Click makes MICs: A short modular synthesis allows the preparation of novel stable heterocycles that feature a lone pair electrons on carbon center. The donor properties these mesoionic compounds are greater than those classical N-heterocyclic carbenes; they accessible by deprotonation corresponding conjugate acids using comparatively mild bases.

ConspectusClassical carbenes are usually described as neutral compounds featuring a divalent carbon with only six electrons in their valence shell. It was 1988 that our group prepared the first isolable example, which carbene center stabilized by push–pull effect, using phosphino and silyl substituent. In last 30 years, myriad of acyclic cyclic push–push carbenes, bearing different heteroatom substituents, have been isolated. Among them, so-called N-heterocyclic (NHCs), include...

The formal cycloaddition between 1,3-diaza-2-azoniaallene salts and alkynes or alkyne equivalents provides an efficient synthesis of 1,3-diaryl-1H-1,2,3-triazolium salts, the direct precursors 1,2,3-triazol-5-ylidenes. These N,N-diarylated mesoionic carbenes (MICs) exhibit enhanced stability in comparison to their alkylated counterparts. Experimental computational results confirm that these MICs act as strongly electron-donating ligands. Their increased allows for preparation ruthenium...

Direct metalation of bis(1,2,3-triazolium) salts affords mononuclear rhodium(I) complexes, which feature a 1,4-bidentate bis(1,2,3-triazol-5-ylidene) (i-bitz) ligand. The topology the ligand is similar to that 2,2′-bipyridines (bpy) and their congeners, as well bis(1,2,4-triazol-5-ylidenes) (bitz). As former, but in contrast latter, free i-bitz can be isolated, paves way for various applications.

The synthesis and X-ray crystal structure of a potassium adduct monoanionic CNC-pincer ligand featuring two mesoionic carbenes is reported. Owing to the peculiar electronic steric properties this ligand, first neutral stable Ni(II)-hydride, an unusual Cu(II) complex displaying seesaw geometry, have been isolated.

A palladium-cornered molecular square with four pyrene-bis(imidazolylidene) bridging ligands is reported. This metallo-polygon can encapsulate C60 and C70 . The X-ray diffraction structures of the empty cage as well cages complexed both fullerenes are described. fullerene encapsulation produces perturbations in structural parameters metallo-square, showing that it adjust shape its cavity to size each fullerene.

Mit einem Klick zu MICs: Eine kurze modulare Synthese führt neuartigen stabilen Heterocyclen mit freien Elektronenpaar an Kohlenstoffzentrum. Diese mesoionischen Verbindungen sind bessere Donoren als klassische N-heterocyclische Carbene, und sie durch Deprotonierung der konjugierten Säuren vergleichsweise milden Basen zugänglich. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents peer-reviewed, but not copy-edited or typeset. They...

In this work we describe the preparation of a new benzene–hexaimidazolylidene ligand, which have coordinated to silver and gold. The complexes constitute unique examples cylinder-like macromolecular arrangements, in six metal atoms are sandwiched between two hexacarbene ligands.

Homoleptic tris-MIC cylinder-like (Ag, Au) and heteroleptic tris-NHC/tris-MIC (Ag) cages are reported. The cage is obtained by unusual ligand rearrangements.

An air-stable rhodium(<sc>i</sc>)–oxygen adduct featuring a CNC-pincer ligand, based on 1,2,3-triazol-5-ylidenes, catalyzes the homo-dimerization and hydrothiolation of alkynes, affording <italic>gem</italic>-enyne α-vinyl sulfide isomers, respectively, with excellent selectivity.

We report the synthesis and reactivity of unusual T-shaped (LXL)Au(I)-pincer complexes, based on a carbazole framework flanked by two mesoionic carbenes (MICs). In contrast to other Au(I) these complexes react with electrophiles. Protonation alkylation occur either at metal or ligand, depending steric factors. Of particular interest, protonation gold leads an unprecedented cationic Au(III) hydride, which gives 1H NMR resonance δ −8.34 ppm. The this "hydride", however, shows protic not...

An effective visible-light-promoted iridium(III)-catalyzed hydrogen production from N-heterocycles is described. A single iridium complex constitutes the photocatalytic system playing a dual task, harvesting visible-light and facilitating C-H cleavage H2 formation at room temperature without additives. The presence of chelating C-N ligand combining mesoionic carbene along with an amido functionality in IrIII essential to attain transformation. Furthermore, also efficient catalyst for thermal...

Two new palladium complexes with a pyracene-linked bis-imidazolylidene (pyrabim) group have been obtained and fully characterized. The related monometallic analogues were from the coordination of an acetanaphthene-supported N-heterocyclic carbene (NHC). catalytic properties all studied in acylation aryl halides hydrocinnamaldehyde, Suzuki-Miyaura coupling boronic acids. results show that presence second metal dimetallic induces some benefits behavior complexes. This effect is more pronounced...

A series of novel cationic and neutral Rh complexes with an N-donor-functionalized 1,2,3-triazol-5-ylidene (TRZ) ligand (in which the pendant N donor is NHBoc, NH2 , or NMe2 ) described. The catalytic activity these was evaluated in hydrothiolation alkynes. Among catalysts, a dicarbonyl complex featuring tethered-NBoc amido-TRZ proved very selective for alkyne aryl thiol. Remarkably, reaction could be carried out absence pyridine base additive. In addition, during reaction, no evidence...

A novel hemilabile MIC^N ligand-based Au( i )-catalytic procedure for the synthesis of γ-substituted γ-butyrolactones through arylation-lactonization reaction corresponding γ-alkenoic acid is presented.

The transition metal catalyzed dehydrogenation of alcohols to carboxylate salts and H2 is an attractive tool due their potential use as LOHCs (Liquid Organic Hydrogen Carriers). Still, most current methods encompass harsh conditions two steps synthesis. Herein, we describe efficient ruthenium(II) hydrogen production from benzylic the corresponding benzyl carboxylates assisted by visible light. Our photocatalytic system comprises a standalone N-heterocyclic carbene based piano stool ruthenium...

Two simple bisimidazolium salts derived from m- or p-bisimidazolebenzenes have been used as ligand precursors for the preparation of a series heterobimetallic RhIII/AuI and IrIII/AuI complexes. All complexes fully characterized, molecular structures selected derivatives determined by X-ray diffraction studies. These analyses showed that, regardless used, direct coordination environment metals is composed identical donors (MIII: CNHC, Cbenzene, η5-Cp*, I–; AuI: CNHC I–) rather similar in The...

Weakly coordinating anions (WCAs) are generally tailored to act as spectators with little or no function. Here we describe the implementation of strongly dianionic carboranyl N-heterocyclic carbenes (NHCs) create organometallic -ate complexes Au(I) that serve both WCAs and functional catalysts. These can be utilized form heterobimetallic (Au(I)−/Ag(I)+; Au(I)−/Ir(I)+) organometallic/main group ion pairs (Au(I)−/(CPh3+ SiEt3+). Because parent unfunctionalized NHC complex 3 is unstable in most...

A simple sequential metalation approach starting from the imidazolium/benzimidazolium salt 4(I)2 yielded heterobimetallic RhIII/M (M = PdII, IrI, AuI, RuII) complexes [6]–[9]. Alternatively, a symmetrical 1,3-imidazolium substituted benzene was used for preparation of M′/PdII (M′ RhIII, IrIII) [12] and [13]. The versatile stepwise [6]–[9] involved deprotonation reaction bisazolium in presence [RhCp*(Cl)2]2 to afford monometallic complex [5]I featuring chelating coordinated bidentate...

A robust bimetallic manganese complex with a mesoionic 1,2,3,-triazolylidene ligand for efficient oxidation of alcohols <italic>tert</italic>-butylhydroperoxide.

Abstract A palladium‐cornered molecular square with four pyrene‐bis(imidazolylidene) bridging ligands is reported. This metallo‐polygon can encapsulate C 60 and 70 . The X‐ray diffraction structures of the empty cage as well cages complexed both fullerenes are described. fullerene encapsulation produces perturbations in structural parameters metallo‐square, showing that it adjust shape its cavity to size each fullerene.

A super pyrazolate: Deprotonation of the flanking hydrogen metal complexes mesoionic carbenes (MICs) offers a simple and general route for preparation bimetallic 1,2-dihapto anionic dicarbene ligand that is isoelectronic with widely used pyrazolate ligands, while conferring greater electron donation stronger ML bonds (see scheme). Detailed facts importance to specialist readers are published as ”Supporting Information”. Such documents peer-reviewed, but not copy-edited or typeset. They made...

A series of novel tris-azolium salt precursors based on 1,3,5-triphenylbenzene have been prepared. These salts exhibit fluorescence emission in the 320–420 nm region. The coordination these to [MCl(COD)]2 (M = Rh, Ir) was carried out presence KHMDS and allowed formation corresponding tris-NHC complexes Rh Ir high yield. electronic properties new were analyzed by means cyclic voltammetry IR spectroscopy related carbonylated species. catalytic activity trirhodium complex toward addition...

The hybrid material composed of palladium nanoparticles (PdNPs) functionalized with N-heterocyclic carbene ligands (NHCs) immobilized onto the surface reduced graphene oxide (rGO) results in an efficient catalytic towards hydrogenation and dehydrogenation N-heterocycles. rGO plays a dual role by acting as carbocatalyst acceptorless N-heterocycles support for facilitating its interaction molecular hydrogen turning this into effective catalyst. Hot filtration experiments heterogeneous nature...