Room temperature C–H bond activation on a [PdI–PdI] platform

Metal species with different size (single atoms, nanoclusters, and nanoparticles) show different catalytic behavior for various heterogeneous catalytic reactions. It has been shown in the literature that many factors including the particle size, shape, chemical composition, metal–support interaction, and metal–reactant/solvent interaction can have significant influences on the catalytic properties of metal catalysts. The recent developments of well-controlled synthesis methodologies and advanced characterization tools allow one to correlate the relationships at the molecular level. In this Review, the electronic and geometric structures of single atoms, nanoclusters, and nanoparticles will be discussed. Furthermore, we will summarize the catalytic applications of single atoms, nanoclusters, and nanoparticles for different types of reactions, including CO oxidation, selective oxidation, selective hydrogenation, organic reactions, electrocatalytic, and photocatalytic reactions. We will compare the results obtained from different systems and try to give a picture on how different types of metal species work in different reactions and give perspectives on the future directions toward better understanding of the catalytic behavior of different metal entities (single atoms, nanoclusters, and nanoparticles) in a unifying manner.

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“…Recently, binuclear compounds are used for C–C coupling reactions, which is also compatible with the cluster-catalyzed mechanism. 359 , 360 …”

Section: Catalytic Applications Of Metal Nanoclustersmentioning

confidence: 99%

Metal Catalysts for Heterogeneous Catalysis: From Single Atoms to Nanoclusters and Nanoparticles

2018

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“…For instance, a BPAN-containing dinuclear Zn complex was 6.4 times faster in performing transesterification of HPNP (2-hydroxypropyl-4-nitrophenyl phosphate, used as an RNA model) than the corresponding mononuclear reference 40. More recently, Bera and co-workers have successfully utilized a range of substituted naphthyridine ligands to examine the reactivity of binuclear complexes of Cu,[43][44][45] Ru,[46][47][48] and Pd 49. Naphthyridine-based ligands are also suitable for the synthesis of pentametallic string complexes of Ni 50 and coordination polymers of Ag 51.…”

mentioning

confidence: 99%

Bimetallics in a Nutshell: Complexes Supported by Chelating Naphthyridine-Based Ligands

et al. 2020

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Conspectus: Bimetallic motifs are a structural feature common to some of the most effective and synthetically useful catalysts known, including in the active sites of many metalloenzymes and on the surfaces of industrially relevant heterogeneous materials. However, the complexity of these systems often hampers detailed studies of their fundamental properties. To glean valuable mechanistic insight into how these catalysts function, this research group has prepared a family of dinucleating 1,8-naphthyridine ligands that bind two first-row transition metals in close proximity, originally designed to help mimic the proposed active site of metal oxide surfaces. Of the various bimetallic combinations examined, dicopper(I) is particularly versatile, as neutral bridging ligands adopt a variety of different binding modes depending on the configuration of frontier orbitals available to interact with the Cu centers. Organodicopper complexes are readily accessible, either through the traditional route of salt metathesis or via the activation of tetraarylborate anions through aryl group abstraction by a dicopper(I) unit. The resulting bridging aryl complexes engage in C-H bond activations, notably with terminal alkynes to afford bridging alkynyl species. The µhydrocarbyl complexes are surprisingly tolerant of water and elevated temperatures. This stability was leveraged to isolate a species that typically represents a fleeting intermediate in Cu-catalyzed azide-alkyne coupling (CuAAC); reaction of a bridging alkynyl complex with an organic azide afforded the first example of a well-defined, symmetrically bridged dicopper triazolide. This complex was shown to be an intermediate during CuAAC, providing support for a proposed bimetallic mechanism. These platforms are not limited to formally low oxidation states; chemical oxidation of the hydrocarbyl complexes cleanly results in formation of mixed-valent Cu I Cu II complexes with varying degrees of distortion in both the bridging moiety and the dicopper core. Higher oxidation states, i.e. dicopper(II), are easily accessed via oxidation of a dicopper(I) compound with air to give a Cu II 2(µ-OH)2 complex. Reduction of this compound with silanes resulted in the unexpected formation of pentametallic copper(I) dihydride clusters or trimetallic monohydride complexes, depending on the nature of the silane. Finally, development of an unsymmetrical naphthyridine ligand with mixed donor side-arms enables selective synthesis of an isostructural series of six heterobimetallic complexes, demonstrating the power of ligand design in the preparation of heterometallic assemblies.

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“…The groups of Bera 44 and Tilley, 45 45 In naphthyridine complexes, the C-H reaction can occur on the naphthyridine ligand itself or on another reactant coordinated to the metal(s). In the former case, the Bera's group synthesized Ru and Pd complexes 46,47 in which the naphthyridine is substituted on one side only, with a phenyl or a heterocycle. This substituent can be deprotonated to become an additional coordination site to the metal (Figure I.5a).…”

Section: -Introduction 1 -Naphthyridine Based Complexesmentioning

confidence: 99%

Unsymmetrical Naphthyridine-Based Dicopper(I) Complexes: Synthesis, Stability, and Carbon–Hydrogen Bond Activations

et al. 2021

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Two unsymmetrical dinucleating naphthyridine-based ligands with di(pyridyl) and phosphino side arms were employed in the synthesis of dicopper(I) chloride cores that activate NaBPh 4 to afford bridging phenyl organocopper complexes. In these compounds, the bridging ligand binds symmetrically, as observed in previously described symmetrical dicopper(I) complexes supported by naphthyridine-based ligands with two di(pyridyl) side arms. Unlike the symmetrical systems, however, these complexes undergo quasireversible electrochemical reductions, and chemical reduction yields a diamagnetic product resulting from the coupling of naphthyridine-based radicals of two complexes. The μ-Ph complexes activate the C−H bonds of terminal alkynes and the electron-poor arene C 6 F 5 H. By DFT calculations, the mechanism of terminal alkyne activation involves H-atom transfer at the cationic dicopper center and is sensitive to subtle changes in copper-ligand interactions as well as the position of the anion.

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Room temperature C–H bond activation on a [PdI–PdI] platform

Abstract: Heteroatom assisted C-H bond activation of 2-substituted naphthyridines with solvated Pd(I)2(CH3CN)6(BF4)2 provides bi- and trinuclear Pd(II) cyclometalated complexes, which provide valuable insight into potential intermediates in palladium catalyzed direct arylation reactions.

Cited by 24 publications

References 28 publications

Metal Catalysts for Heterogeneous Catalysis: From Single Atoms to Nanoclusters and Nanoparticles

Metal Catalysts for Heterogeneous Catalysis: From Single Atoms to Nanoclusters and Nanoparticles

Bimetallics in a Nutshell: Complexes Supported by Chelating Naphthyridine-Based Ligands

Unsymmetrical Naphthyridine-Based Dicopper(I) Complexes: Synthesis, Stability, and Carbon–Hydrogen Bond Activations

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