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We present the synthesis of metal oxide frameworks composed of the Preyssler anion, [NaP

International audience; Organic circularly polarized luminescence (CPL)-active molecular emitters featuring dynamic propeller-like luminophores were prepared in one step from cyclic(alkyl)(amino) carbenes (CAACs). These molecules exhibit through-space arene-arene π- delocalization and rapid intramolecular inter-system crossing (ISC) in line with their helical character.

Dipolar coupling is rarely invoked as a driving force for slow relaxation dynamics in lanthanide-based single-molecule magnets, though it is often the strongest mechanism available for mediating inter-ion magnetic interactions in such species. Indeed, for multinuclear lanthanide complexes, the magnitude and anisotropy of the dipolar interaction can be considerable given their ability to form highly directional, high-moment ground states. Herein, we present a mono-, di-, and trinuclear erbium-based single-molecule magnet sequence, ([Er-TiPS

The controlled isomerization and functionalization of alkenes is a cornerstone achievement in organometallic catalysis that is now widely used industrially to produce detergents, fragrances, and pharmaceuticals. In particular, the addition of carbon monoxide (CO) and hydrogen (H(2)) to an alkene, also known as the oxo-process, is used in a constantly expanding industry that produces linear aldehydes from crude alkene feedstocks. In these catalytic reactions, isomerization is governed by thermodynamics, giving rise to functionalization at the most stable alkylmetal species. Despite the ubiquitous industrial applications of tandem alkene isomerization/functionalization reactions, selective functionalization at internal positions has remained largely unexplored. Here we report that the simple W(0) precatalyst, W(CO)(6), catalyzes the isomerization of alkenes to unactivated internal positions and subsequent hydrocarbonylation with CO. The 6- to 7-coordinate geometry changes that are characteristic of the W(0)/W(II) redox cycle and the conformationally flexible directing group are key factors in allowing isomerization to take place over multiple positions and stop at a defined unactivated internal site that is primed for in situ functionalization.

We report the synthesis and characterization of various compounds containing 1,7,9-hydroxylated closo-dodecahydrododecaborate (B12H9(OH)32-) cluster motif. Specifically, we show how the parent compound can be synthesized on the multigram scale and further perhalogenated, leading to a new class of vertex-differentiated weakly coordinating anions (WCAs). We show that a post-modification of the hydroxyl groups by alkylation affords further opportunities for tailoring these anions' stability, steric bulk, and solubility properties. The resulting dodecaborate-based salts were subjected to a full thermal and electrochemical stability evaluation, showing that many of these anions maintain thermal stability up to 500 °C and feature no redox activity below ~1 V vs. Fc/Fc+. Mixed hydroxylated/halogenated clusters show enhanced solubility compared to their purely halogenated analogs and retain weakly coordinating properties in the solid-state, as demonstrated by ionic conductivity measurements of their Li+ salts.

This work demonstrates the first successful electrochemical cycling of a redox-active boron cluster-based material in the solid state. Specifically, we designed and synthesized an ether-functionalized dodecaborate cluster, B12(OCH3)12, which is the smallest redox-active building block in the B12(OR)12 family. This species can reversibly access four oxidation states in solution, ranging from a dianion to a radical cation. We show that a chemically isolated and characterized neutral [B12(OCH3)12]0 cluster can be utilized as a cathode active material in a PEO-based rechargeable all-solid-state cell with a lithium metal anode. The cell exhibits an impressive active material utilization close to 95% at C/20 rate, a high Coulombic efficiency of 96%, and excellent reversibility, with only 4% capacity fade after 16 days of cycling. This work represents a conceptual departure in the development of redox-active components for electrochemical storage and serves as an entry point to a broader class of borane-based materials.

The synthesis, structure, and reactivity of a μ3-SnH capped trinuclear nickel cluster, [Ni3(dppm)3(μ3-H)(μ3-SnH)], is reported. This complex undergoes oxidative addition chemistry, alkyne insertion, and subsequent hydrogenation.

Oxidation of a 1,4-di-iodobenzene having four adjacent p-tBu-C6H4 group (Ar′) substituents (1) yields the hypervalent iodine compound 1,4-[I(OAc)2]2-2,3,5,6-Ar′4-C6 (2), that undergoes cyclization to produce dicyclic di-iodonium salt (3).

Chalcogen-containing carboranes have been known for several decades and possess stable exopolyhedral B(9)-Se and B(9)-Te σ bonds despite the electron-donating ability of the B(9) vertex. While these molecules are known, little has been done to thoroughly evaluate their electrophilic and nucleophilic behavior. Herein, we report an assessment of the electrophilic reactivity of meta-carboranyl selenyl (II), tellurenyl (II), and tellurenyl (IV) chlorides and establish their reactivity pattern with Grignard reagents, alkenes, alkynes, enolates, and electron-rich arenes. These electrophilic reactions afford unique electron-rich B-Y-C (Y = Se, Te) bonding motifs not commonly found before. Furthermore, we show that meta-carboranyl selenolate, and even meta-carboranyl tellurolate, can be competent nucleophiles and participate in nucleophilic aromatic substitution reactions. Arene substitution chemistry is shown to be further extended to electron-rich species via the palladium mediated cross-coupling chemistry.

A flurry of recent research has centered on harnessing the power of nickel catalysis in organic synthesis. These efforts have been bolstered by contemporaneous development of well-defined nickel (pre)catalysts with diverse structure and reactivity. In this report, we present ten different bench-stable, 18-electron, formally zero-valent nickel-olefin complexes that are competent pre-catalysts in various reactions. Our investigation includes preparations of novel, bench stable Ni(COD)(L) complexes (COD = 1,5-cyclooctadiene), in which L = quinone, cyclopentadienone, thiophene-S-oxide, and fulvene. Characterization by NMR, IR, single-crystal X-ray diffraction, cyclic voltammetry, thermogravimetric analysis, and natural bond orbital analysis sheds light on the structure, bonding, and properties of these complexes. Applications in an assortment of nickel-catalyzed reactions underscore the complementary nature of the different pre-catalysts within this toolkit.

Multivalency plays a key role in achieving strong, yet reversible interactions in nature, and provides critical chemical organization in biological recognition processes. Chemists have taken an interest in designing multivalent synthetic assemblies to both better understand the underlying principles governing these interactions, and to build chemical tools that either enhance or prevent such recognition events from occurring in biology. Rationally tailoring synthetic strategies to achieve the high level of chemical control and tunability required to mimic these interactions, however, is challenging. Here, we introduce a systematic and modular synthetic approach to the design of well-defined molecular multivalent protein-binding constructs that allows for control over size, morphology, and valency. A series of supramolecular mono-, bi-, and tetrametallic Fe(ii) complexes featuring a precise display of peripheral saccharides was prepared through coordination-driven self-assembly from simple building blocks. The molecular assemblies are fully characterized, and we present the structural determination of one complex in the series. The mannose and maltose-appended assemblies display strong multivalent binding to model lectin, Concanavalin A (K d values in μM), where the strength of the binding is a direct consequence of the number of saccharide units decorating the molecular periphery. This versatile synthetic strategy provides chemical control while offering an easily accessible approach to examine important design principles governing structure-function relationships germane to biological recognition and binding properties.

Surface immobilization of organometallic catalysts is a promising approach to developing new catalytic systems that combine molecular catalysts with heterogenous surfaces to probe surface mechanisms. The orientation of the catalyst relative to the surface is one important parameter that must be considered in such hybrid systems. In this work, we synthesize three new sulfide-modified Ir piano-stool complexes with sulfide-modified bipyridine and phenylpyridine ligands for the attachment to Au(111) surfaces. Self-assembled monolayers made from (Cp*Ir(2,2'-bipyridine-4-sulfide)Cl)

A unique family of N,N,π,C-palladacycles are synthesized from 8-aminoquinoline-coupled nopol derivatives through directed 1,2-migratory insertion of in situ generated arylpalladium(II) species followed by β-carbon elimination. These palladacycles have exceptional stability under air and moisture at room temperature, enabling successful isola-tion and characterization by X-ray crystallography, NMR, and high-resolution mass spectrometry. Computational studies shed light on the facile β-alkyl elimination step and the origins of the high stability of these post β-carbon-elimination complexes.

Tetrahydrothiophene-functionalized N,S-heterocyclic carbene palladium(II) complexes are synthesized through an unexpected rearrangement that proceeds with palladium(II) trifluoroacetate and not with palladium(II) acetate, palladium(II) bromide, or palladium(II) chloride. A series of these complexes were isolated and characterized by X-ray crystallography. The mechanism of formation of these [3.2.1]-palladabicycles was explored, and the catalytic capabilities of these complexes were demonstrated in representative C-C coupling reactions.

Since its outbreak, the severe acute respiratory syndrome—coronavirus 2 (SARS‐CoV‐2) has impacted the quality of life and cost hundreds‐of‐thousands of lives worldwide. Based on its global spread and mortality, there is an urgent need for novel treatments which can combat this disease. To date, the 3‐chymotrypsin‐like protease (3CLpro), which is also known as the main protease, is considered among the most important pharmacological targets. The vast majority of investigated 3CLpro inhibitors are organic, non‐covalent binders. Herein, the use of inorganic, coordinate covalent binders is proposed that can attenuate the activity of the protease. ReI tricarbonyl complexes were identified that demonstrate coordinate covalent enzymatic inhibition of 3CLpro. Preliminary studies indicate the selective inhibition of 3CLpro over several human proteases. This study presents the first example of metal complexes as inhibitors for the 3CLpro cysteine protease., The outbreak of the severe acute respiratory syndrome—coronavirus 2 has impacted the life quality and cost hundreds‐of‐thousands of lives worldwide. Herein, a novel approach using ReI tricarbonyl complexes as coordinate covalent inhibitors for the main protease is presented. These complexes target the active site cysteine residue and show selective inhibition of the main protease over several human proteases.

Introducing a tri-coordinate boron-based functional group (e.g., boronic ester) into an unactivated C–H bond in the absence of directing groups is an ongoing challenge in synthetic chemistry. Despite previous developments in transition metal-catalyzed and -free approaches, C–H borylation of sterically hindered arenes remains a largely unsolved problem to date. Here, we report a synthetic strategy of a precious metal-free electrophilic C–H borylation of sterically hindered alkyl- and haloarenes to generate aryl boronic esters. The reported approach consists of two simple steps that can be carried out under open flask conditions. The first step relies on electrophilic aromatic substitution (SEAr) induced by cage-opening of Cs2[closo-B10H10], forming a 6-Ar-nido-B10H13 product containing a B–C bond. This is followed by an unprecedented cage deconstruction of arylated decaboranes promoted by diols leading to selective breakage of B–B bonds in the cluster while preserving the B–C bond. The combination of these two steps allows for the preparation of aryl boronic esters that are hard-ly accessible by current direct C–H borylation approaches. Unlike the previous arene C–H borylations, this reaction does not require any precious metals, highly-engineered ligands, pre-functionalized boron reagents, or inert conditions. In addition, the unique properties of a non-classical boron cluster electrophile intermediate, B10H13+, afforded an unprecedented regi-oselectivity with unique steric and electronic control without the undesirable side reactions common in electrophilic aro-matic substitution. This work showcases how inorganic cluster chemistry can be leveraged to access new modes of reactivi-ty relevant to organic synthesis.

Appendicoliths are commonly found obstructing the lumen of the appendix at the time of appendectomy. To identify factors that might contribute to their formation we investigated the composition of appendicoliths using laser ablation inductively coupled plasma mass spectroscopy, gas chromatography, polarized light microscopy, X-ray crystallography, and protein mass spectroscopy. Forty-eight elements, 32 fatty acids, and 109 human proteins were identified within the appendicoliths. The most common elements found in appendicoliths are calcium and phosphorus, 11.0 + 6.0 and 8.2 + 4.2 % weight, respectively. Palmitic acid (29.7%) and stearate (21.3%) are the most common fatty acids. Some stearate is found in crystalline form—identifiable by polarized light microscopy and confirmable by X-ray crystallography. Appendicoliths have an increased ratio of omega-6 to omega-3 fatty acids (ratio 22:1). Analysis of 16 proteins common to the appendicoliths analyzed showed antioxidant activity and neutrophil functions (e.g., activation and degranulation) to be the most highly enriched pathways. Considered together, these preliminary findings suggest oxidative stress may have a role in appendicolith formation. Further research is needed to determine how dietary factors such as omega-6 fatty acids and food additives, redox-active metals, and the intestinal microbiome interact with genetic factors to predispose to appendicolith formation.

The rhodium benzyl complexes Rh(diphos*)(η3-CH2Ph) (1–14, diphos* = chiral bis(phosphine)), potential precursors for asymmetric catalysis, were prepared either by treatment of Rh(COD)(η3-CH2Ph) (15...

It has long been recognized that the first intermediate in chemical reactions mediated by Fe(CO)5 is Fe(CO)4. However, the extreme instability of this unsaturated, high-spin species has hampered de...

Isocyanide coordination networks (ISOCNs), which consist of multitopic isocyanide linker groups and transition-metal-based secondary building units (SBUs), are a promising class of organometallic f...

A series of technetium complexes with the sterically encumbered m-terphenyl isocyanides CNArDipp2 (Dipp = 2,6-diisopropylphenyl) and CNArMes2 (Mes = 2,4,6-trimethylphenyl) has been prepared. The pr...

A flurry of recent research has centered on harnessing the power of nickel catalysis in organic synthesis. These efforts have been bolstered by contemporaneous synthesis, characterization, and optimization of well-defined nickel (pre)catalysts with diverse structure and reactivity. In this report, we present the development of ten different bench-stable, 18-electron, formally zero-valent nickel–olefin complexes that are shown to be competent pre-catalysts in various reactions. Our investigation includes preparations of novel, bench stable Ni(COD)(L) complexes, in which L = quinone, cyclopentadienone, thiophene-S-oxide, and fulvene. Characterization by a battery of techniques, including NMR, IR, single-crystal X-ray diffraction, cyclic voltammetry, thermogravimetric analysis, and natural bond orbital analysis sheds light on the structure, bonding, and properties of these complexes. Kinetic profiling across a series of representative reactions reveals reactivity differences that stem from the nature of the ancillary ligand, underscoring the complementary relationships between each pre-catalyst within this toolkit.

Chalcogen-containing carboranes have been known for several decades and possess stable exopolyhedral B(9)-Se and B(9)-Te σ bonds despite the electron-donating ability of the B(9) vertex. While these molecules are known, little has been done to thoroughly evaluate their electrophilic and nucleophilic behavior. Herein, we report an assessment of the electrophilic reactivity of meta-carboranyl selenyl (II), tellurenyl (II), and tellurenyl (IV) chlorides and establish their reactivity pattern with Grignard reagents, alkenes, alkynes, enolates, and electron-rich arenes. These electrophilic reactions afford unique electron-rich B-Y-C (Y = Se, Te) bonding motifs not commonly found before. Furthermore, we show that meta-carboranyl selenolate, and even meta-carboranyl tellurolate, can be competent nucleophiles and participate in nucleophilic aromatic substitution reactions. Arene substitution chemistry is shown to be further extended to electron-rich species via the palladium mediated cross-coupling chemistry.

Mixed-metal solid-state framework materials are emerging candidates for advanced applications in catalysis and chemical separations. Traditionally, the syntheses of mixed-metal framework systems rely on postsynthetic ion exchange, metalloligands, or metal-deposition techniques for the incorporation of a second metal within a framework material. However, these methods are often incompatible with the incorporation of low-valent metal centers, which preferentially bind to electronically "soft" ligands according to the tenets of hard/soft acid/base theory. Here we present the electronically differentiated isocyanide/carboxylate heteroditopic linker ligand 1,4-CNArMes2C6H4CO2H (TIBMes2H; TIB = terphenyl isocyanide benzoate; ArMes2 = 2,6-(2,4,6-Me3C6H2)2C6H2), which is capable of selective binding of low-valent metals via the isocyano group and complexation of hard Lewis acidic metals through the carboxylate unit. This heteroditopic ligand also possesses an encumbering m-terphenyl backbone at the isocyanide function to foster coordinative unsaturation. The treatment of TIBMes2H with [Cu(NCMe)4]PF6 in a 3:1 ratio results in preferential binding of the isocyanide group to the Cu(I) center as assayed by multinuclear NMR and IR spectroscopies. IR spectroscopy also provides strong evidence for the formation of a copper(I) tris(isocyanide) complex, wherein the carboxylic acid group remains unperturbed. The addition of TIBMes2 to [Cu(NCMe)4]PF6 in a 4:1 ratio results in crystallization of the hydrogen-bonding network, [Cu(TIBMes2H)4]PF6, in which the formation of R22(8) hydrogen bonds results in a 7-fold interpenetrated diamondoid lattice structure. The preassembly of a copper(I) tris(isocyanide) complex using TIBMes2H, followed by deprotonation and the introduction of ZnCl2, generates a novel and unusual zwitterionic solid-state phase (denoted as Cu/Zn-ISOCN-5; ISOCN = isocyanide coordination network) consisting of a coordinatively unsaturated [Cu(CNR)3]+ cationic secondary building unit (SBU) and an anionic, paddlewheel-type Zn(II)-based SBU of the formulation [Cl2Zn2(O2CR)3]-. Inductively coupled plasma mass spectrometry analysis provided firm evidence for a 2:1 Zn-to-Cu ratio in the network, thereby indicating that the isocyanide and carboxylate groups selectively bind soft and hard Lewis acidic metal centers, respectively. The extended structure of Cu/Zn-ISOCN-5 is a densely packed, noninterpenetrated AB-stacked layer network with modest surface area. However, it is thermally robust, and its formation and compositional integrity validate the use of an electronically differentiated linker for the formation of mixed-metal frameworks incorporating low-valent metal centers.

The increased interest in white solid-state lighting devices addresses the urgent challenge to develop semiconductors with broad band emission. In recent years, low dimensional hybrid organic/inorganic lead perovskites have shown great potential as single white-light emitters. Herein, we show that it is possible to control the chirality of lead bromide perovskites by incorporating enantiopure (R or S) or racemic (RS) β-methylphenethylammonium. The incorporation of such cations allows us to control the chirality of the resulting materials and yields the first examples of 2D chiral perovskites that emit white light. Furthermore, we demonstrate that these materials exhibit second harmonic generation. Our results demonstrate the potential of this kind of materials for chiroptical applications and non-linear optics.

Akin to the expansion in compositional diversity that halide double perovskites provided to three-dimensional perovskites, layered double perovskites could further expand the diversity of two-dimen...

Tungsten catalysis has played an instrumental role in the history of organometallic chemistry, with electrophilic, fully oxidized W(VI) catalysts featuring prominently in olefin polymerization and metathesis reactions. Here, we report that the simple W(0) precatalyst, W(CO)6, catalyzes the isomerization and hydrocarbonylation of alkenes via a W(0)/W(II) redox couple. The 6- to 7-coordinate geometry changes associated with this redox process are key in allowing isomerization to take place over multiple positions and stop at a defined unactivated internal site that is primed for in situ functionalization. DFT studies and crystallographic characterization of multiple directing-group-bound W(II) model complexes illuminate potential intermediates of this redox cycle and showcase the capabilities of the 7-coordinate W(II) geometry to facilitate challenging alkene functionalizations.

Tungsten catalysis has played an instrumental role in the history of organometallic chemistry, with electrophilic, fully oxidized W(VI) catalysts featuring prominently in olefin polymerization and metathesis reactions. Here, we report that the simple W(0) precatalyst, W(CO)6, catalyzes the isomerization and hydrocarbonylation of alkenes via a W(0)/W(II) redox couple. The 6- to 7-coordinate geometry changes associated with this redox process are key in allowing isomerization to take place over multiple positions and stop at a defined unactivated internal site that is primed for in situ functionalization. DFT studies and crystallographic characterization of multiple directing-group-bound W(II) model complexes illuminate potential intermediates of this redox cycle and showcase the capabilities of the 7-coordinate W(II) geometry to facilitate challenging alkene functionalizations.

Tetrahydrothiophene-functionalized N,S-heterocyclic carbene palladium(II) complexes are synthesized through an unexpected rearrangement that proceeds with palladium(II) trifluoroacetate and not with palladium(II) acetate, palladium(II) bromide, or palladium(II) chloride. A series of these complexes were isolated and characterized by X-ray crystallography. The mechanism of formation of these [3.2.1]-palladabicycles was explored, and the catalytic capabilities of these complexes were demonstrated in representative C–C coupling reactions.

The Preyssler polyoxoanion, [NaP5 W30 O110 ]14- ({P5 W30 }), is used as a platform for evaluating the role of nonbridging cations in the formation of transition-metal-bridged polyoxometalate (POM) coordination frameworks. Specifically, the assembly architecture of Co2+ -bridged frameworks is shown to be dependent on the identity and amount of alkali or alkaline-earth cations present during crystallization. The inclusion of Li+ , Na+ , K+ , Mg2+ , or Ca2+ in the framework synthesis is used to selectively synthesize five different Co2+ -bridged {P5 W30 } structures. The influence of the competition between K+ and Co2+ for binding to {P5 W30 } in dictating framework assembly is evaluated. The role of ion pairing on framework assembly structure and available void volume is discussed. Overall, these results provide insight into factors governing the ability to achieve controlled assembly of POM-based coordination networks.

International audience; HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Tetraisocyanide complex Co(CNArMes2)4 (ArMes2 = 2,6-(2,4,6-Me3C6H2)2C6H3) serves as a crystallographically characterized, thermally stable isocyano analogue of the reactive binary carbonyl Co(CO)4. The enhanced stability of Co(CNArMes2)4 allows for a systematic investigation of its reactivity profile in an operationally convenient manner, which is not possible for transient Co(CO)4. Zero-valent Co(CNArMes2)4 undergoes ligand exchange reactions with a variety of 2e– donor, L-type ligands, including triphenylphosphine, tert-butylethylene, and phenylacetylene. Kinetic studies of ligand substitution of Co(CNArMes2)4 with phenylacetylene using UV–vis spectroscopy indicates an associative reaction mechanism. This is consistent with the mechanisms proposed for other isolable 17e– transition-metal carbonyls but contrasts with studies proposing zero-valent CoL4 complexes to react via dissociative reaction pathways. Zero-valent Co(CNArMes2)4 also reacts with elemental phosphorus and sulfur and with diphenyl disulfi...

Copper(I) and gold(I) thiolates were synthesized in quantitative or near-quantitative yield by the direct reaction of aqueous Cu(NO3)2 or HAuCl4 with aqueous thiols HSCH2CH2OH and HSCH2CH2OCH2CH2OH. The resulting highly insoluble thiolates had spectroscopic and bulk characteristics consistent with the formation of coordination polymers of general formula [M(SR)]n. The gold(I) thiolates were found to be amorphous solids with significant aurophilic interactions. The copper(I) thiolates, however, formed crystalline solids without discernible cuprophilic interactions. Characterization of the solid state structure of these latter thiolates showed that they consisted of covalently linked ca. two-atom thick Cu–S layers separated by layers of hydrogen bonded thiol side chains.

[Y(N(SiMe3)2)3] reacts with (Ad,MeArOH)3mes to form the Y3+ complex [((Ad,MeArO)3mes)Y], 1-Y. This complex reacts with potassium metal in the presence of 2.2.2-cryptand to give a cocrystallized mixture of [K(2.2.2-cryptand)][((Ad,MeArO)3mes)Y], 2-Y, and [K(2.2.2-cryptand)][((Ad,MeArO)3mes)YH], 3-Y. The electron paramagnetic resonance spectrum of this crystalline mixture exhibits an isotropic signal at 77 K (giso = 2.000, Wiso = 1.8 mT), suggesting that 2-Y is best described as a Y3+ complex of the tris(aryloxide)mesitylene radical ((Ad,MeArO)3mes)4–. Evidence of the hydride ligand in 3-Y was obtained by 89Y–1H heteronuclear multiple quantum coherence NMR spectroscopy, and a coupling constant of JYH = 93 Hz was observed. A single crystal of 3-Y was also obtained in pure form and structurally characterized for comparison with the crystal data on the mixed component 2-Ln/3-Ln crystals. The origin of the hydride in 3-Ln is unknown, but further studies of the reduction of 1-La, previously found to form 2-La, r...

Antimony and bismuth ⟨111⟩ layered perovskites have recently attracted significant attention as possible, nontoxic alternatives to lead halide perovskites. Unlike lead halide perovskites, however, ⟨111⟩ halide perovskites have shown limited ability to tune their optical and electronic properties. Herein, we report on the metal alloying of manganese and copper into the family of materials with formula Cs4Mn1–xCuxSb2Cl12 (x = 0–1). By changing the concentration of manganese and copper, we show the ability to modulate the bandgap of this family of compounds over the span of 2 electron volts, from 3.0 to 1.0 eV. Furthermore, we show that in doing so, we can also adjust other relevant properties such as their magnetic behavior and their electronic structure.

Electrocatalytic energy conversion with molecular f-element catalysts is still in an early phase of its development. We here report detailed electrochemical investigations on the recently reported trivalent lanthanide coordination complexes [((Ad,MeArO)3mes)Ln] (1–Ln), with Ln = La, Ce, Pr, Nd, Sm, Gd, Dy, Er, and Yb, which were now found to perform as active electrocatalysts for the reduction of water to dihydrogen. Reactivity studies involving complexes 1–Ln and the Ln(II) analogues [K(2.2.2-crypt)][((Ad,MeArO)3mes)Ln] (2–Ln) suggest a reaction mechanism that differs significantly from the reaction pathway found for the corresponding uranium catalyst [((Ad,MeArO)3mes)U] (1–U). While complexes 1−Ln activate water via a radical pathway, only upon a 1 e− reduction to yield the reduced species 2−Ln, the 5f analogue 1−U directly reduces H2O via a 2 e− pathway. The electrocatalytic H2O reduction by complexes 1–Ln is initiated by the respective Ln(III)/Ln(II) redox couples, which gradually turn to more positiv...

Surface modification of glassy carbon electrodes (GCEs) with molecular electrocatalysts is an important step towards developing more efficient heterogeneous CO2 reduction materials. Here, we report direct anodic electrografting of [Ni(alkynyl-cyclam)]2+ catalysts to the surface of GCEs in one simple step using inexpensive earth-abundant chemicals. When modified, these electrodes show reversible electrochemistry in organic solvents with zero peak-to-peak separations (ΔE = 0) and non-diffusive I (V) profiles that are typical for heterogeneous redox materials. CPE of these electrodes showed enhanced formation of H2 gas relative to CO compared to homogeneous catalysts.

A permanently porous, three-dimensional metal–organic material formed from zero-valent metal nodes is presented. Combination of ditopic m-terphenyl diisocyanide, [CNArMes2]2, and the d10 Ni(0) precursor Ni(COD)2, produces a porous metal–organic material featuring tetrahedral [Ni(CNArMes2)4]n structural sites. X-ray absorption spectroscopy provides firm evidence for the presence of Ni(0) centers, whereas gas-sorption and thermogravimetric analysis reveal the characteristics of a robust network with a microdomain N2-adsorption profile.

The synthesis of two biscarboranyl (bc) magnesium reagents is described. Treatment of 1,1'-bis(o-carborane) (H2-bc) or 8,8',9,9',10,10',12,12'-octamethyl-1,1'-bis(o-carborane) (H2-Mebc) with Mg(n-Bu)2 in 1,2-dimethoxyethane (DME) affords (bc)Mg(DME)2 (1a-b) as crystalline solids. The magnesium compounds, which have been characterized by NMR spectroscopy and single crystal X-ray crystallography in the case of 1a, serve as competent Grignard-type reagents to generate bc-containing species of tin from Me2SnCl2 (2a-b). The type of substitution of the bis(o-carboranyl) ligand framework is found to strongly effect the electronic character of the tin center, as judged by 119Sn NMR spectroscopy. The disclosed compounds, which are stable solids under an atmosphere of dry nitrogen gas at room temperature, provide a new class of bc-transfer reagents.

(1,3-bis[2,6-bis[di(4-tert-butylphenyl)methyl]-4-methylphenyl]imidazol-2-ylidene)CuOPh [(IPr**)CuOPh] reacts with poly(methylhydrosiloxane) as the hydride donor to afford the monomeric (IPr**)CuH complex, which was spectroscopically characterized. The latter is in equilibrium in solution with [(IPr**)CuH]2, the dimer being exclusively present in the solid state. These results support the hypothesis that copper hydride aggregates dissociate in solution. In contrast, addition of pinacolborane to [(IPr**)AgOPh] at −40 °C allows the isolation of the monomeric (IPr**)AgH complex, which was crystallographically characterized.

We present the synthesis of metal oxide frameworks composed of [NaP5W30O110]14– assembled with Mn, Fe, Co, Ni, Cu, or Zn bridging metal ions. X-ray diffraction shows that the frameworks adopt the s...