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We report here the preparation and characterization of new well‐defined silica‐supported Ti imido complexes that present an L‐ligand variation in a structure of currently the most active oxo/imido heterometathesis catalyst (≡SiO)Ti(=NtBu)(Me2Pyr)(py)2 (1s), where py is replaced with stronger electron‐donating 4‐(N,N‐dimethylamino)pyridine (2s) or bidentate 2,2′‐bipyridine (3s). The materials were characterized with elemental and mass balance analyses and IR and solid‐state NMR that confirmed the selective formation of surface Ti species with terminal imido ligand. Evaluation of the catalytic oxo/imido heterometathesis activity of the obtained materials demonstrated that L‐ligands have a pronounced influence on the catalytic performance. In particular, the replacement of pyridine with stronger donating ligands resulted in a significant drop of activity. The catalytic results are discussed in view of the reaction mechanism and implications for further catalyst development. [ABSTRACT FROM AUTHOR]

Karl Ziegler is considered one of the most outstanding chemists of the 20th century. In particular, his work on organometallic mixed catalysts, which allows the polymerization of ethylene at normal pressure, led to a revolution in plastics production and changed the everyday life of all mankind. In 1963, he was awarded the Nobel Prize in Chemistry for this work, together with Giulio Natta. This article focuses on Ziegler's early career, which has received little attention to date. It describes his youth and study years in Marburg, which partly coincide with the First World War. Subsequently, his postdoctoral period is examined, which led him via Marburg and Frankfurt to his first associate professorship in Heidelberg. Special attention is paid to his relationship to National Socialism, which he opposed. As a result, Ziegler experienced professional difficulties in the 1930s, such as repeated rejection when filling various professorships. His appointment as a full professor in Halle and his subsequent directorship at the Max‐Planck‐Institut für Kohlenforschung (Coal Research), where he finally achieved his greatest research achievement, are described in the following. [ABSTRACT FROM AUTHOR]

Imido ligand is a ubiquitous motif in organometallic chemistry, serving roles spanning from ancillary ligands to reactive sites. The nature of M=N bond is highly depended on the metal centres and their d‐electron configuration, with late transition metal (TM) imido complexes exhibiting contrasting features when compared to their early TM analogues. Envisioning to uncover general electronic descriptor for the nature of imido ligands, we computationally investigate the solid‐state 15N NMR signatures of late TM imido complexes with various central metals, geometries and d‐electron counts, and compare them against these of the corresponding early TM systems. The spectroscopic signatures are mostly driven by the presence of filled, π‐symmetry orbitals in late TM imido complexes, suggesting the development of high‐lying π(M=N) and low‐lying σ/σ*(M=N) orbitals. This contrasts with what is observed for the reported early TM systems, for which high‐lying σ‐type orbitals determine the NMR signature. Noteworthily, Ni‐ and Pd‐imido complexes with formal d10 configurations exhibit highly asymmetric nitrogen‐15 NMR signature with extremely deshielded principal components, because of the presence of filled, high‐lying antibonding π*(M=N) orbitals, consistent with their high reactivity. The sensitive response of 15N NMR signature to the nature of metal sites further highlights that chemical shift is a useful reactivity descriptor. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis and characterization of a small family of Ir(I) and Ir(III) complexes supported by β‐thioketoiminates (SacNac) ligands. All complexes were fully characterized by IR, 1D and 2D NMR, and Elemental Analysis (e.a.) experiments. X‐ray diffraction studies were carried out to corroborate the structure of compounds [Ir(cod)(SacNac)] (1) (cod=1,5‐cyclooctadiene), [Ir(dmb)(SacNac)] (2) (dmb=2,3‐dimethyl‐1,3‐butadiene) and [IrCp*(SacNac‐H)(Cl)2] (8) (Cp*=pentamethyl‐cyclopentadienyl). Complexes 1 and 2 are Ir(I) species and have square‐planar geometry in solid state, with bond angles and distances that suggest semi‐aromaticity in the six‐membered ring. To the best of our knowledge, we report the first mono‐coordination mode of a SacNac ligand via sulfur atom in complex 8. Also, we report the first application of iridium‐SacNac complexes as catalytic precursors in hydroboration reactions, where Ir(III) species give the best results. [ABSTRACT FROM AUTHOR]

Supported catalysts are central to industrial catalytic processes. While traditional synthesis methods often yield poorly defined materials, thus complicating structural elucidation, Surface Organometallic Chemistry (SOMC) offers a solution, producing well‐defined structures. Recent advances in SOMC precursor development have shown that amidinate‐based complexes are a privileged class of precursors to generate supported metallic nanoparticles. In that context, this study investigates the grafting mechanism of a prototypical amidinate precursor, Ir(COD)(DIA) (1‐Ir), onto SiO2. Unique to amidinate complexes, grafting is shown to occur without ligand release, creating a reversible covalent bond. Using tris(tert‐butoxy)silanol as a molecular analogue for a silanol group on SiO2, the structure of the grafted species is elucidated by single X‐Ray diffraction, comparison of IR spectroscopy, and X‐Ray absorption spectroscopy (XAS) data. The reversibility of the reaction with O−H groups is demonstrated using variable‐temperature NMR spectroscopy, IR spectroscopy, and is supported by DFT calculations. Notably, we show that a partial degrafting is also possible at elevated temperatures under vacuum. [ABSTRACT FROM AUTHOR]

ABSTRACT NHC pincers (NHC = N‐heterocyclic carbene), which combine the structural benefits of both carbenes and pincer platforms, have shown diverse applications, spanning from fundamental organometallic chemistry to homogeneous catalysis. Although aryl‐bridged bis(NHCs) represent the earliest developed and most studied type of NHC pincers, such [C^C^C]‐platforms have been underutilized in the synthesis of rhodium complexes. In this study, we present several less explored organorhodium(III) complexes featuring [C^C^C]‐pincers. Their synthetic route via a convenient oxidative addition approach has been explored, and the obtained cyclorhodium(III) complexes show versatile coordination geometry (square pyramidal or octahedral). Additionally, these cyclorhodium(III) complexes exhibit very different regioselectivity in catalytic alkyne hydrosilylations compared to known Rh(III) NHC catalytic systems. Finally, a few mechanistic studies have also been conducted, and a plausible mechanism was proposed. [ABSTRACT FROM AUTHOR]

Since the dawn of organometallic chemistry, transition metal complexes of unsaturated organic molecules, namely π-complexes, have remained a central focus: our thorough understanding of the electronic nature of such species, and their importance in countless reactive processes continues to drive research in their synthesis and utilisation. Since the late 1900s, research regarding the related chemistry for the heavier group 14 elements has become increasingly more fervent. Today, heavier congeners of a vast array of classical π-complexes have been realised, from alkene to arene systems, involving Si, Ge, Sn, and Pb. This has given deeper insights into the bonding observed for these heavier elements, which typically involves a lessened degree of π-bonding and an increased polarisation. This review aims to summarise this field, identifying these disparities, and highlighting areas which we believe may be exciting for future exploration. [ABSTRACT FROM AUTHOR]

Since the late 19th century, heavier tetrylene- and tetrylyne-transition metal chemistry has formed an important cornerstone in both main-group and organometallic chemistry alike. Driven by the success of carbene systems, significant efforts have gone towards the thorough understanding of the heavier group 14 derivatives, with examples now known from across the d-block. This now leads towards applications in cooperative bond activation, and moves ultimately towards well-defined catalytic systems. This review aims to summarise this vast field, from initial discoveries of tetrylene and tetrylyne complexes, to the most recent developments in reactivity and catalysis, as a platform to the future of this exciting, blossoming field. [ABSTRACT FROM AUTHOR]

The use of dissolving metal electrodes for the direct electrochemical synthesis of metal complexes has been used widely in the last decade. A major benefit of the electrochemical approach is the minimal by‐products resulting from the synthesis. As such, metal complexes can be produced on‐demand and used directly in catalysis without the need for purification. Furthermore, the electrochemical method enables the production of metal complexes that cannot be synthesized using other methods, including those with base‐sensitive ligands. General principles of the electrochemical method and recent advances in the field are discussed. [ABSTRACT FROM AUTHOR]

Paramagnetic molecules, such as main‐group radicals and transition metal complexes, play crucial roles in catalytic and enzymatic reactions in organometallic and bioinorganic chemistry. Electron paramagnetic resonance (EPR) spectroscopy emerges as a powerful tool for probing the intricate electronic and geometric structures of these molecules. The application of EPR spectroscopy spans a wide spectrum of chemical entities, from simple radicals to transition metal complexes, metalloproteins, and metal clusters, emphasizing its versatility across various fields of chemistry. This review introduces the EPR spectra of transition metal complexes, offering a comprehensive theoretical foundation along with illustrative examples from both bioinorganic and organometallic chemistry. These examples highlight the effectiveness of EPR spectroscopy in characterizing transition metal complexes, reinforcing our understanding of their structure and reactivity. [ABSTRACT FROM AUTHOR]

The post‐assembly modification (PAM) of metallosupramolecular assemblies plays an important role in obtaining diverse architectures and expanding new functions. In this work, the trinuclear organometallic assemblies [Ag3(L)2](PF6)3 (L = 1a–c) were generated from the corresponding internal olefin‐bridged trisimidazolium, trisbenzoimidazolium, and trisimidazo[1,5‐ɑ]pyridinium salts H3‐L(PF6)3 (L = 1a–c) with Ag2O through coordination‐driven self‐assembly. Subsequently, complexes [Ag3(L)2](PF6)3 (L = 1a, 1b) were converted into corresponding gold(I) complexes [AuI3(L)2](PF6)3 (L = 1a, 1b) by transmetalation reaction. The oxidation addition of the gold(I) complexes [AuI3(L)2](PF6)3 (L = 1a, 1b) were carried out using iodine as an oxidant to give gold(III) complexes [AuIII3(L)2I6](PF6)3 (L = 1a, 1b). Irradiation of complexes [Ag3(L)2](PF6)3 (L = 1a, 1b) in solution leaded to structural transform into the corresponding cyclobutane‐bridged complexes [Ag3(L′)](PF6)3 (L′ = 2a, 2b) with quantitative yields. [ABSTRACT FROM AUTHOR]

N-Heterocyclic carbenes (NHCs) represent a pivotal class of ligands in coordination chemistry owing to their unique electronic properties. In particular, hemilabile N-heterocyclic carbenes have garnered significant attention over the past decade due to their capacity to transiently coordinate to metals and open coordination sites. However, hemilabile NHC ligands have been predominantly limited to N, O and P donors, while NHC ligands bearing versatile S-donors have been severely underdeveloped. Herein, we report wingtip-flexible, sterically hindered NHC ligands that feature N,C/S,C-chelating thiazole donors in combination with the powerful IPr* (IPr* = (2,6-bis(diphenylmethyl)-4-methylphenyl)imidazol-2-ylidene) scaffold. These ligands are prepared using a highly modular SNAr arylation of thiazole derivatives. Full structural and electronic characterization is reported. The ligands feature a high barrier to rotation around the N-thiazole axis (10 kcal mol−1). The ligands are evaluated for their steric, electron-donating and π-accepting properties as well as coordination chemistry to Ag(I), Pd(II), Rh(I) and Se. Preliminary studies on Ag, Pd and Rh catalysis are presented. The efficiency of the approach is highlighted by preparing a library of unsymmetrical imidazolium precursors. The mono-IPr* wingtip provides a highly hindered yet sterically flexible environment adjusting to metal centers, while the N-thiazolyl wingtip displays a fluxional behavior that interchanges from the hard/soft N,C to soft/soft S,C coordination. Considering the importance of hemilabile N-heterocyclic carbene ligands in metal stabilization in inorganic and organometallic chemistry, we expect that this class of ligands will be of broad interest. [ABSTRACT FROM AUTHOR]

This review deals with C1 carbenoid chemistry, with a focus on lithium carbenoid species generated in flash flow systems. Strict control of the temperature, residence time, and mixing efficiency has led to various transformation reactions involving epoxidation, cyclopropanation, and homologation, among others. The use of other metal species, including trifluoromethylpotassium (CF3 K) and magnesium/ zinc carbenoids, in flow systems is also introduced. 1 Introduction 1.1 Lithium Carbenoids in C1 Chemistry 1.2 Flow Chemistry for C1 Lithium Carbenoids 2 Flow Reactions Involving Carbenoid Species 2.1 Deprotonative Generation of Lithium Carbenoid Species 2.2 Generation of Lithium Carbenoid Species via Halogen–Lithium Exchange 2.3 Generation of Lithium Carbenoid Species via Reductive Lithiation 2.4 Generation of Lithium Carbenoid Species via Alkyllithiation 2.5 Generation of Trifluoromethylpotassium Species in Flow 2.6 Generation of Other Metal Carbenoid Species 3 Conclusion [ABSTRACT FROM AUTHOR]

Carborane compounds, known for their exceptional thermal stability and non‐toxic attributes, have garnered widespread utility in medicine, supramolecular design, coordination/organometallic chemistry, and others. Although there is considerable interest among chemists, the integration of suitable carborane molecules into ferroelectric materials remains a formidable challenge. In this study, we employ the quasi‐spherical design strategy to introduce functional groups at the boron vertices of the o‐carborane cage, aiming to reduce molecular symmetry. This approach led to the successful synthesis of the pioneering ferroelectric crystals composed of cage‐like carboranes: 9‐OH‐o‐carborane (1) and 9‐SH‐o‐carborane (2), which undergo above‐room ferroelectric phase transitions (Tc) at approximately 367 K and 347 K. Interestingly, 1 and 2 represent uniaxial and multiaxial ferroelectrics respectively, with 2 exhibiting six polar axes and as many as twelve equivalent polarization directions. As the pioneering instance of carborane ferroelectric crystals, this study introduces a novel structural archetype for molecular ferroelectrics, thereby providing fresh insights into the exploration of molecular ferroelectric crystals with promising applications. [ABSTRACT FROM AUTHOR]

Carbodicarbenes are strong C‐donor ligands, which have found numerous applications in organometallic and main group element chemistry. Herein, we report a structurally distinct carbodicarbene ligand, which is formed by dinitrogenative coupling of a Fischer carbene complex with an N‐heterocyclic diazoolefin. The resulting carbonyl complex serves as a stable source for the mixed Arduengo‐Fischer carbodicarbene ligand. Facile ligand transfer reactions were demonstrated to occur with gold(I), copper(I), palladium(II), and rhodium(I) complexes. [ABSTRACT FROM AUTHOR]

By exploiting the electronic capabilities of the N‐heterocyclic boryloxy (NHBO) ligand, we have synthesized "naked" acyclic gallyl [Ga{OB(NDippCH)2}2]− and indyl [In{OB(NDippCH)2}2]− anions (as their [K(2.2.2‐crypt)]+ salts) through K+ abstraction from [KGa{OB(NDippCH)2}2] and [KIn{OB(NDippCH)2}2] using 2.2.2‐crypt. These systems represent the first O‐ligated gallyl/indyl systems, are ultimately accessed from cyclopentadienyl GaI/InI precursors by substitution chemistry, and display nucleophilic reactivity which is strongly influenced by the presence (or otherwise) of the K+ counterion. [ABSTRACT FROM AUTHOR]

Continuing our investigation of catalytic oxo/imido heterometathesis as novel water‐free method for C=N bond construction, we report here the application of classical transition metal oxides dispersed on silica (MOx/SiO2, M=V, Mo, W) as cheap, robust and readily available alternative to the catalysts prepared via Surface Organometallic Chemistry (SOMC). The oxide materials demonstrated activity in heterometathetical imidation of ketones, WO3/SiO2 being the most efficient. We also describe a new well‐defined supported W imido complex (≡SiO)W(=NMes)2(Me2Pyr) (Mes=2,4,6‐Me3C6H2, Me2Pyr=2,5‐dimethylpyrrolyl) and characterize it with SOMC protocols, which allowed us to identify the position of W on the oxo/imido heterometathesis activity scale (Mo

Manganese is currently experiencing a great deal of attention in homogeneous catalysis as a sustainable alternative to platinum group metals due to its abundance, affordable price and low toxicity. While homogeneous nitrogen fixation employing well‐defined transition metal complexes has been an important part of coordination chemistry, manganese derivatives have been only sporadically used in this research area. In this contribution, the authors systematically cover manganese organometallic chemistry related to N2 activation spanning almost 60 years, identify apparent pitfalls and outline encouraging perspectives for its future development. [ABSTRACT FROM AUTHOR]

In the past 18 years, metal‐catalyzed deallylation has proven a useful tool for studying biological processes in cellulo and in the early development of innovative therapeutic catalytic strategies. This reaction is catalyzed by Ru‐piano stool complexes and has been reported to be compatible with air, water, and thiol‐containing compounds such as glutathione. However, little is known about the true influence of biological components on the outcome of this reaction. The results presented herein reveal that the co‐solvent used in the reaction affects the complex's stability and activity in air, while the presence of glutathione contributes to minimizing the formation of N‐allylated by‐products. In addition, we studied the effect of air on the Ru‐catalyzed deallylation. Importantly, we found that, in the presence of air, the complex is deactivated and oxidizes glutathione into its disulfide. [ABSTRACT FROM AUTHOR]

o‐Aminoazotoluene (OAT), capable of photoisomerization, and o‐vanillin, a potent comutagen, have been used to synthesize a new ligand, HL, [C6H4(CH3)N=NC6H3(CH3)N=CHC6H3(OH)(OCH3)], which, upon complexation with copper(II), results in a new copper(II) complex‐Cu(L)2, [Cu{C6H4(CH3)N=NC6H3(CH3)N=CHC6H3(OCH3)O}2]. Both HL and Cu(L)2 have been characterized by single‐crystal X‐ray diffraction measurements along with other analytical techniques, for example, IR spectroscopy, NMR spectroscopy, UV–Vis spectroscopy, elemental analysis and mass spectrometry. These compounds were tested with different in vitro anticancer assay as well as with in silico studies. A comparative study has been demonstrated on anticancer activity of HL and Cu(L)2 with the ligand HAZ, {C6H5N=NC6H4N=CHC6H3(OH)(OCH3)} and its Cu‐complex, [Cu(AZ)2, Cu{C6H5N=NC6H4N=CHC6H3(OCH3)O}2]. The sensing properties of HAZ, along with the synthesis and structural properties of both HAZ and Cu(AZ)2, have been reported by our group earlier. Cytotoxicity measurements on MCF7 cell lines show that Cu(L)2 and Cu(AZ)2 have higher anticancer activity than their corresponding ligands. The apoptotic effect of Cu‐complex was studied through nuclear fragmentation assay and AO/EB dual‐staining assay on MCF7 cell line. The IC50 value of Cu(L)2 in 0.01% DMSO/water after 24‐h treatment was found 4.2 μM, which is one of the lowest values with this response time compared to the other analogous anticancer compounds. Finally, we have evaluated the expression of hERα protein with respect to Cu‐complexes, and it was observed that Cu(L)2 caused more down‐regulation of hERα as compared to Cu(AZ)2. [ABSTRACT FROM AUTHOR]

The field of coordination chemistry has evolved to intersect with organic chemistry and biochemistry, giving rise to the disciplines of organometallic and bioinorganic chemistry. Nuclear magnetic resonance (NMR) spectroscopy can be applied for characterizing transition metal complexes, spanning both diamagnetic and paramagnetic complexes prevalent in organometallic compounds and metalloproteins. This review offers a comprehensive overview of a wide variety of characterization techniques, ranging from basic 1H and 13C NMR spectroscopy to advanced methods such as heteronuclear experiments, polarization transfer techniques, relaxometry, and multidimensional NMR spectroscopy. The diverse array of NMR spectroscopic methods outlined here promises to enhance our comprehension of transition metal complexes, facilitating the development of innovative catalysts and therapeutics. [ABSTRACT FROM AUTHOR]

Carbonylation processes have become widely recognized as a versatile, convenient, and low-cost method for the synthesis of high-value compounds. Given the great importance of heterocyclic compounds, the carbonylative approach has become increasingly important for their synthesis. In this mini-review, as a class of benzo-fused nitrogen-containing heterocyclic compounds, we summarized and discussed the recent achievements on the synthesis and functionalization of indole derivatives via carbonylative approaches.

Rationale Methods Results Conclusions Mass spectrometry (MS) is introduced to high school students in the UK in many pre‐university course syllabi. As such, we have identified the use of MS as a key technique that should be taught practically to undergraduates from the outset of their studies. This mini‐review describes how we introduce and develop students' use of MS throughout our three‐year undergraduate spiral curriculum practical programme, using atmospheric pressure chemical ionization MS (APCI‐MS).We have used an Advion ExpressionL spectrometer, fitted with an atmospheric solids analysis probe or a Plate Express TLC sampler for sample introduction.We have successfully demonstrated the use of APCI‐MS in a range of practicals and experiments covering organic and organometallic chemistries, with large cohorts of students gaining hands‐on instrumental experience in authentic research settings.APCI‐MS has proven to be an easy‐to‐use and valuable addition to our undergraduate practical course. The robustness of the spectrometer enables routine use by large cohorts of students with minimal supervision, and routine maintenance can be carried out by non‐specialist technicians. Students can readily process and interpret results for a series of routine analyses, as well as demonstrate uses in problem‐solving exercises. [ABSTRACT FROM AUTHOR]

The synthesis of lanthanide‐based organometallic sandwich compounds is very appealing regarding their potential for single‐molecule magnetism. Here, it is exploited by on‐surface synthesis to design unprecedented lanthanide‐directed organometallic sandwich complexes on Au(111). The reported compounds consist of Dy or Er atoms sandwiched between partially deprotonated hexahydroxybenzene molecules, thus introducing a distinct family of homoleptic organometallic sandwiches based on six‐membered ring ligands. Their structural, electronic, and magnetic properties are investigated by scanning tunneling microscopy and spectroscopy, X‐ray absorption spectroscopy, X‐ray linear and circular magnetic dichroism, and X‐ray photoelectron spectroscopy, complemented by density functional theory‐based calculations. Both lanthanide complexes self‐assemble in close‐packed islands featuring a hexagonal lattice. It is unveiled that, despite exhibiting analogous self‐assembly, the erbium‐based species is magnetically isotropic, whereas the dysprosium‐based compound features an in‐plane magnetization. [ABSTRACT FROM AUTHOR]

We conducted a joint synthetic, spectroscopic and computational study to explore the reactivity towards cyanide (from Bu4NCN) of a series of dinuclear complexes based on the M2Cp2(CO)3 scaffold (M = Fe, Ru; Cp = η5-C5H5), namely [M2Cp2(CO)2(µ-CO){µ,η1:η2-CH=C=CMe2}]BF4 (1Fe-Ru), [Ru2Cp2(CO)2(µ-CO){µ,η1:η2-C(Ph)=CHPh}]BF4 (2Ru) and [M2Cp2(CO)2(µ-CO){µ-CN(Me)(R)}]CF3SO3 (3Fe-Ru). While the reaction of 1Fe with Bu4NCN resulted in prevalent allenyl deprotonation, preliminary CO-NCMe substitution in 1Ru enabled cyanide addition to both the allenyl ligand (resulting in the formation of a h1:h2-allene derivative, 5A) and the two metal centers (affording 5B1 and 5B2). The mixture of 5B1-2 was rapidly converted into 5A in heptane solution at 100 °C, with 5A being isolated with a total yield of 60%. Following carbonyl-chloride substitution in 2Ru, CN− was incorporated as a terminal ligand upon Cl− displacement, to give the alkenyl complex 6 (84%). The reactivity of 3Fe and 3Ru is strongly influenced by both the metal element, M, and the aminocarbyne substituent, R. Thus, 7aRu was obtained with a 74% yield from cyanide attack on the carbyne in 3aRu (R = Cy, cyclohexyl), whereas the reaction involving the diiron counterpart 3aFe yielded an unclean mixture of the metastable 7aFe and the CO/CN− substitution product 8aFe. The cyano-alkylidene complexes 7aRu (R = Cy) and 7bFe (R = Me) underwent CO loss and carbene to carbyne conversion in isopropanol at 60–80 °C, giving 8aRu (48%) and 8bFe (71%), respectively. The novel compounds 5A, 5B1-2, 6 and 7aRu were characterized by IR and NMR spectroscopy, with the structure of 7aRu further elucidated by single crystal X-ray diffraction analysis. Additionally, the DFT-optimized structures of potential isomers of 5A, 5B1-2 and 6 were calculated. [ABSTRACT FROM AUTHOR]

The flash organometallic catalysis is a new concept that refers to the study of fast and controlled organometallic catalytic reactions by using microfluidic devices. Flash reactions' kinetics (ms‐s scale) is often ignored due to the lack of proper research tool in organometallic chemistry. The development of microfluidic systems offers the opportunity to discover under‐studied mechanisms and new reactions. In this concept, the basic theory of kinetic measurement in a microreactor is briefly reviewed and then two examples on studying flash organometallic catalytic transformation are introduced. One example is the discovery of a highly active palladium catalytic species for Suzuki Coupling and the other example is the study of a neglected isomerization catalytic cycle with a time scale of seconds before isomerization‐hydroformylation by customized microfluidic devices. The last part is summary and prospect of this new area. Customizing a microfluidic device with good engineering design for a target reaction supports flash reactions' kinetic experimentation and could become a general strategy in chemistry lab. [ABSTRACT FROM AUTHOR]

Molecular junctions, which involve sandwiching molecular structures between electrodes, play a crucial role in molecular electronics. Recent advances in this field have revealed the vital role of organometallic chemistry in the investigation of molecular junctions, which has added to their well-known contributions to catalysis and materials chemistry. This review summarizes the recent examples of organometallic chemistry applications in molecular junctions, which can be categorized into three types, i.e., class I encompassing molecular junctions with bridging organometallic complexes, class II involving molecular junctions with covalent and noncovalent metal electrode-carbon bonds, and class III comprising organometallic reactions within molecular junctions. [ABSTRACT FROM AUTHOR]

Typically reactions of N‐heterocyclic carbenes with transition metals are straightforward and require a carbene salt, a base strong enough to deprotonate such a salt and a metal. Yet when carbene precursors are in the form of triazolium salts, reaction may not proceed as easily as expected. In our work, we intended to obtain a triazolylidene complex of iron(II) chloride, but due to the presence of small amounts of water in the tetrahydrofuran solvent used, bis(acetonitrile)tetrakis(1‐benzyl‐1H‐1,2,4‐triazole‐κN4)iron(II) μ‐oxido‐bis[trichloridoferrate(III)] acetonitrile disolvate, [Fe(C9H9N3)4(CH3CN)2][Fe2Cl6O]·2CH3CN – an interesting anion with a linear geometry of the O atom – was formed instead of the iron carbene complex. Reaction proceeded via cleavage of the alkyl N‐substituent of the triazolium salt. The formation of the product was confirmed by X‐ray crystallography. The crystal structure and possible reaction pathways are discussed. [ABSTRACT FROM AUTHOR]

N-Heteroaromatics are key elements of pharmaceuticals, agrochemicals, and materials. N-Heteroarynes provide a scaffold to build these essential molecules but are underused because five-membered N-heteroarynes have been largely inaccessible on account of the strain of a triple bond in that small of a ring. On the basis of principles of metal-ligand interactions that are foundational to organometallic chemistry, in this work we report the stabilization of five-membered N-heteroarynes in the nickel coordination sphere. A series of 1,2-bis(dicyclohexylphosphino)ethane nickel 7-azaindol-2,3-yne complexes were synthesized and characterized crystallographically and spectroscopically. Ambiphilic reactivity of the nickel 7-azaindol-2,3-yne complexes was observed with multiple nucleophilic, electrophilic, and enophilic coupling partners. [ABSTRACT FROM AUTHOR]

A Surface OrganoMetallic Chemistry (SOMC) approach is used to prepare a novel hafnium‐iridium catalyst immobilized on silica, HfIr/SiO2, featuring well‐defined [≡SiOHf(CH2tBu)2(μ‐H)3IrCp*] surface sites. Unlike the monometallic analogous materials Hf/SiO2 and Ir/SiO2, which promote n‐pentane deuterogenolysis through C−C bond scission, we demonstrate that under the same experimental conditions (1 bar D2, 250 °C, 3 h, 0.5 mol %), the heterobimetallic catalyst HfIr/SiO2 is highly efficient and selective for the perdeuteration of alkanes with D2, exemplified on n‐pentane, without substantial deuterogenolysis (<2 % at 95 % conversion). Furthermore this HfIr/SiO2 catalyst is robust and can be re‐used several times without evidence of decomposition. This represents substantial advance in catalytic H/D isotope exchange (HIE) reactions of C(sp3)−H bonds. [ABSTRACT FROM AUTHOR]

This mini-review offers a comprehensive overview of the advancements made over the last three years in utilizing highly polar s-block organometallic reagents (specifically, RLi, RNa and RMgX compounds) in organic synthesis run under bench-type reaction conditions. These conditions involve exposure to air/moisture and are carried out at room temperature, with the use of sustainable solvents as reaction media. In the examples provided, the adoption of Deep Eutectic Solvents (DESs) or even water as non-conventional and protic reaction media has not only replicated the traditional chemistry of these organometallic reagents in conventional and toxic volatile organic compounds under Schlenk-type reaction conditions (typically involving low temperatures of −78 °C to 0 °C and a protective atmosphere of N2 or Ar), but has also resulted in higher conversions and selectivities within remarkably short reaction times (measured in s/min). Furthermore, the application of the aforementioned polar organometallics under bench-type reaction conditions (at room temperature/under air) has been extended to other environmentally responsible reaction media, such as more sustainable ethereal solvents (e.g., CPME or 2-MeTHF). Notably, this innovative approach contributes to enhancing the overall sustainability of s-block-metal-mediated organic processes, thereby aligning with several key principles of Green Chemistry. [ABSTRACT FROM AUTHOR]

This document is a preface to a special issue of the journal Catalysts, focusing on advances in transition metal catalysis. The preface highlights the significant impact of transition metal catalysis on science and technology, particularly in the development of efficient synthetic processes. The special issue covers a range of topics, including new catalytic materials and processes for sustainable organic synthesis. The preface provides a brief overview of the contributions in the special issue, which include research papers and reviews on various catalytic reactions and materials. The authors express their gratitude to the journal and the contributors, and emphasize the importance of further research in this field. [Extracted from the article]

The regularized and restored semilocal meta-generalized gradient approximation (meta-GGA) exchange–correlation functional r2SCAN [Furness et al., J. Phys. Chem. Lett. 11, 8208–8215 (2020)] is used to create three global hybrid functionals with varying admixtures of Hartree–Fock "exact" exchange (HFX). The resulting functionals r2SCANh (10% HFX), r2SCAN0 (25% HFX), and r2SCAN50 (50% HFX) are combined with the semi-classical D4 London dispersion correction. The new functionals are assessed for the calculation of molecular geometries, main-group, and metalorganic thermochemistry at 26 comprehensive benchmark sets. These include the extensive GMTKN55 database, ROST61, and IONPI19 sets. It is shown that a moderate admixture of HFX leads to relative improvements of the mean absolute deviations for thermochemistry of 11% (r2SCANh-D4), 16% (r2SCAN0-D4), and 1% (r2SCAN50-D4) compared to the parental semi-local meta-GGA. For organometallic reaction energies and barriers, r2SCAN0-D4 yields an even larger mean improvement of 35%. The computation of structural parameters (geometry optimization) does not systematically profit from the HFX admixture. Overall, the best variant r2SCAN0-D4 performs well for both main-group and organometallic thermochemistry and is better or on par with well-established global hybrid functionals, such as PW6B95-D4 or PBE0-D4. Regarding systems prone to self-interaction errors (SIE4x4), r2SCAN0-D4 shows reasonable performance, reaching the quality of the range-separated ωB97X-V functional. Accordingly, r2SCAN0-D4 in combination with a sufficiently converged basis set [def2-QZVP(P)] represents a robust and reliable choice for general use in the calculation of thermochemical properties of both main-group and organometallic chemistry. [ABSTRACT FROM AUTHOR]

Palladium‐catalyzed Suzuki‐Miyaura and Buchwald‐Hartwig cross‐coupling reactions have become indispensable tools in the synthesis of otherwise inaccessible compounds because of the efficient, catalytic nature of these styles of reactions. The development of novel monophosphine ligands to achieve the cross‐coupling of substrates that are generally unreactive under standard conditions has developed into an extremely important area of research in the field of organometallic chemistry. Herein, we show the use of an imidazopyridine monophosphine ligand JagPhos I in the Suzuki‐Miyaura palladium‐catalyzed cross‐coupling reaction to deliver sterically‐hindered biaryls and unsymmetrical biheterocycles. We also report the scope and limitations of imidazopyridine monophosphine ligand JagPhos II in the Buchwald‐Hartwig amination reactions of (hetero)aryl halides with anilines, secondary amines, and primary amines. [ABSTRACT FROM AUTHOR]

The reactivity and selectivity of a transition metal catalyst is intimately related to its ligand‐sphere geometry, and, in many cases, the ideal ligand geometry for one step of a catalytic cycle is poorly matched to the ideal ligand geometry for another. For this reason, methods for reversibly modulating ligand geometry on the time scale of catalytic turnover or monomer enchainment are highly desirable. Mechanical force represents a heretofore untapped approach to modulate catalyst geometry and/or reactivity, with the potential to do so on the timescale of catalytic turnover or monomer enchainment. Macroscopic mechanical forces are large, directional and localized to an extent that differentiates them from other forms of energy input such as heat or light. In this Concept, we describe our efforts to address the fundamental challenges associated with force‐modulated transition metal catalysis by employing molecular force probe ligands comprising a stiff stilbene photoswitch tethered to rotationally flexible biaryl bisphosphine ligand. Our efforts to date include the modulation of catalytic activity through force‐mediated ligand perturbations, quantification of the force‐coupled ligand effects on the energetics of elementary organometallic transformations, and evaluation of the mechanisms of force transduction in these systems. [ABSTRACT FROM AUTHOR]

Whereas indications of radical reactivity in bismuth compounds can be traced back to the 19th century, the preparation and characterization of both transient and persistent bismuth‐radical species has only been established in recent decades. These advancements led to the emergence of the field of bismuth radical chemistry, mirroring the progress seen for other main‐group elements. The seminal and fundamental studies in this area have ultimately paved the way for the development of catalytic methodologies involving bismuth‐radical intermediates, a promising approach that remains largely untapped in the broad landscape of synthetic organic chemistry. In this review, we delve into the milestones that eventually led to the present state‐of‐the‐art in the field of radical bismuth chemistry. Our focus aims at outlining the intrinsic discoveries in fundamental inorganic/organometallic chemistry and contextualizing their practical applications in organic synthesis and catalysis. [ABSTRACT FROM AUTHOR]

Beryllium possesses a unique amalgamation of characteristics, its electronegativity included, that not only make it a vital component in a wide range of technical sectors and consumer industries, but also make it an interesting candidate for forming covalently bonded compounds. However, the extremely toxic nature of beryllium, which can cause chronic beryllium disease, has limited the exploration of its chemistry, making beryllium one of the least studied (non-radioactive) elements. The development of selective chelating ligands, sterically encumbered substituents and, moreover, the boom of N-heterocyclic carbenes in organometallic chemistry and main group chemistry has revived the interest in beryllium chemistry. Therefore, some quite remarkable progress in the coordination and organometallic chemistry of beryllium has been made in the last two decades. For example, low oxidation state beryllium compounds, antiaromatic/aromatic beryllium compounds, where beryllium is involved in π-electron delocalization, and the isolation of beryllium-beryllium bonded species have all been achieved. This article provides an oversight over the recent developments in the organometallic chemistry of beryllium. [ABSTRACT FROM AUTHOR]

Arylation of gold holds paramount importance in the domain of organometallic chemistry; however, the exploration of arylgold nanoclusters remains in its infancy primarily due to the synthetic challenge. Here, we present a facile and effective arylation strategy to directly synthesize two arylgold nanoclusters (Au44a and Au44b), by using tetraarylborates, capable of transferring aryl fragments to metal centers. X-ray crystallography reveals that both Au44 nanoclusters contain an Au44 kernel co-protected by six aryl groups, two tetrahydrothiophene, and 16 alkynyl-ether ligands, the latter is generated in situ through Williamson ether reaction during the assembly processes. Notably, Au44 nanoclusters exhibit near-infrared (NIR) phosphorescence (λmax = 958 nm) and microsecond radiative relaxation at ambient condition, which is a thermal-controlled single/dual-channel phosphorescent emission revealed by temperature-dependent NIR, time-resolved emission, and femtosecond/nanosecond transition absorption spectra. This work represents a breakthrough in using aryl as protective ligands for the construction of gold nanoclusters, which is poised to have a transformative impact on organometallic nanoclusters. [ABSTRACT FROM AUTHOR]

Wide applications of anhydrous rare‐earth (RE) trichlorides RECl3 in organometallic chemistry, for the synthesis of optical and magnetic materials, and as catalysts require a facile approach for their synthesis. The known methods use or produce toxic substances, are complicated and have limited reliability and upscaling. It has been shown that task‐specific ionic liquids (ILs) can dissolve many metal oxides without special reaction conditions at moderate temperature, making the metals accessible to downstream chemistry. Using imidazolium chloridoaluminate ILs, pure crystalline anhydrous RECl3 (RE=La−Nd, Sm−Dy) can be synthesized in one step from RE oxides in high yield. The Lewis acidic IL acts as solvent and reaction partner. The by‐product [Al4O2Cl10]2−, which was detected spectroscopically, remains in solution. The reacted IL can be removed quantitatively by washing. ILs with various imidazolium cations and AlCl3 content and the effect of temperature and reaction time were tested. [ABSTRACT FROM AUTHOR]

Solar hydrogen production at a high efficiency holds the significant importance in the age of energy crisis, while the micro‐environment manipulation of active sites on photocatalysts plays a profound role in enhancing the catalytic performance. In this work, a series of well‐defined single‐site Ni‐grafted TiO2 photocatalysts with unique and specific coordination environments, 2,2′‐bipyridine‐Ni−O−TiO2 (T−Ni Bpy) and 2‐Phenylpyridine‐Ni−O−TiO2 (T−Ni Phpy), were constructed with the methods of surface organometallic chemistry combined with surface ligand exchange for visible‐light‐induced photocatalytic hydrogen evolution reaction (HER). A prominent rate of 33.82 μmol ⋅ g−1 ⋅ h−1 and a turnover frequency of 0.451 h−1 for Ni are achieved over the optimal catalyst T−Ni Bpy for HER, 260‐fold higher than those of Ni−O−TiO2. Fewer electrons trapped oxygen vacancies and a larger portion of long‐lived photogenerated electrons (>3 ns, ~52.9 %), which were demonstrated by the electron paramagnetic resonance and femtosecond transient IR absorption, correspond to the photocatalytic HER activity over the T−Ni Bpy. The number of long‐lived free electrons injected from the Ni photoabsorber to the conduction band of TiO2 is one of the determining factors for achieving the excellent HER activity. [ABSTRACT FROM AUTHOR]

Computational studies of the coordination chemistry and bonding of lanthanides have grown in recent decades as the need for understanding the distinct physical, optical, and magnetic properties of these compounds increased. Density functional theory (DFT) methods offer a favorable balance of computational cost and accuracy in lanthanide chemistry and have helped to advance the discovery of novel oxidation states and electronic configurations. This Frontier article examines the scope and limitations of DFT in interpreting structural and spectroscopic data of low-valent lanthanide complexes, elucidating periodic trends, and predicting their properties and reactivity, presented through selected examples. [ABSTRACT FROM AUTHOR]

The ethylene polymerization Phillips catalyst has been employed for decades and is central to the polymer industry. While Cr(III) alkyl species are proposed to be the propagating sites, there is so far no direct experimental evidence for such proposal. In this work, by coupling Surface organometallic chemistry, EPR spectroscopy, and machine learning‐supported XAS studies, we have studied the electronic structure of well‐defined silica‐supported Cr(III) alkyls and identified the presence of several surface species in high and low‐spin states, associated with different coordination environments. Notably, low‐spin Cr(III) sites are shown to participate in ethylene polymerization, indicating that similar Cr(III) alkyl species could be involved in the related Phillips catalyst. [ABSTRACT FROM AUTHOR]

This review article provides a comprehensive overview of recent advancements in the realm of cyclophosphazenes, encompassing their preparation methodologies, distinctive properties, and diverse applications. The synthesis approaches are explored, highlighting advancements in the preparation of these cyclic compounds. The discussion extends to the distinctive properties exhibited by cyclophosphazenes, including thermal stability characteristics, and other relevant features. Furthermore, we examine the broad spectrum of applications for cyclophosphazenes in various fields, such as coatings, adhesives, composites, extractants, metal complexes, organometallic chemistry, medicine, and inorganic chemistry. This review aims to offer insights into the evolving landscape of cyclophosphazenes and their ever-expanding roles in contemporary scientific and technological arenas. Future possibilities are emphasized, and significant research data shortages are identified. [ABSTRACT FROM AUTHOR]

Joint damage is a major symptom of osteoarthritis, a degenerative disease that worsens over time. The purpose of this review was to assess the effectiveness and safety of nanomaterials as an alternative to the widely used methods. Due to its poor regenerative and self-healing properties, cartilage repair after lesions or debilitating disease is a major clinical issue. Here, we use the organometallic chemistry identity of chondroitin sulphate to repair cartilage lesions by creating a nano-elemental particle through electrostatic interactions. As an integral part of the extracellular matrix, chondroitin sulphate (CS) is shown to improve osteogenesis in this review. The injectability of hydrated cement products was greatly improved by the addition of CS, but there was no discernible change in their phase, morphology, apparent porosity, or compressive strength. This review article provides a thorough analysis of the results from the use of nanocomposites in orthopaedic drug delivery and bone remodelling engineering. [ABSTRACT FROM AUTHOR]

Abstract The synthesis of lanthanide‐based organometallic sandwich compounds is very appealing regarding their potential for single‐molecule magnetism. Here, it is exploited by on‐surface synthesis to design unprecedented lanthanide‐directed organometallic sandwich complexes on Au(111). The reported compounds consist of Dy or Er atoms sandwiched between partially deprotonated hexahydroxybenzene molecules, thus introducing a distinct family of homoleptic organometallic sandwiches based on six‐membered ring ligands. Their structural, electronic, and magnetic properties are investigated by scanning tunneling microscopy and spectroscopy, X‐ray absorption spectroscopy, X‐ray linear and circular magnetic dichroism, and X‐ray photoelectron spectroscopy, complemented by density functional theory‐based calculations. Both lanthanide complexes self‐assemble in close‐packed islands featuring a hexagonal lattice. It is unveiled that, despite exhibiting analogous self‐assembly, the erbium‐based species is magnetically isotropic, whereas the dysprosium‐based compound features an in‐plane magnetization.