Abstract We present a free web application for the calculation of buried volume (% V Bur ) NHC ligands. The provides graphic and user‐friendly interface to Samb ca program, developed % values not only ligands but also other classic organometallic such as, example, phosphanes cyclopentadienyl‐based To provide reliable procedure we tested our approach in interpretation binding energies Cp*Ru(NHC)Cl complexes terms steric electronic parameters.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451...

Developing more efficient catalysts remains one of the primary targets organometallic chemists. To accelerate reaching this goal, effective molecular descriptors and visualization tools can represent a remarkable aid. Here, we present Web application for analyzing catalytic pocket metal complexes using topographic steric maps as general unbiased descriptor that is suitable every class catalysts. show broad applicability our approach, first compared map series transition presenting popular...

The relationship between the NMR chemical shifts of phosphinidene and selenourea compounds π-accepting ability related carbene ligands has been investigated.

Readily available ascorbic acid was discovered as an environmentally benign hydrogen bond donor for the synthesis of cyclic organic carbonates from CO2 and epoxides in presence nucleophilic cocatalysts. The acid/TBAI (TBAI: tetrabutylammonium iodide) binary system could be applied cycloaddition to various under ambient or mild conditions. Density functional theory calculations catalysis experiments revealed intriguing bifunctional mechanism step insertion involving different hydroxyl...

A ligand-controlled and site-selective nickel catalyzed Suzuki–Miyaura cross-coupling reaction with aromatic esters alkyl organoboron reagents as coupling partners was developed. This methodology provides a facile route for C(sp2)–C(sp3) bond formation in straightforward fashion by successful suppression of the undesired β-hydride elimination process. By simply switching phosphorus ligand, ester substrates are converted into alkylated arenes ketone products, respectively. The utility this...

The past decade has seen N-heterocyclic carbenes (NHC) emerging as a credible alternative to ubiquitous tertiary phosphines ligands in organic and organometallic chemistry. In many cases NHC have proven more effective than ancillary catalysis, while some they also enable unexpected welcomed chemical routes new products.(1) These initial discoveries paved the way continued search for NHCs able promote and/or unprecedented catalysis. Nevertheless, useful remains an arduous task, because, date,...

Density functional theory (DFT, B3PW91) calculations have been carried out on the reactivity of ethene with model systems M(⋮NR)(CHCH3)(X)(Y) for M = Mo or W, R methyl phenyl, X CH2CH3, OCH3, OSiH3, and Y which are representative experimental olefin metathesis catalysts, results compared to those previously obtained Re(⋮CCH3)(CHCH3)(X)(Y). The general pathway comprises four steps: coordination, [2+2] cycloaddition, cycloreversion, de-coordination. Two key factors found control detailed shape...

Abstract The current approach to improve and tune the enantioselective performances of transition‐metal catalysts for asymmetric synthesis is mostly focused modifications steric properties ancillary ligands active metal. Nevertheless, it also known that electrostatic effects can have a remarkable role promote selectivity in synthesis. Using Rh‐catalyzed 1,4‐addition phenylboronic acid 2‐cyclohexenone leading chiral 3‐phenylcyclohexanone as an example, we could show high enantioselectivity be...

We present a detailed static and dynamics characterization of 11 N-heterocyclic carbene (NHC) ligands in Ru complexes the general formula (NHC)Cl(2)Ru horizontal lineCH(2). Analysis dynamic trajectories indicates that nature N substituent can result extremely different flexibilities complexes. In almost all cases trans to Ru-ylidene bond is severely folded so it protects vacant coordination position at center. Limited flexibility instead associated with on side bond. NHCs single ortho...

The present study provides mechanistic details of a mild aromatic C−H activation effected by copper(II) center ligated in triazamacrocylic ligand, affording equimolar amounts CuIII-aryl species and CuI as reaction products. At low temperatures the CuII complex 1 forms three-center, three-electron C−H···CuII interaction, identified pulse electron paramagnetic resonance spectroscopy supported density functional theory calculations. bond cleavage is coupled with copper oxidation, product 2...

Recent discoveries highlighted the activity and intriguing mechanistic features of NbCl5 as a molecular catalyst for cycloaddition CO2 epoxides under ambient conditions. This has inspired preparation novel silica-supported Nb species by reacting niobium precursor, [NbCl5·OEt2], with silica dehydroxylated at 700 °C (SiO2-700) or 200 (SiO2-200) to generate diverse surface complexes. The product reaction between SiO2-700 [NbCl5·OEt2] was identified monopodal supported species, [≡SiONbCl4·OEt2]...

An unexpected regioselectivity reversal was observed in the synthesis of vinylgold(I) complexes from propargyl carboxamides. The use [Au(IPr)(OH)] affords preferentially resulting a 5-exo-dig cyclization, whereas [Au(IPr)]+ species, generated situ starting [Au(IPr)(Cl)] and AgOTf, leads to which form via 6-endo-dig This "selectivity switch" for this cyclization led us propose two different reaction pathways enabling formation products. One mechanism involves species with "classical" π...

An iron(0) complex bearing a cyclopentadienone ligand catalyzed N-methylation and N-ethylation of aryl aliphatic amines with methanol or ethanol in mild basic conditions through hydrogen autotransfer borrowing process is reported. A broad range aromatic underwent mono- dimethylation high yields. DFT calculations suggest molecular acts not only as reducing agent but also an additive to displace thermodynamic equilibria.

Reductive amination under hydrogen pressure is a valuable process in organic chemistry to access amine derivatives from aldehydes or ketones. Knölker's complex has been shown be an efficient iron catalyst this reaction. To determine the influence of substituents on cyclopentadienone ancillary ligand, series modified complexes was synthesised and fully characterised. These were also transformed into their analogous acetonitrile iron-dicarbonyl complexes. Catalytic activities these evaluated...

The [Pd(SIPr)(PCy3)] complex efficiently promotes a tandem process involving dehydrogenation of formic acid and hydrogenation C-C multiple bonds using H2 formed in situ. isolation key catalytic hydridoformatopalladium species, [Pd{OC(O)H}(H)(IPr)(PCy3)], is reported. plays role the Pd(0)-mediated formation hydrogen from acid. Mechanistic computational studies delineate operational palladium this efficient sequence.

Abstract The development of hydrogen bond donors (HBDs) as catalytic moieties in the cycloaddition carbon dioxide to epoxides is an active field research access efficient, inexpensive and sustainable metal‐free systems for conversion useful chemicals. Thus far, no systematic attempt correlate activity a diverse selection HBDs their physico‐chemical properties has been undertaken. In this work, we investigate factors influencing hydroxyl from different chemical families under ambient...

Abstract We report a combined experimental and computational investigation of the Suzuki–Miyaura cross‐coupling amides enabled by [Pd(NHC)(allyl)Cl] precatalysts. Most crucially, mechanistic details pertaining to Pd 0 /NHC catalytic cycle were elucidated methods. Mechanistic insights shed light on role each ligand about metal. Sterics play key in initial activation catalyst. As insight, we have shown that water participates Pd‐NHC system. Easier has led effect room temperature broad range...

A recent study showed that a Mn-pincer could catalyze the acceptorless dehydrogenative coupling of nitriles and alcohols to yield acrylonitriles. The reaction mechanism proposed in work contained some intermediates that, most cases, were not characterized. Moreover, one involved charged separation, which is unlikely apolar solvents. To clarify this critical reaction, we decided perform DFT study. Our results prove existence cooperative effect metal ligand several steps catalytic cycle. We...