Viscosity Calculation for Binary Mixtures of Organic Solvents Based on Modified Eyring-Modified Two-Suffix-Margules (MTSM) Model

Recently, the Eyring-modified two-suffix-margules (MTSM) model for calculating viscosities of ionic liquid mixtures was proposed by Atashrouz et al. (Atashrouz, S.; Zarghampour, M.; Abdolrahimi, S.; Pazuki, G.; Nasernejad, B. <i>J. Chem. Eng. Data</i> <b>2014</b>, <i>59</i>, 3691–3704). In this work, a simple modification of the Eyring-MTSM model was presented and applied to the viscosity calculation of binary mixtures of organic solvents. The accuracy of the modified model was assessed by comparing experimental viscosities at atmospheric pressure for 182 binary mixtures, and the overall average relative deviation (ARD) between the calculated results and literatures is 0.61%. In addition, the relationship between the parameters in the model and the boiling point of mixtures was established. Experimental viscosities containing 478 binary mixtures were used to evaluate the reliability of the relations, and good agreement was obtained between experimental and calculated values with ARD of 1.62%. Furthermore, the modified Eyring-MTSM model was extended to the viscosities of high pressures. The ARD is 1.61% for the high-pressure viscosities of 63 binary mixtures. The predictive ability of the model was also tested, and the model is suitable for the prediction of the homologous mixtures

Densities and excess molar volumes of the binary system <i>N</i>-methyldiethanolamine + (2-aminoethyl)ethanolamine and its ternary aqueous mixtures from 283.15 to 363.15 K

<p>Experimental density data of the binary mixtures of <i>N</i>-methyldiethanolamine + (2-aminoethyl)ethanolamine and the ternary mixtures of <i>N</i>-methyldiethanolamine + (2-aminoethyl)ethanolamine + water were reported at atmospheric pressure over the entire composition range at temperatures from 283.15 to 363.15 K. Density measurements were performed using an Anton Paar digital vibrating U-tube densimeter. Excess molar volumes were calculated from the experimental data and correlated as the Redlich-Kister equation for the binary mixtures, and as the Nagata-Tamura equation for the ternary mixtures. Several empirical models were applied to predict the excess molar volumes of ternary mixtures from the corresponding binary mixture values. It indicates that the best agreement with the experimental data was achieved by the Redlich-Kister, Kohler, and Jacob-Fitzner models.</p

High-Spin Iron(II) Alkynyl Complexes with N‑Heterocyclic Carbene Ligation: Synthesis, Characterization, and Reactivity Study

High-spin iron­(II) alkynyl complexes [(IPr₂Me₂)₂­Fe­(CCBu^<i>t</i>)₂] (<b>1</b>) and [(IPr₂Me₂)₂Fe­(CCR)­(NHMes)] (R = Bu^<i>t</i> <b>2</b>, SiMe₃ <b>3</b>) bearing a monodentate N-heterocyclic carbene ligand IPr₂Me₂ (1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) have been prepared by salt metathesis and/or amine elimination methods and characterized by various spectroscopic methods. Complex <b>1</b> reacts with PMe₃ (4 equiv) and Bu^<i>t</i>NC (4 equiv) to form <i>trans</i>-[(PMe₃)₄­Fe­(CCBu^<i>t</i>)₂] (<b>4</b>) and [η³-{(Bu^<i>t</i>CC)­(Bu^<i>t</i>)­CC­(IPr₂Me₂)­C­(NBu^<i>t</i>)}­Fe­(NCBu^<i>t</i>)₃] (<b>5</b>), respectively. In contrast, the reactions of <b>1</b> with 4-Pr^<i>i</i>-C₆H₄NCO and Pr^<i>i</i>NCNPr^<i>i</i> lead to the formation of the zwitterionic salts 4-Pr^<i>i</i>-C₆H₄NC­(O)­(IPr₂Me₂) and (Pr^<i>i</i>N)₂C­(IPr₂Me₂), respectively. The interaction of <b>1</b> with I₂ gives Bu^<i>t</i>CCCCBu^<i>t</i> and (IPr₂Me₂)₂FeI₂. The C­(sp)–C­(sp³) cross-coupling products <i>n</i>-C₈H₁₇CCBu^<i>t</i> and <i>c</i>-C₆H₁₁CCBu^<i>t</i> are formed in high yields when <b>1</b> is treated with the corresponding alkyl halides <i>n</i>-C₈H₁₇X and <i>c</i>-C₆H₁₁X (X = Br, Cl). The formation of the ring-opening product 7,7-dimethyloct-1-en-5-yne in the reaction of <b>1</b> with cyclopropylmethyl bromide supports the radical character of the cross-coupling reaction

Maximizing the Spread of Influence via Generalized Degree Discount

<div><p>It is a crucial and fundamental issue to identify a small subset of influential spreaders that can control the spreading process in networks. In previous studies, a degree-based heuristic called <i>DegreeDiscount</i> has been shown to effectively identify multiple influential spreaders and has severed as a benchmark method. However, the basic assumption of <i>DegreeDiscount</i> is not adequate, because it treats all the nodes equally without any differences. To consider a general situation in real world networks, a novel heuristic method named <i>GeneralizedDegreeDiscount</i> is proposed in this paper as an effective extension of original method. In our method, the status of a node is defined as a probability of not being influenced by any of its neighbors, and an index generalized discounted degree of one node is presented to measure the expected number of nodes it can influence. Then the spreaders are selected sequentially upon its generalized discounted degree in current network. Empirical experiments are conducted on four real networks, and the results show that the spreaders identified by our approach are more influential than several benchmark methods. Finally, we analyze the relationship between our method and three common degree-based methods.</p></div

The spreading influence of GeneralizedDegreeDiscount and three adaptive centrality-based methods under different effective spreading rates.

<p>The numbers of spreaders are 100 in all networks, and the results are obtained by averaging over 200 implementations of the SIR model.</p

Dually Heterogeneous Hydrogels via Dynamic and Supramolecular Cross-Links Tuning Discontinuous Spatial Ruptures

Biological tissues are often highly and multiply heterogeneous in both structure and composition, but the integrity of multiheterogeneity in artificial materials is still a big challenge. Herein, dually heterogeneous hydrogels were constructed with two distinct strategies via dynamic bonds and supramolecular cross-links. The hydrogels showed discontinuous spatial ruptures, and the mechanical behaviors of hydrogels could be tuned. The primary heterogeneity resulted from a nonuniform distribution of dynamic and/or static cross-links. The presence of only primary heterogeneity within hydrogels led to uneven mechanical properties that were represented by discontinuous spatial ruptures during the stretching the hydrogel and therefore caused the necking deformation. Further introduction of the secondary heterogeneity by incorporating anisotropic cellulose nanocrystals (CNC) into the hydrogels allowed the adjustment of the necking phenomenon. Moreover, distinct CNC with diverse surface functionalities exhibited different effects: the “active” CNC with surface-attached dynamic bonds retarded the necking propagation, while the “neutral” CNC without further surface modification promoted the extension of necking points. Thus, the regulation of deformation and fracture mode of hydrogels was achieved by the synergy of dually heterogeneous structure

The spreading influence of nine methods on four networks under different effective spreading rates.

<p>The parameters are <i>λ</i> = 1.1, <i>q</i> = 1/〈<i>k</i>〉 for all networks, and all results are obtained by averaging over 200 implementations of the SIR model.</p

The similarities between <i>GeneralizedDegreeDiscount</i> and <i>Degree</i>, <i>SingleDiscount</i>, <i>DegreeDiscount</i>.

<p>The fraction of spreaders is 1%.</p

Monomeric Bis(anilido)iron(II) Complexes with <i>N</i>‑Heterocyclic Carbene Ligation: Synthesis, Characterization, and Redox Reactivity toward Aryl Halides

Using monodentate <i>N</i>-heterocyclic carbenes as the ancillary ligands, seven monomeric bis­(anilido)­iron­(II) complexes [(IPr₂Me₂)₂Fe­(NHAr)₂] (IPr₂Me₂ = 2,5-diisopropyl-3,4-dimethylimidazol-1-ylidene; Ar = Ph, C₆H₄-2-Pr^<i>i</i>, Mes, C₆H₃-2,6-Cl₂, Dipp) and [(IPr)­Fe­(NHAr)₂] (IPr = 2,5-di­(2,6-diisopropylphenyl)­imidazol-1-ylidene; Ar = C₆H₃-2,6-Cl₂, Dipp) have been prepared by the one-pot reactions of [Fe­(Mes)₂]₂ with the corresponding <i>N</i>-heterocyclic carbenes, and anilines. These high-spin diamido complexes have been fully characterized by ¹H NMR, solution magnetic susceptibility, UV–vis, IR, X-ray diffraction, cyclic voltammetry, as well as elemental analysis. The strong affinity of the <i>N</i>-heterocyclic carbene ligands toward ferrous centers, and the steric protection exerted by the NHC ligands are the key factors to stabilize these bis­(anilido)­iron complexes in a monomeric manner. Reactivity studies revealed the four-coordinate complex [(IPr₂Me₂)₂Fe­(NHMes)₂] can react with 1 equiv of 1-iodo-3,5-dimethylbenzene or 1-bromo-3,5-dimethylbenzene in C₆D₆ and THF-d₈ to furnish 1-C₆D₅-3,5-Me₂C₆H₃, and 5-D-1,3-Me₂C₆H₃, respectively. Under similar conditions, the three-coordinate compound [(IPr)­Fe­(NHDipp)₂] is inert toward these halides

The diagram of <i>DegreeDiscount</i>.

<p>Nodes filled by gray denote the selected spreaders, and others denote normal nodes.</p