Homogeneous Dimers Research Articles

Highly accurate computation of chronopotentiograms for a charge transfer followed by homogeneous dimerization or disproportionation reactions

A theoretical model of constant current chronopotentiometry is considered, for a reversible charge transfer followed by an irreversible homogeneous dimerization or disproportionation reactions at a planar electrode. The model is expressed by a system of two partial differential reaction–diffusion equations, one or both being nonlinear. This system decomposes into two independent initial boundary value problems, which allows one to obtain semi-analytical series solutions of the model. Detailed derivations and analysis of the series are presented. Highly accurate numerical reference solutions are also obtained. Hybrid algorithms are devised for computing electrode potential-time responses. The algorithms combine the series solution for small time, with asymptotic approximants for large time, and fitted polynomials for intermediate time. The algorithms are efficient and highly accurate: the relative error modulus does not exceed ca. 10−19−10−18, except for the small neighbourhoods of the transition time, and of the time where the potential response passes through zero. A set of C++ routines for these calculations is made available.

An Evaluation of Moderate-Refractive-Index Nanoantennas for Enhancing the Photoluminescence Signal of Quantum Dots.

The use of nanostructures to enhance the emission of single-photon sources has attracted some attention in the last decade due to the development of quantum technologies. In particular, the use of metallic and high-refractive-index dielectric materials has been proposed. However, the utility of moderate-refractive-index dielectric nanostructures to achieve more efficient single-photon sources remains unexplored. Here, a systematic comparison of various metallic, high-refractive-index and moderate-refractive-index dielectric nanostructures was performed to optimize the excitation and emission of a CdSe/ZnS single quantum dot in the visible spectral region. Several geometries were evaluated in terms of electric field enhancement and Purcell factor, considering the combination of metallic, high-refractive-index and moderate-refractive-index dielectric materials conforming to homogeneous and hybrid nanoparticle dimers. Our results demonstrate that moderate-refractive-index dielectric nanoparticles can enhance the photoluminescence signal of quantum emitters due to their broader electric and magnetic dipolar resonances compared to high-refractive-index dielectric nanoparticles. However, hybrid combinations of metallic and high-refractive-index dielectric nanostructures offer the largest intensity enhancement and Purcell factors at the excitation and emission wavelengths of the quantum emitter, respectively. The results of this work may find applications in the development of single-photon sources.

Catalytic Synthesis of Butene-1 and Hexene-1 in the Homogeneous Oligomerization of Ethylene in the Presence of Nickel Complexes Based on N-Heteroaryl-Substituted α-Diphenylphosphinoglycines

It has been experimentally shown that N-heteroaryl-substituted α-diphenylphosphinoglycines N-(pyrazin-2-yl)-α-diphenylphosphinoglycine, N-(pyridin-2-yl)-α-diphenylphosphinoglycine and N-(pyrimidin-2-yl)-α-diphenylphosphinoglycine obtained by the reaction of three-component condensation of diphenylphosphine, the corresponding primary amine and glyoxylic acid monohydrate are capable in combination with Ni(COD)₂, where COD is cyclooctadiene-1,5, to form active forms of catalysts for selective homogeneous dimerization and trimerization of ethylene with the formation of butene-1 and hexene-1 as the main products. It has been established that the obtained organo-nickel catalytic systems provide a yield of short-chain (C₄–C₆) olefins at the level of 90% with a selectivity for linear α-olefins of 97%. The study of the influence of temperature on the process of homogeneous ethylene oligomerization using the obtained compounds made it possible to establish that the optimal temperature for ethylene oligomerization, providing the highest selectivity to butene-1 and hexene-1, is 80–105°C at the optimum pressure of ethylene is 20–35 atm. Under these conditions, the selectivity for butenes is 71.4–72.6% (selectivity for butene-1 – 69.3–71.1%), for hexenes 20.6–21.2% (selectivity for hexene-1 – 19.2–19.5%), and the optimal duration of the oligomerization process at a temperature 105°C is 1.5 h, which provides the rate of formation of butene-1 equal to 168.1 golig gNi⁻¹h⁻¹) and the rate of formation of hexene-1 – 47.3 golig gNi⁻¹h⁻¹).

Computational analysis of hydrogen bonds network dynamics in the water layers surrounding Aβ(1-42) and Aβ(1-40) peptide dimers

The amyloid-β peptide (Aβ) dimer is involved in the development of Alzheimer’s disease through forming amyloid plaques. Aβ(1-40) and Aβ(1-42) are the most common and poisonous species causing Alzheimer’s disease. They form homogeneous dimers containing two similar peptides and heterogeneous dimers containing different ones. The low molecular weight, fast dynamics, and varying compositions of these dimers make it difficult to study them by conventional experimental methods. Hence, we clarify the effect of the diversity of the Aβ dimers on the structure of the water molecules around the peptides by the molecular dynamics (MD) simulation method in this study. MD simulations of the Aβ(1-40) and Aβ(1-42) monomers are also performed for the comparison. The calculations are repeated in the presence of dimethyl sulfoxide (DMSO). The water molecules positioned at distances of 0.5, 0.75, 1, 1.25, and 1.5 nm from the protein were chosen to investigate the distribution and dynamics of hydrogen bonds in the layers surrounding the peptide. The results show that the heterogeneity of the dimer system increases the percentage of hydrogen (H) atoms not involved in any water-water hydrogen bonds around the peptides in the different layers. While it decreases the percentage of H atoms involved in one and two water-water hydrogen bonds. The DMSO presence reduces the percentage of H atoms involved in two hydrogen bonds in the systems containing a mixture of water and DMSO. The average interaction energy of the dimers demonstrates the enhanced interactions of the two peptides in water in comparison with that in the mixture of water and DMSO. The behavior of the water molecules around the heterogeneous dimer is very similar to that around the Aβ(1-42) homogeneous dimer.

Quantum Drude oscillators coupled with Coulomb potential as an efficient model for bonded and non-covalent interactions in atomic dimers.

The quantum Drude oscillator (QDO) model has been widely used as an efficient surrogate to describe the electric response properties of matter as well as long-range interactions in molecules and materials. Most commonly, QDOs are coupled within the dipole approximation so that the Hamiltonian can be exactly diagonalized, which forms the basis for the many-body dispersion method [Phys. Rev. Lett. 108, 236402 (2012)]. The dipole coupling is efficient and allows us to study non-covalent many-body effects in systems with thousands of atoms. However, there are two limitations: (i) the need to regularize the interaction at short distances with empirical damping functions and (ii) the lack of multipolar effects in the coupling potential. In this work, we convincingly address both limitations of the dipole-coupled QDO model by presenting a numerically exact solution of the Coulomb-coupled QDO model by means of quantum Monte Carlo methods. We calculate the potential-energy surfaces of homogeneous QDO dimers, analyzing their properties as a function of the three tunable parameters: frequency, reduced mass, and charge. We study the coupled-QDO model behavior at short distances and show how to parameterize this model to enable an effective description of chemical bonds, such as the covalent bond in the H2 molecule.

Dissecting the Molecular Mechanisms of the Co-Aggregation of Aβ40 and Aβ42 Peptides: A REMD Simulation Study.

The aggregation of amyloid-β protein (Aβ) into oligomers and amyloid fibrils is closely related to Alzheimer's disease (AD). Aβ40 and Aβ42, as two most prominent isoforms of Aβ peptides, can cross-interact with each other and form co-aggregates, which affect the progression of the disease. However, the molecular determinants underlying Aβ40 and Aβ42 cross-interaction and the structural details of their co-oligomers remain elusive. Herein, we performed all-atom explicit-solvent replica exchange molecular dynamics simulations on Aβ40-Aβ42 heterogeneous and Aβ40/Aβ42 homogeneous dimer systems to dissect the co-aggregation mechanisms of the two isoforms. Our results show that the interpeptide main-chain interaction of Aβ40-Aβ42 is stronger than that of Aβ40-Aβ40 and Aβ42-Aβ42. The positions of hotspot residues in heterodimers and homodimers display high similarity, implying similar molecular recognition sites for both cross-interaction and self-interaction. Contact maps of Aβ40-Aβ42 heterodimers reveal that residue pairs crucial for cross-interaction are mostly located in the C-terminal hydrophobic regions of Aβ40 and Aβ42 peptides. Conformational analysis shows that Aβ40 and Aβ42 monomers can co-assemble into β-sheet-rich heterodimers with shorter β-sheets than those in homodimers, which is decremental to monomer addition. Similar molecular recognition sites and β-sheet distribution of Aβ40 and Aβ42 peptides are observed in heterodimers and homodimers, which may provide the molecular basis for the two isoforms' co-aggregation and cross-seeding. Our work dissects the co-aggregation mechanisms of Aβ40 and Aβ42 peptides at the atomic level, which will help for in-depth understanding of the cross-talk between the two Aβ isoforms and the pathogenesis of AD.

Coordinated regulation of plant defense and autoimmunity by paired trihelix transcription factors ASR3/AITF1 in Arabidopsis.

Plants perceive pathogens and induce robust transcriptional reprogramming to rapidly achieve immunity. The mechanisms of how immune-related genes are transcriptionally regulated remain largely unknown. Previously, the trihelix transcriptional factor ARABIDOPSIS SH4-RELATED 3 (ASR3) was shown to negatively regulate pattern-triggered immunity (PTI) in Arabidopsis thaliana. Here, we identified another trihelix family member ASR3-Interacting Transcriptional Factor 1 (AITF1) as an interacting protein of ASR3. ASR3-Interacting Transcriptional Factor 1 and ASR3 form heterogenous and homogenous dimers in planta. Both aitf1 and asr3 single mutants exhibited increased resistance against the bacterial pathogen Pseudomonas syringae, but the double mutant showed reduced resistance, suggesting AITF1 and ASR3 interdependently regulate immune gene expression and resistance. Overexpression of AITF1 triggered autoimmunity dependently on its DNA-binding ability and the presence of ASR3. Notably, autoimmunity caused by overexpression of AITF1 was dependent on a TIR-NBS-LRR (TNL) protein suppressor of AITF1-induced autoimmunity 1 (SAA1), as well as enhanced disease susceptibility 1 (EDS1), the central regulator of TNL signaling. ASR3-Interacting Transcriptional Factor 1 and ASR3 directly activated SAA1 expression through binding to the GT-boxes in SAA1 promoter. Collectively, our results revealed a mechanism of trihelix transcription factor complex in regulating immune gene expression, thereby modulating plant disease resistance and autoimmunity.

Molecular aggregation effect on the antagonistic adsorption of pharmaceuticals from aqueous solution using bone char: DFT calculations and multicomponent experimental studies

This study reports theoretical calculations and experimental results to understand the impact of molecular aggregation on the multicomponent adsorption of three non-steroidal anti-inflammatory drugs (i.e., acetaminophen, diclofenac and naproxen) on bone char from aqueous solutions. DFT calculations were performed to estimate the main molecular properties of monomers, dimers and trimers of these pharmaceuticals. The molecular properties of single compounds and their aggregates were used to explain the steric factors involved in the antagonistic and endothermic adsorption of these pharmaceuticals in binary and ternary systems. It was established that the molecular properties of homogeneous and heterogeneous dimers and trimers of these adsorbates played a relevant role in the multicomponent adsorption mechanism using bone char. Results showed that a transition from a multilayer to monolayer adsorption process could occur depending on the adsorption temperature and the presence of pharmaceutical co-adsorbate(s). Overall, the multicomponent adsorption of naproxen was not significantly affected by the competition effect generated by other pharmaceuticals present in the aqueous solution but its removal mechanism was essentially via the formation of a monolayer. In contrast, the acetaminophen adsorption implied a multilayer mechanism mainly due to the molecular dimensions of its aggregates. Adsorbent characterization results suggested that the phosphate group from hydroxyapatite contained in bone char played a relevant role in the multicomponent adsorption of these organic compounds. These new findings are useful to comprehend the role of molecular aggregation of organic pollutants on the adsorbent performance for water depollution.

A Disulfide-Stabilized Aβ that Forms Dimers but Does Not Form Fibrils.

Aβ dimers are a basic building block of many larger Aβ oligomers and are among the most neurotoxic and pathologically relevant species in Alzheimer's disease. Homogeneous Aβ dimers are difficult to prepare, characterize, and study because Aβ forms heterogeneous mixtures of oligomers that vary in size and can rapidly aggregate into more stable fibrils. This paper introduces AβC18C33 as a disulfide-stabilized analogue of Aβ42 that forms stable homogeneous dimers in lipid environments but does not aggregate to form insoluble fibrils. The AβC18C33 peptide is readily expressed in Escherichia coli and purified by reverse-phase HPLC to give ca. 8 mg of pure peptide per liter of bacterial culture. SDS-PAGE establishes that AβC18C33 forms homogeneous dimers in the membrane-like environment of SDS and that conformational stabilization of the peptide with a disulfide bond prevents the formation of heterogeneous mixtures of oligomers. Mass spectrometric (MS) studies in the presence of dodecyl maltoside (DDM) further confirm the formation of stable noncovalent dimers. Circular dichroism (CD) spectroscopy establishes that AβC18C33 adopts a β-sheet conformation in detergent solutions and supports a model in which the intramolecular disulfide bond induces β-hairpin folding and dimer formation in lipid environments. Thioflavin T (ThT) fluorescence assays and transmission electron microscopy (TEM) studies indicate that AβC18C33 does not undergo fibril formation in aqueous buffer solutions and demonstrate that the intramolecular disulfide bond prevents fibril formation. The recently published NMR structure of an Aβ42 tetramer (PDB: 6RHY) provides a working model for the AβC18C33 dimer, in which two β-hairpins assemble through hydrogen bonding to form a four-stranded antiparallel β-sheet. It is anticipated that AβC18C33 will serve as a stable, nonfibrilizing, and noncovalent Aβ dimer model for amyloid and Alzheimer's disease research.

Reconstitution of purified membrane protein dimers in lipid nanodiscs with defined stoichiometry and orientation using a split GFP tether

Many membrane proteins function as dimers or larger oligomers, including transporters, channels, certain signaling receptors, and adhesion molecules. In some cases, the interactions between individual proteins may be weak and/or dependent on specific lipids, such that detergent solubilization used for biochemical and structural studies disrupts functional oligomerization. Solubilized membrane protein oligomers can be captured in lipid nanodiscs, but this is an inefficient process that can produce stoichiometrically and topologically heterogeneous preparations. Here, we describe a technique to obtain purified homogeneous membrane protein dimers in nanodiscs using a split GFP (sGFP) tether. Complementary sGFP tags associate to tether the coexpressed dimers and control both stoichiometry and orientation within the nanodiscs, as assessed by quantitative Western blotting and negative-stain EM. The sGFP tether confers several advantages over other methods: it is highly stable in solution and in SDS-PAGE, which facilitates screening of dimer expression and purification by fluorescence, and also provides a dimer-specific purification handle for use with GFP nanobody–conjugated resin. We used this method to purify a Frizzled-4 homodimer and a Frizzled-4/low-density lipoprotein receptor–related protein 6 heterodimer in nanodiscs. These examples demonstrate the utility and flexibility of this method, which enables subsequent mechanistic molecular and structural studies of membrane protein pairs.

SERS and RI sensing properties of heterogeneous dimers of Au and Si nanospheres

Heterogeneous dimers of Au and Si nanoparticles are expected to exhibit different plasmon properties from that of homogeneous noble metal nanoparticle dimers. It is crucial to unveil the potential applications in surface-enhanced Raman scattering (SERS) and refractive-index (RI) sensing of the prototype dimer of Au and Si nanospheres. The near-field coupling between the two components within the dimer is revealed to not affect the resonance energy of Si mode in the extinction spectra, but decrease that of Au mode. It also accounts for the plasmon ruler behavior of the fractional shifts of both its dipolar peak wavelength of localized surface plasmon resonance (LSPR) and corresponding RI sensitivity factor [Formula: see text], which provide another kind of substitute to estimate the gap distance in between components within the dimer as that of noble metal nanoparticle dimers. Additionally, by tracking the inflection point shift of the corresponding extinction spectra, its [Formula: see text] is revealed to improve 36% than that of traditional one. The maximum [Formula: see text] and SERS enhancement factor [Formula: see text] at 2 nm gap distance are demonstrated to reach 336 nm RIU[Formula: see text] and [Formula: see text], respectively. This work paves a new way for developing efficient SERS and RI sensing substrates by combining noble metal and dielectric nanoparticles.

Electrochemical Study of Propofol (2,6-diisopropylphenol): A Novel Insight into the Dimerization of Propofol

Electrochemical oxidation of propofol (2,6-diisopropylphenol) (PPF) has been studied in a water/acetonitrile (50/50, v/v) mixture by cyclic voltammetry, differential pulse voltammetry and galvanostatic coulometry. The results show that PPF can be electrochemically oxidized in a chemically irreversible one-electron/one-proton process to form the corresponding radical (PPF • ) which couples to yield propofol dimer (PD). Due to the easier oxidation of PD compared to PPF, the PD is oxidized in a reversible two-electron/two-proton process to form 3,3′,5,5′-tetraisopropyl-[1,1′-bi(cyclohexylidene)]-2,2′,5,5′-tetraene-4,4′-dione (PDQ). We call this mechanism EDE for simplicity, where E represents an electron transfer at an electrode surface and D represents a homogeneous dimerization step. We also investigated the catalytic effect of sulfite ions on the oxidation of PPF and found strong evidence to support it. The electrochemical synthesis of PDQ was successfully carried out directly using drug samples or by using commercial samples of PPF in the presence of sodium sulfite as a catalyst. The electrochemical dimerization of PPF is carried out under mild conditions at room temperature and atmospheric pressure in an undivided cell using carbon anode and stainless steel cathode, using the electrode as an electron source instead of toxic oxidants, under greener conditions.

Arc self-association and formation of virus-like capsids are mediated by an N-terminal helical coil motif.

Activity-regulated cytoskeleton-associated protein (Arc) is a protein interaction hub with diverse roles in intracellular neuronal signaling, and important functions in neuronal synaptic plasticity, memory, and postnatal cortical development. Arc has homology to retroviral Gag protein and is capable of self-assembly into virus-like capsids implicated in the intercellular transfer of RNA. However, the molecular basis of Arc self-association and capsid formation is largely unknown. Here, we identified a 28-amino-acid stretch in the mammalian Arc N-terminal (NT) domain that is necessary and sufficient for self-association. Within this region, we identified a 7-residue oligomerization motif, critical for the formation of virus-like capsids. Purified wild-type Arc formed capsids as shown by transmission and cryo-electron microscopy, whereas mutant Arc with disruption of the oligomerization motif formed homogenous dimers. An atomic-resolution crystal structure of the oligomerization region peptide demonstrated an antiparallel coiled-coil interface, strongly supporting NT-NT domain interactions in Arc oligomerization. The NT coil-coil interaction was also validated in live neurons using fluorescence lifetime FRET imaging, and mutation of the oligomerization motif disrupted Arc-facilitated endocytosis. Furthermore, using single-molecule photobleaching, we show that Arc mRNA greatly enhances higher-order oligomerization in a manner dependent on the oligomerization motif. In conclusion, a helical coil in the Arc NT domain supports self-association above the dimer stage, mRNA-induced oligomerization, and formation of virus-like capsids. DATABASE: The coordinates and structure factors for crystallographic analysis of the oligomerization region were deposited at the Protein Data Bank with the entry code 6YTU.

Intriguing Radical–Radical Interactions in Doubly Reduced Dimers: Cytosine Anion Radical versus Hydrogenated Cytosine Radical

In the present work, we computationally investigate a series of the homogeneous and heterogeneous base dimers of the reduced cytosine (single-electron-reduced C•– and 5/6/3-site hydrogenated CH5•/C...

Effect of surface interactions on spin contamination errors of homogeneous spin dimers, chains, and films: model calculations of Au/MgO and Au/BaO systems

It is well known that unrestricted density functional theory (UDFT) calculations include spin contamination errors. While errors in UDFT/plane-wave calculations have not been clarified thus far, some effects of these errors are investigated. Recently, our group estimated spin contamination errors in UDFT/plane-wave calculation results by developing and applying the approximate spin projection (AP) scheme [Chem. Phys. Lett., 701: 103 (2018), Mol. Phys., 117: 2251 (2019), Molecules, 24: 505 (2019), Appl. Phys. Express, 12: 115506 (2019)]. In this study, a systematic theoretical investigation of the surface effects on the spin contamination error was performed. For this purpose, we selected model systems such as Au dimers, chains, and film adsorptions onto MgO and BaO (001) surfaces. The calculation results showed the dependence on the dimensions of the supported materials and lattice constants of the supports. In general, the effects of spin contamination errors are decreased by interaction with the surface. The effects of the errors increased by increasing dimension; i.e. the increasing order of spin contamination errors is film > chain > dimer. In addition, the spin-polarised states are stabilised because of the interaction with the surfaces, and spin contamination errors occur in some cases where the Au–Au distances are small.

Combined Experimental and Theoretical Studies on the Prediction of the Isobaric Vapor–Liquid Association Phenomena for Binary and Ternary Mixtures of Water, Ethanoic Acid, and Propanoic Acid

It is a considerable challenge for the phase behavior of chemical separation industry to correlate and predict the vapor–liquid equilibria (VLE) data of the binary and ternary systems containing associating components because it is not known how these forms exist in the experimental condition, such as homogeneous or heterogeneous dimers or trimers, even polymers, and so on. Herein, VLE data for the associating ternary system, water + ethanoic acid + propanoic acid, and the three-constituent binary systems have been measured by different liquid-phase compositions using a Fischer ebulliometer at 101.33 kPa. The structures and distribution of various clusters in water, ethanoic acid, and propanoic acid systems were fully optimized at the B3LYP/6-31+G(d) level of theory using Gaussian 09. Then, we developed a strategy that could calculate the liquid activity coefficients by considering the distribution of the associating components in the strong association systems. This method is called the discrete clusters (DC) model, and, for comparison, Wilson, NRTL, and UNIQUAC models were employed to correlate the VLE data for the three-constituent binary systems. Also, the VLE data of the ternary system were estimated from the DC, Wilson, NRTL, and UNIQUAC models without any additional adjustment. Our DC model, which considered the explicit number of various clusters, showed better agreement and a smaller deviation from the experimental data. These VLE data derived from the DC model can be used for the design and simulation of the distillation behavior of the binary and ternary association systems.

Non resonant Raman spectra of homogeneous and inhomogeneous individual dimers of Single-walled Carbon Nanotubes (SWNTs)

We study the effects of the coupling between single-walled carbon nanotubes (SWNTs) on the phonons in homogeneous (identical nanotubes) and inhomogeneous (different nanotubes) dimers of SWNTs. Bond polarization theory and the spectral moments method (SMM) are used to calculate the non-resonant Raman frequencies of the breathing-like modes (BLMs) and tangential-like ones (TLMs). The dependence of the phonons on different structural parameters such as diameter and chirality is investigated. We focus on the dependence of the so-called Breathing-Like Modes (BLMs) of dimers originating from the van der Waals coupling of the Radial Breathing Modes (RBMs) of each individual tube forming the dimer. On the other hand, the TLM of dimer is reported and discussed. Distinct behaviors of the TLM are evidenced. The calculated of spectra are compared with the few experimental Raman data obtained on individual dimers.

Di(imino)pyridine Complexes as Catalysts for Homogeneous Olefin Oligomerization Reactions

The synthesis of bis(arylimino)pyridine complexes of seven different transition metals and their applications after activation with methylaluminoxane (MAO) in homogeneous olefin dimerization and oligomerization reactions is described. The synthesis of bis(arylimino)pyridine ligand precursors was achieved via condensation reactions of 2,6-diacetylpyridine with different substituted anilines. The bis(arylimino)pyridine compounds were reacted with 3d transition metal halides of the metals Ti, V, Cr, Mn, Fe, Ni and Co to give the corresponding mono-ligated complexes. Among a series of complexes with varying metal centers, but containing the same ligand, the bis(arylimino)pyridine iron(III) complex provided the best results for the dimerization of 1-hexene after activation with MAO. Beside linear products, methyl branched olefins were detected as well. For all product compositions, a marginal higher amount of hexene dimers was observed, e.g. the insertion of 1-hexene proceeds slightly faster than the insertion of 1-pentene.

Simple and rapid method for homogeneous dimer formation of gold nanoparticles in a bulk suspension based on van der Waals interactions between alkyl chains

We developed a simple and rapid method for dimer and higher multimer formation of gold nanoparticles (AuNPs) in bulk suspension. A coupling of AuNPs modified with COOH-terminated alkanethiol by van-der-Waals interaction between alkyl chains was employed. We demonstrated the tunability of the interparticle gap by changing the alkyl chain length from C5 to C15. Efficient dimer formation that avoids unwanted aggregation was demonstrated for AuNPs with a diameter ranging from 20 nm to 80 nm. For all cases, we found that the interparticle gap is well-defined and uniform. For the shortest alkyl chain (C5), we achieved an interparticle gap as small as 1.0 nm.

Exploration of Homogeneous Ethylene Dimerization Mediated by Tungsten Mono(imido) Complexes

In combination with EtAlCl2, complexes {[WCl3(μ-Cl)(N-2,6-iPr2C6H3)]2}, [WCl4(NR)(thf)] (R = Et, iPr, cHx, Ph, 2,6-iPr2C6H3, 4-F-C6H4, and 2,4,6-F3-C6H2), and [WCl2(NR′)(PMe3)3] (R′ = Ph, 2,6-iPr2C...