Molecular Interactions in Binary Mixtures of Benzene with 1-Alkanols(C5,C7,C8) at 35℃:An Ultrasonic Study

Densities and ultrasonic speeds have been measured in binary mixtures of benzene with 1‐pentanol, 1‐heptanol and 1‐octanol, and in the pure components, as a function of composition at 35 °C. The isentropic compressibility, intermolecular free length, relative association, acoustic impedance, isothermal compressibility, thermal expansion coefficient, deviations in isentropic compressibility, excess free length, excess volume, deviations in ultrasonic speed, excess acoustic impedance, apparent molar compressibility, apparent molar volume, partial molar volume of 1‐alkanol in benzene have been calculated from the experimental data of densities and ultrasonic speeds. The variation of these parameters with composition indicates weak interaction between the component molecules and this interaction decreases in the order: 1‐pentanol > l‐heptanol> 1‐octanol. Further, theoretical values of ultrasonic speeds were evaluated using free length theory, collision factor theory, Nomoto's relation and Van Dæl‐Vangeel ideal mixing relation. The relative merits of these theories and relations were discussed for these systems.     

Volumetric Properties of (Difurylmethane + Alkan-1-ol) Binary Mixtures at 298.15 K

Densities (ρ)of the binary systems of {difurylmethane + (ethanol or propan-1-ol or butan-1-ol or pentan-1-ol or hexan-1-ol)} have been measured with an Anton Paar DMA 4500 vibrating-tube densimeter over the entire composition range at 298.15,K and atmospheric pressure. Excess molar volumes (V _m ^E ) of each binary system were determined and correlated by the Redlich-Kister equation. Limiting (V _i ^E,∞) and excess partial molar volumes (V _i ^E ) of components of each binary system have been calculated to provide insight into the intermolecular interactions present and the packing efficiencies. The results have been discussed in terms of specific intermolecular interactions, dispersive forces and structural effects.     

Densities and Viscosities for the Binary Mixtures (2-Methyl-1-Chloropropane + Isomeric Butanol) at 298.15 and 313.15 K

Abstract

This paper reports excess volumes, V^E , and viscosity deviations, Δ\eta, for binary mixtures of 2-methyl-1-chloropropane with an isomer of butanol at the temperatures 298.15 K and 313.15 K. These properties were obtained from density and viscosity measurements. The results are correlated by means of a Redlich-Kister type equation, and interpreted in terms of molecular interactions. The systems show positive values of V^E except in a short range of compositions for mixtures containing primary butanols (1-butanol at both temperatures and 2-methyl-1-propanol at 298.15 K), whereas Δ\eta presents negative values at both temperatures over the whole composition range.     

Volumetric Behaviour of Acrylic Esters (Methyl-, Ethyl-, and Butyl Acrylate) + 1-Alcohol (Heptanol,Octanol, Decanol and Dodecanol) at 298.15 K and 308.15 K

Abstract

New experimental data on densities and excess volumes (V^E) for methyl acrylate (MA)+, ethyl acrylate (EA)+, or butyl acrylate (BA)+1-heptanol, +1-octanol, +1-decanol and +1-dodecanol are reported at (298.15 and 308.15) K. The excess volumes were fitted to Redlisch-Kister type equation. The variations in excess volumes with the alkyl chain length of both the components are explained in terms of molecular interactions.     

Density, Viscosity, Refractive Index, and Speed of Sound in Binary Mixtures of Pyridine and 1-Alkanols (C6, C7, C8, C10) at 303.15 K

The densities (ρ), viscosities (η), refractive indices (nD), and speeds of sound (u), of binary mixtures of pyridine with 1-hexanol, 1-heptanol, 1-octanol and 1-decanol, including those of pure liquids, were measured over the entire composition range at 303.15 K and atmospheric pressure. From these experimental data, the values of excess molar volumes (VE), deviations in isentropic compressibilities (Δks), viscosities (Δh), molar refractions (ΔRm), apparent and partial molar volumes (Vf,2 and ), apparent and partial molar compressibilities (Kf,2 and ), of alkanols in pyridine and their corresponding deviations (ΔV and ΔK) were calculated. The variations of these parameters with composition of the mixtures suggest that the strength of interactions in these mixtures follow the order: 1-hexanol＞1-heptanol＞1-octanol＞1-decanol. All the excess and deviation functions were fitted to Redlich-Kister polynomial equation to determine the fitting coefficients and the standard deviations.     

Volumetric,viscometric and acoustic properties of binary mixtures of 2-propanol with n -alkanes (C6, C8, C10) at 298.15 and 308.15 K

Densities (ρ), viscosities (η), and speeds of sound, (u) of the binary mixtures of 2-propanol with n-alkanes (n-hexane, n-octane, and n-decane) were measured over the entire composition range at 298.15 and 308.15 K and at atmospheric pressure. Using the experimental values of density, viscosity and speed of sound, the excess molar volumes (V ^E), viscosity deviations (Δη), deviations in speed of sound (Δu), isentropic compressibility (κ _s), deviations in isentropic compressibility (Δκ _s), and excess Gibbs energies of activation of viscous flow (ΔG* ^E) were calculated. These results were fitted to the Redlich–Kister type polynomial equation. The variations of these excess parameters with composition were discussed from the viewpoint of intermolecular interactions in these mixtures. The excess properties are found to be either positive or negative depending on the molecular interactions and the nature of liquid mixtures.     

Densities, Viscosities, and Excess Gibbs Energy of Activation for Viscous Flow, for Binary Mixtures of Dimethyl Phthalate (DMP) with 1-Pentanol, 1-Butanol, and 1-Propanol at Two Temperatures

Summary. Density (ρ) and viscosity (η) values of the binary mixtures of DMP + 1-pentanol, 1-butanol, and 1-propanol over the entire range of mole fraction at 298.15 and 303.15 K were measured in atmospheric pressure. The excess molar volume (V ^E), viscosity deviations (Δη), and excess Gibbs energy of activation for viscous flow (G^*E) were calculated from the experimental measurements. These results were fitted to Redlich–Kister polynomial equation to estimate the binary interaction parameters. The viscosity data were correlated with equations of McAllister. The calculated functions have been used to explain the intermolecular interaction between the mixing components.     

Dielectric Relaxation Studies of Binary Mixture of α‐Picoline and Methanol Using Time Domain Reflectometry at Different Temperatures

Complex permittivity spectra of binary mixtures of varying concentrations of α‐picoline and methanol (MeOH) were obtained using time domain reflectometry (TDR) technique over frequency range 10 MHz to 25 GHz at 283.15 K, 288.15 K, 293.15 K and 298.15 K temperatures. The dielectric relaxation parame‐ ters namely static permittivity (σ₀), high frequency limit permittivity (σ_oo1) and the relaxation time (ρ) were determined by fitting complex permittivity data to the single Debye/Cole‐Davidson model. Complex non linear least square (CNLS) fitting procedure was carried out using LEVMW software. The excess static permittivity (σ₀^E) and the excess inverse relaxation time (1/ρ)^E which contains information regarding mo‐ lecular structure and interaction between polar — polar liquids, were also determined. From the experimental data, effective Kirkwood correlation factor (g^eff) and Bruggeman factor (f_B) were calculated. Excess parameters were fitted to the Redlich‐Kister polynomial equation. The values of static permittivity and relaxation time increase non‐linearly with increase in the mol fraction of MeOH at all temperatures. The values of excess static permittivity (σ₀^E) and the excess inverse relaxation time (1/ρ)^E are negative for the studied α‐picoline — MeOH system at all temperatures.     

Synthesis and Characterization of Iron(III) Complexes of 5‐(8‐Carboxy‐1‐naphthyl)‐10, 15, 20‐tritolyl Porphyrin

5‐(8‐Carboxy‐1‐naphthyl)‐10, 5, 20‐tritolyl porphyrin (H₃CNTTP) and its iron(III) complexes, [Fe(CNTTP)]₂ and [Fe(CNTTP)(N‐MeIm)₂], were synthesized and characterized. X‐ray crystallography revealed that the carboxylate group is “hanging” over the porphyrin plane. The rigid framework makes the distance between the carboxylate oxygen and iron in the same porphyrin too long to form a coordination bond. On the other hand, the carboxylate group is not bulky enough to block the axial binding site. In the presence of OH^–, the carboxylate oxygen is coordinated to iron in the symmetry‐related unit, which led to the dimeric structure, [Fe(CNTTP)]₂. In the presence of excess N‐methylimidazole, a six‐coordinate species, [Fe(CNTTP)(N‐MeIm)₂], was obtained. In such a structure, CH ··· O interactions between the carboxylate group and imidazole probably play an important role to determine the orientation of imidazole plane. Two imidazole planes have relative parallel orientation. For [Fe(CNTTP)(N‐MeIm)₂], ¹H NMR shows pyrrole protons at the region –10 to –25 ppm. EPR shows rhombic spectrum. Those suggest [Fe(CNTTP)(N‐MeIm)₂] is a type II low‐spin iron(III) porphyrinate.     

Ultrasonic velocity study of poly(R,R,4,4-cyclohexylidene diphenylene diphenyl ether-4,4-disulfonate) solutions at 30, 35 and 40 °C

Ultrasonic velocity (2 MHz) and acoustic parameters of poly(R,R^′-4,4^′-cyclohexylidene diphenylene diphenyl ether-4,4^′-disulfonate) (PS-1: RR^′H; PS-2: RCH₃ and R^′H; PS-4: RCH₃ and R^′Cl) solutions (chloroform, 1,2-dichloroethane and tetrahydrofuran (THF)) at 30, 35 and 40 °C have been determined to understand the effect of methyl and chlorine substituents on molecular interactions to support solvophilic or solvophobic nature of the polymers. The linear increase of U, Z, R, b, π, (α/f²)_Cl and τ with C and decrease of K_s, r, L_f and V_f with C suggested the existence of strong molecular interactions and hence solvophilic nature of the polymers, which is supported by positive values of S_n. A rise in temperature resulted in less ordered structure and more spacing between the molecules. The solvophilic nature of the polymers caused nonlinear variation of φ_v2 and φ_Ks with C and T. A powerful solvation exists in THF system. Structural modification is found above 2% for PS-2 and PS-4. The decrease of S_n with C and T indicated the presence of polymer-polymer interactions. The decrease of S_n with T is due to disruption of the structure formed by predominant thermal energy over molecular interaction energy.     

Isolated BMI+ Cations are More than Isolated PF6− Anions in the Room Temperature 1‐Butyl‐3‐Methylimidazolium Hexafluorophosphate (BMI‐PF6) Ionic Liquid

Assuming various ionic states in ionic liquids (ILs) are in equilibrium with exchange rates too high to be distinguished by NMR experiments and the overall response of measured diffusivity is viewed as the sum of weighted responses of diffusivity of all possible components, the ratio of cation diffusivity to anion diffusivity, D⁺/D^?, in a specified IL affords the physical meaning: relative association degrees observed by anion‐containing components to cation‐containing components. These values decrease with increasing temperature showing the equilibrium between ionic states shifting to smaller components. In the neat 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMI‐PF₆), (BMI‐PF₆)_nPF₆^? anions are found preferred to (BMI‐PF₆)_nBMI⁺ cations and this phenomenon is termed as hyper anion preference (HAP). The counterpart statement, “isolated BMI⁺Cations Are More than Isolated PF₆^? Anions in the Room Temperature in the BMI‐PF₆ Ionic Liquid” is employed as the research title. The HAP approach can be employed to explain the temperature‐dependent values of D⁺/D^? obtained for BMI‐PF₆/2,2,2‐trifluoroethane (TFE) mixtures at two different compositions (χ_TFE = 0.65 and 0.80). More significantly, this argument can rationalize numerous physical properties published for this IL: (1) higher sensitive of anionic diffusivity towards temperatures than cationic diffusivity, (2) temperature‐dependent cationic transference number, (3) low anionic donicity and high ionicity and (4) high viscosity.     

Reductive Hydrogenation of Cs‐C70(CF3)8 and C1‐C70(CF3)10

CF₃‐derivatized fullerenes prove once again to be promising scaffolds for regioselective fullerene functionalization: now with the smallest possible addends—hydrogen atoms. Hydrogenation of C_s‐C₇₀(CF₃)₈ and C₁‐C₇₀(CF₃)₁₀ by means of reduction with Zn/Cu couple in the presence of water proceeds regioselectively, yielding only one major isomer of C₇₀(CF₃)₈H₂ and only two for C₇₀(CF₃)₁₀H₂, whose addition patterns are combined in the only abundant isomer of C₇₀(CF₃)₁₀H₄. The observed selectivity is governed by the electronic structure of trifluoromethylated substrates. Interestingly, we discovered that Clar's theory can be utilized to predict the regiochemistry of functionalization, and we look forward to testing it on forthcoming cases of derivatization of pre‐functionalized fullerene building blocks.     

[Na(DB18-C-6)(H2O)2][Na(DB18-C-6)(SCN)2]：Two-Di-mensional Network Complex Assembled by π-π Stacking Interactios,Hydrogen Bonds and Electrostatic Interactions

A novel two‐dimensional network dibenzo‐18‐crown‐6 (DB18‐C6) complex: [Na (DB18‐C‐6) (H₂O)₂] [Na (DB18‐C‐6) (SCN)₂] has been isolated and characterized by elemental, IR and X‐ray diffraction analysis. The crystal structure belongs to monoclinic, space group P2₁/c with cell dimensions a = 1.06178(7), b = 1.40243(8), c = 3.03496(19) nm, β = 90.4220(10)°, V = 4.5292(5) nm³, Z=4, D_calcd =1.351 g/ cm³, F(000) = 1936, R₁ = 0.0369, wR₂ = 0.0821. The most interesting feature in this structure is that complex cation and complex anion form a two‐dimensional network via τ‐τ stacking interactions, hydrogen bonds and electrostatic interactions.     

Stereoselective Total Synthesis of Oxylipins: (6S,7E,9R,10S)‐6,9,10‐Trihydroxyoctadec‐7‐enoic Acid and (6Z,8R,9R,10S)‐8,9,10‐Trihydroxyoctadec‐6‐enoic Acid

The stereoselective total syntheses of oxylipins 1b and 1c are described starting from readily accessible natural sugars via the Grubbs cross‐metathesis, Wittig olefination, and Zn‐mediated reductive elimination as key steps.     

Pentamethylcyclopentadienyl(η6‐cyclooctatrienyl)ruthenium Tetrachlorozincate, [RuCp*(η6‐C8H10)]2ZnCl4

The crystal and molecular structures of the title compound, the first for a complex of the type [RuCp*(η⁶‐C₈‐ring)]⁺, is presented, the material being obtained serendipitously from a reaction between RuCl(cod)Cp* and 1‐ferrocenylbuta‐1,3‐diyne in the presence of ZnCl₂. <Ru‐C(Cp*)> (2.21 Å) is appreciably longer than in RuCp*₂ (2.18 Å) and similar to the value for the Ru‐η⁶ component (2.22 Å).     

Excess Thermodynamic Properties of Binary Liquid Mixtures Containing N,N -Dimethylacetamide with Some Alkan-1-Ols (C 1 -C 6 ) At 298.15 K

Excess molar enthalpies, $ H_m^E $ of N , N -dimethylacetamide + methanol, + ethanol, + propan-1-ol, + butan-1-ol, + pentan-1-ol, and + hexane-1-ol have been determined at 298.15 K and atmospheric pressure using a Parr 1455 solution calorimeter. While the excess molar enthalpies are negative for methanol and ethanol mixtures, those for propan-1-ol, butan-1-o1, pentane-1-ol, and hexan-1-ol mixtures are positive over the entire range of composition of N , N -dimethylacetamide. The $ H_m^E $ at around x , 0.5 follow the order: methanol<ethanol<propan-1-ol<butan-1-ol<pentan-1-ol<hexan-1-ol. The results are explained in terms of the self-association exhibited by the alkan-1-ols and the formation of aggregates between unlike molecules through OHO hydrogen bonding. The experimental results for mixtures are well represented by the Redlich - Kister equation.     

Synthese von (C6F5)2SF+MF6− (M  As,Sb) und Kristallstruktur von (C6F5)2SF+SbF6− [1]

Preparation of (C₆F₅)₂SF⁺MF₆^? (M ? As, Sb) and Crystal Structure of (C₆F₅)₂SF⁺SbF₆^? XeF⁺MF₆^? (M ? As, Sb) reacts with (C₆F₅)₂S in HF to form (C₆F₅)₂SF⁺MF₆^?. The deeply violet sulfonium salts can be kept without decomposition up to 24 h at room temperature. The hexafluoroantimonate salt crystallizes in the monoclinic space group P2₁/n with a = 1056.4(7) pm, b = 1446.3(10) pm, c = 1102.9(8) pm, β = 91.29(6)° und Z = 4. The SF-bond distance with 158.4(3) pm is of unusual length. Cations and anions are connected via interionic fluorine contacts to an infinite chain, in which cations and anions form to ABAB sequence along the chain.     

Synthesis and Crystal Structure of [Nd(η6‐1, 3, 5‐C6H3Me3)‐(AlCl4)3](C6H6) and Structural Comparison of Ln(η6‐arene)‐(AlCl4)3

Reaction of Ndcl₃ with AlCl₃ and mesitylene in benzene gives complex [Nd(η⁶‐1, 3, 5‐C₆H₃Me₃)‐(AlCl₄)₃](C₆H₆) (1) which was characterized by elemental analysis, IR spectra, MS and X‐ray diffractions. The X‐ray determination indicates that 1 has a distorted pentagonal bipyramidal geometry and crystallizes in the monoclinic, space group P2₁/n with a = 0.9586(2), b = 1.1717(5), c = 2.8966(7) nm, β = 90.85 (2)°, V = 3.2529 (6) nm³,D_c= 1.573 g/cm³, Z = 4. A comparison of bond parameters for all the reported Ln (η⁶‐Ar) (AlCl₄)₃ complexes indicates that the bond distance of La? C is shortened with the increasing of methyl group on benzene and with the decreasing of radius of lanthanide ions.     

A comparative study of the packing of two polymorphs of the nickel(II) pincer complex [2,6‐bis(di‐tert‐butylphosphinoyl)‐4‐(3,5‐dinitrobenzoyloxy)phenyl‐κ3P,C1,P′]chloridonickel(II)

Pincer complexes can act as catalysts in organic transformations and have potential applications in materials, medicine and biology. They exhibit robust structures and high thermal stability attributed to the tridentate coordination of the pincer ligands and the strong σ metal–carbon bond. Nickel derivatives of these ligands have shown high catalytic activities in cross‐coupling reactions and other industrially relevant transformations. This work reports the crystal structures of two polymorphs of the title Ni^II POCOP pincer complex, [Ni(C₂₉H₄₁N₂O₈P₂)Cl] or [NiCl{C₆H₂‐4‐[OCOC₆H₄‐3,5‐(NO₂)₂]‐2,6‐(OP^tBu₂)₂}]. Both pincer structures exhibit the Ni^II atom in a distorted square‐planar coordination geometry with the POCOP pincer ligand coordinated in a typical tridentate manner via the two P atoms and one arene C atom via a C—Ni σ bond, giving rise to two five‐membered chelate rings. The coordination sphere of the Ni^II centre is completed by a chloride ligand. The asymmetric units of both polymorphs consist of one molecule of the pincer complex. In the first polymorph, the arene rings are nearly coplanar, with a dihedral angle between the mean planes of 27.9 (1)°, while in the second polymorph, this angle is 82.64 (1)°, which shows that the arene rings are almost perpendicular to one another. The supramolecular structure is directed by the presence of weak C—H…O=X (X = C or N) interactions, forming two‐ and three‐dimensional chain arrangements.