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N‐Heterocyclic carbenes, carbocyclic carbenes, remote N‐heterocyclic carbenes and N‐heterocyclic silylenes are known to form L→N+ coordination bonds. However, mesoionic carbenes (MICs) are not reported to form coordination bonds with cationic nitrogen. Herein, synthesis and quantum chemical studies were performed on 1,2,3‐triazol‐5‐ylidene stabilized N+ center. Six compounds with MIC→N+←NHC were synthesized. Density functional theory calculations and energy decomposition analysis were carried out to explore the bonding situation between MIC and N+ center. The C→N+ bond lengths were in the range of 1.295–1.342 Å and bond dissociation energies were <400 kcal/mol. Natural bond orbital analysis supported the presence of excess electron density (>3 electrons) at the N+ center. The computational and X‐ray diffraction analysis results confirmed the presence of divalent NI character of center nitrogen and MIC→N+←NHC coordination interactions. Mesoionic divalent NI Compounds. Mesoionic 1,2,3‐triazolyl‐5‐ylidene containing nitreones with the general representation MIC→N+←NHC were designed quantum chemically and proven to be synthetically feasible by synthesizing six molecules. Quantum chemical calculations and X‐ray structure analysis revealed the presence of C→N+ coordination bonds with the C−N bond lengths ranging between 1.295–1.342 Å. Low bond dissociation energies (<400 kcal/mol) and the presence of two lone pairs of electrons on the central nitrogen further confirm the presence of C→N+ coordination bonds in these mesoionic nitreones.

N -heterocyclic carbene-catalyzed enantioselective kinetic resolutions, dynamic kinetic resolutions, and desymmetrization reactions are systematically reviewed. The content is organized according to the activation modes involved in these transformations. Future advances within this highly active research field are discussed from our perspectives on the topic.

while N-heterocyclic carbene (NHC) catalyzed electron-pair-transfer processes have been developed into an important tool for synthetically important bond formations during the past decades, the corresponding radical reactions via NHC catalysis have only received growing attention in the past six years. Taking into account the advantages NHC-catalyzed radical reactions might bring, such as creating new activation modes that were previously unobtainable, it is worthwhile to provide a conceptual understanding of this emerging area. Therefore, herein we give an overview of NHC-catalyzed radical reactions via different synthetic techniques.

Industrial effluents containing dyes are the dominant pollutants, making the drinking water unfit. Among the dyes, methylene orange (MO) dye is mutagenic, carcinogenic and toxic to aquatic organisms. Therefore, its removal from water bodies through effective and economical approach is gaining increased attention in the last decades. Photocatalytic degradation has the ability to convert economically complex dye molecules into non-toxic and smaller species via redox reactions, by using photocatalysts. g-C[sub.3] N[sub.4] is a metal-free n-type semiconductor, typical nonmetallic and non-toxici polymeric photocatalyst. It widely used in photocatalytic materials, due to its easy and simple synthesis, fascinating electronic band structure, high stability and abundant availability. As a photocatalyst, its major drawbacks are its limited efficiency in separating photo-excited electron–hole pairs, high separated charge recombination, low specific surface area, and low absorption coefficient. In this review, we report the recent modification strategies adopted for g-C[sub.3] N[sub.4] for the efficient photodegradation of MO dye. The different modification approaches, such as nanocomposites and heterojunctions, as well as doping and defect introductions, are briefly discussed. The mechanism of the photodegradation of MO dye by g-C[sub.3] N[sub.4] and future perspectives are discussed. This review paper will predict strategies for the fabrication of an efficient g-C[sub.3] N[sub.4] -based photocatalyst for the photodegradation of MO dye.

We report herein a class of superatomic Au 13 clusters stabilized by different N-heterocyclic carbenes (NHCs). The clusters show diverse metal surface structures, properties and functions as exemplified by: (1) the first anionic Au 13 cluster [Au 13 (NHC-1) 6 Br 6 ] - , which has bulky NHC-1 ligands that lead to a rather open metal surface contributing to its high catalytic activity; (2) the tricationic cluster [Au 13 (NHC-2) 5 Br 2 ] 3+ which has bidentate, benzyl-rich NHC-2 ligands that make it ultra-stable and highly-luminescent, suitable for bio-imaging; and (3) by bearing two pyridyl groups on NHC-3, the dicationic cluster [Au 13 (NHC-3) 9 CI 3 ] 2+ exhibits reversible and stable visible absorption and solubility responses to protonation/deprotonation cycles, making it a potential pH sensor (NHC-1 = 1,3-diisopropylbenzimidazolin-2-ylidene; NHC-2 = 1,3-bis(1-benzyl-1H-benzimidazol-1-ium-3-yl)propane; NHC-3 = 1,3-bis(picolyl)benzimidazolin-2-ylidene). The study nicely demonstrates the importance of ligands in designing metal nanoclusters with desired functionalities.

The reaction of readily available N,N′ -diaryl-4-chloromethylimidazolium chlorides with thiols afforded 4-(alkyl)arylsulfanylmethyl- N,N′ -diarylimidazolium salts. The oxidation of these salts with hydrogen peroxide catalyzed by ammonium paramolybdate gave the previously unknown 4-(alkyl)arylsulfonylmethyl- N,N′ -diarylimidazolium salts. The synthesized imidazolium salts can be used as sources of N -heterocyclic carbenes (NHCs). The conditions were found for the selective palladation of these compounds involving the C(2) atom of the imidazole ring. Palladium complexes with NHC ligands functionalized with RSCH 2 and RSO 2 CH 2 groups were synthesized. The potential applicability of these complexes as catalysts for cross-coupling reactions was demonstrated.

The adhesive industry faces significant challenges in developing effective, simple, safe, and economical surface treatment methods to achieve strong bond strengths and long‐term durability. Conventionally, surface treatments have relied on hexavalent chromium compounds and strong acids, which pose serious safety and health concerns. In this study, we explore the use of a non‐toxic organic molecule known as an N‐heterocyclic carbene (NHC) for adhesion promotion applications. The functionalization of aluminum alloy 6061 (AA6061) with an NHC was achieved using an immersion process and confirmed through X‐ray photoelectron spectroscopy (XPS) and laser desorption/ionization (LDI) spectrometry. Accelerated electrochemical corrosion and environmental corrosion chamber studies demonstrate that NHC–functionalized AA6061 has higher corrosion resistance compared to untreated AA6061. The impact of NHC functionalization on the adhesive joint strength and durability was also evaluated by a single‐lap‐shear test following up to >900 h of continuous exposure in a corrosion chamber. This simple immersion‐based approach shows great promise for enhancing the adhesion strength of AA6061‐epoxy bonding using surface organic chemistry. N‐heterocyclic carbenes as novel non‐toxic surface primers for aluminum alloys for better adhesive bonding, because strong adhesive bonding shouldn't come at the cost of poisoning the human body. The impact of NHC functionalization on adhesive joint strength and durability is also evaluated using a single‐lap‐shear test, following continuous exposure for over 900 h in a corrosion chamber.

Magic-number gold nanoclusters are atomically precise nanomaterials that have enabled unprecedented insight into structure–property relationships in nanoscience. Thiolates are the most common ligand, binding to the cluster via a staple motif in which only central gold atoms are in the metallic state. The lack of other strongly bound ligands for nanoclusters with different bonding modes has been a significant limitation in the field. Here, we report a previously unknown ligand for gold( 0 ) nanoclusters—N-heterocyclic carbenes (NHCs)—which feature a robust metal–carbon single bond and impart high stability to the corresponding gold cluster. The addition of a single NHC to gold nanoclusters results in significantly improved stability and catalytic properties in the electrocatalytic reduction of CO 2 . By varying the conditions, nature and number of equivalents of the NHC, predominantly or exclusively monosubstituted NHC-functionalized clusters result. Clusters can also be obtained with up to five NHCs, as a mixture of species. Magic-number Au 11 clusters containing N-heterocyclic carbene (NHC) ligands are prepared by ligand exchange on known phosphine clusters and the introduction of even a single NHC results in improved cluster stability. The use of NHC-containing clusters in the electrocatalytic reduction of CO 2 to CO is described and correlates with cluster stability.

N -heterocyclic carbene (NHC) organocatalytic reactions that have been developed for asymmetric construction of axial and planar chirality are systematically summarized and discussed in this review. The challenges and limitations inherent to this highly reactive research field are highlighted towards the end of the review. Additionally, based on our understanding of the current advancements in NHC organocatalysis, we propose potential future directions for further exploration.