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Electrochemical methods for nitrogen reduction have received extensive attention due to the mild reaction conditions. In order to gain an insight into the mechanism of the electrochemical nitrogen reduction process, theoretical simulations are necessary. However, current simulation studies contain many imprecise approximations that may hinder the real recognition of the reaction process. Although solvation methods have recently been developed to provide efficient descriptions, their further applications are hindered by controversy over modeling of solvents and the enormous computational effort required. In this work, we simplify the solvation conditions by using water clusters and compare them with an accurate water layer model. The results demonstrate that the simplified water clusters can effectively capture protons, simulate the surface electric environment, and enable the calculation of the activation energy of the reaction. This method offers an affordable approach for simulating the surface potentials and solvents and provides a new reference for the theoretical study of the electrochemical nitrogen reduction reaction. [ABSTRACT FROM AUTHOR]

Unlike one-dimensional polymers, the theoretical framework on the behaviors of two-dimensional (2D) polymers is far from completeness. In this study, we model single-layer flexible 2D polymers of different sizes and examine their scaling behaviors in solution, represented by Rg ∼ Lν, where Rg is the radius of gyration and L is the side length of a 2D polymer. We find that the scaling exponent ν is 0.96 for a good solvent and 0.64 for under poor solvent condition. Interestingly, we observe a previously unnoticed phenomenon: under intermediate solvent conditions, the 2D polymer folds to maintain a flat structure, and as L becomes larger, multiple folded structures emerge. We introduce a shape parameter Q to diagram the relationship of folded structures with the polymer size and solvent condition. Theoretically, we explain the folding transitions by the competition between bending and solvophobic free energies. [ABSTRACT FROM AUTHOR]

Gas-phase molecules are a promising platform to elucidate the mechanisms of action and scope of polaritons for optical control of chemistry. Polaritons arise from the strong coupling of a dipole-allowed molecular transition with the photonic mode of an optical cavity. There is mounting evidence of modified reactivity under polaritonic conditions; however, the complex condensed-phase environment of most experimental demonstrations impedes mechanistic understanding of this phenomenon. While the gas phase was the playground of early efforts in atomic cavity quantum electrodynamics, we have only recently demonstrated the formation of molecular polaritons under these conditions. Studying the reactivity of isolated gas-phase molecules under strong coupling would eliminate solvent interactions and enable quantum state resolution of reaction progress. In this Perspective, we contextualize recent gas-phase efforts in the field of polariton chemistry and offer a practical guide for experimental design moving forward. [ABSTRACT FROM AUTHOR]

Aqueous mixtures of deep eutectic solvents (DESs) have emerged as a subject of interest in recent years for their tailored physicochemical properties. However, a comprehensive understanding of water's multifaceted influence on the microscopic dynamics, including its impact on improved transport properties of the DES, remains elusive. Additionally, the diffusion mechanisms within DESs manifest heterogeneous behavior, intricately tied to the formation and dissociation kinetics of complexes and hydrogen bonds. Therefore, it is imperative to explore the intricate interplay between bond kinetics, diffusion mechanism, and dynamical heterogeneity. This work employs water as an agent to explore their relationships by studying various relaxation phenomena in a DES based on acetamide and lithium perchlorate over a wide range of water concentrations. Notably, acetamide exhibits Fickian yet non-Gaussian diffusion across all water concentrations with Fickian ( τ f ) and Gaussian ( τ g ) timescales following a power-law relationship, τ g ∝ τ f γ , γ ∼ 1.4. The strength of coupling between bond kinetics and different diffusion timescales is estimated through various power-law relationships. Notably, acetamide–water hydrogen bond lifetime is linked to diffusive timescales through a single power-law over the entire water concentration studied. However, the relationship between diffusive timescales and the lifetime of acetamide–lithium complexes shows a sharp transition in behavior at 20 wt. % water, reflecting a change from vehicular diffusion below this concentration to structural diffusion above it. Our findings emphasize the critical importance of understanding bond dynamics within DESs, as they closely correlate with and regulate the molecular diffusion processes within these systems. [ABSTRACT FROM AUTHOR]

The solvent effect on H-BEA catalyzed cyclohexanol dehydration was investigated in water, dioxane, and cyclohexanol. The dynamic evolution of the Brønsted acid site of zeolite and its interaction with reactant molecules in different solvents were explored with ab initio molecular dynamics simulations, providing reliable configuration sampling to obtain configurations at equilibrium. Solvent profoundly changes the adsorption as well as the dehydration reaction of cyclohexanol in H-BEA, where the reaction is determined to follow the E2 mechanism in water and dioxane but the E1 mechanism in cyclohexanol untill saturation uptake. Near saturation uptake, all three solvents significantly reduce the cyclohexanol dehydration rates in H-BEA. Cyclohexanol loading also dramatically affects the kinetics of the dehydration reaction, displaying an overall decreasing trend with a local minimum present at intermediate loading of 6 molecules per unit cell, which is a result of the entropic effect associated with greater freedom of motion of the transition state. Rigorous quantification of enthalpy and entropy contributions to cyclohexanol adsorption and activation shed light on the solvent effect of zeolite-catalyzed alcohol dehydration. [ABSTRACT FROM AUTHOR]

We discuss key parameters that affect the reliability of hybrid simulations in the aqueous phase based on an efficient multi-scale coarse-grained polarizable pseudo-particle approach, denoted as pppl, to model the solvent water, whereas solutes are modeled using an all atom polarizable force field. Among those parameters, the extension of the solvent domain (SD) at the solute vicinity (domain in which each solvent particle corresponds to a single water molecule) and the magnitude of solute/solvent short range polarization damping effects are shown to be pivotal to model NaCl salty aqueous solutions and the hydration of charged systems, such as the hydrophobic polyelectrolyte polymer that we have recently investigated [Masella et al., J. Chem. Phys. 155, 114903 (2021)]. Strong short range damping is pivotal to simulate aqueous salt NaCl solutions at moderate concentration (up to 1.0M). The SD extension (as well as short range damping) has a weak effect on the polymer conformation; however, it plays a pivotal role in computing accurate polymer/solvent interaction energies. As the pppl approach is up to two orders of magnitude computationally more efficient than all atom polarizable force field methods, our results show it to be an efficient alternative route to investigate the equilibrium properties of complex charged molecular systems in extended chemical environments. [ABSTRACT FROM AUTHOR]

The celebrated generalized Stokes law predicts that the velocity of a particle pulled through a liquid by an external force, Fex, is directly proportional to the force and inversely proportional to the friction ζ acted by the medium on the particle. We investigate the range of validity of the generalized Stokes law at molecular length scales by employing computer simulations to calculate friction by pulling a tagged particle with a constant force. We thus calculate friction for two model interaction potentials, Lennard-Jones and soft sphere, for several particle sizes, ranging from radius (a) smaller than the solvent particles to three times larger. We next obtain friction from diffusion (D) by using Einstein's relation between diffusion and friction ζ in an unperturbed liquid. We find a quantitative agreement between the two at a small-to-intermediate pulling force regime for all the sizes studied. The law does break down at a large pulling force beyond a threshold value. Importantly, the range of validity of Stokes' scheme to obtain friction increases substantially if we turn off the attractive part of the interaction potential. Additionally, we calculate the viscosity (η) of the unperturbed liquid and find a good agreement with the Stokes–Einstein relation ζ = Cηa for the viscosity dependence with a value of C close to 5 π, which is intermediate between the slip and stick boundary condition. [ABSTRACT FROM AUTHOR]

The multiparticle collision dynamics (MPCD) simulation method is an attractive technique for studying the effects of hydrodynamic interactions in colloidal suspensions because of its flexibility, computational efficiency, and ease of implementation. Here, we analyze an extension of the basic MPCD method in which colloidal particles are discretized with a surface mesh of sensor nodes/particles that interact with solvent particles (MPCD + Discrete Particle or MPCD + DP). We use several situations that have been described analytically to probe the impact of colloidal particle mesh resolution on the ability of the MPCD + DP method to resolve short-ranged hydrodynamic interactions, which are important in crowded suspensions and especially in self-assembling systems that create high volume fraction phases. Specifically, we consider (A) hard-sphere diffusion near a wall, (B) two-particle diffusion, (C) hard-sphere diffusion in crowded suspensions, and (D) the dynamics of aggregation in an attractive colloidal suspension. We show that in each case, the density of sensor nodes plays a significant role in the accuracy of the simulation and that a surprisingly high number of surface nodes are needed to fully capture hydrodynamic interactions. [ABSTRACT FROM AUTHOR]

Identifying the stable surface phases under a given electrochemical conditions serves as the basis for studying the atomistic mechanism of reactions at solid/water interfaces. In this work, we systematically compare the performance of the two main approaches that are used to capture the impact of an aqueous environment, implicit and explicit solvent, on surface energies and phase diagrams. As a model system, we consider the magnesium/water interface with (i) Ca substitution and (ii) proton and hydroxyl adsorption. We show that while the implicit solvent model is computationally very efficient, it suffers from two shortcomings. First, the choice of the implicit solvent parameters significantly influences the energy landscape in the vicinity of the surface. The default parameters benchmarked on solvation in water underestimate the energy of the dissolved Mg ion and lead to spontaneous dissolution of the surface atom, resulting in large differences in the surface energetics. Second, in systems containing a charged surface and a solvated ion, the implicit solvent model may not converge to the energetically stable ionic charge state but remain in a high-energy metastable configuration, representing the neutral charge state of the ion. When these two issues are addressed, surface phase diagrams that closely match the explicit water results can be obtained. This makes the implicit solvent model highly attractive as a computationally-efficient surrogate model to compute surface energies and phase diagrams. [ABSTRACT FROM AUTHOR]

The technological landscape for industrial processes handling asphaltene is evolving at a rapid pace due to the increase in the extraction of heavy crude oil. The main underlying challenges in this regard are the flow assurance, the recovery of the spent solvent, and the sophisticated extractor setup required to develop the process to an industrial scale. The number of studies focused on the handling of the asphaltene at the atomic and molecular scales is growing enormously in order to identify new sustainable solvents for the effective extraction of asphaltene from heavy crude oil or oil-bearing sands. This Perspective focuses on the importance of density functional theory and molecular dynamics simulations to explore the broader range of asphaltene inhibitors, e.g., nanoparticles, ionic liquids, and deep eutectic solvents, to prevent asphaltene precipitation. We provide a concise overview of the major accomplishments, analyze the aspects that require attention, and highlight the path-breaking studies having a significant impact on the process of chemical enhanced oil recovery from heavy crude oil reservoirs primarily based on atomistic and molecular simulations. [ABSTRACT FROM AUTHOR]

We theoretically investigate homogeneous crystal nucleation in a solution containing a solute and a volatile solvent. The solvent evaporates from the solution, thereby continuously increasing the concentration of the solute. We view it as an idealized model for the far-out-of-equilibrium conditions present during the liquid-state manufacturing of organic electronic devices. Our model is based on classical nucleation theory, taking the solvent to be a source of the transient conditions in which the solute drops out of the solution. Other than that, the solvent is not directly involved in the nucleation process itself. We approximately solve the kinetic master equations using a combination of Laplace transforms and singular perturbation theory, providing an analytical expression for the nucleation flux. Our results predict that (i) the nucleation flux lags slightly behind a commonly used quasi-steady-state approximation. This effect is governed by two counteracting effects originating from solvent evaporation: while a faster evaporation rate results in an increasingly larger influence of the lag time on the nucleation flux, this lag time itself is found to decrease with increasing evaporation rate. Moreover, we find that (ii) the nucleation flux and the quasi-steady-state nucleation flux are never identical, except trivially in the stationary limit, and (iii) the initial induction period of the nucleation flux, which we characterize as a generalized induction time, decreases weakly with the evaporation rate. This indicates that the relevant time scale for nucleation also decreases with an increasing evaporation rate. Our analytical theory compares favorably with results from a numerical evaluation of the governing kinetic equations. [ABSTRACT FROM AUTHOR]

The hydrophilic pore morphology and solvent diffusion within model (amphiphilic) polymer membranes are simulated by dissipative particle dynamics (DPD). The polymers are composed of a backbone of 18 covalently bonded A beads to which at regular intervals side chains are attached. The side chains are composed of linear Ap chains (i.e., –A1–A2...Ap) from which two branches, [AsC] and [ArC], split off (s ≤ r). C beads serve as functionalized hydrophilic pendent sites. The branch lengths (s + 1 and r + 1) are varied. Five repeat unit designs (with general formula A3[Ap[AsC][ArC]]) are considered: A2[A3C][A3C] (symmetric branching), A2[A2C][A4C], A2[AC][A5C], A2[C][A6C] (highly asymmetric branching), and A4[AC][A3C]. The distribution of water (W) and W diffusion through nanophase segregated hydrophilic pores is studied. For similar primary length p, an increase in side chain symmetry favors hydrophilic pore connectivity and long-range water transport. C beads located on the longer [ArC] branches reveal the highest C bead mobility and are more strongly associated with water than the C beads on the shorter [AsC] branches. The connectivity of hydrophilic (W and W + C) phases through mapped replica of selected snapshots obtained from Monte Carlo tracer diffusion simulations is in line with trends found from the W bead diffusivities during DPD simulations. The diffusive pathways for protons (H+) in proton exchange membranes and for hydronium (OH−) in anion exchange membranes are the same as for solvents. Therefore, control of the side chain architecture is an interesting design parameter for optimizing membrane conductivities. [ABSTRACT FROM AUTHOR]

Glass formation and reorientational motions are widespread but often-neglected features of deep eutectic solvents although both can be relevant for the technically important ionic conductivity at room temperature. Here, we investigate these properties for two mixtures of ethylene glycol and ZnCl2, which were recently considered superior electrolyte materials for application in zinc-ion batteries. For this purpose, we employed dielectric spectroscopy performed in a broad temperature range, extending from the supercooled state at low temperatures up to the liquid phase around room temperature and beyond. We find evidence for a relaxation process arising from dipolar reorientation dynamics, which reveals the clear signatures of glassy freezing. This freezing also governs the temperature dependence of the ionic dc conductivity. We compare the obtained results with those for deep eutectic solvents that are formed by the same hydrogen-bond donor, ethylene glycol, but by two different salts, choline chloride and lithium triflate. The four materials reveal significantly different ionic and reorientational dynamics. Moreover, we find varying degrees of decoupling of rotational dipolar and translational ionic motions, which can partly be described by a fractional Debye–Stokes–Einstein relation. The typical glass-forming properties of these solvents strongly affect their room-temperature conductivity. [ABSTRACT FROM AUTHOR]

BackgroundMaternal solvent exposure has been suspected to increase offspring cancer risk. The study aimed to evaluate the associations between maternal residential exposure to solvents from industrial pollution during pregnancy and childhood cancer.MethodsThe present study included 15,744 cancer cases (aged 0-19 years at diagnosis) identified from California Cancer Registry and 283,141 controls randomly selected from California Birth Registry (20:1 frequency-matched by birth year: 1998-2016). We examined industrial releases of tetrachloroethylene and 1,1,1-trichloroethane within 3 km of the birth address, while we used a 5 km buffer for carbon disulfide. We calculated the total exposure from all linked Toxic Release Inventory sites during each index pregnancy and assigned "ever/never" and "high/low exposed/unexposed" exposure, using median values. We performed quadratic decay models to estimate cancer risks associated with maternal solvent exposure in pregnancy.Results1,1,1-Trichloroethane was associated with rhabdomyosarcoma (adjusted Odds Ratio (aOR): 1.96; 95% Confidence Interval (CI): 1.16, 3.32) in the "ever exposed" group. Ever exposure to carbon disulfide was associated with increased risks of medulloblastoma (OR = 1.85, 95% CI 1.01, 3.40) and ependymoma (OR = 1.63, 95% CI 0.97, 2.74).ConclusionsOverall, our findings suggested maternal residential exposure to solvents from industrial sources might be associated with elevated childhood cancer risks.

The genus Clostridium is a large and diverse group within the Bacillota (formerly Firmicutes), whose members can encode useful complex traits such as solvent production, gas-fermentation, and lignocellulose breakdown. We describe 270 genome sequences of solventogenic clostridia from a comprehensive industrial strain collection assembled by Professor David Jones that includes 194 C. beijerinckii, 57 C. saccharobutylicum, 4 C. saccharoperbutylacetonicum, 5 C. butyricum, 7 C. acetobutylicum, and 3 C. tetanomorphum genomes. We report methods, analyses and characterization for phylogeny, key attributes, core biosynthetic genes, secondary metabolites, plasmids, prophage/CRISPR diversity, cellulosomes and quorum sensing for the 6 species. The expanded genomic data described here will facilitate engineering of solvent-producing clostridia as well as non-model microorganisms with innately desirable traits. Sequences could be applied in conventional platform biocatalysts such as yeast or Escherichia coli for enhanced chemical production. Recently, gene sequences from this collection were used to engineer Clostridium autoethanogenum, a gas-fermenting autotrophic acetogen, for continuous acetone or isopropanol production, as well as butanol, butanoic acid, hexanol and hexanoic acid production.

Cytoskeletal gels are engineered prototypes that mimic the contractile behavior of a cell in vitro. They are composed of an active polymer matrix and a liquid solvent. Their contraction kinetics is governed by two dynamic phenomena: mechanotransduction (molecular motor activation) and solvent diffusion. In this paper, we solve the transient problem for the simple case of a thin gel slab in uniaxial contraction under two extreme conditions: motor-limited or slow motor (SM) activation regime, and diffusion-limited or fast motor (FM) activation regime. The former occurs when diffusion is much faster than mechanotransduction, while the latter occurs in the opposite case. We observe that in the SM regime, the contraction time scales as t / t 0 ∼ (λ / λ 0) − 3 , with t 0 being the nominal contraction time, and λ and λ 0 being the final and initial stretches of the slab. t 0 is proportional to 1 / w ˙ , where w ˙ is the average mechanical power generated by the molecular motors per unit reference (dry polymer) volume. In the FM regime, the contraction time scales as t / t 1 ∼ (1 − λ / λ 0) 2 , with t 1 being the nominal contraction time, here proportional to the ratio L 2 / D , where L is the reference (dry polymer) thickness, and D is the diffusivity of the solvent in the gel. The transition between the SM and FM regimes is defined by a characteristic power density w ˙ ∗ , where w ˙ ≪ w ˙ ∗ gives the SM regime and w ˙ ≫ w ˙ ∗ gives the FM regime. Intuitively, w ˙ ∗ is proportional to D / L 2 , where, at a given power density w ˙ , a thinner gel slab (smaller L) or including smaller solvent molecules (higher D) is more likely to be in the SM regime given that solvent diffusion will occur faster than motor activation. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs) emerged as potential alternative solvent media in multiple areas, including biomolecular (cryo)preservation. Herein, we studied the stability of a small protein (ubiquitin) in water and a betaine-glycerol-water (B:G:W) (1:2:ζ; ζ = 0, 1, 2, 5, 10) DES, through molecular dynamics. An AMBER-based model that accurately describes the density and shear viscosity of the DES is proposed. We find that water molecules are largely trapped in the solvent, precluding the formation of a full hydration layer, seemingly opposite to osmolytes' preferential exclusion/preferential hydration mechanism. Although the protein is stable in the DES, structural fluctuations are largely suppressed and only recovered upon sufficient hydration. This is explained by a solvent-slaving mechanism where β-fluctuations are key, with the non-monotonic hydration of some amino acids with the water content providing an explanation to the non-monotonic folding of some proteins in aqueous DESs. A major thermal stability enhancement in the DES is also observed, caused by a similar slowdown of the backbone torsional dynamics. Our results support a kinetic stabilization of the protein in the DES, whereas a possible thermodynamic stabilization does not follow a preferential hydration or water entrapment mechanism. [ABSTRACT FROM AUTHOR]

For photosensitive polyurethane systems, reactive diluents are indispensable components whose main role is to reduce the viscosity of the polyurethane prepolymer to meet the requirements of the photocurable 3D printing technology for high fluidity of the precursor solution. Generally, the reactive diluent would be involved in the photocuring reaction, which in turn has a remarkable impact on the mechanical, reaction kinetics, and thermodynamic characteristics of the photosensitive polyurethane system. However, this feature is usually neglected in the study of photosensitive urethane acrylate (PUA) systems, so there is a considerable necessity to investigate the mechanism of active diluents in the photocured reaction of PUA systems. In this work, the effects of α-methyl groups along the chains of diluent molecules on the photoreaction kinetics, photocurable 3D printing, mechanical and mechanical properties, and thermodynamic characteristics of PUAs were investigated employing hydroxyethyl methacrylate and hydroxyethyl acrylate as active diluents, respectively. The relationship between chemical structure and kinetics of PUA systems was also elucidated by using dynamic mechanical analysis tests. The results demonstrated that the α-methyl group blocks the migration of reactive radicals, reduces the efficiency of the photoreaction, and causes an increase in the rigidity and strength of the molecular chain. This study not only revealed the effect of α-methyl on the kinetic mechanical and thermal performance of PUA systems but also paves the way for the development of a new class of photosensitive PUA materials used for the photocurable 3D printing technology. [ABSTRACT FROM AUTHOR]

The Adaptive Solvent-Scaling (AdSoS) scheme [J. Chem. Phys. 155 (2021) 094107] is an adaptive-resolution approach for performing simulations of a solute embedded in a fine-grained (FG) solvent region surrounded by a coarse-grained (CG) solvent region, with a continuous FG ↔ CG switching of the solvent resolution across a buffer layer. Instead of relying on a distinct CG solvent model, AdSoS is based on CG models defined by a dimensional scaling of the FG solvent by a factor s, accompanied by the s-dependent modulation of its mass and interaction parameters. The latter changes are designed to achieve an isomorphism between the dynamics of the FG and CG models, and to preserve the dispersive and dielectric solvation properties of the solvent with respect to a solute at FG resolution. As a result, the AdSoS scheme minimizes the thermodynamic mismatch between different regions of the adaptive-resolution system. The present article generalizes the scheme initially introduced for a pure atomic liquid in slab geometry to more practically relevant situations involving (i) a molecular dipolar solvent (e.g., water); (ii) a radial geometry (i.e., spherical rather than planar layers); and (iii) the inclusion of a solute (e.g., water molecule, dipeptide, ion, or ion pair). [ABSTRACT FROM AUTHOR]

We have studied diffusion and thermodiffusion in the ternary system polystyrene + toluene + cyclohexane over the entire composition range of the binary solvent toluene + cyclohexane and for polymer concentrations up to 0.1 mass fractions by multi-color optical beam deflection. The polystyrene molar masses were 4.88 and 17.90 kg/mol. The inversion problem of the contrast factor matrix could be avoided by reasonable a priori assumptions about the diffusion eigenvectors. The fast mode of the bimodal dynamics is attributed to the interdiffusion of the two solvents at constant polymer concentration, whereas the slow mode is due to the diffusion of the polymer with respect to the binary solvent. The amplitude of the fast mode vanishes in the pure toluene and the pure cyclohexane limits of the mixed solvent. The amplitude of the slow mode increases with polymer concentration. The composition and temperature dependence of the slow diffusion eigenvalue, the hydrodynamic correlation length, and the Soret coefficient of the polymer reflect the transition from a good to a theta solvent with increasing cyclohexane content and with decreasing temperature. Due to cross diffusion, cyclohexane reverses its migration direction between the fast and the slow mode, leading to a positive thermodiffusion but a negative Soret coefficient. The polymer thermodiffusion coefficients during the slow mode vary by approximately a factor of two, depending on the solvent composition. Rescaling with the solvent viscosity collapses all data onto a single master curve with an extrapolated value of ηDT ≈ 6 × 10−15 Pa m2 K−1 in the dilute limit. This value is well known from various other binary polymer/solvent mixtures. [ABSTRACT FROM AUTHOR]

Polariton chemistry may provide a new means to control molecular reactivity, permitting remote, reversible modification of reaction energetics, kinetics, and product yields. A considerable body of experimental and theoretical work has already demonstrated that strong coupling between a molecular vibrational mode and the confined electromagnetic field of an optical cavity can alter chemical reactivity without external illumination. However, the mechanisms underlying cavity-altered chemistry remain unclear in large part because the experimental systems examined previously are too complex for detailed analysis of their reaction dynamics. Here, we experimentally investigate photolysis-induced reactions of cyanide radicals with strongly-coupled chloroform (CHCl3) solvent molecules and examine the intracavity rates of photofragment recombination, solvent complexation, and hydrogen abstraction. We use a microfluidic optical cavity fitted with dichroic mirrors to facilitate vibrational strong coupling (VSC) of the C–H stretching mode of CHCl3 while simultaneously permitting optical access at visible wavelengths. Ultrafast transient absorption experiments performed with cavities tuned on- and off-resonance reveal that VSC of the CHCl3 C–H stretching transition does not significantly modify any measured rate constants, including those associated with the hydrogen abstraction reaction. This work represents, to the best of our knowledge, the first experimental study of an elementary bimolecular reaction under VSC. We discuss how the conspicuous absence of cavity-altered effects in this system may provide insights into the mechanisms of modified ground state reactivity under VSC and help bridge the divide between experimental results and theoretical predictions in vibrational polariton chemistry. [ABSTRACT FROM AUTHOR]

Absorption spectra of the solvatochromic dye 2,6-diphenyl-4-2,4,6-triphenyl-1-pyridinophenolate (B30) were measured in seven solvents of varying polarity over temperature ranging from each solvent's freezing point to 300 K. The excitation energies and their variances allowed calculations of the solvent reorganization energies, reorganization free energies and reorganization entropies as functions of temperature. The entropies of solvent packing around the chromophore are found to make major contributions to the reorganization free energies. The variances of the excitation energies depend only weakly on temperature, in disagreement with an expression that is often used for solvent reorganization free energies. Polar solvents reduce the transition dipole strength of B30's long-wavelength absorption band, probably because interactions with the solvent enhance the charge-transfer character of the transition. The dipole strength drops further at low temperatures. [ABSTRACT FROM AUTHOR]

Intramolecular electron transfer between two biphenyl groups linked by an androstane spacer and excitation of the pyridinium-N-phenolate betaine dye B30 to the first excited singlet state are studied by quantum/classical molecular-dynamics simulations at temperatures between 150 and 300 K in solvents with a range of polarities. Temperature dependences of the solvent reorganization energies, free energies, entropies, and the inhomogeneous broadening of B30's absorption band are examined. The variances of fluctuations of the energy gap between the reactant and product states do not have the direct proportionality to temperature that often is assumed to hold. An explanation for the observations is suggested. [ABSTRACT FROM AUTHOR]

The aluminum ion battery (AIB) is a promising technology, but there is a lack of understanding of the desired nature of the batteries' electrolytes. The ionic charge carriers in these batteries are not simply Al3+ ions but the anionic AlCl4− and Al2Cl7−, which form in the electrolyte. Using computational analysis, this study illustrates the effect of mole ratios and organic solvents to improve the AIB electrolytes. To this end, molecular dynamics simulations were conducted on varying ratios forming acidic, neutral, and basic mixtures of the AlCl3 salt with 1-ethyl-3-methylimidazolium chloride (EMImCl) ionic liquid (IL) and an organic solvent electrolyte [dichloromethane (DCM) or toluene]. The data obtained from diffusion calculations indicates that the solvents could improve the transport properties. Both DCM and toluene lead to higher diffusion coefficients, and higher conductivity. Detailed calculations demonstrated solvents can effectively improve the formation of AlCl3⋯Cl (AlCl4−) and AlCl4−···AlCl4− (Al2Cl7−) especially in acidic mixtures. The densities, around 1.25 g/cm3 for electrolyte mixtures of AlCl3-EMImCl, were consistent with experiment. These results, in agreement with experimental findings, strongly suggest that DCM in acidic media with AlCl3 and EMImCl might provide a promising basis for battery development. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Given the crucial role of film morphology in determining the photovoltaic parameters of organic solar cells (OSCs), solvent or solid additives have been widely used to realize fine‐tuned film morphological features to further improve the performance of OSCs. However, most high‐performance OSCs are processed only using single component additive, either solvent additive or solid additive. Herein, a simple molecular building block, namely thieno[3,4‐b]thiophene (TT), was utilized as the solid additive to coordinate with the widely used solvent additive, 1‐chloronaphthalene (CN), to modulate the film morphology. Systematical investigations revealed that the addition of TT could prevent the excessive aggregation to form a delicate nanoscale phase separation, leading to enhanced charge transport and suppressed charge recombination, as well as superior photovoltaic performance. Consequently, the PM6:Y6 based OSCs with the addition of hybrid additive of CN + TT demonstrated the optimal PCE of 18.52%, with a notable FF of 79.6%. More impressively, the PM6:Y6:PC71BM based ternary OSCs treated with the hybrid additives delivered a remarkable efficiency of 19.05%, which ranks among the best values of Y6‐based OSCs reported so far. This work highlights the importance of the hybrid additive strategy in regulating the active layer morphology towards significantly improved performance. [ABSTRACT FROM AUTHOR]

The regular solution model is used with Hankinson-Brobst-Thomson (HBT) molar volume correlation for saturates, aromatics, resins and asphaltenes (SARA) fractions for pure crude oils and blends to predict the precipitation of asphaltenes. The parameters of the HBT correlation were tuned with experimental data for SARA fractions densities. At the same temperature and pressure conditions, the precipitation of asphaltenes is greatly influenced by the presence of other compounds. SARA fractions were obtained according with ASTM D2007 using n-heptane as precipitant solvent. The use of average properties for saturates, aromatics and resins and the assumptions made in the model could reproduce precipitation curves for all study cases. Calculations of asphaltene precipitation prediction for pure oils showed an average absolute deviation between 0.12 and 0.69% for oil of Gulf of Mexico and Cold Lake oil, respectively. For blends it showed values between 0.08 and 0.65% for Cold Lake/Lloydminster-Asphaltene free blend and Cold Lake/Lloydminster-Gulf of Mexico blend respectively. The proposed model maintains its simplicity and can predict the asphaltene precipitation accurately. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Given the crucial role of film morphology in determining the photovoltaic parameters of organic solar cells (OSCs), solvent or solid additives have been widely used to realize fine‐tuned film morphological features to further improve the performance of OSCs. However, most high‐performance OSCs are processed only using single component additive, either solvent additive or solid additive. Herein, a simple molecular building block, namely thieno[3,4‐b]thiophene (TT), was utilized as the solid additive to coordinate with the widely used solvent additive, 1‐chloronaphthalene (CN), to modulate the film morphology. Systematical investigations revealed that the addition of TT could prevent the excessive aggregation to form a delicate nanoscale phase separation, leading to enhanced charge transport and suppressed charge recombination, as well as superior photovoltaic performance. Consequently, the PM6:Y6 based OSCs with the addition of hybrid additive of CN + TT demonstrated the optimal PCE of 18.52%, with a notable FF of 79.6%. More impressively, the PM6:Y6:PC71BM based ternary OSCs treated with the hybrid additives delivered a remarkable efficiency of 19.05%, which ranks among the best values of Y6‐based OSCs reported so far. This work highlights the importance of the hybrid additive strategy in regulating the active layer morphology towards significantly improved performance. [ABSTRACT FROM AUTHOR]

Bismuth sulfide, Bi2S3, was prepared by a one-pot reaction using various choline chloride-based deep eutectic solvents (DESs) as the reaction field. Rod-like particles obtained with acetamide–thioacetamide-based DESs were found to exhibit specifically dominant detection properties for H2S gas, and the gas detection mechanism was discussed by adsorption reaction. [ABSTRACT FROM AUTHOR]

PVDF/SiO2 composite films with a hierarchical structure were prepared by water bath solvent exchange and they realized the integration of self-cleaning and radiative cooling. The high scattering properties of SiO2 effectively enhanced the radiative cooling performance of the films, and the weathering stability of the composite films was evaluated by UV radiation treatment and friction resistance analysis. [ABSTRACT FROM AUTHOR]

The effect of temperature, pressure, and specific solvent consumption on extraction yield from Leptocarpha rivularis stalks was studied using a Box–Behnken design. The effect of pressure on extraction yield was the most important, followed by temperature and specific solvent consumption (p ≤ 0.05). The extraction yield correlated (p ≤ 0.05) positively with the CO2 density. A diffusion model adequately described the cumulative extraction curve with the highest yield at the selected extraction condition. The inhibition of linoleic acid oxidation and the inhibition of lipoxygenase enzyme were higher in the supercritical (SC) extract than in the hydroethanolic extract. SC extraction could be used to isolate compounds from L. rivularis stalks with functional value. [ABSTRACT FROM AUTHOR]

Liquid phase microextraction techniques are considered as the miniaturized version of traditional liquid-liquid extraction, which use only several microliters of a proper solvent to extract the analytes from sample. In these methods, the target analytes are migrated into a water-immiscible organic solvent (acceptor phase) from an aqueous sample (donor phase). They are mainly classified into three main groups including (a) single-drop microextraction, (b) dispersive liquid–liquid microextraction, and (c) hollow fiber-liquid phase microextraction. These techniques have been successfully applied to the assessment of different analytes in food samples, pharmaceuticals, beverages, and so on. This review mainly focuses on up-to-date information on the application of liquid phase microextraction techniques in dairy products. The advantages and disadvantages of the developed liquid phase microextraction methods were discussed. [ABSTRACT FROM AUTHOR]

Chirally pure enantiomers of differently protected 7‐azatryptophan derivatives (R‐3c, S‐3c, R‐3i, S‐3i, R‐3m, S‐3m, R‐3aa, and S‐3aa) were synthesized, which showed solvent‐dependent optical rotation. The obtained results not only exhibited changes in the values but also showed the variation in sign (− or +) with the different solvents studied. The change in optical rotation value was essentially attributed to the electron‐donating property, which can be correlated to the donor number of the solvents. There are two types of hydrogen bonds, intramolecular (i.e., form within the structure) and intermolecular (i.e., form with external groups such as solvents). These hydrogen bonds are responsible for the value and sign variations, and 1H NMR experiments were used to further characterize them. The NMR data suggested that hydrogen bond formation is occurring between the Fmoc NH group vicinal to the chiral center and donor group of the corresponding solvent. [ABSTRACT FROM AUTHOR]

The 1H and 13C NMR spectra of the N‐(3,5‐dichloro‐4‐hydroxyphenyl)‐ 2,4,6‐triphenylpyridinium perchlorate and of its deprotonated betaine 4‐(2,4,6‐triphenylpyridinio)‐2,6‐dichlorophenolate (Wolfbeis's ET(33) dye) were recorded in various solvents and analyzed in search of solvent‐dependent shifts that characterize their solvatomagnetism, which was compared with the well‐known UV–vis spectral behavior of this important solvatochromic dye. Although the NMR spectra of ET(33) and its phenolic precursor in different solvents correlated only poorly with their UV–vis spectral responses, they provided valuable information on specific structural features and solute–solvent interactions that are not available from their UV–vis spectra. [ABSTRACT FROM AUTHOR]

Background: Volatile substance use is an increasing public health issue. Previous studies have always focused on adolescents. However, volatile substance use also occurs in young adults, something we often ignore, especially among housewife mothers. Methods and results: Here, we present a 32-year-old housewife mother with two years of inhaling volatile solvents. She was admitted to our unit for dizziness, slurred speech, and increased sleepiness. Magnetic resonance imaging showed broadly abnormal signals in the brain's bilateral corticomedullary junction, thalamus, basal ganglia, and dentate nucleus. Substance use-induced toxic encephalopathy was diagnosed. Conclusions: No previous reports of toxic encephalopathy due to volatile solvents use in housewife mothers have been made. Awareness of the risks associated with volatile solvents use in housewife mothers is necessary. [ABSTRACT FROM AUTHOR]

Purpose: The study aimed to explore different extraction methods, extraction solvents, as well as solvent/water mixtures that could potentially yield(s) the best growth-enhancing, yield- and qualitypromoting effects of Moringa oleifera leaf extracts (MLEs), when applied foliarly to tomatoes and peppers. Research Method: This study was laid out following a complete randomized design with three replications. Foliar application of MLEs tested included: control, aqueous (hot water, MLE HW), aqueous (cold water, MLE CW), ethanolic (MLE ETH) and methanolic (MLE METH) extracts. These treatments were repeatedly sprayed onto the leaves of selected plants, from two weeks after transplanting in weekly intervals until fruit set. Findings: Foliar application of all MLEs significantly enhanced growth of both pepper and tomato plants compared with the control. MLE HW application positively affected yield parameters, followed by MLE ETH and MLE METH. All MLEs significantly enhanced the colour coordinate a* and TSS, excluding MLE CW. Carotenoids in red peppers were significantly higher, following all MLE treatments, excluding the MLE CW, while in red tomatoes MLEs enhanced lycopene and ß-carotene content. The concentration of Vitamin C was also significantly enhanced by MLE application to peppers, while in tomatoes, only MLE METH and MLE ETH positively altered the fruit Vit C concentration. These results generally prove that MLE application could potentially be used to improve crop production and their nutritive value. Research limitations: There were no limitations identified. Originality/Value: The results obtained in this study highlight the potential MLEs, particularly hot water MLE, to enhance growth, yield and nutritional quality of pepper and tomato, without compromising human health and environmental sustainability. [ABSTRACT FROM AUTHOR]

Research on solvent effects is an important and long-standing topic, but there still is some room, especially for the special solvent effect of fluoroalcohols. In this work, we investigated the stability of phenoxyl radical in monohydric alcohol solvents through in-situ electron paramagnetic resonance detections. The decay behavior of phenoxyl radical showed a reasonable relationship with the mesoscopic structure of alcohols, characterized by smalland wide-angle X-ray scattering. Moreover, the distinct solvent effects of fluoroalcohols were emphasized, and the significant influence of van der Waals distance in the solvents was suggested. Overall, the stability of phenoxyl radical in alcohols was quantified and correlated with the solvent structures. We believe that the established method for stability study on radicals will encourage solvent effect studies on various organic reactions, and the proposed solvent effects in fluoroalcohols may inspire the development of green solvents in both industrial conversions and organic synthesis. [ABSTRACT FROM AUTHOR]

AbstractThe compound 6-fluoro-4-hydroxyquinolin-2(1H)-one (1) was synthesized and reacted with diazotized 2, 4-dimethylaniline in a basic medium, yielding the hydrazone derivative (2) as a deep yellow crystalline compound. The structure of the purified product was confirmed through FT-IR, 1D and 2D NMR, and mass spectroscopic analyses. The results showed that the product exclusively adopts a hydrazone structure, existing as an equilibrium mixture of E and Z geometrical isomers in solution. DFT quantum calculations at the B3LYP/6-311++G (d, p) level indicated that the hydrazone form of compound (2) is more stable than the proposed azo structure, with the Z-hydrazone isomer having the lowest total energy. Additionally, UV-Vis spectroscopy studies of the E and Z isomers of hydrazone compound (2) in solvents of varying polarities showed that the E isomer is the predominant species in non-polar solvents. [ABSTRACT FROM AUTHOR]

Herein, we report the first example of Rh-catalyzed C(sp²)-H difluoroallylation of α,β-unsaturated amides with 3-bromo-3, 3-difluoropropene under mild conditions. The features of this protocol for difluoroallylation are unprecedented vinylic substrates, ethanol as a green solvent, good functional group and air compatibility, and scale-up synthesis with low catalyst loading. [ABSTRACT FROM AUTHOR]

Two T‐shaped 14‐electron rhodium complexes 2 a and 2 b, “framed” and thus stabilized by PNP pincer ligands have been synthesized. The bis(t‐butyl)phosphine derived PNPtBu‐rhodium complex 2 a was isolated from pentane as the more stable cyclometalated Rh(III) hydrido complex and found to be in equilibrium with the T‐shaped 14e− Rh(I) complex 2 aT which itself could be directly crystallized upon change of the solvent. The cyclometallation is suppressed using an adamantyl substituted PNPAd ligand to give the analogous T‐shaped Rh(I) species 2 b, stabilized through an agostic interaction with one of the adamantyl C−Hs. Depending on the solvent, complex 2 a reacted with ethylene either by π‐coordination (4 a) or C−H activation giving a hydrido‐vinyl Rh(III) species 4 b, both isomers being in equilibrium in solution. Complex 2 b was found to reversibly C−H activate arenes to form the hydrido‐aryl Rh(III) complexes. [ABSTRACT FROM AUTHOR]

A new substituted Hqnal ligand, Hqnal-5-Brq, and four resulting FeIII complexes [Fe(qnal-5-Brq)2]A·sol (A = NO3−, sol = CH3OH 1; A = ClO4−, sol = CH3OH 2; A = OTf−, sol = 2CH3OH·H2O 3; and A = NTf2−, sol = CH2Cl24; Hqnal-5-Brq = N-(5-bromo-8-quinolinyl)-2-hydroxynaphthaldimine), have been synthesized and characterized. All four complexes, despite having different anions, adopt similar 1D [Fe(qnal-5-Brq)2]+ cation chains linked by orthogonal π⋯π interactions. These chains are further connected to form 2D and 3D structures by other supramolecular interactions. Complexes 1–3 all exhibit abrupt spin crossover behaviors, with the transition temperatures being 230, 189, and 185 K, respectively, while complex 4 is in a high-spin state. The influence of solvents on spin crossover properties was assessed via magnetic measurements on the desolvated samples. Following desolvation, while complexes 1 and 2 show slight variations in their transition temperatures, complexes 3 and 4 undergo significant changes in their magnetic profiles. Desolvation in complex 3 leads to either a HS state or a very incomplete hysteretic transition with a low transition temperature for different sample batches. In contrast, the gradual desolvation in complex 4 leads to diminished solvent residues and progressive transition from a stable HS state to an SCO-active state. [ABSTRACT FROM AUTHOR]

A methodology was developed for synthesizing N -acyl- N '-sulfonyl hydrazides through acyl substitution reactions between activated amides and arylsulfonyl hydrazides. Optimization of the reaction conditions revealed that using Cs₂CO₃ as a base and 1,4-dioxane as a solvent at 25 °C for 12 hours produced the highest yields. Among various amides tested, N -benzoylsuccinimide was found to be the most reactive, with reduced reactivity observed for N -mesityl-, N -tosyl-, and N -Boc-substituted tertiary benzoyl amides. Cross-reactions between a diverse range of N -benzoylsuccinimides and arylsulfonyl hydrazides successfully produced the corresponding N -acyl- N′ -sulfonyl hydrazides with yields ranging from 63% to 94%. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Poly‐NHC‐based organometallic assemblies 3‐PF6, 3‐SbF6 and 3‐OTf were obtained and verified by NMR spectroscopy, ESI mass spectrometry and single‐crystal X‐ray diffraction analyses. Controllable structural interconversion was observed between the poly‐NHC‐based organometallic assemblies and their self‐aggregated dimers in solution affected by concentration, solvent and metal ion. 1H NMR spectra of assembly 3‐PF6 in CD3CN at different concentrations demonstrated controllable structural interconversion, and 19F NMR spectrum of assembly 3‐PF6 at high concentration further evidenced the presence of the free hexafluorophosphate anion and encapsulated hexafluorophosphate anion for its two sets of signals. In addition, single‐crystal X‐ray diffraction analysis provided clear evidence that in the solid state, two assemblies 3‐PF6 were vertically stuck, forming a self‐aggregated dimer with an encapsulated hexafluorophosphate anion. Investigating the reversible structural interconversion is beneficial for revealing the intrinsic nature on the atom level and paving the way to design the stimuli‐responsive functional system. [ABSTRACT FROM AUTHOR]

A sensitive, rapid, efficient, inexpensive, and easy-to-use vortex-assisted eutectic solvent microextraction process was extended to quantify Ponceau-4R (PN4R) in beverage samples followed by spectrophotometric detection. Here, a green solvent consisting of tetrabutylammonium bromide: n-octanol at a ratio of 1:3 was tested in the PN4R microextraction process. Also, different parameters affecting PN4R quantification through deep eutectic solvent in the microextraction model, including microliter volumes of extraction solvent, concentration of salt, extraction time, and pH were studied using multivariate procedures. Using this model, the maximum response was achieved with a eutectic solvent volume of 262 μL, extraction time of 5.3 min, pH 6.7, and 0.9% salt with Desirability = 1. The linear range was determined in optimum conditions to be from 15 to 1200 μg L−1. The enrichment factor and limit of detection were achieved to be 50-fold and 4.5 μg L−1, respectively. The limit of quantitation was 15 μg L−1. To monitor PN4R, this model has been used in fruit juice samples with favorable recoveries in the range of 97.8%–101%. [ABSTRACT FROM AUTHOR]

This compound is a synthetic macrocycle comprising three pivaloyl‐protected resorcinarene units connected by six pentylene chains. We conducted a conformational study using 1H‐NMR, X‐ray diffraction (XRD), and computational analyses. The macrocycle adopts two conformers, one open, the other closed. The ratio of the open to closed forms depended on the solvent used. Only the open form existed in [D8]toluene, both forms coexisted in [D6]benzene, and the closed form was the major conformer in [D1]chloroform. The benzene‐solvated open form observed in the solid state suggests that cavity solvation by solvent molecules directs the open form. The open form was the major or only conformer in [D10]o‐ and [D10]m‐xylene and [D12]mesitylene, whereas the closed form was the major conformer in [D6]acetone. The open and closed forms were equally populated in [D10]p‐xylene, suggesting that the size, shape, and dimensions of the solvent molecules most likely influenced the conformation of the protected trisresocinarene. [ABSTRACT FROM AUTHOR]

Given the importance of quinazolines and quinazolinethiones in therapeutic and Food and Drug Administration (FDA)‐approved molecules, we thought interesting to consider their synthesis in green solvents. We have shown that obtain 4‐(arylamino)quinazoline‐2‐(1H)‐thiones and 4‐(arylamino)pteridine‐2‐(1H)‐thiones analogues was efficient in green solvents derived from biomass, especially eucalyptol. Although reaction times are somewhat long to achieve good yields, the products were obtained by simple filtration. This considerably limited the loss of atoms due to the use of large quantities of solvents for purification on silica gel columns, and makes our route a sustainable one. [ABSTRACT FROM AUTHOR]

This study aimed to provide new data on the chemical composition and biological properties of Corrigiola. telephiifolia Pourr., demonstrating the influence of different extraction solvents and geographic locations on these properties. It presents novel findings on the phytochemical contents, antioxidant activity, and antimicrobial effects of various fractions of Corrigiola telephiifolia Pourr. roots collected from three distinct regions in Morocco. The obtained results reveal significant variations in TPC, TFC, and antioxidant activity depending on the extraction fraction and geographic origin. Notably, the fraction of raw extract exhibited the highest TPC values in all sampled sites (44.76 ± 0.05 in Agouray, 35.89±0.02 in Sefrou, and 14.99 ± 0.03 mg·GAE/g·dw in Azrou). The peak values of TFC were recorded in the fraction of raw extracts for all sampling sites (20.80 ± 0.01 in Agouray, 18.62 ± 0.01 in Sefrou, and 11.54 ± 0.01 mg QAE/g dw in Azrou). The highest values of FRAP were recorded in the fraction of raw extract of Agouray (2.00±0.00). Furthermore, the hexane fraction showed the highest DPPH and Chelating power with IC50 equal to 0.46 ± 0.02 mg·mL-1 and 0.10 ± 0.00 mg·mL-1, respectively. All fractions showed significant and variable antibacterial activities. The highest antimicrobial activity was recorded in in ethyl acetate fraction of the sample from Agouray against E. coli (MIC = 0.039). The highest anti-microbial effect was recorded also in ethyl acetate fraction against E. coli and P. aeruginosa, and raw fraction against B. subtilis and P. aeruginosa (MBC = 0.313 against both microorganisms). Agouray consistently demonstrated superior results across multiple parameters, indicating it as the best region for the highest phytochemical and bioactive properties. This study evaluated the chemical compounds and biological properties of Corrigiola. telephiifolia Pourr. and demonstrated the effect of the sampled area and solvent. [ABSTRACT FROM AUTHOR]

A simple, straightforward, and highly efficient greener approach for synthesizing bis(6‐aminouracil‐5‐yl)methane derivatives was developed by employing β‐cyclodextrin‐SO3H as supramolecular catalyst in water at 100 °C. A total of 16 bis(6‐aminouracil‐5‐yl)methanes were synthesized via a one‐pot reaction between substituted aromatic aldehydes, 6‐amino‐1,3‐dimethyluracil, and 10% β‐cyclodextrin‐SO3H in water with 84%–92% yield within 20–120 min. The salient features of this protocol included water as green solvent, β‐cyclodextrin‐SO3H as recyclable supramolecular catalyst, mild reaction conditions, easy isolation of pure products, and good to excellent yields. [ABSTRACT FROM AUTHOR]

We report a study of solvent effects on the rate, selectivity, and mechanism of (hetero)aryl (pseudo)halide oxidative addition to Pd(PCy3)2 as an exemplar of L2Pd(0) species. First, 2‐chloro‐3‐aminopyridine is observed to undergo faster oxidative addition in toluene compared to more polar solvents, which is not consistent with the trend we observe with many other 2‐halopyridines. We attribute this to solvent basicity hydrogen bonding between solvent and substrate. Greater hydrogen bond donation from the substrate leads to a more electron‐rich aromatic system, and therefore slower oxidative addition. We demonstrate how this affects rate and site‐selectivity for hydrogen bond donating substrates. Second, electron‐deficient multihalogenated pyridines exhibit improved site‐selectivity in polar solvents, which we attribute to different C−X sites undergoing oxidative addition by two different mechanisms. The C−X site that favours the more polar nucleophilic displacement transition state is preferred over the site that favours a less‐polar 3‐centered transition state. Finally, (hetero)aryl triflates consistently undergo faster oxidative addition in more polar solvents, which we attribute to highly polar nucleophilic displacement transition states. This leads to improved site‐selectivity for C−OTf oxidative addition, even in the presence of highly reactive 2‐pyridyl halides. [ABSTRACT FROM AUTHOR]