; doi:10.1038/s41586-023-05987-9

Dual-atom catalysts (DACs) have been a new frontier in heterogeneous catalysis due to their unique intrinsic properties. The synergy between dual atoms provides flexible active sites, promising to enhance performance and even catalyze more complex reactions. However, precisely regulating active site structure and uncovering dual-atom metal interaction remain grand challenges. In this review, we clarify the significance of the inter-metal interaction of DACs based on the understanding of active center structures. Three diatomic configurations are elaborated, including isolated dual single-atom, N/O-bridged dual-atom, and direct dual-metal bonding interaction. Subsequently, the up-to-date progress in heterogeneous oxidation reactions, hydrogenation/dehydrogenation reactions, electrocatalytic reactions, and photocatalytic reactions are summarized. The structure-activity relationship between DACs and catalytic performance is then discussed at an atomic level. Finally, the challenges and future directions to engineer the structure of DACs are discussed. This review will offer new prospects for the rational design of efficient DACs toward heterogeneous catalysis.

A heterogeneous Pd₁−Ru₁ dual-single-atoms catalyst supported on porous ionic polymers was fabricated via a wet impregnation method and applied in acetylene dialkoxycarbonylation. The molecular structure of the Pd₁−Ru₁ catalyst was determined to be [P]⁺−[PdI₃−I−RuCl₂(CO)₃]⁻, with a synergetic effect between the neighboring Pd₁ and Ru₁ single sites elevating the overall activity and stabilizing the active site.

Abstract

Heterogeneous single-metal-site catalysts usually suffer from poor stability, thereby limiting industrial applications. Dual Pd₁−Ru₁ single-atom-sites supported on porous ionic polymers (Pd₁−Ru₁/PIPs) were constructed using a wetness impregnation method. The two isolated metal species in the form of a binuclear complex were immobilized on the cationic framework of PIPs through ionic bonds. Compared to the single Pd- or Ru-site catalyst, the dual single-atom system exhibits higher activity with 98 % acetylene conversion and near 100 % selectivity to dialkoxycarbonylation products, as well as better cycling stability for ten cycles without obvious decay. Based on DFT calculations, it was found that the single-Ru site exhibited a strong CO adsorption energy of −1.6 eV, leading to an increase in the local CO concentration of the catalyst. Notably, the Pd₁−Ru₁/PIPs catalyst had a much lower energy barrier of 2.49 eV compared to 3.87 eV of Pd₁/PIPs for the rate-determining step. The synergetic effect between neighboring single sites Pd₁ and Ru₁ not only enhanced the overall activity, but also stabilized Pd^II active sites. The discovery of synergetic effects between single sites can deepen our understanding of single-site catalysts at the molecular level.

Abstract

The employing visible light to drive organic transformations is the most promising choice to meet the needs for green synthesis, in which the reactions promoted by visible light may provide a more efficient and greener method. Currently, the most abundant methods for activation and functionalization of reaction substrates have relied on the direct single-electron transfer (SET) between the excited photocatalyst and substrates, and these wonderful works were summarized and docoumented in many reviews. As a complement to the above reactions, the photoredox-mediated atom transfer transformations (photocatalyst-to-HAT catalyst-to-substrates) to generate radical species are showing an explosively growing trend. In this review, we highlight recent significant developments in this rapidly growing area, mainly focusing on the photoinduced base-to-substrates charge transfer reactions.

Nature Synthesis, Published online: 08 June 2023; doi:10.1038/s44160-023-00342-2

The Front Cover shows the commitment that our generation must keep towards future generations: reconciling our well-being with planetary health, while preserving the same opportunities for posterity. It depends on our ability to produce useful and specialty chemicals in economical, environmentally friendlier, resource-preserving, and energy-efficient ways. Organocatalysis allows to leave a greener world to our children when applied to the efficient utilization and upgrading of raw low-value renewable resources, addressing the principles of the circular economy and sustainable development. Cover design by Sara Meninno and Luca Meninno. More information can be found in the Review by S. Meninno.

Base metal catalyzed oxidative alkane dehydrogenation has emerged as a viable strategy for olefin synthesis for its usage of cheap catalysts, compatibility with various functional groups, and low reaction temperature. In this review, we discuss recent development of base metal catalyzed alkane dehydrogenation under oxidative conditions and their application in constructing complex molecules.

Abstract

Preparing valuable olefins from cheap and abundant alkane resources has long been a challenging task in organic synthesis, which mainly suffers from harsh reaction conditions and narrow scopes. Homogeneous transition metals catalyzed dehydrogenation of alkanes has attracted much attention for its excellent catalytic activities under relatively milder conditions. Among them, base metal catalyzed oxidative alkane dehydrogenation has emerged as a viable strategy for olefin synthesis for its usage of cheap catalysts, compatibility with various functional groups, and low reaction temperature. In this review, we discuss recent development of base metal catalyzed alkane dehydrogenation under oxidative conditions and their application in constructing complex molecules.

p -Toluenesulfonyl (Tosyl) and nitrobenzenesulfonyl (Nosyl) are two of the most common sulfonyl protecting groups for amines in contemporary organic synthesis. While p-toluenesulfonamides are known for their high stability and robustness, their use in multistep synthesis is plagued by difficult removal. Nitrobenzenesulfonamides, on the other hand, are easily cleaved but display limited stability to various reaction conditions. In an effort to resolve this conundrum, we herein present Nms-amides, initially developed through in silico studies, which overcome these previous limitations and leave no room for compromise, enabling a range of transformations that are not possible with traditional sulfonamide protecting groups.

Abstract

p-Toluenesulfonyl (Tosyl) and nitrobenzenesulfonyl (Nosyl) are two of the most common sulfonyl protecting groups for amines in contemporary organic synthesis. While p-toluenesulfonamides are known for their high stability/robustness, their use in multistep synthesis is plagued by difficult removal. Nitrobenzenesulfonamides, on the other hand, are easily cleaved but display limited stability to various reaction conditions. In an effort to resolve this predicament, we herein present a new sulfonamide protecting group, which we term Nms. Initially developed through in silico studies, Nms-amides overcome these previous limitations and leave no room for compromise. We have investigated the incorporation, robustness and cleavability of this group and found it to be superior to traditional sulfonamide protecting groups in a broad range of case studies.

Early discoveries of diazoalkenes (R₂C=C=N₂) in organic synthesis and the identification of room-temperature-stable diazoalkenes since 2021 are summarized in this Minireview. The synthesis, properties, and reactivity of this novel molecule class are presented, and its use in organic synthesis, main-group, and transition-metal chemistry highlighted.

Abstract

Over decades diazoalkenes (R₂C=C=N₂) were postulated as reactive intermediates in organic chemistry even though their direct spectroscopic detection proved very challenging. In the 1970/80ies several groups probed their existence mainly indirectly by trapping experiments or directly by matrix-isolation studies. In 2021, our group and the Severin group reported independently the synthesis and characterization of the first room-temperature stable diazoalkenes, which initiated a rapidly expanding research field. Up to now four different classes of N-heterocyclic substituted room-temperature stable diazoalkenes have been reported. Their properties and unique reactivity, such as N₂/CO exchange or utilization as vinylidene precursors in organic and transition metal chemistry are presented. This review summarizes the early discoveries of diazoalkenes from their initial postulation as transient, elusive species up to the recent findings of the room-temperature stable derivatives.

A visible-light promoted radical reaction between α-bromoacetophenone and thiosulfate has been reported. Two C−S bonds or one C−S and one C−Se bond can be stably constructed and the thiosulfonate is fully utilised with good atomic economy. The reaction uses ethanol as a green solvent, with mild reaction conditions and good substrate universality.

Abstract

A photoinduced synthesis of β-keto thiosulfone/β-keto selenosulfone by the reaction of α-bromoacetophenone with thiosulfonate/selenosulfonate under metal-free and visible light irradiation conditions is developed. Two C−S bonds or one C−S bond and one C−Se bond were constructed simultaneously.

Synthesis
DOI: 10.1055/a-2039-5424

Atropisomeric molecules are a privileged class of stereogenic material that have important applications in catalysis, materials science and medicines. To date, the majority of work has been focused upon biaryl and heterobiaryl scaffolds involving restricted rotation between a pair of cyclic fragments, but C–N atropisomeric molecules based upon amines and amides, where the nitrogen atom is not part of a ring system, are rapidly emerging as an important class of stereogenic molecules. This is the focus of this Short Review, which begins by discussing the factors which influence the configurational stability of such molecules and provides a historical background to their synthesis. This is followed by a detailed discussion of state-of-the-art catalytic asymmetric strategies that are now available to access C–Nacyclic atropisomers including carboxamides, sulfonamides, sulfinamides, phosphamides and diarylamines. A variety of different synthetic approaches are discussed, including kinetic resolution/desymmetrization, amination, C–H functionalization, N-functionalization, and annulation.1 Introduction2 Atropisomerism in Acyclic Amines and Amides3 Synthesis Directed by a Chiral Auxiliary4 Atropselective Synthesis4.1 Kinetic Resolution and Desymmetrization4.2 Electrophilic Amination4.3 C–H Functionalization4.4 N-Functionalization4.5 Annulation5 Conclusions and Outlook
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Article in Thieme eJournals:
Table of contents  |  Abstract  |  open access Full text

Inspired by paired metal sites in enzymes, dual-atom catalysts (DACs) were developed as a frontier in heterogeneous catalysis. DACs possess many unique advantages and surpass their counterparts in various catalytic processes. Herein, we summarize the up-to-date advancements in synthesis, characterization, structure-activity relationship of DACs and outlook the future development in this field with combination from computational insights.

Abstract

The pursuit of high metal utilization in heterogeneous catalysis has triggered the burgeoning interest of various atomically dispersed catalysts. Our aim in this review is to assess key recent findings in the synthesis, characterization, structure-property relationship and computational studies of dual-atom catalysts (DACs), which cover the full spectrum of applications in thermocatalysis, electrocatalysis and photocatalysis. In particular, combination of qualitative and quantitative characterization with cooperation with DFT insights, synergies and superiorities of DACs compare to counterparts, high-throughput catalyst exploration and screening with machine-learning algorithms are highlighted. Undoubtably, it would be wise to expect more fascinating developments in the field of DACs as tunable catalysts.

Nature, Published online: 05 June 2023; doi:10.1038/d41586-023-01833-0

Nature, Published online: 02 June 2023; doi:10.1038/d41586-023-01818-z

Publication date: July 2023

Source: Trends in Chemistry, Volume 5, Issue 7

Author(s): Jayabrata Das, Wajid Ali, Debabrata Maiti