Victor Polo

• Ph.D.
• Professor (Full) at University of Zaragoza

The [2+2+2] cycloaddition of alkynes and nitriles is an efficient and atom-economic method for the synthesis of pyridines. However, most of the examples so far reported entail the use of...

BACKGROUND Ceratocystis fimbriata is a fungal pathogen that infects sweet potato roots, producing enormous economic losses. Cyclic polyhydroxy compound quinic acid is a common metabolite synthesized in plant tissues, including sweet potato tubers, showing weak antifungal properties. Although several O‐acylated quinic acid derivatives have been synt...

We report herein, by means of structural and computational analyses, a comprehensive study of the capability of differently substituted haloalkenes to behave as electron density acceptors in noncovalent interactions. The nature of these interactions between haloalkenes and Lewis bases highly depends on the number and nature of the halogen atoms bou...

Methyl groups bound to electronegative atoms, such as N or O, are recognized to participate in tetrel bonding as Lewis acids. On the other hand, the capability of methyl groups bound to electropositive atoms, such as B or Al, to act as Lewis bases has been recently reported. Herein, we analyze the combination of these two behaviors to establish att...

Enzymes catalysing sequential reactions have developed different mechanisms to control the transport and flux of reactants and intermediates along metabolic pathways, which usually involve direct transfer of metabolites from an enzyme to the next one in a cascade reaction. Despite the fact that metabolite or substrate channelling has been widely st...

Catalytic systems based on sub-nanoclusters deposited over different supports are promising for very relevant chemical transformations such as many electrocatalytic processes as the ORR. These systems have been demonstrated to be very fluxional, as they are able to change shape and interconvert between each other either alone or in the presence of...

The catalytic system [Ir(CF3CO2)(κ2-NSiMe)2] [1; NSiMe = (4-methylpyridin-2-yloxy)dimethylsilyl]/B(C6F5)3 promotes the selective reduction of CO2 with tertiary silanes to the corresponding bis(silyl)acetal. Stoichiometric and catalytic studies evidenced that species [Ir(CF3COO-B(C6F5)3)(κ2-NSiMe)2] (3), [Ir(κ2-NSiMe)2][HB(C6F5)3] (4), and [Ir(HCOO-...

Fungal pathogens can invade not only the fruit peel but also the outer part of the fruit mesocarp, limiting the efficacy of fungicides. In this study, the relationships between fungicide structure, diffusion capacity and in vivo efficacy were evaluated for the first time. The diffusion capacity from pear peel to mesocarp of 11 antifungal compounds,...

Fungal pathogens can invade not only the fruit peel but also the external part of the fruit mesocarp, which limits the efficacy of fungicides. In this study, the relationships between fungicide structure, diffusion capacity and in vivo efficacy were examined for the first time. The diffusion capacity from pear peel to mesocarp of 11 antifungal comp...

The dinuclear complex [Rh(μ‐Cl)(η²‐coe)(IPr)]2 is an efficient catalyst for the O‐selective Markovnikov‐type addition of 2‐pyridones to terminal alkynes. DFT calculations support a hydride‐free pathway entailing intramolecular oxidative protonation of a π‐alkyne by a κ¹N‐hydroxypyridine ligand. Subsequent O‐nucleophilic attack on a metallacycloprop...

The dinuclear complex [Rh(μ‐Cl)(η 2 ‐coe)(IPr)] 2 is an efficient catalyst for the O ‐selective Markovnikov‐type addition of 2‐pyridones to terminal alkynes. DFT calculations support a hydride‐free pathway entailing intramolecular oxidative protonation of a π‐alkyne by a κ 1 N ‐hydroxypyridine ligand. Subsequent O ‐nucleophilic attack on a metallac...

Using a low loading of the iridium(III) complexes [Ir(CF3SO3)(κ2-NSiiPr)2] (1) (NSiiPr = (4-methylpyridin-2-yloxy)diisopropylsilyl) and [{Ir(κ2-NSiMe)2}2(μ-CF3SO3)2] (2) (NSiMe = (4-methylpyridin-2-yloxy)dimethylsilyl) in the presence of Et3N, it has been possible to achieve the solventless selective dehydrogenation of formic acid. The best catalyt...

Complex [(CNC)MesRh(PMe2Ph)]PF6 (1) has been found to be an effective catalyst for solventless formic acid (FA) dehydrogenation, affording exclusively H2 and CO2 as decomposition products. The effect of the addition...

The catalysts [Ir(COD)(κ³-P,C,P′-PCNHCP)]BF4 and [Ir(COD)(κ²-P,C-PCNHCO)]BF4 proved to be active in the solventless dehydrogenation of formic acid. The impact of various cosolvents on the activity was evaluated, showing an outstanding improvement of the catalytic performance of [Ir(COD)(κ²-P,C-PCNHCO)]BF4] in “green” organic carbonates: namely, dim...

The orbital physics relevant in electrocatalytic activity present subtle differences between oxygen evolution (OER) and reduction reactions (ORR). Achieving maximum efficiency in (electro)catalysis requires a detailed understanding on the electronic interactions. Quantum correlations and, in particular, spin-exchange interactions are decisive to un...

Iridium(III) complexes of the general formula [Ir(X)(κ²-NSiiPr2)2] (NSiiPr2 = (4-methyl-pyridine-2-yloxy)diisopropylsilyl; X = Cl, 3; CF3SO3, 5; CF3CO2, 6) have been prepared and fully characterized, including X-ray diffraction studies and theoretical calculations. The presence of isopropyl substituents at the silicon atom favours the monomeric str...

Bimetallic Pt-based alloys have drawn considerable attention in the last decades as catalysts in proton-exchange membrane fuel cells (PEMFCs) because they closely fulfill the two major requirements of high performance and good stability under operating conditions. Pt3Fe, Pt3Co, and Pt3Ni stand out as major candidates, given their good activity towa...

PMMA composites and solids of complexes of formulas [AgX(P-P)] n [n = 1 and 2; X = Cl, NO3, ClO4, CF3COO, and OTf; P-P = dppb, xantphos, (PR2)2C2B10H10 (R = Ph and iPr)] display the whole palette of colors from blue to red upon selection of the anionic ligand (X) and the diphosphane (P-P). The diphosphane seems to play the most important role in tu...

Human riboflavin kinase (HsRFK) catalyzes vitamin B2 (riboflavin) phosphorylation to flavin mononucleotide (FMN), obligatory step in flavin cofactor synthesis. HsRFK expression is related to protection from oxidative stress, amyloid‐β toxicity, and some malignant cancers progression. Its downregulation alters expression profiles of clock‐controlled...

The zwitterionic compound [Cp*RhCl{(MeIm)2CHCOO}] is an efficient catalyst for the hydrosilylation of terminal alkynes with excellent regio- and stereoselectivity towards the less thermodynamically stable β-(Z)-vinylsilane isomer under mild reaction conditions. A broad range of linear 1-alkynes, cycloalkyl acetylenes and aromatic alkynes undergo th...

The use of protic ligands to generate metal-ligand bifunctional catalysts has proved an excellent strategy to enhance the catalytic activity in formic acid dehydrogenation. We present here synthetic routes for complexes of general formula [Ir(H)2(IPr) (PR3) (CH3CN)2]BF4 (1a-c), [Ir (8-AQ) (H)2(IPr) (PR3)]BF4 (2a-c and 3), and [Ir(IPr) (C-N) (8-AQ)H...

A simple Bond Charge Model is proposed to predict \textit{intrinsic} bond energies. Model parameters can be derived from the topology of the Electron Localization Function and equilibrium geometries through classic considerations. Results for carbon-carbon covalent bonds are shown to be very accurate in different chemical environments. Insight can...

The zwitterionic complex [Cp*IrCl{(MeIm)2CHCOO}] (1) efficiently catalyzes the selective hydrosilylation of CO2 to afford the corresponding silylformate. The best reaction performance has been achieved in acetonitrile at 348 K using HSiMe2Ph. The 1‐catalyzed reaction of pyrrolidine with CO2 and HSiMe2Ph strongly depends on the CO2 pressure. At low...

The unsaturated hydride complex RhClH{2-N,C-(C11H8N)}(IPr) {IPr = 1,3-bis-(2,6-diisopropylphenyl)imidazolin-2-carbene} (2) has been prepared via C-H activation of 2-phenylpyridine and fully characterized by spectroscopic methods and X-ray diffraction analysis. Complex 2 efficiently catalyzes the isomerization of terminal and internal olefins under...

This work attempts to provide a clear picture on the relative quality of different Density Functional Approximations through the use of Quantum Chemical Topology on molecular electronic densities. In particular, two simple yet ever-important systems are studied, the \ce{N2} and \ce{CO} molecules. Our results exemplify how real-space descriptors can...

Brucella ovis encodes a bacterial subclass 1 ferredoxin-NADP(H) reductase (BoFPR) that, by similarity with other FPRs, is expected either to deliver electrons from NADPH to the redox-based metabolism and/or to oxidize NADPH to regulate the soxRS regulon that protects bacteria against oxidative damage. Such potential roles for the pathogen survival...

This work attempts to provide a clear picture on the relative quality of different Density Functional Approximations through the use of Quantum Chemical Topology on molecular electronic densities. In particular, two simple yet ever-important systems are studied, the N2 and CO molecules. Our results exemplify how real-space descriptors can clearly a...

The iridium(III) complex [Ir(CF3CO2)(κ2-NSi)2] (3) (NSi = 4-methylpyridine-2-yloxydimethylsilyl) has proven to be an effective catalyst for the reduction of CO2 with HSiMe(OSiMe3)2 under mild reaction conditions. 1H NMR studies of the 3-catalyzed reactions of CO2 with HSiMe(OSiMe3)2 in C6D6 at 298 K evidenced that the selectivity of these reduction...

Reaction of [Ir(μ-Cl)(COE)2]2 (COE = cis-cyclooctene) with tris(3,5-dimethylpyrazol-1-yl)methane (MeTpm) affords complex [IrCl(κ1-N-MeTpm)(COD)] (1) (COD = 1,5-cyclooctadiene). The formation of 1 implies the transfer dehydrogenation of a COE ligand to give COD and COA (cyclooctane). A mechanistic proposal based on DFT calculations that explains thi...

The electronic rearrangements involved in Noyori hydrogenation reactions with double bonds (ethene and formaldehyde) are analysed using the bonding evolution theory. The study and analysis of the changes on the electron localisation function topology along a given reaction path reveals fluxes of electron density, allowing to unambiguously identify...

A sturdy iridium complex that features a PCP ligand based on an N-heterocyclic olefin shows remarkable activity for the solventless dehydrogenation of formic acid. Reactivity studies highlight the importance of...

New mixed gold(III) derivatives with dithiocarbamate and thiolate ligands have been synthesized and characterized. They display high anticancer activity against colon cancer cell lines without affecting to differentiated enterocytes, high stability in phosphate-buffered saline solution, and resistance to gold reduction in the presence of reducing a...

Reactions involving nitrogen fixation and transfer are of great industrial interest. In this regard, unveiling the physical principles that determine their activity would be enormously beneficial for the rational design of novel catalysts with improved performance. Within this context, this work explores the activity of bulk molybdenum‐based transi...

The pincer ligand HN(CH2CH2PPh2)2 (1; PNHP) reacted with [{Ir(μ-X)(cod)}2] (X = Cl, OMe), affording complexes [fac-(PNHP)Ir(cod)]Cl (2) and [fac-(PNP)Ir(cod)] (3), respectively. The X-ray molecular structure of 2 showed that the PNP ligand coordinates in a facial fashion, with the N atom in an axial site and both P atoms coordinated in the equatori...

The study of magnetic perovskite oxides has led to novel and very active compounds for O2 generation and other energy applications. Focusing on three different case studies, we summarise the bulk electronic and magnetic properties that initially serve to classify active perovskite catalysts for the oxygen evolution reaction (OER). Ab-initio calcula...

An analysis of the electronic rearrangements for the oxidative addition of ammonia to a set of five representative (PXP)Ir pincer complexes (X= B, CH, O, N, SiH) is performed. We aim to understand the factors controlling activation and reaction energies of this process by combining different theoretical strategies based on DFT calculations. Interes...

The reaction of alkyl-benzoxazoles with enals has been reported using a synergistic approach. It consists on the activation of enals with a secondary amine catalyst and the activation of benzoxazoles with a metal Lewis acid. This approach has also been applied to the synthesis of cyclopropanes with excellent results. We demonstrated the applicabili...

Herein we report on the different chemical reactivity displayed by two mononuclear terminal amido compounds depending on the nature of the coordinated diene. Hence, treatment of amido-bridged iridium complexes [{Ir(-NH2)(tfbb)}3] (1; tfbb = tetrafluorobenzobarrelene) with dppp (dppp = bis(diphenylphosphane)propane) leads to the rupture of the amid...

The hydrosilylation of CO2 with different silanes such as HSiEt3, HSiMe2Ph, HSiMePh2, HSiMe(OSiMe3)2 and HSi(OSiMe3)3 in presence of catalytic ammounts of the iridium(III) complex [Ir(H)(CF3CO2)(NSiN*)(coe)] (1; NSiN* = fac-bis-(4-methylpyridine-2-yloxy); coe = cis-cyclooctene) has been comparatively studied. The activity of the hydrosilylation cat...

New RhI-IPr (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-carbene) complexes bearing an N,O-pyridine-2-methanolato (N-O) bidentate ligand have been prepared. The carbonyl complex Rh(N-O)(IPr)(CO) efficiently catalyzes the hydrothiolation of a range of alkynes with high selectivity to α-vinyl sulfides. Reactivity studies and DFT calculations hav...

The chiral photoinduction in a photoresponsive gel based on an achiral 2D architecture with high geometric anisotropy and low roughness has been investigated. Circularly polarized light (CPL) was used as a chiral source and an azobenzene chromophore was employed as a chiral trigger. The chiral photoinduction was studied by evaluating the preferenti...

A well-defined NHC-Ir(III) catalyst, [Ir(H)2(IPr)(py)3][BF4] (IPr = 1,3-bis-(2,6-diisopropylphenyl)imidazol-2-ylidene), that provides access to a wide range of aryl- and heteroarylsilanes by intermolecular dehydrogenative C–H bond silylation has been prepared and fully characterized. The directed and non-directed functionalisation of C–H bonds has...

Manganese oxides with a half-metallic ground state are particularly active for oxygen reduction reactions (ORR). La0.67Sr0.33MnO3 (LSMO) perovskite is the archetypal example for compositions with a Curie temperature (TC) above room temperature, and with a high intrinsic activity for the partial reduction of triplet state O2. The ferromagnetic (FM)...

The synthesis of a wide variety of carbamates from amines, alcohols and carbon monoxide has been achieved by means of a Rh-catalysed oxidative carbonylation reaction that uses Oxone as a stoichiometric oxidant. In-depth studies on the reaction mechanism shed light on the intimate role of Oxone in the catalytic cycle.

RhI–NHC–olefin complexes bearing a N,O-quinolinolate bidentate ligand have been prepared from [Rh(μ-OH)(NHC)(η2-olefin)]2 precursors (olefin = cyclooctene, ethylene). The disposition of the chelate ligand with regard to the carbene in the square planar derivatives is strongly influenced by the steric hindrance exerted by the coordinated olefin. The...

The positive effect of the addition of water to acetone hydrogenation by [RhH2(PR3)2S2](+) catalysts has been studied by DFT calculations. The studied energetic profiles reveal that the more favourable mechanistic path involves a hydride migration to the ketone followed by a reductive elimination that is assisted by two water molecules.

Treatment of acetone solutions of the known chlorido-bridged complexes [{M(m-Cl)(cod)}2] (M = Ir, Rh; cod = 1,5-cyclooctadiene) under an ammonia atmosphere afforded the cationic complexes [M(cod)(kN,kN-NH2-C(CH3)2-CH2-C(CH3)=NH)]Cl (M = Ir (3), Rh (4)). The molecular structures of 3 and 4 showed the formation of six-membered metallacycles due to th...

A series of rhodium–NSiN complexes (NSiN=bis (pyridine-2-yloxy)methylsilyl fac-coordinated) is reported, including the solid-state structures of [Rh(H)(Cl)(NSiN)(PCy3)] (Cy=cyclohexane) and [Rh(H)(CF3SO3)(NSiN)(coe)] (coe=cis-cyclooctene). The [Rh(H)(CF3SO3)(NSiN)(coe)]-catalyzed reaction of acetophenone with silanes performed in an open system was...

The Ir(i) complexes [Ir(cod)(κP,C,P'-NHO(PPh2))]PF6 and [IrCl(cod)(κC-NHO(OMe))] (cod = 1,5-cyclooctadiene, NHO(PPh2) = 1,3-bis(2-(diphenylphosphanyl)ethyl)-2-methyleneimidazoline) and NHO(OMe) = 1,3-bis(2-(methoxyethyl)-2-methyleneimidazoline), both featuring an N-heterocyclic olefin ligand (NHO), have been tested in the transfer hydrogenation rea...

Rearrangements and their control are a hot topic in supramolecular chemistry due to the possibilities that these phenomena open in the design of synthetic receptors and molecular machines. Macrocycle aza-scorpiands constitute an interesting system that can reorganize their spatial structure depending on pH variations or the presence of metal cation...

By changing the temperature from 283 to 233 K, the S (99 % ee) or R (96 % ee) enantiomer of the Friedel-Crafts (FC) adduct of the reaction between N-methyl-2-methylindole and trans-β-nitrostyrene can be obtained by using (SRh ,RC )-[(η(5) -C5 Me5 )Rh{(R)-Prophos}(H2 O)][SbF6 ]2 as the catalyst precursor. This catalytic system presents two other unc...

The treatment of [(Ir(μ-Cl)(cod))2] (cod = 1,5-cyclooctadiene) with 2,5-norbornadiene (nbd) in the presence of triethylphosphane under an atmosphere of ammonia afforded the cation complex [Ir(κC,κC-C21H24)(NH3)3(PEt3)]Cl (1a) and complex [Ir(κC,κC-C21H24)Cl(NH3)2(PEt3)] (1b), the structures of which include a novel seven-membered iridacycle formed...

The chloro complex [IrCl(cod)(dppe)] (dppe = bis(diphenylphosphane)ethane; cod = 1,5-cyclooctadiene) was found to react with gaseous ammonia, affording the amido-bridged diiridium complex [{Ir(μ-NH2)H(dppe)(NH3)}2][Cl]2 (1), whose molecular structure has been solved by X-ray methods. The related cationic complexes [{Ir(μ-NH2)H(dppp)(NH3)}2][BF4]2 (...

The reactivity of thiophene (T), 2-methylthiophene (2-MeT), and benzothiophene (BT) with [Ir(cod)(IPr)(L)]BF4 complexes (L = acetone (1), pyridine (2) or dimethylphenylphosphine (3); IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) in the presence of molecular hydrogen has been investigated. Under these conditions the 1,5-cyclooctadiene liga...

The reaction mechanisms of the palladium-catalyzed alkoxycarbonylation of α,β-unsaturated amides are studied by means of density functional theory (DFT) at the B3LYP/def2-TZVP//B3LYP/def2-SVP level of theory including solvent and dispersion corrections. Two possible pathways, hydride and alkoxy, are examined and their corresponding intermediates an...

[{Rh(μ-Cl)(H)2 (IPr)}2 ] (IPr = 1,3-bis-(2,6-diisopropylphenyl)imidazole-2-ylidene) was found to be an efficient catalyst for the synthesis of novel propargylamines by a one-pot three-component reaction between primary arylamines, aliphatic aldehydes, and triisopropylsilylacetylene. This methodology offers an efficient synthetic pathway for the pre...

The complex [Ir(H)(CF3SO3)(NSiN)(coe)] (NSiN=bis(pyridine-2-yloxy)methylsilyl fac-coordinated) (1) is an effective catalyst precursor for the solvent-free synthesis of silyl carbamates from reaction of aliphatic secondary amines with CO2 and HSiMe(OSiMe3)2. The preferential formation of the silyl carbamate instead of the expected formamide or methy...

is used for the hydroalkynylation of imines

A variety of [M(L)2(L′)2{κC,C′-bis(NHC)}]BF4 complexes (M = Rh or Ir; L = CH3CN or wingtip group; L′ = I– or CF3COO–; NHC=N-heterocyclic carbene) have been tested as pre-catalysts for the transfer hydrogenation of ketones and imines. The conversions and TOF's obtained are closely related to the nature of the ligand system and metal centre, more str...

In this work, a computational study at the DFT level is carried out to determine the reaction mechanism for the N–H bond activation of ammonia by dinuclear [{M(μ-OMe)(cod)}2] complexes (M = Ir, Rh) to yield amido species [{M(μ-NH2)(cod)}2] reported experimentally by Mena et al. (Angew. Chem., Int. Ed. 2011, 50, 11735–11738). A stepwise mechanism is...

Methoxo-bridged diiridium complexes of the type [{Ir(μ-OMe)(diolefin)}2] (diolefin = 1,5-cyclooctadiene, tetrafluorobenzobarrelene), in the presence on P- or N-donor ligands, are active catalyst precursors in the catalytic hydrogen transfer of iPrOH to acetophenone. Both the nature of the diolefin and that of additional P- and N-donor ligands have...

A new PCP-type ligand based on an N-heterocyclic olefin (NHO) scaffold has been prepared. The flexibility of this ligand, which is able to adopt facial coordination modes in Ir(I) or meridional in Ir(III) complexes, can be attributed to the dual nature ylide-olefin of the NHO scaffold. This results in a rare case of olefin “slippage” that is suppor...

The mechanism of the addition of lithium enolates derived from esters, ketones and aldehydes to nitrones (Mannich-type reaction) has been studied using DFT methods. While the reactions with α-methoxy and α-methyl enolates takes place through a stepwise mechanism, consisting of an initial nucleophilic attack of the enolate to the nitrone carbon foll...

The new Ir(II) complex [{Ir(μ-κCNHC,η6Dipp-IDipp)(H)}2][BF4]2 has been prepared and fully characterised. This complex acts as a catalyst for the hydroalkynylation of imines according to a unprecedented diiridium-mediated mechanism.

The mechanism of the reaction between nitrones and lithium ynolates has been studied using DFT methods at M06-2X/cc-pVTZ/PCM=THF level. After the formation of a starting complex, without energy barrier, in which the lithium atom is coordinated to both nitrone and ynolate, the reaction takes place in one single kinetic step through a single transiti...

The rhodium(I) complex [Rh(Cl)(COD)(2-methoxyphenyl-NHC-(CH2)3Si(OiPr)3)] (2a) catalyzes the solvent-free homogeneous hydrosilylation of acetophenone with HSiMe(OSiMe3)2. Kinetic studies show that 2a behaves differently to the related homogeneous catalysts [Rh(Cl)(COD)(R-NHC-(CH2)3Si(OiPr)3)] (R = 2,6-diisopropylphenyl, (2b); R = 2-methoxyethyl (2c...

The rhodium(I) complexes [Rh(Cl)(COD)(R-NHC-(CH2)3Si(OiPr)3)] [COD=cyclooctadiene; R=2,6-diisopropylphenyl (1 a); n-butyl (1 b)] are effective catalyst precursors for the homogeneous hydrodechlorination of benzyl chloride using HSiEt3 as hydrogen source. This reaction is selective to the formation of toluene. However, in presence of a stoichiometri...

[Rh(μ-Cl)(H)2(IPr)]2 (IPr=1,3-bis-(2,6-diisopropylphenyl)imidazol-2-ylidene) catalyzes the selective functionalization of 2-(2-thienyl)pyridine efficiently with a range of alkenes and internal alkynes. A catalytic cycle is proposed on the basis of the identification of key reaction intermediates and the study of their reactivity by NMR spectroscopy...

A mechanistic DFT study has been carried out on the ethene hydrogenation catalyzed by the [IrH2(NCMe)(3)((PPr3)-Pr-i)](++) complex (1). First, the reaction of (1) with ethene has been theoretically characterized, and three mechanistic proposals (AC) have been made for an identification of the preferred pathways for the alkene hydrogenation catalyti...

In the presence of phosphanes (PR3), the amido-bridged trinuclear complex [{Ir(μ-NH2)(tfbb)}3] (tfbb=tetrafluorobenzobarrelene) transforms into mononuclear discrete compounds [Ir(1,2-η2-4-κ-C12H8F4N)(PR3)3], which are the products of the CN coupling between the amido moiety and a vinylic carbon of the diolefin. An alternative synthetic approach to...

Reaction of Fe3(CO)12 with 1,2-dithiolene HSC6H2Cl2SH affords a mixture of complexes [Fe2(CO)6(μ-SC6H2Cl2S)] , [Fe2(SC6H2Cl2S)4] and [Fe3(CO)7(μ3-SC6H2Cl2S)2] . In the course of the reaction the trimetallic cluster is first formed and then converted into the known dinuclear compound to afford finally the neutral diiron tetrakis(dithiolato) derivati...

The iridium(III) complex [Ir(H)(CF3SO3)(NSiN)(coe)] (NSiN=fac-coordinated bis(pyridine-2-yloxy)methylsilyl, coe=cyclooctene) has been proven to be an effective catalyst precursor for hydrogen production from the hydrolysis of hydrosilanes at room temperature. The reaction performance depends both on the nature of the silane and the solvent. Interes...

Recent reports on homogeneous catalytic transformation of carbon dioxide by iridium complexes have prompted us to review the area. Progress on new iridium catalysts for carbon dioxide transformations should take into account the interaction of carbon dioxide with the iridium center, which seems to be governed by the oxidation state of iridium and t...

The β-Z selectivity in the hydrosilylation of terminal alkynes has been hitherto explained by introduction of isomerisation steps in classical mechanisms. DFT calculations and experimental observations on the system [M(I)2 {κ-C,C,O,O-(bis-NHC)}]BF4 (M=Ir (3 a), Rh (3 b); bis-NHC=methylenebis(N-2-methoxyethyl)imidazole-2-ylidene) support a new mecha...

Selected secondary phosphanes (H-PR2; R = Ph, Cy, (i)Pr) smoothly react with a parent amido-bridged diiridium cyclooctadiene complex affording mixed amido/(bis)phosphido dinuclear species. A careful investigation of the reaction profile, carried out by experimental and theoretical tools, revealed that, after an initial amido/phosphido exchange, at...

The new Rh–hydroxo dinuclear complexes stabilized by an N-heterocyclic carbene (NHC) ligand of type [Rh(μ-OH)(NHC)(η2-olefin)]2 (coe, IPr (3), IMes (4); ethylene, IPr (5)) are efficient catalyst precursors for alkyne hydrothiolation under mild conditions, presenting high selectivity toward α-vinyl sulfides for a varied set of substrates, which is e...

Iodoalkynes [1,4-bis(iodoethynyl)benzene (p-BIB) and 1,3-bis(iodoethynyl)benzene (m-BIB)] have been used successfully to prepare halogen bonding complexes with a range of 4-pyridine derivatives showing liquid crystalline organizations. The trimeric halogen-bonded complexes ob-tained from p-BIB have a rod-like structure and exhibited high order cala...

A general regioselective rhodium-catalyzed head-to-tail dimerization of terminal alkynes is presented. The presence of a pyridine ligand (py) in a Rh-N-heterocyclic-carbene (NHC) catalytic system not only dramatically switches the chemoselectivity from alkyne cyclotrimerization to dimerization but also enhances the catalytic activity. Several inter...

A new mechanism of H2 activation is reported to occur on a carbene-ligated rhodathiaborane that features metal-thiaborane bifunctional synergistic effects. The key is the creation of vacant coordination sites by an isonido-nido structural transformation leading to the heterolytic H-H bond splitting.

At non-zero temperature and when a system has low-lying excited electronic states, the ground-state Born-Oppenheimer approximation breaks down and the low-lying electronic states are involved in any chemical process. In this work, we use a temperature-dependent effective potential for the nuclei which can accommodate the influence of an arbitrary n...

CO 2 als Rohstoff: Ein luft‐ und feuchtigkeitsstabiler Iridium(III)‐Katalysator vermittelt die Hydrosilylierung von CO2. Diese Reaktion verläuft effizient unter milden Bedingungen, höchstwahrscheinlich über einen Außensphären‐Mechanismus, wie theoretische Rechnungen andeuten, und führt hochselektiv zu Silylformiat.

A general protocol to access Mo(3)FeS(4)(4+) clusters selectively modified at the Fe coordination site is presented starting from the all-chlorine Mo(3)(FeCl)S(4)(dmpe)(3)Cl(3) (1) [dmpe = 1,2-bis(dimethylphosphane-ethane)] cluster and tetrabutylammonium salts (n-Bu(4)NX) (X = CN(-), N(3)(-), and PhS(-)). Clusters Mo(3)(FeX)S(4)(dmpe)(3)Cl(3) [X =...

CO(2) as feedstock: An air- and moisture-stable iridium(III) catalyst effectively promotes the hydrosilylation of CO(2) . This reaction leads to silyl formate in a highly selective manner and proceeds efficiently under mild conditions, most likely by an outer-sphere mechanism, as suggested by theoretical calculations.

The electron precise incomplete cuboidal complex [Mo(3)S(4)(dppe)(3)Br(3)]Br () with 6 cluster skeletal electrons (CSE) and its halogen-mixed analogue [Mo(3)S(4)(dppe)(3)(Br,Cl)(3)](Br,Cl) () can be smoothly reduced to the paramagnetic [Mo(3)S(4)(dppe)(3)X(3)] clusters (, X = Br; , X = Cl/Br) with 7 CSE by treatment with liquid Ga.

A synthon for a 14-electron Ir(III) species is described. The geometrical control exerted by the ligand system over the Ir-alkenyl intermediate in hydrosilylation of terminal alkynes precludes formation of the more thermodynamically stable β-(E)-vinylsilane, thus affording the β-(Z) isomer in excellent yields.

From amido to imido: A dinuclear amido-bridged iridium complex promotes the dehydrogenation of alcohols, affording unusual mixed amido/imido Ir(4) and bis(imido) Ir(3) clusters. Theoretical calculations suggest that bridging μ-NH(2) linkages are crucial to achieve the formation of hydrido amine diiridium species, as a result of a concerted net hydr...

At non-zero temperature and when a system has low-lying excited electronic states, the ground-state Born--Oppenheimer approximation breaks down and the low-lying electronic states are involved in any chemical process. In this work, we use a temperature-dependent effective potential for the nuclei which can accomodate the influence of an arbitrary n...

Rh-N-heterocyclic carbene compounds [Rh(μ-Cl)(IPr)(η(2)-olefin)](2) and RhCl(IPr)(py)(η(2)-olefin) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-carbene, py = pyridine, olefin = cyclooctene or ethylene) are highly active catalysts for alkyne hydrothiolation under mild conditions. A regioselectivity switch from linear to 1-substituted vinyl sulfid...

A Re(IV) cluster complex [Re(3)(μ(3)-S)(μ-S)(3)(dppe)(3)Br(3)](+) with nine cluster skeletal electrons (CSE) and a quadruplet ground state has been prepared by treatment of [Re(3)S(7)Br(6)]Br with 1,2-bis(diphenylphosphino)ethane (dppe) in MeCN.