N‐Heterocyclic Carbene Organocatalysis: Activation Modes and Typical Reactive Intermediates

Chinese Journal of Chemistry, Journal Year: 2020, Volume and Issue: 38(10), P. 1167 - 1202

Published: May 10, 2020

N ‐Heterocyclic carbene (NHC) organocatalysis has been developed as an important approach in modern organic synthesis. Versatile activation modes within NHC have established with countless transformations being realized both efficient and selective fashion. We would like to provide overview on the key progresses achieved this field past two decades. Since numerous excellent reviews documented area, we will mainly focus scientific development of research based basic reaction typical intermediates.

Language: Английский

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Recent Developments of Supramolecular Metal-based Structures for Applications in Cancer Therapy and Imaging

Theranostics, Journal Year: 2019, Volume and Issue: 9(11), P. 3150 - 3169

Published: Jan. 1, 2019

The biomedical application of discrete supramolecular metal-based structures, including coordination complexes (SCCs), is still an emergent field study.However, pioneering studies over the last 10 years demonstrated potential these compounds as novel anticancer drugs, endowed with different mechanisms action compared to classical small-molecules, often related their peculiar molecular recognition properties.In addition, robustness and modular composition structures allows for incorporation functionalities in same system enable imaging cells via modalities, but also active tumor targeting stimuli-responsiveness.Although most reported so far exploit systems therapy, may constitute ideal scaffolds develop multimodal theranostic agents.Of note, host-guest chemistry 3D self-assembled -within metallacages family -can be exploited design drug delivery chemotherapeutics.In this review, we aim at summarizing pivotal concepts fascinating research area, starting main principles illustrating representative examples while providing a critical discussion state-of-the-art.A section included on organometallic (SOCs) whereby (organic) linker forming bond metal node, whose biological applications are explored.Certainly, myriad possible almost limitless modularity tunability suggests that such complex chemical entities will continue along already promising path.

Language: Английский

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N-Heterocyclic Carbenes: A Door Open to Supramolecular Organometallic Chemistry

Accounts of Chemical Research, Journal Year: 2020, Volume and Issue: 53(7), P. 1401 - 1413

Published: July 9, 2020

ConspectusThe field of metallosupramolecular chemistry is clearly dominated by the use O-, N-, and P-donor Werner-type polydentate ligands. These molecular architectures are high interest because their wide range applications, which include encapsulation, stabilization reactive species, supramolecular catalysis, drug delivery, among others. Only recently, organometallic ligands have allowed preparation a variety coordination complexes, term complexes (SOCs) gaining space within chemistry. While early examples SOCs referred to mostly containing bisalkenyl, diphenyl, or bisalkynyl linkers, development during past decade has been boosted parallel multidentate N-heterocyclic carbene (NHC) The first NHC-based assemblies based on NHC bound group 11 metals. However, last 10 years, several planar poly-NHC extended π-conjugated systems facilitated formation large in can contain metals other than Cu, Ag, Au. Such Janus di-NHCs trigonal-planar tris-NHCs—most them prepared our research group—which vast compounds with interesting host–guest properties. Although number increased few for purposes still its earliest infancy. In this Account, we describe achievements that made 4 years toward broadening applications organometallic-based structures, including as hosts some selected organic inorganic guests, together catalytic properties displayed inclusion complexes. Our contribution describes design Ni-, Pd-, Au-based metallorectangles metalloprisms, used encapsulation substrates, such polycyclic aromatic hydrocarbons (PAHs) fullerenes. binding affinities found ascribed incorporation two cofacial panels systems, provide optimum conditions guest recognition π–π-stacking interactions. We also series digold(I) metallotweezers substrates. were "naked" metal cations hydrocarbons. these highly dependent nature rigid connector ancillary constitute arms tweezer. A peculiar balance between self-aggregation tweezer ability encapsulate guests observed.

Language: Английский

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Molecular Barrels as Potential Hosts: From Synthesis to Applications

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(14), P. 7692 - 7711

Published: March 28, 2023

Self-assembled discrete molecular architectures that show selective recognition within their internal cavities are highly desirable. Such hosts often guest through several noncovalent interactions. This emulates the activity of naturally occurring enzymes and proteins. Research in formation 3D cages different shapes sizes has progressed rapidly since development coordination-driven self-assembly dynamic covalent chemistry. find applications catalysis, stabilization metastable molecules, purification isomeric mixtures via encapsulation, even biomedical applications. Most these stem from ability host to bind guests strongly a fashion, providing suitable environment for perform functions. Molecular having closed with small windows either poor encapsulation or inhibit easy release while those wide open structures fail form stable host-guest complexes. In this context, barrels obtained by metal-ligand/covalent bond techniques possess optimized architectures. With hollow-walled cavity two large openings, satisfy structural requirements many perspective, we will discuss detail synthetic strategies obtaining barrel-like employing coordination interactions, structure-based classification, storing transient separation chemicals, photoinduced antibacterial activity. We aim highlight advantages over other efficiently carrying out functions new

Language: Английский

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Metal-N-Heterocyclic Carbene Chemistry Directed toward Metallosupramolecular Synthesis and Beyond

Accounts of Chemical Research, Journal Year: 2023, Volume and Issue: 56(10), P. 1213 - 1227

Published: April 26, 2023

ConspectusAs versatile, modular, and strongly coordinating moieties in organometallic compounds, N-heterocyclic carbenes (NHCs) have led to numerous breakthroughs transition-metal catalysis, main group chemistry, organocatalysis. In contrast, the chemistry of NHC-based metallosupramolecular assemblies, which discrete individual components are held together via metal (M)–CNHC bonds, has been underdeveloped. Integrating NHCs into supramolecular assemblies would endow them with some unforeseen functions. However, one most critical challenges is seeking an appropriate combination rigid CNHC–M–CNHC units resulting topologies applications. Toward this goal, for last decade we focused on development M–NHC directed toward synthesis. This Account aims summarize our contributions application synthesis from structural design postassembly modification (PAM) their functional applications since integrating garnered much attention among organometallic, photochemical, researchers. While presenting representative examples architectures, try illustrate purposes concepts behind systems developed aid rational approach fabrication complex M–NHC-templated photochemical reactions.We present synthetic approaches new architectures by starting NHC precursors, including poly-NHC-based mechanically interlocked metallacages heteroleptic based electronic complementary self-sorting mechanisms. The regulation increasing topological complexity elaborated selective combinations tetraphenylethylene (TPE) units, backbones, N-wingtip substituents a controllable manner.Subsequently, move elucidating PAM that leads organic cages featuring polyimidazolium/triazolium groups different shapes sizes difficult access using alternative approaches. These possess well-defined cavities, situ-generated sites ideal platforms stabilizing nanoparticles (MNPs) within cavities improved catalytic performance.Finally, demonstrate how templates synthesize cyclobutane derivatives homogeneous solutions fashion. Selected template-dependent transformations photoreactions discussed. Their molecular recognition, aggregation-induced emission (AIE), cell imaging, anticancer activity, radical stimuli-responsive materials also described.Taken together, proven be powerful methods constructing diverse methodology still its infancy, tremendous growth potential promising future. We believe will guide researchers fascinating valuable M–carbene species

Language: Английский

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Molecular Co-Catalyst Confined within a Metallacage for Enhanced Photocatalytic CO₂ Reduction

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(3), P. 2275 - 2285

Published: Jan. 12, 2024

The construction of structurally well-defined supramolecular hosts to accommodate catalytically active species within a cavity is promising way address catalyst deactivation. resulting catalysts can significantly improve the utilization catalytic sites, thereby achieving highly efficient chemical conversion. In this study, Co-metalated phthalocyanine (

Language: Английский

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A stable rhodium-coordinated carbene with a σ ⁰ π ² electronic configuration

Science, Journal Year: 2024, Volume and Issue: 383(6678), P. 81 - 85

Published: Jan. 4, 2024

Isolable singlet carbenes have universally adopted a σ

Language: Английский

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Ultrastable and Highly Catalytically Active N‐Heterocyclic‐Carbene‐Stabilized Gold Nanoparticles in Confined Spaces

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(38), P. 16683 - 16689

Published: June 13, 2020

Controlling the size and surface functionalization of nanoparticles (NPs) can lead to improved properties applicability. Herein, we demonstrate efficiency metal-carbene template approach (MCTA) synthesize highly robust soluble three-dimensional polyimidazolium cages (PICs) different sizes, each bearing numerous imidazolium groups, use these as templates stabilize catalytically active, cavity-hosted, dispersed poly-N-heterocyclic carbene (NHC)-anchored gold NPs. Owing stabilization NHC ligands effective confinement cage cavities, as-prepared poly-NHC-shell-encapsulated AuNPs displayed promising stability towards heat, pH, chemical regents. Most notably, all Au@PCCs (PCC=polycarbene cage) exhibited excellent catalytic activities in various reactions, together with high durability.

Language: Английский

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Endo- and Exo-Functionalized Tetraphenylethylene M₁₂L₂₄ Nanospheres: Fluorescence Emission inside a Confined Space

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(24), P. 9673 - 9679

Published: May 24, 2019

The intrinsic relationship between the properties of green fluorescent protein (GFP) and its encapsulated small molecular light machine has spurred many biomimicking studies, aiming at revealing detailed mechanism further promoting wide applications in different disciplines. However, how to build a similar confined microenvironment mimic cavity β-barrel fluorescence turn-on process is fundamental challenge for both chemists biologists. Herein, two distinct exo- endo-functionalized tetraphenylethylene (TPE)-based M12L24 nanospheres with precise distribution anchored TPE moieties unique photophysical were constructed by means coordination-driven self-assembly strategy. Under dilute conditions, fluoresce more strongly than corresponding subcomponents. Meanwhile, sphere able induce higher local concentration restrained motion enclosed 24 units compared exo-functionalized counterpart thus induces much stronger emission due restriction rotation pendant units. biomimetic methodology developed here represents promising way understand construct artificial GFP materials on platforms supramolecular coordination complexes.

Language: Английский

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A Strategy for the Construction of Triply Interlocked Organometallic Cages by Rational Design of Poly-NHC Precursors

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(31), P. 13614 - 13621

Published: July 9, 2020

Three-dimensional (3D) triply interlocked catenanes are a family of chemical topologies that consist two identical, mechanically coordination cage components with intriguingly complex structures. Although only few successful constructions 3D have been achieved to date via metal-mediated assembly, these structures thus far targeted by metal–nitrogen/oxygen techniques. Here, taking advantage rational ligand design, we report the efficient construction series [2]catenanes formula [Ag3L2]2, wherein metal ions exclusively form bonds N-heterocyclic carbene (NHC) units, and their subsequent transmetalation corresponding [Au3L2]2 gold analogues. The formation reactions proceed under mild conditions generally applicable. A characterization techniques were applied confirm structure desired architectures: multinuclear NMR spectroscopy, ESI-MS, single-crystal X-ray diffraction analysis. solid-state [Ag3(1a)2]2(PF6)6 unambiguously confirms existence catenane consists trinuclear hexacarbene components. interlocking cages into [2]catenane is driven π···π stacking triazine–triazine stacks cooperative interactions between imidazo[1,5-a]pyridine subunits. Notably, organometallic exhibit good stability toward various organic solvents, concentrations, temperatures, no disassembly occurred in presence coronene or pyrene. future architectures using metal–carbene rather than metal–nitrogen may provide assemblies interesting properties for as-yet-unimagined applications fields such as sensors molecular electrical conductors.

Language: Английский

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