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Complex oxides Eu2MeO6 (Me–Mo, W), Eu2W2O9 were obtained by a solid‐phase reaction between binary oxides. The thermodynamic and kinetic mechanisms of the reaction processes were established using a variety of physical‐chemical methods. All compounds obtained in this work crystallize in the low‐symmetry monoclinic system, forming complex framework structures, which determine a set of very valuable physical‐chemical properties. Comparison of experimental Kubelka‐Munk functions and DFT‐ calculated absorption spectra shows adequate agreement and reveals the origin of the fundamental absorption. In addition, the deficiency in DFT calculations in the part of mutual contribution of CTBs of Mo−O and W−O, from one side, and Eu−O contributions, from the other side, is reported. Calculations of absorption spectra are shown to be superior to band structure analysis in the determination of optical band gaps. Additionally, luminescent properties of Eu2MeO6 and Eu2W2O9 compounds were investigated. These studies provide a better understanding of the electronic and optical properties of the compounds Eu2MeO6 and Eu2W2O9, along with their potential applications in various areas. [ABSTRACT FROM AUTHOR]

The assembly of molybdenum polyoxometalates (POMs) has afforded large discrete nanoclusters with varied degrees of reduction such as the ~20 % reduced molybdenum blues. While many heterometals have been incorporated into these clusters to afford new properties, uranium has yet to be reported. Here we report the first uranium containing molybdenum blue clusters and the unique properties exhibited by this incorporation. The uranyl ion (UO22+) directs formation of Mo72U8, a square POM comprised of two faces connected by eight edge‐sharing molybdenum dimers. Mo72U8, a chiral cluster, crystallizes as a racemic mixture and, in the solid state, has a 'negative' charge localized on one face of the cluster opposite the 'positively' charged face of another cluster. Using U(IV) as both heterometal and molybdenum reductant afforded crystals of Mo97U10, a wheel cluster with a heptamolybdate cap on one face. Mo97U10 dissociates in solution, losing the heptamolybdate, to form Mo90U10. Using more solvent during synthesis afforded crystals of Mo90U10S4 which, instead of heptamolybdate, contains four sulfate ions. Crystals of Mo90U10S4 undergo a dehydration induced phase change where clusters form a sheet through oxide bridges. Half of the bridges are cation‐cation interactions between the uranyl oxygen atom and molybdenum, the first reported of this kind. [ABSTRACT FROM AUTHOR]

The conversion of an azacalixpyridine‐supported Mo(0) tricarbonyl into a Mo(VI) trioxo complex with dioxygen (O2) is investigated in homogeneous solution and in a molecular film adsorbed on Au(111) using a variety of spectroscopic and analytical methods. These studies in particular show that the dome‐shaped carbonyl complex adsorbed on the metal surface has the ability to bind and activate gaseous oxygen, overcoming the so‐called surface trans‐effect. Furthermore, the rate of the conversion dramatically increases by irradiation with light. This observation is explained with the help of complementary DFT calculations and attributed to two different pathways, a thermal and a photochemical one. Based on the experimental and theoretical findings, a molecular mechanism for the conversion of the carbonyl to the oxo complex is derived. [ABSTRACT FROM AUTHOR]

Adsorption of metal‐organic complexes on metallic surfaces to produce well‐defined single site catalysts is a novel approach combining the advantages of homogeneous and heterogeneous catalysis. To avoid the "surface trans‐effect" a dome‐shaped molybdenum(0) tricarbonyl complex supported by an tolylazacalix[3](2,6)pyridine ligand is synthesized. This vacuum‐evaporable complex both activates CO and reacts with molecular oxygen (O2) to form a Mo(VI) trioxo complex which in turn is capable of catalytically mediating oxygen transfer. The molybdenum tricarbonyl‐ and trioxo complexes are investigated in the solid state, in homogeneous solution and on noble metal surfaces (Cu, Au) employing a range of spectroscopic and analytical methods. [ABSTRACT FROM AUTHOR]

Adsorption of metal‐organic complexes on metallic surfaces to produce well‐defined single site catalysts is a novel approach combining the advantages of homogeneous and heterogeneous catalysis. To avoid the "surface trans‐effect" a dome‐shaped molybdenum(0) tricarbonyl complex supported by an tolylazacalix[3](2,6)pyridine ligand is synthesized. This vacuum‐evaporable complex both activates CO and reacts with molecular oxygen (O2) to form a Mo(VI) trioxo complex which in turn is capable of catalytically mediating oxygen transfer. The molybdenum tricarbonyl‐ and trioxo complexes are investigated in the solid state, in homogeneous solution and on noble metal surfaces (Cu, Au) employing a range of spectroscopic and analytical methods. [ABSTRACT FROM AUTHOR]

The electrophilic functionalization of the triple‐decker sandwich complex [{Cp*Mo}2(μ,η6:6‐P6)] (A) and its mono‐oxidized counterpart [{Cp*Mo}2(μ,η6:6‐P6)][SbF6] (B) with reactive main‐group electrophiles as well as radical scavengers is shown to be a reliable method for the selective functionalization of the hexaphosphabenzene ligand. Depending on the electrophile used, the regioselectivity of the functionalization can be adjusted. Using group 16 electrophiles, the trisubstituted compounds [{Cp*Mo}2{(μ,η3 : 3‐P3)(μ,η1 : 1 : 1 : 1‐1,3‐(SePh)2‐2‐Br‐P3)}][TEF] (1), [{Cp*Mo}2(μ,η3 : 3‐P3)(μ,η1 : 1 : 1 : 1‐1,2,3‐(EPh)3‐P3)][SbF6] (E=S (2), Se (3)) as well as the side product [{Cp*Mo}2(μ,η4:4‐P4)(μ,η1 : 1‐P(SPh)2)][SbF6] (4) are obtained. By switching to phosphenium ions as group 15 electrophiles, the ring‐inserted products [{Cp*Mo}2(μ,η3 : 3 : 2 : 2‐P7R2)][TEF] (R=Cy (5), iPr (6)) are isolated, showing an unprecedented P7R2 structural motif. Furthermore, the reaction with MeOTf yields the dimeric [{Cp*Mo}4(1,4‐Me2‐μ4,η1 : 1 : 1 : 1 : 1 : 1‐P6)(μ,η3 : 3‐P3)2][TEF]2 (7) as the first example of a complex featuring two interconnected cyclo‐P6 middle deck ligands. Finally, by combination of the methylation step with Ph2Se2, the mixed group 14/16 complex [{Cp*Mo}2{(μ,η3 : 3‐P3)(μ,η1 : 1 : 1 : 11,2‐(SePh)2‐3‐Me‐P3)}][OTf] (8) is obtained. [ABSTRACT FROM AUTHOR]

The electrophilic functionalization of the triple‐decker sandwich complex [{Cp*Mo}2(μ,η6:6‐P6)] (A) and its mono‐oxidized counterpart [{Cp*Mo}2(μ,η6:6‐P6)][SbF6] (B) with reactive main‐group electrophiles as well as radical scavengers is shown to be a reliable method for the selective functionalization of the hexaphosphabenzene ligand. Depending on the electrophile used, the regioselectivity of the functionalization can be adjusted. Using group 16 electrophiles, the trisubstituted compounds [{Cp*Mo}2{(μ,η3 : 3‐P3)(μ,η1 : 1 : 1 : 1‐1,3‐(SePh)2‐2‐Br‐P3)}][TEF] (1), [{Cp*Mo}2(μ,η3 : 3‐P3)(μ,η1 : 1 : 1 : 1‐1,2,3‐(EPh)3‐P3)][SbF6] (E=S (2), Se (3)) as well as the side product [{Cp*Mo}2(μ,η4:4‐P4)(μ,η1 : 1‐P(SPh)2)][SbF6] (4) are obtained. By switching to phosphenium ions as group 15 electrophiles, the ring‐inserted products [{Cp*Mo}2(μ,η3 : 3 : 2 : 2‐P7R2)][TEF] (R=Cy (5), iPr (6)) are isolated, showing an unprecedented P7R2 structural motif. Furthermore, the reaction with MeOTf yields the dimeric [{Cp*Mo}4(1,4‐Me2‐μ4,η1 : 1 : 1 : 1 : 1 : 1‐P6)(μ,η3 : 3‐P3)2][TEF]2 (7) as the first example of a complex featuring two interconnected cyclo‐P6 middle deck ligands. Finally, by combination of the methylation step with Ph2Se2, the mixed group 14/16 complex [{Cp*Mo}2{(μ,η3 : 3‐P3)(μ,η1 : 1 : 1 : 11,2‐(SePh)2‐3‐Me‐P3)}][OTf] (8) is obtained. [ABSTRACT FROM AUTHOR]

A neutral silylyne complex with a Cr≡Si triple bond was prepared by dehydrogenation of a chromium silylene complex with Cr−H and Si−H bonds, and was isolated as monomeric crystals, unlike dimeric forms of its tungsten and molybdenum congeners. The strong Cr(δ−)−Si(δ+) bond polarity was revealed by the reaction with MeOH and DFT calculations. The chromium silylyne complex reacted with H2 under LED (365 nm) irradiation to reproduce the precursor silylene complex with a (H)Cr=Si(H) moiety, as a result of 1,2‐H−H addition across the Cr≡Si triple bond. Similarly, the chromium silylyne complex reacted with benzene under irradiation to afford an 1,2‐addition product with a (H)Cr=Si(Ph) moiety, via benzene C−H bond activation accompanied by Si−C bond forming. [ABSTRACT FROM AUTHOR]

The Sabatier principle suggests that an excessive adsorption of lithium polysulfides (LiPSs) by metal compounds may hinder their conversion in the absence of a conversion module. Therefore, it is imperative to establish a synergetic effect mechanism between "strong adsorption" and "rapid conversion" for LiPSs. To achieve this coexistence, a molybdenum‐doped MnS/MnO@C porous structure is designed as a multifunctional coating on the polypropylene (PP) separator. The incorporation of MnS/MnO@C enhances the adsorption capacity towards LiPSs, while molybdenum facilitates subsequent conversion. Benefiting from the synergistic effect of each component and its large specific surface area, the cell with Mo‐doped MnS/MnO@C coating achieves smooth adsorption‐diffusion‐conversion processes and exhibits an appreciable rate performance with outstanding cycling stability. Even when sulfur loading increases to 9.68 mg cm−2, the modified battery delivers an excellent initial areal capacity of 11.69 mAh cm−2 and maintains 6.97 mAh cm−2 after 50 cycles at 0.1 C. This study presents a promising approach to simultaneously accomplish "strong adsorption" and "rapid conversion" of polysulfides, offering novel perspectives for devising dual‐functional modified separators. [ABSTRACT FROM AUTHOR]

Electrocatalytic water splitting is one of the most commercially valuable pathways of hydrogen production especially combined with renewable electricity; however, efficient and durable electrocatalysts are urgently needed to reduce electric energy consumption. Here, we reported a Ru and Fe co‐doped Mo2C on nitrogen doped carbon via a controllable two‐step method, which can be used for efficient and enduring hydrogen evolution reaction. At 10, 100 and 200 mA cm−2 in acidic electrolyte, the resultant Ru‐Fe/Mo2C@NC delivered low overpotentials of 31, 78 and 103 mV, respectively, which are comparable to that of the commercial Pt/C (20 wt %). At an applied current density of 100 mA cm−2, stable hydrogen production was conducted for 120 h without obvious degradation. In alkaline media, Ru‐Fe/Mo2C@NC can also deliver a current density of 100 mA cm−2 for more than 100 h. Furthermore, the Ru‐Fe/Mo2C@NC electrocatalyst was used as cathode in an anion exchange membrane water electrolyzer under industrial environments for robust hydrogen production. The characterization and electrochemical results prove the synergism effects between Ru, Fe dopants and Mo2C for promoting hydrogen evolution activity. This work would pave a new avenue to fabricate low‐cost, high‐performance hydrogen evolution electrocatalysts for industrial water electrolyzers. [ABSTRACT FROM AUTHOR]

A neutral silylyne complex of molybdenum was synthesized by the stepwise dehydrogenation method and its properties were compared with those of the tungsten analog. The complex takes a dimeric form as crystals but afford a monomer‐dimer equilibrium in solution. The replacement of the central metal from W to Mo led to a monomer dominant (~98 %) solution at room temperature. The monomer‐dimer dynamics was investigated based on thermodynamic parameters. The molybdenum silylyne complex underwent [2+2] cycloaddition with alkynes much faster than the tungsten analog. The reactions with organic azides led to the formation of the first example of silaiminoacyl complexes through [2+3] cycloaddition. The structures and bonding aspects of the products were clarified by multiple measurements and DFT calculations. [ABSTRACT FROM AUTHOR]

Octahedral chiral‐at‐metal complexes MX2(a‐chel)2 (a‐chel=asymmetric chelate) can rearrange their ligands by four mechanisms known as the Bailar (B), Ray‐Dutt (RD), Conte‐Hippler (CH), and Dhimba‐Muller‐Lammertsma (DML) twists. Racemization involves their interconnections, which were computed for MoO2(acnac)2 (acnac=β‐ketoiminate) using density functional theory at ωB97x‐D with the 6‐31G(d,p) and 6‐311G(2d,p) basis sets and LANL2DZ for molybdenum. Racemizing the cis(NN) isomer, being the global energy minimum with trans oriented imine groups, is a three step process (DML‐CH‐DML) that requires 17.4 kcal/mol, while all three cis isomers (cis(NN), cis(NO), and cis(OO)) interconvert at ≤17.9 kcal/mol. The B and RD twists are energetically not competitive and neither are the trans isomers. The interconnection of all enantiomeric minima and transition structures is summarized in a graph that also visualizes valley ridge inflection points for two of the three CH twists. Geometrical features of the minima and twists are given. Lastly, the influence of N‐substitution on the favored racemization pathway is evaluated. The present comprehensive study serves as a template for designing chiral‐at‐metal MX2(a‐chel)2 catalysts that may retain their chiral integrity. [ABSTRACT FROM AUTHOR]

Octahedral chiral‐at‐metal complexes MX2(a‐chel)2 (a‐chel=asymmetric chelate) can rearrange their ligands by four mechanisms known as the Bailar (B), Ray‐Dutt (RD), Conte‐Hippler (CH), and Dhimba‐Muller‐Lammertsma (DML) twists. Racemization involves their interconnections, which were computed for MoO2(acnac)2 (acnac=β‐ketoiminate) using density functional theory at ωB97x‐D with the 6‐31G(d,p) and 6‐311G(2d,p) basis sets and LANL2DZ for molybdenum. Racemizing the cis(NN) isomer, being the global energy minimum with trans oriented imine groups, is a three step process (DML‐CH‐DML) that requires 17.4 kcal/mol, while all three cis isomers (cis(NN), cis(NO), and cis(OO)) interconvert at ≤17.9 kcal/mol. The B and RD twists are energetically not competitive and neither are the trans isomers. The interconnection of all enantiomeric minima and transition structures is summarized in a graph that also visualizes valley ridge inflection points for two of the three CH twists. Geometrical features of the minima and twists are given. Lastly, the influence of N‐substitution on the favored racemization pathway is evaluated. The present comprehensive study serves as a template for designing chiral‐at‐metal MX2(a‐chel)2 catalysts that may retain their chiral integrity. [ABSTRACT FROM AUTHOR]

The carbide ligand in the iron–molybdenum cofactor (FeMoco) in nitrogenase bridges iron atoms in different oxidation states, yet it is difficult to discern its ability to mediate magnetic exchange interactions due to the structural complexity of the cofactor. Here, we describe two mixed‐valent diiron complexes with C‐based ketenylidene bridging ligands, and compare the carbon bridges with the more familiar sulfur bridges. The ground state of the [Fe2(μ‐CCO)2]+ complex with two carbon bridges (4) is S=1/2 ${{ 1/2 }}$ , and it is valence delocalized on the Mössbauer timescale with a small thermal barrier for electron hopping that stems from the low Fe−C force constant. In contrast, one‐electron reduction of the [Fe2(μ‐CCO)] complex with one carbon bridge (2) affords a mixed‐valence species with a high‐spin ground state (S=7/2 ${ 7/2 }$), and the Fe−Fe distance contracts by 1 Å. Spectroscopic, magnetic, and computational studies of the latter reveal an Fe−Fe bonding interaction that leads to complete valence delocalization. Analysis of near‐IR intervalence charge transfer transitions in 5 indicates a very large double exchange constant (B) in the range of 780–965 cm−1. These results show that carbon bridges are extremely effective at stabilizing valence delocalized ground states in mixed‐valent iron dimers. [ABSTRACT FROM AUTHOR]

The reactivity of the mixed dipnictogen complexes [{CpMo(CO)2}2(μ,η2 : 2‐PE)] (E=P, As, Sb) towards different group 14 electrophiles is reported. The resulting library of cationic compounds [{CpMo(CO)2}2(μ,η2 : 2‐EPR)]+ (R=Mes (2,4,6‐C6H2Me3), CH3, CPh3, SnMe3) represents formally inorganic diazonium homologs which are stabilized by transition metal units. Modifying the steric and electronic properties of the electrophile drastically impacts the respective P−R bond lengths and is accompanied by increasing (SnMe3>CPh3>CH3) dynamic behavior in solution. In contrast to the well‐studied organic analogs, the prepared compounds are stable at room temperature. The subsequent reaction of the model substrate [{CpMo(CO)2}2(μ,η2 : 2‐P2Me)][OTf] ([OTf]−=[CF3SO3]−) with different N‐heterocyclic carbenes (NHCs) leads to an addition at the unsubstituted P atom which is also predicted by computational methods. NMR spectroscopy confirms the formation of two isomers sync/gauche‐[{CpMo(CO)2}(μ,η2 : 1‐P(NHC)PMe){CpMo(CO)2}][OTf]. X‐ray crystallographic characterization and additional DFT calculations shed light on the spatial arrangement as well as on the possible formation pathways of the isomers. [ABSTRACT FROM AUTHOR]

The first neutral and cationic Mo imido alkylidene cyclic alkyl amino carbene (CAAC) complexes of the general formulae [Mo(N−Ar)(CHCMe2Ph)(X)2(CAAC)] and [Mo(N−Ar)(CHCMe2Ph)(X)(CAAC)][B(ArF)4] (X=Br, Cl, OTf, OC6F5; CAAC=1‐(2,6‐iPr2‐C6H3)‐3,3,5,5‐tetramethyltetrahydropyrrol‐2‐ylidene) have been synthesized from molybdenum imido bishalide alkylidene DME precursors. Different combinations of the imido and "X" ligands have been employed to understand synthetic peculiarities. Selected complexes have been characterized by single‐crystal X‐ray analysis. Due to the pronounced σ‐donor/π‐acceptor characteristics of CAACs, the corresponding neutral and cationic molybdenum imido alkylidene CAAC complexes do not require the presence of stabilizing donor ligands such as nitriles. Calculations on the PBE0‐D3BJ/def2‐TZVP level for PBE0‐D3BJ/def2‐SVP optimized geometries revealed partial charges at molybdenum similar to the corresponding molybdenum imido alkylidene N‐heterocyclic carbene (NHC) complexes with a slightly higher polarization of the molybdenum alkylidene bond in the CAAC complexes. All cationic complexes have been tested in olefin metathesis reactions and showed improved activity compared to the analogous NHC complexes for hydrocarbon‐based substrates, allowing for turnover numbers (TONs) up to 9500 even at room temperature. Some Mo imido alkylidene CAAC complexes are tolerant towards functional groups like thioethers and sulfonamides. [ABSTRACT FROM AUTHOR]

Benzene‐1,2,4,5‐tetrathiolate (btt) has been used as a bridging ligand to prepare a redox active (molybdenocene dithiolene)‐based bimetallic complex Cp2Mo(btt)MoCp2, which exhibits four successive electron transfers up to the tetracation. Spectro‐electrochemical investigations together with DFT and TD‐DFT calculations evidence that the two electroactive MoS2C2 metallacycles are electronically coupled in the monocationic as in the dicationic state. Two salts of the dication [Cp2Mo(btt)MoCp2]2+ have been structurally characterized with PF6− and HSO4− counterions, showing different chair or boat conformations associated with variable folding angles of the two MoS2C2 metallacycles along the S−S hinge. The bis‐oxidized dicationic complex exhibits a diradical character, with both radicals essentially localized on the metallacycles and with antiferromagnetic coupling evidenced from magnetic susceptibility measurements. [ABSTRACT FROM AUTHOR]

Two different dinitrogen‐derived molybdenum nitrido complexes varying by their geometry, ligand spheres and oxidations states were shown to engage their N ligand in dative bonding with the strong Lewis acid B(C6F5)3. The stable adducts were assessed for frustrated Lewis pair‐type heterolytic E−H bond splitting of hydrosilanes (E=Si) and HB(C6F5)2. Whereas Si−H bond activation was achieved, HB(C6F5)2 was shown to substitute B(C6F5)3 in a quantitative or equilibrated fashion, depending on the nature of the nitrido complex. No B−H bond splitting was observed. Thermodynamics of these reactions, computed by DFT, are in agreement with the experimental outcomes. [ABSTRACT FROM AUTHOR]

Molybdenum dinitrogen complexes have played a major role as catalytic model systems of nitrogenase. In comparison, analogous tungsten complexes have in most cases found to be catalytically inactive. Herein, a tungsten complex was shown to be supported by a pentadentate tetrapodal (pentaPod) phosphine ligand, under conditions of N2 fixation, primarily catalyzes the hydrogen evolution reaction (HER), in contrast to its Mo analogue, which catalytically mediates the nitrogen‐reduction reaction (N2RR). DFT calculations were employed to evaluate possible mechanisms and identify the most likely pathways of N2RR and HER activities exhibited by Mo‐ and W‐pentaPod complexes. Two mechanisms for N2RR by PCET are considered, starting from neutral (M(0) cycle) and cationic (M(I) cycle) dinitrogen complexes (M=Mo, W). The latter was found to be energetically more favorable. For HER three scenarios are treated; that is, through bimolecular reactions of early M‐NxHy intermediates, pure hydride intermediates or mixed M(H)(NxHy) species. [ABSTRACT FROM AUTHOR]

At near neutral to basic pH, hydrolysis‐induced aggregation to insoluble bulk iron‐oxide is often regarded as the pitfalls of molecular iron clusters. Iron‐oxide nanocrystals are encouragingly active over the molecular clusters and/or bulk oxides albeit, stabilizing such nanostructures in aqueous pH and under turnover condition remain a perdurable challenge. Herein, an Anderson‐type [Mo7O24]6− isopolyanion, a small (dimension ca. 0.85 nm) isolable polyoxometalate (POM) possessing only {31} atoms, has been introduced for the first time as a covalent linker to stabilize an infinitely stable and aqueous‐soluble γ‐FeO(OH) nanocore. During the hydrothermal isolation of the material, a partial dissociation of the parent [Mo7O24]6− may lead to the in situ generation of few analogous [MoxOy]n− clusters, proved by Raman study, which can also participate in stabilizing the γ‐FeO(OH) nanocore, MoxOy@FeO(OH). However, due to high ionic charge on {Mo=O} terminals of the [MoxOy]n−, they are covalently linked via MoVI‐μ2O‐FeIII bridging to γ‐FeO(OH) core in MoxOy@FeO(OH), established by numerous spectroscopic and microscopic evidence. Such bonding mode is more likely as precedent from the coordination motif documented in the transition metal clusters stabilized by this POM. The γ‐FeO(OH) nanocore of MoxOy@FeO(OH) behaves as potent active center for electrochemical water oxidation with a overpotential, 263 mV @ 10 mA cm−2, lower than that observed for bare γ‐FeO(OH). Despite of some molybdenum dissolution from the POM ligands to the electrolyte, residual anionic POM fragments covalently bound to the OER active γ‐FeO(OH) core of the MoxOy@FeO(OH) makes the surface predominantly ionic that results in an ordered electrical double layer to promote a better charge transport across the electrode‐electrolyte junction, less likely in bulk γ‐FeO(OH). [ABSTRACT FROM AUTHOR]

Freshwater production using solar‐driven interfacial evaporation is regarded as a green and sustainable strategy. The biggest barrier to practical deployment of solar desalination, however, continues to be the lack of options for renewable materials. Herein, we present a facile two‐step carbonization approach that is sustainable for developing innovative two‐dimensional (2D) molybdenum carbide (Mo2C) materials derived from carbonized fruit wastes. The resultant 2D Mo2C photothermal layer has an efficient water evaporation rate of 1.52 kg m−2 h−1 with a photothermal conversion efficiency of 94 % under one sun irradiation, which is among the best reported values so far. The broad solar absorption band, high specific surface area (555.1 m2 g−1) with large micro‐ and meso porosity, of the Mo2C photothermal layer are responsible for these outstanding results. The conversion of food wastes into valuable products, in this case MXene, can potentially inspire greener developments of advanced materials for solar water evaporator. [ABSTRACT FROM AUTHOR]

Molybdenum(VI) bis(imido) complexes [Mo(NtBu)2(LR)2] (R=H 1 a; R=CF31 b) combined with B(C6F5)3 (1 a/B(C6F5)3, 1 b/B(C6F5)3) exhibit a frustrated Lewis pair (FLP) character that can heterolytically split H−H, Si−H and O−H bonds. Cleavage of H2 and Et3SiH affords ion pairs [Mo(NtBu)(NHtBu)(LR)2][HB(C6F5)3] (R=H 2 a; R=CF32 b) composed of a Mo(VI) amido imido cation and a hydridoborate anion, while reaction with H2O leads to [Mo(NtBu)(NHtBu)(LR)2][(HO)B(C6F5)3] (R=H 3 a; R=CF33 b). Ion pairs 2 a and 2 b are catalysts for the hydrosilylation of aldehydes with triethylsilane, with 2 b being more active than 2 a. Mechanistic elucidation revealed insertion of the aldehyde into the B−H bond of [HB(C6F5)3]−. We were able to isolate and fully characterize, including by single‐crystal X‐ray diffraction analysis, the inserted products Mo(NtBu)(NHtBu)(LR)2][{PhCH2O}B(C6F5)3] (R=H 4 a; R=CF34 b). Catalysis occurs at [HB(C6F5)3]− while [Mo(NtBu)(NHtBu)(LR)2]+ (R=H or CF3) act as the cationic counterions. However, the striking difference in reactivity gives ample evidence that molybdenum cations behave as weakly coordinating cations (WCC). [ABSTRACT FROM AUTHOR]

This work tackles the photochemistry of a series of mononuclear Cr0, Mo0 and W0 carbonyl complexes containing a bidentate mesoionic carbene ligand of the 1,2,3‐triazol‐5‐ylidene type. FTIR spectroscopy, combined with density functional theory calculations, revealed a clean photo‐induced reaction in organic solvents (acetonitrile, pyridine, valeronitrile) to give mainly one photoproduct with monosubstitution of a carbonyl ligand for a solvent molecule. The highest photodissociation quantum yields were reached for the Cr0 complex under UV irradiation (266 nm). Based on previous investigations, the kinetics of the dark reverse reactions have now been determined, with reaction times of up to several hours in pyridine. Photochemical studies in the solid state (KBr matrix, frozen solution) also showed light‐induced reactivity with stabilization of the metastable intermediate with a free coordination site at very low temperature. The identified reactive species emphasizes a mechanism without ligand–sphere reorganization. [ABSTRACT FROM AUTHOR]

Tailored molybdenum(VI)‐oxo complexes of the form MoOCl2(OR)2(OEt2) catalyse olefin metathesis upon reaction with an organosilicon reducing agent at 70 °C, in the presence of olefins. While this reactivity parallels what has recently been observed for the corresponding classical heterogeneous catalysts based on supported metal oxide under similar conditions, the well‐defined nature of our starting molecular systems allows us to understand the influence of structural, spectroscopic and electronic characteristics of the catalytic precursor on the initiation and catalytic proficiency of the final species. The catalytic performances of the pre‐catalysts are determined by the highly electron withdrawing (σ‐donation) character of alkoxide ligands, OtBuF9 being the best. This activity correlates with both the 95Mo chemical shift and the reduction potential that follows the same trend: OtBuF9>OtBuF6>OtBuF3. [ABSTRACT FROM AUTHOR]

Molybdenum( 0)- Tricarbonyl Complex Supported by anAzacalix- pyridine Ligand: Synthesis, Characterization, Surface Deposition and Conversion to a Molybdenum( VI)- Trioxo Complex with O2 [Extracted from the article]

During the reduction of molybdenum trioxide (MoO3) to metallic molybdenum, the first reduction step yielding molybdenum dioxide as an intermediary product is of crucial importance. In this study, we examined the impact of the parameters reduction temperature, water influx, and potassium content on the hydrogen reduction of this first reaction step. Beginning from the same starting material, the chemical vapor transport mechanism was utilized to yield the phase pure MoO2. Analyses including powder X‐ray diffraction, inductively coupled plasma‐mass spectrometry, scanning electron microscopy, and high performance optical microscopy were performed on the product phases. Modulations of the specific surface areas of molybdenum dioxide ranging from 2.28 to 0.41 m2/g were possible. Furthermore, a distinct shift from small plate‐like grains to cuboid‐like forms was achieved. [ABSTRACT FROM AUTHOR]

The iron‐molybdenum cofactor (FeMoco) is responsible for dinitrogen reduction in Mo nitrogenase. Unlike the resting state, E0, reduced states of FeMoco are much less well characterized. The E2 state has been proposed to contain a hydride but direct spectroscopic evidence is still lacking. The E2 state can, however, relax back the E0 state via a H2 side‐reaction, implying a hydride intermediate prior to H2 formation. This E2→E0 pathway is one of the primary mechanisms for H2 formation under low‐electron flux conditions. In this study we present an exploration of the energy surface of the E2 state. Utilizing both cluster‐continuum and QM/MM calculations, we explore various classes of E2 models: including terminal hydrides, bridging hydrides with a closed or open sulfide‐bridge, as well as models without. Importantly, we find the hemilability of a protonated belt‐sulfide to strongly influence the stability of hydrides. Surprisingly, non‐hydride models are found to be almost equally favorable as hydride models. While the cluster‐continuum calculations suggest multiple possibilities, QM/MM suggests only two models as contenders for the E2 state. These models feature either i) a bridging hydride between Fe2 and Fe6 and an open sulfide‐bridge with terminal SH on Fe6 (E2‐hyd) or ii) a double belt‐sulfide protonated, reduced cofactor without a hydride (E2‐nonhyd). We suggest both models as contenders for the E2 redox state and further calculate a mechanism for H2 evolution. The changes in electronic structure of FeMoco during the proposed redox‐state cycle, E0→E1→E2→E0, are discussed. [ABSTRACT FROM AUTHOR]

The first example of a diphosphaborolediide, the benzo‐fused [C6H4P2BPh]2− (12−), is prepared from ortho‐bis(phosphino)benzene (C6H4{PH2}) and dichlorophenylborane, via a sequential lithiation approach. The dilithio‐salt can be obtained as an oligomeric THF solvate or discrete TMEDA adduct, both of which are fully characterized, including by X‐ray diffraction. Alongside NICS calculations, data strongly suggest some aromaticity within 12−, which is further supported by preliminary coordination studies that demonstrate η5‐coordination to a zerovalent molybdenum center, as observed crystallographically for the oligomeric [{Mo(CO)3(η5‐1)}{μ‐η1‐Mo(CO)3(TMEDA)}2] ⋅ [μ‐Li(THF)][μ‐Li(TMEDA)]. [ABSTRACT FROM AUTHOR]

Molybdenum alkylidyne complexes with a trisilanolate podand ligand framework ("canopy catalysts") are the arguably most selective catalysts for alkyne metathesis known to date. Among them, complex 1 a endowed with a fence of lateral methyl substituents on the silicon linkers is the most reactive, although fairly high loadings are required in certain applications. It is now shown that this catalyst decomposes readily via a bimolecular pathway that engages the Mo≡CR entities in a stoichiometric triple‐bond metathesis event to furnish RC≡CR and the corresponding dinuclear complex, 8, with a Mo≡Mo core. In addition to the regular analytical techniques, 95Mo NMR was used to confirm this unusual outcome. This rapid degradation mechanism is largely avoided by increasing the size of the peripheral substituents on silicon, without unduly compromising the activity of the resulting complexes. When chemically challenged, however, canopy catalysts can open the apparently somewhat strained tripodal ligand cages; this reorganization leads to the formation of cyclo‐tetrameric arrays composed of four metal alkylidyne units linked together via one silanol arm of the ligand backbone. The analogous tungsten alkylidyne complex 6, endowed with a tripodal tris‐alkoxide (rather than siloxide) ligand framework, is even more susceptible to such a controlled and reversible cyclo‐oligomerization. The structures of the resulting giant macrocyclic ensembles were established by single‐crystal X‐ray diffraction. [ABSTRACT FROM AUTHOR]

The development of NIR emitters based on earth‐abundant elements is an important goal in contemporary science. We present here Cr(0), Mo(0), and W(0) carbonyl complexes with a pyridyl‐mesoionic carbene (MIC) based ligand. A detailed photophysical investigation shows that all the complexes exhibit dual emissions in the VIS and in the NIR region. The emissive excited states are assigned to two distinct triplet states by time‐resolved emission and step‐scan FTIR spectroscopy at variable temperature, supported by density functional theory. In particular, the NIR emissive triplet state exhibits unprecedented lifetimes of up to 600±10 ns and quantum yields reaching 1.7 ⋅ 10−4 at room temperature. These are the first examples of Cr(0), Mo(0) and W(0) complexes that emit in the NIR II region. [ABSTRACT FROM AUTHOR]

Hydrogen storage in the form of intermediate artificial fuels such as methanol is important for future chemical and energy applications, and the electrochemical regeneration of hydrogen from methanol is thermodynamically favorable compared to direct water splitting. However, CO produced from methanol oxidation can adsorb to H2‐evolution catalysts and drastically reduce activity. In this study, we explore the origins of CO immunity in Mo‐containing H2‐evolution catalysts. Unlike conventional catalysts such as Pt or Ni, Mo‐based catalysts display remarkable immunity to CO poisoning. The origin of this behavior in NiMo appears to arise from the apparent inability of CO to bind Mo under electrocatalytic conditions, with mechanistic consequences for the H2‐evolution reaction (HER) in these systems. This specific property of Mo‐based HER catalysts makes them ideal in environments where poisons might be present. [ABSTRACT FROM AUTHOR]

In order to improve and extend the rare class of tetrahedral mixed main group transition metal compounds, a new synthetic route for the complexes [{CpMo(CO)2}2(μ,η2:η2‐PE)] (E=As (1), Sb (2)) is described leading to higher yields and a decrease in reaction steps. Via this route, also the so far unknown heavier analogues containing AsSb (3 a), AsBi (4) and SbBi (5) ligands, respectively, are accessible. Single crystal X‐ray diffraction experiments and DFT calculations reveal that they represent very rare examples of compounds comprising covalent bonds between two different heavy pnictogen atoms, which show multiple bond character and are stabilised without any organic substituents. A simple one‐pot reaction of [CpMo(CO)2]2 with ME(SiMe3)2 (M=Li, K; E=P, As, Sb, Bi) and the subsequent addition of PCl3, AsCl3, SbCl3 or BiCl3, respectively, give the complexes 1–5. This synthesis is also transferable to the already known homo‐dipnictogen complexes [{CpMo(CO)2}2(μ,η2:η2‐E2)] (E=P, As, Sb, Bi) resulting in higher yields comparable to those in the literature reported procedures and allows the introduction of the bulkier and better soluble Cp′ (Cp′=tert butylcyclopentadienyl) ligand. [ABSTRACT FROM AUTHOR]

A series of 4d/4f‐polyarsenides, ‐polyarsines and ‐polystibines was obtained by reduction of the Mo‐pnictide precursor complexes [{CptMo(CO)2}2(μ,η2:2‐E2)] (E=As, Sb; Cpt=tBu substituted cyclopentadienyl) with two different divalent samarocenes [Cp*2Sm] and [(CpMe4nPr)2Sm]. For the reductive conversion of the Mo‐stibide only one product was isolated, featuring a planar tetrastibacyclobutadiene moiety as an unprecedented ligand for organometallic compounds. For the corresponding Mo‐arsenide a tetraarsacyclobutadiene and a second species with a side‐on coordinated As22− anion was isolated. The latter can be considered as reaction intermediate for the formation of the tetraarsacyclobutadiene. [ABSTRACT FROM AUTHOR]

Photodynamic and photothermal therapies (PDT, and PTT, respectively) are promising candidates for multimodal anticancer therapies (i.e., combinations of therapies), since their action is based on mechanisms that generally cannot be resisted by cancer cells, that is, generation of highly oxidizing oxygen species and high temperature, respectively. Herein, hybrid materials that combine octahedral molybdenum clusters as potential PDT agents and plasmonic spherical gold nanoparticles (AuNPs) as PTT agents are reported. Partial overlap of the photoemission spectrum of the cluster and the surface plasmon resonance band of the AuNPs facilitates energy transfer between the photoactive components, which resulted in synergetic enhancement of their photophysical properties. Specifically, by careful selection of the spacing between the cluster and the gold nanoparticle, a significant increase in luminescence and photosensitizing properties of the cluster was achieved in comparison with similar, but gold‐free, particles. On the other hand, the cluster complex facilitated energy conversion to heat by gold particles and hence increased the heating rate under laser irradiation. [ABSTRACT FROM AUTHOR]

An unprecedented bird‐nest high‐nuclear molybdenum(V) cobalto‐phosphate nanosized wheel modified by imidazole (im) and pyridine (py), {[H55(Mo24O48)(Co4O)2Co16(PO4)42(py)6(EtOH)2(H2O)11]‐ @[(Him)2(Hpy)]}(N‐Et‐py)(H2PO4)(py)7(EtOH)⋅12 H2O (1), has been successfully synthesized by self‐assembly. The anionic huge wheel consists of two rare {Co4O} squares, four {Co4} tetramers, four {Mo4} tetramers and four {Mo2} dimers, linked by bridging oxygen atoms and [PO4] groups and encloses two imidazolium cations and a protonated pyridium for charge balance. Surprisingly, 1 represents the first twisted wheel‐shaped cluster with a record high‐nuclear molybdenum(V) cobalto‐phosphate. The delocalized electron effects of the cluster are enhanced with the help of coordinated py ligands, which endows 1 with an excellent third‐order nonlinear optical (NLO) response. Additionally, 1 also shows a better photocatalytic water oxidation activity than Co(NO3)2 with the O2 production of 205 μmol during 6 h in the absence of the [Ru(bpy)3]2+ photosensitizer. [ABSTRACT FROM AUTHOR]

With [Mo(N2)(P2MePP2Ph)] the first Chatt‐type complex with one coordination site catalytically converting N2 to ammonia is presented. Employing SmI2 as reductant and H2O as proton source 26 equivalents of ammonia are generated. Analogous Mo0‐N2 complexes supported by a combination of bi‐ and tridentate phosphine ligands are catalytically inactive under the same conditions. These findings are interpreted by analyzing structural and spectroscopic features of the employed systems, leading to the conclusion that the catalytic activity of the title complex is due to the strong activation of N2 and the unique topology of the pentadentate tetrapodal (pentaPod) ligand P2MePP2Ph. The analogous hydrazido(2‐) complex [Mo(NNH2)(P2MePP2Ph)](BArF)2 is generated by protonation with HBArF in ether and characterized by NMR and vibrational spectroscopy. Importantly, it is shown to be catalytically active as well. Along with the fact that the structure of the title complex precludes dimerization this demonstrates that the corresponding catalytic cycle follows a mononuclear pathway. The implications of a PCET mechanism on this reactive scheme are considered. [ABSTRACT FROM AUTHOR]

The reaction of the organometallic diarsene complex [Cp2Mo2(CO)4(μ,η2‐As2)] (B) (Cp = C5H5) with Ag[FAl{OC6F10(C6F5)}3] (Ag[FAl]) and Ag[Al{OC(CF3)3}4] (Ag[TEF]), respectively, yields three unprecedented supramolecular assemblies [(η2‐B)4Ag2][FAl]2 (4), [(μ,η1:η2‐B)3(η2‐B)2Ag3][TEF]3 (5) and [(μ,η1:η2‐B)4Ag3][TEF]3 (6). These products are only composed of the complexes B and AgI. Moreover, compounds 5 and 6 are the only supramolecular assemblies featuring B as a linking unit, and the first examples of [AgI]3 units stabilized by organometallic bichelating ligands. According to DFT calculations, complex B coordinates to metal centers through both the As lone pair and the As−As σ‐bond thus showing this unique feature of this diarsene ligand. [ABSTRACT FROM AUTHOR]

Cycling between molybdenum(I)‐dinitrogen and molybdenum(IV)‐nitride complexes was investigated under ambient reaction conditions. A kinetic study of the second‐order reaction rate for the conversion of the molybdenum‐dinitrogen complex into the molybdenum‐nitride complex indicates that the formation of the dinitrogen‐bridged dimolybdenum complex is involved in the rate‐determining step. DFT calculations indicate that the molybdenum‐dinitrogen complex transforms into the molybdenum‐nitride complex via direct cleavage of the nitrogen‐nitrogen triple bond of the bridging dinitrogen ligand of the dinitrogen‐bridged dimolybdenum complex. The corresponding reaction of the molybdenum‐nitride complex transforming into the molybdenum‐dinitrogen complex proceeds via the ligand exchange of ammonia for dinitrogen at the dinitrogen‐bridged dimolybdenum complexes. A new modified reaction pathway has been proposed based on the findings of our experimental and theoretical results. [ABSTRACT FROM AUTHOR]

The versatile coordination behavior of the P4 butterfly complex [{Cp*Cr(CO)3}2(μ,η1:1‐P4)] (1) towards Lewis acidic pentacarbonyl compounds of Cr, Mo and W is reported. The reaction of 1 with [W(CO)4(nbd)] (nbd=norbornadiene) yields the complex [{Cp*Cr(CO)3}2(μ3,η1:1:1:1‐P4){W(CO)4}] (2) in which 1 serves as a chelating P4 butterfly ligand. In contrast, reactions of 1 with [M(CO)4(nbd)] (M=Cr (a), Mo (b)) result in the step‐wise formation of [{Cp*Cr(CO)2}2(μ3,η3:1:1‐P4){M(CO)5}] (3 a,b) and [{Cp*Cr(CO)2}2‐(μ4,η3:1:1:1‐P4){M(CO)5}2] (4 a,b) which contain a folded cyclo‐P4 unit. Complex 4 a undergoes an unprecedented P1/P3‐fragmentation yielding the cyclo‐P3 complex [Cp*Cr(CO)2(η3‐P3)] (5) and the as yet unknown phosphinidene complex [Cp*Cr(CO)2{Cr(CO)5}2(μ3‐P)] (6). The identity of 6 is confirmed by spectroscopic methods and by the in situ formation of [{Cp*Cr(CO)2(tBuNC)}P{Cr(CO)5}2(tBuNC)] (7). DFT calculations throw light on the bonding situation of the reported products. [ABSTRACT FROM AUTHOR]

Discrete molecular species that can perform certain functions in response to multiple external stimuli constitute a special class of multifunctional molecular materials called smart molecules. Herein, cyanido‐bridged coordination clusters {[FeII(2‐pyrpy)2]4[MIV(CN)8]2}⋅4 MeOH⋅6 H2O (M=Mo (1 solv), M=W (2 solv) and 2‐pyrpy=2‐(1‐pyrazolyl)pyridine are presented, which show persistent solvent driven single‐crystal‐to‐single‐crystal transformations upon sorption/desorption of water and methanol molecules. Three full desolvation–resolvation cycles with the concomitant change of the host molecules do not damage the single crystals. More importantly, the Fe4M2 molecules constitute a unique example where the presence of the guests directly affects the pressure‐induced thermal spin crossover (SCO) phenomenon occurring at the FeII centres. The hydrated phases show a partial SCO with approximately two out‐of‐four FeII centres undergoing a gradual thermal SCO at 1 GPa, while in the anhydrous form the pressure‐induced SCO effect is almost quenched with only 15 % of the FeII centres undergoing high‐spin to low‐spin transition at 1 GPa. [ABSTRACT FROM AUTHOR]

Two transition‐metal atoms bridged by hydrides may represent a useful structural motif for N2 activation by molecular complexes and the enzyme active site. In this study, dinuclear MoIV‐FeII complexes with bridging hydrides, CpRMo(PMe3)(H)(μ‐H)3FeCp* (2 a; CpR=Cp*=C5Me5, 2 b; CpR=C5Me4H), were synthesized via deprotonation of CpRMo(PMe3)H5 (1 a; CpR=Cp*, 1 b; CpR=C5Me4H) by Cp*FeN(SiMe3)2, and they were characterized by spectroscopy and crystallography. These Mo−Fe complexes reveal the shortest Mo−Fe distances ever reported (2.4005(3) Å for 2 a and 2.3952(3) Å for 2 b), and the Mo−Fe interactions were analyzed by computational studies. Removal of the terminal Mo−H hydride in 2 a–2 b by [Ph3C]+ in THF led to the formation of cationic THF adducts [CpRMo(PMe3)(THF)(μ‐H)3FeCp*]+ (3 a; CpR=Cp*, 3 b; CpR=C5Me4H). Further reaction of 3 a with LiPPh2 gave rise to a phosphido‐bridged complex Cp*Mo(PMe3)(μ‐H)(μ‐PPh2)FeCp* (4). A series of Mo−Fe complexes were subjected to catalytic silylation of N2 in the presence of Na and Me3SiCl, furnishing up to 129±20 equiv of N(SiMe3)3 per molecule of 2 b. Mechanism of the catalytic cycle was analyzed by DFT calculations. [ABSTRACT FROM AUTHOR]

Two transition‐metal atoms bridged by hydrides may represent a useful structural motif for N2 activation by molecular complexes and the enzyme active site. In this study, dinuclear MoIV‐FeII complexes with bridging hydrides, CpRMo(PMe3)(H)(μ‐H)3FeCp* (2 a; CpR=Cp*=C5Me5, 2 b; CpR=C5Me4H), were synthesized via deprotonation of CpRMo(PMe3)H5 (1 a; CpR=Cp*, 1 b; CpR=C5Me4H) by Cp*FeN(SiMe3)2, and they were characterized by spectroscopy and crystallography. These Mo−Fe complexes reveal the shortest Mo−Fe distances ever reported (2.4005(3) Å for 2 a and 2.3952(3) Å for 2 b), and the Mo−Fe interactions were analyzed by computational studies. Removal of the terminal Mo−H hydride in 2 a–2 b by [Ph3C]+ in THF led to the formation of cationic THF adducts [CpRMo(PMe3)(THF)(μ‐H)3FeCp*]+ (3 a; CpR=Cp*, 3 b; CpR=C5Me4H). Further reaction of 3 a with LiPPh2 gave rise to a phosphido‐bridged complex Cp*Mo(PMe3)(μ‐H)(μ‐PPh2)FeCp* (4). A series of Mo−Fe complexes were subjected to catalytic silylation of N2 in the presence of Na and Me3SiCl, furnishing up to 129±20 equiv of N(SiMe3)3 per molecule of 2 b. Mechanism of the catalytic cycle was analyzed by DFT calculations. [ABSTRACT FROM AUTHOR]

The reactions of the fluoride‐ion donor, XeF6, with the fluoride‐ion acceptors, M′OF4 (M′=Cr, Mo, W), yield [XeF5]+ and [Xe2F11]+ salts of [M′OF5]− and [M2O2F9]− (M=Mo, W). Xenon hexafluoride and MOF4 react in anhydrous hydrogen fluoride (aHF) to give equilibrium mixtures of [Xe2F11]+, [XeF5]+, [(HF)nF]−, [MOF5]−, and [M2O2F9]− from which the title salts were crystallized. The [XeF5][CrOF5] and [Xe2F11][CrOF5] salts could not be formed from mixtures of CrOF4 and XeF6 in aHF at low temperature (LT) owing to the low fluoride‐ion affinity of CrOF4, but yielded [XeF5][HF2]⋅CrOF4 instead. In contrast, MoOF4 and WOF4 are sufficiently Lewis acidic to abstract F− ion from [(HF)nF]− in aHF to give the [MOF5]− and [M2O2F9]− salts of [XeF5]+ and [Xe2F11]+. To circumvent [(HF)nF]− formation, [Xe2F11][CrOF5] was synthesized at LT in CF2ClCF2Cl solvent. The salts were characterized by LT Raman spectroscopy and LT single‐crystal X‐ray diffraction, which provided the first X‐ray crystal structure of the [CrOF5]− anion and high‐precision geometric parameters for [MOF5]− and [M2O2F9]−. Hydrolysis of [Xe2F11][WOF5] by water contaminant in HF solvent yielded [XeF5][WOF5]⋅XeOF4. Quantum‐chemical calculations were carried out for M′OF4, [M′OF5]−, [M′2O2F9]−, {[Xe2F11][CrOF5]}2, [Xe2F11][MOF5], and {[XeF5][M2O2F9]}2 to obtain their gas‐phase geometries and vibrational frequencies to aid in their vibrational mode assignments and to assess chemical bonding. [ABSTRACT FROM AUTHOR]

The development of improved technologies for biomass processing into transportation fuels and industrial chemicals is hindered due to a lack of efficient catalysts for selective oxygen removal. Here we report that platinum nanoparticles decorated with subnanometer molybdenum clusters can efficiently catalyze hydrodeoxygenation of acetic acid, which serves as a model biomass compound. In contrast with monometallic Mo catalysts that are inactive and monometallic Pt catalysts that have low activities and selectivities, bimetallic Pt–Mo catalysts exhibit synergistic effects with high activities and selectivities. The maximum activity occurs at a Pt to Mo molar ratio of three. Although Mo atoms themselves are catalytically inactive, they serve as preferential binding anchors for oxygen atoms while a catalytic transformation proceeds on neighboring surface Pt atoms. Beyond biomass processing, Pt–Mo nanoparticles are promising catalysts for a wide variety of reactions that require a transformation of molecules with an oxygen atom and, more broadly, in other fields of science and technology that require tuning of surface–oxygen interactions. [ABSTRACT FROM AUTHOR]

Earth-abundant transition-metal-based catalysts for electrochemical water splitting are critical for sustainable energy schemes. In this work, we use a rational design method for the synthesis of ultrasmall and highly dispersed bimetallic CoMo carbide/oxide particles deposited on graphene oxide. Thermal conversion of the molecular precursors [H3PMo12O40], Co(OAc)2·4H2O and melamine in the presence of graphene oxide gives the mixed carbide/oxide (Co6Mo6C2/ Co2Mo3O8) nanoparticle composite deposited on highly dispersed, N,P-doped carbon. The resulting composite shows outstanding electrocatalytic water-splitting activity for both the oxygen evolution and hydrogen evolution reaction, and superior performance to reference samples including commercial 20% Pt/C & IrO2. Electrochemical and other materials analyses indicate that Co6Mo6C2 is the main active phase in the composite, and the N,P-doping of the carbon matrix increases the catalytic activity. The facile design could in principle be extended to multiple bimetallic catalyst classes by tuning of the molecular metal oxide precursor. [ABSTRACT FROM AUTHOR]

Amorphous MoO3−x nanosheets were fabricated by the room‐temperature oxidation of molybdenum powder with H2O2, followed by light‐irradiation reduction in methanol. When applied as a substrate for surface‐enhanced Raman spectroscopy (SERS), these nanosheets exhibit higher sensitivity than the crystalline counterpart for a wide range of analytes. Moreover, the SERS activity remains stable on repeated oxygen insertion/extraction. In contrast, the performance of crystalline MoO3−x continuously deteriorates on successive redox treatments. This unique SERS activity allows the recycling of the substrate through an H2O2‐based Fenton‐like reaction. More importantly, the non‐invasive SERS was unprecedentedly used for the self‐diagnosis of amorphous MoO3−x as a more selective photocatalyst than its crystalline counterpart. [ABSTRACT FROM AUTHOR]

Esters and amides were mechanochemically prepared by palladium‐catalyzed carbonylative reactions of aryl iodides by using molybdenum hexacarbonyl as a convenient solid carbonyl source and avoiding a direct handling of gaseous carbon monoxide. Real‐time monitoring of the mechanochemical reaction by in situ pressure sensing revealed that CO is rapidly transferred from Mo(CO)6 to the active catalytic system without significant release of molecular carbon monoxide. [ABSTRACT FROM AUTHOR]

Esters and amides were mechanochemically prepared by palladium‐catalyzed carbonylative reactions of aryl iodides by using molybdenum hexacarbonyl as a convenient solid carbonyl source and avoiding a direct handling of gaseous carbon monoxide. Real‐time monitoring of the mechanochemical reaction by in situ pressure sensing revealed that CO is rapidly transferred from Mo(CO)6 to the active catalytic system without significant release of molecular carbon monoxide. [ABSTRACT FROM AUTHOR]

The synthesis, characterization and biological activity of molybdenum(IV) complexes containing Trofimenko's scorpionato ligand, hydrotris(3‐isopropylpyrazolyl)borate (TpiPr), in addition to varying biologically active as well as other conventional ligands is described. Ligands employed include (O,O‐) (S,O‐) (N,N‐) donors that have been successfully coordinated to the molybdenum center by means of oxygen‐atom transfer (OAT) reactions from the known MoVI starting material, TpiPrMoO2Cl. The synthesized complexes were characterized by standard analytical methods and where possible by X‐ray diffraction analysis. The aqueous stability of the compounds was studied by means of UV/Vis spectroscopy and the impact of the attached ligand scaffolds on the oxidation potentials (MoIV to MoV) was studied by cyclic voltammetry. Utilizing polyvinylpyrrolidone (PVP) as a solubilizing agent, adequate aqueous solubility for biological tests was obtained. Anticancer activity tests and preliminary mode of action studies have been performed in vitro and in vivo. [ABSTRACT FROM AUTHOR]

Improving the performance of anode materials for lithium‐ion batteries (LIBs) is a hotly debated topic. Herein, hollow Ni−Co skeleton@MoS2/MoO3 nanocubes (NCM‐NCs), with an average size of about 193 nm, have been synthesized through a facile hydrothermal reaction. Specifically, MoO3/MoS2 composites are grown on Ni−Co skeletons derived from nickel–cobalt Prussian blue analogue nanocubes (Ni−Co PBAs). The Ni−Co PBAs were synthesized through a precipitation method and utilized as self‐templates that provided a larger specific surface area for the adhesion of MoO3/MoS2 composites. According to Raman spectroscopy results, as‐obtained defect‐rich MoS2 is confirmed to be a metallic 1T‐phase MoS2. Furthermore, the average particle size of Ni−Co PBAs (≈43 nm) is only about one‐tenth of the previously reported particle size (≈400 nm). If assessed as anodes of LIBs, the hollow NCM‐NC hybrids deliver an excellent rate performance and superior cycling performance (with an initial discharge capacity of 1526.3 mAh g−1 and up to 1720.6 mAh g−1 after 317 cycles under a current density of 0.2 A g−1). Meanwhile, ultralong cycling life is retained, even at high current densities (776.6 mAh g−1 at 2 A g−1 after 700 cycles and 584.8 mAh g−1 at 5 A g−1 after 800 cycles). Moreover, at a rate of 1 A g−1, the average specific capacity is maintained at 661 mAh g−1. Thus, the hierarchical hollow NCM‐NC hybrids with excellent electrochemical performance are a promising anode material for LIBs. [ABSTRACT FROM AUTHOR]