Heat capacities and densities of mixtures of very polar substances. 3. Mixtures containing either trichloromethane or 1,4-dioxane or diisopropylether

Excess molar heat capacities C _P ^E at constant pressure and excess molar volumes V ^E have been determined, as a function of mole fraction x₁ at 25°C and atmospheric pressure, for 10 binary liquid mixtures containing either trichloromethane (series I) with C₆H₅CH₃, or C₆H₅Cl, or C₅H₅N, or CH₃COCH₃, or C₆H₅NO₂; 1,4-dioxane (series II) with (C₂H₅)₃N, or (CH₃)₂CHOCH(CH₃)₂, or (CH_{3 2}SO); or diisopropyl ether (di-1-methylethyl ether) (series III) with (C₂H₅)₃N, or CHCl₃. The dipole momentsp (10^–30C-m) of the substances range from nearly 0 to 14.1 for nitrobenzene. The C _P ^E of series I and III are all positive, with C _P ^E (x₁=0.5) (J-K^–1-mol^–1) ranging from 1.04 for {x₁CHCl₃+x₂C₆H₅Cl} to 16.66 for {x₁(CH₃)₂CHOCH(CH₃)₂+x₂CHCl₃}. In series II, the C _P ^E are positive and small for {x₁1,4-C₄H₈O₂+x₂(CH₃)₂CHOCH(CH₃)₂}, S-shaped and small for {x₁1,4-C₄H₈O₂+x₂(C₂H₅)₃N}, and negative and small for {x₁1,4-C₄H₈O₂+x₂(CH₃)₂SO}. The excess volumes are small and positive for {x₁CHCl₃+x₂C₆H₅CH₃}, S-shaped for {x₁CHCl₃+x₂CH₃COCH₃}, {x₁1,4-C₄H₈O₂+x₂(C₂H₅)₃N} and {x₁(CH₃)₂CHOCH(CH₃)₂+x₂(C₂H₅)₃N}, and negative for the other systems.Presented at the Symposium, 76^th CSC Congress, Sherbrooke, Quebec, May 30–June 3, 1993, honoring Professor Donald Patterson on the occasion of his 65^th birthday     

Thermodynamics of aqueous gallium chloride. Apparent molar volumes and heat capacities at 25°C

Apparent molar volumes and heat capacities of aqueous GaCl₃ have been measured at 25°C in binary GaCl₃ solutions up to 3 mol-kg^–1, and in ternary GaCl₃-HCl solutions, containing 0.1345 mol-kg^–1 HCl to suppress hydrolysis, up to a concentration of 1 mol-kg^–1 GaCl₃. Using the Pitzer interaction model for the excess properties, and using ridge regression for the derivation of physically meaningful regression parameters, the measurements yield the following results for the standard molar properties and Pitzer parameters at 25°C: V⁰(GaCl₃)=12.85 cm³-mol^–1; ₀ ^v (GaCl₃)=1.10×10^–4 kg-mol^–1–J^–1–cm^–3; _v ¹ (GaCl₃)=2.12×10^–3 kg–mol^–1–J^–1–cm³; Cv(GaCl₃)=1.34×10^–5 kg²–J^–1–cm³; V^o(GaOHCl₂)=13.84 cm³–mol^–1; C _o ^p (GaCl₃)=–480.8 J–K^–1–mol^–1; _J ⁰ (GaCl₃)=–8.02×10^–6 kg–mol^–1–K^–2; _J ¹ (GaCl₃)=0.73×10^–4 kg–mol^–1–K^–2; C_J(GaCl₃)=–2.52×10^–6 kg²-mol^–2-K^–2; C _p ⁰ (GaOHCl₂)=20.4 J-K^–1-mol^–1. The latter parameter has only mathematical significance, its physical meaning is unclear. Comparison of the present experimental results for the standard molar properties of Ga³⁺ with semi-empirical correlations casts doubt upon the general validity of these correlation methods for trivalent cations.     

Synthesis of Schiff bases and benzylamino derivatives containing [1-B<Subscript>10</Subscript>H<Subscript>9</Subscript>NH<Subscript>3</Subscript>]<Superscript>−</Superscript> anion

Reactions of an amino derivative of the closo-decaborate anion [1-B₁₀H₉NH₃]^– with aromatic aldehydes afforded Schiff bases [1-B₁₀H₉NH=CHAr]^– (Ar=Ph, C₆H₄-2-OMe, or C₆H₄-4-NHCOMe). The reduction of the latter with sodium borohydride gave the corresponding benzylamino derivatives [1-B₁₀H₉NH₂CH₂Ar]^–.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2004–2007, September, 2004.     

Thermodynamics of liquid mixtures containing n-alkanes and strongly polar components: VE and C P E of mixtures with either pyridine or piperidine

Excess molar volumes V _E and excess molar heat capacities C _P ^/E at constant pressure have been obtained, as a function of mole fraction x₁, for several binary liquid mixtures belonging either to series I: pyridine+n-alkane (C_lH_2l+2), with l=7, 10, 14, 16, or series II: piperidine+n-alkane, with l=7, 8, 10, 12, 14. The instruments used were a vibrating-tube densimeter and a Picker flow microcalorimeter, respectively. V ^E of pyridine+n-heptane shows a S-shaped composition dependence with a small negative part in the region rich in pyridine (x₁>0.90). All the other systems show positive V ^E only. The excess volumes increase with increasing chain length l of the n-alkane. The excess molar heat capacities of the mixtures belonging to series II are all negative, except for a small positive part for piperidine+n-heptane in the region rich in piperidine (x₁>0.87). The C _P ^/E at the respective minima, C _P ^/E (x_1,min ), become more negative with increasing l, and the x_1,min values range from about 0.26 (l=7) to 0.39 (l=14). Most interestingly, mixtures of series I exhibit curves of C _P ^/E against x₁ with two minima and one maximum, the so-called W-shape curves.Dedicated to Professor A. Néckel on the occasion of his 65^th birthday. Communicated in part at the XVII^èmes Journées de Calorimétrie, d'Analyse Thermique et de Thermodynamique Chimique, Ferrara, Italy, 27–30 October, 1986.     

Control of Hydrolysis and Condensation Reactions of Titanium tert-butoxide by Chemical Modification with Catechol

Titanium tert-butoxide (Ti(OC(CH₃)₃)₄; Ti(O ^t Bu)₄) was chemically modified with catechol (C₆H₄(OH)₂) and hydrolysis and condensation behavior of a resultant modified alkoxide was studied. Spectroscopic results revealed that the reaction between titanium tert-butoxide and catechol resulted in the formation of catecholate groups (C₆H₄O₂ ^2–) bound to titanium and corresponding release of tert-butanol. The mass spectrometry and cryoscopy indicated that main species was a dimer [(C₆H₄O₂)₂Ti₂(O ^t Bu)₄]. The hydrolysis of the modified alkoxide in the system with Ti:tetrahydrofuran (THF):H₂O = 1:10:x (x = 0.5–10) resulted in the partial hydrolysis, and all the hydrolyzed products after the drying under reduced pressure were soluble in THF and chloroform.     

Densities and Excess Molar Volumes of Binary and Ternary Mixtures of Aqueous Solutions of 2,2,2-Trifluoroethanol with Acetone and Alcohols at the Temperature of 298.15 K and Pressure of 101 kPa

Excess molar volumes V_m^E of the binary mixtures of (trifluoroethanol + 1-propanol), (trifluoroethanol + 2-propanol), (acetone + water), (methanol + water), (ethanol + water), (1-propanol + water), (2-propanol + water), and the ternary mixtures of (trifluoroethanol + methanol + water), (trifluoroethanol + ethanol + water), (trifluoroethanol~+ 1-propanol + water), (trifluoroethanol + 2-propanol + water) and (trifluoroethanol + acetone + water) were measured with a vibrating tube densimeter at the temperature of 298.15 K and the pressure 101 kPa. The extrema in V_m^E of trifluoroethanol mixtures occur at –0.690 cm³-mol^–1 for (trifluoroethanol + 1-propanol), at –0.990~cm³-mol^–1 for (trifluoroethanol + 2-propanol); at 0.562 and –0.973 cm³-mol^–1 for (trifluoroethanol + methanol + water), at 0.629 and –0.973 cm³-mol^–1 for (trifluoroethanol + ethanol + water), at 1.082 and –0.659 cm³-mol^–1 for (trifluoroethanol~+ 1-propanol + water), at 0.998 and –0.991 cm³-mol^–1 for (trifluoroethanol~+ 2-propanol + water), and at 0.515 and –1.472 cm³-mol^–1 for (trifluoroethanol + acetone + water). The experimental ternary V_m^E values were predicted by empirical expressions using binary solution data.     

Molecular electrochemistry of hydrofullerenes C70H36—46

Electrochemistry of a mixture of hydrofullerenes C₇₀H_36—46 composed of C₇₀H₃₆, C₇₀H₃₈, C₇₀H₄₄, and C₇₀H₄₆ (50, 20, 14, and 15%, respectively) was studied by cyclic voltammetry in THF and CH₂Cl₂ in the –43—–13 °C temperature range. Two cathodic peaks, namely, one-electron reversible (E° = –3.16 V (Fc^0/+), Fc is ferrocene) and irreversible (E _p = –3.37 V (Fc^0/+)) were observed for this mixture in THF. The irreversible broad oxidation peak (E _p = 1.22 V (Fc^0/+)) was observed in CH₂Cl₂. The reversible reduction peak (E° = –3.16 V) and irreversible oxidation peak (E _p = 1.22 V) were attributed to the most stable hydrofullerene C₇₀H₃₆. The irreversible reduction (E _p = –3.37 V) and oxidation (E _p = 1.22 V) peaks were attributed to hydrofullerenes C₇₀H_44—46 with a higher degree of hydrogenation. The values of an electrochemical gap, which is an analog of the energy gap (HOMO—LUMO), are 4.38 and 4.59 V for C₇₀H₃₆ and C₇₀H_44—46, respectively, and indicate that these hydrofullerenes are sufficiently hard molecules with low reactivity in redox reactions.     

Thermodynamics of tri- and pentabromide anions in aqueous solution

Formation constants for the tribromide and pentabromide anions were measured by a vapor partitioning method from 5 to 80°C. The molal thermodynamic parameters for these respective species at 25°C are: K ₃ –16.73, H ^o =–5.90 kJ-mol ^–1 , Cp ^o =–29 J-K ^–1 -mol ^–1 , and S ^o =3.6 J-K ^–1 -mol ^–1 ; K ₅ =37.7, H ^o =–13.0 kJ-mol ^–1 , S ^o =–13.6 J-K ^–1 -mol ^–1 , with Cp ^o assumed zero. These results are used to reevaluate published emf results for the bromine/bromide couple.     

Chromium(III) Hydroxide Solubility in The Aqueous Na+-OH?-H2PO?4-HPO2?4-PO3?4-H2O System: A Thermodynamic Model

Chromium(III)-phosphate reactions are expected to be important in managing high-level radioactive wastes stored in tanks at many DOE sites. Extensive studies on the solubility of amorphous Cr(III) solids in a wide range of pH (2.8–14) and phosphate concentrations (10^–4 to 1.0 m) at room temperature (22±2)°C were carried out to obtain reliable thermodynamic data for important Cr(III)-phosphate reactions. A combination of techniques (XRD, XANES, EXAFS, Raman spectroscopy, total chemical composition, and thermodynamic analyses of solubility data) was used to characterize solid and aqueous species. Contrary to the data recently reported in the literature,⁽¹⁾ only a limited number of aqueous species [Cr(OH)₃H₂PO^–₄, Cr(OH)₃(H₂PO₄)^2–₂), and Cr(OH)₃HPO^2–₄] with up to about four orders of magnitude lower values for the formation constants of these species are required to explain Cr(III)-phosphate reactions in a wide range of pH and phosphate concentrations. The log K^o values of reactions involving these species [Cr(OH)₃(aq)+H₂PO^–₄&#x21CC;Cr(OH)₃H₂PO^–₄; Cr(OH)₃(aq)+2H₂PO^–₄&#x21CC;Cr(OH)₃(H₂PO₄)^2–₂; Cr(OH)₃(aq)+HPO^2–₄&#x21CC;Cr(OH)₃HPO^2–₄] were found to be 2.78±0.3, 3.48±0.3, and 1.97±0.3, respectively.     

Exploring the Dual Characteristics of CH3OH Adsorption to Metal Atomic Structures on Si (111)-7 × 7 Surface

Metal atoms were deposited on an Si (111)-7 × 7 surface, and they were adsorbed with alcohol gases (CH₃OH/C₂H₅OH/C₃H₇OH). Initially, C_nH_2n+1OH adsorption was simply used as an intermediate layer to prevent the chemical reaction between metal and Si atoms. Through scanning tunneling microscopy (STM) and a mass spectrometer, the C_nH_2n+1OH dissociation process is further derived as the construction of a surface quasi-potential with horizontal and vertical directions. With the help of three typical metal depositions, the surface characteristics of CH₃OH adsorption are more clearly presented in this paper. Adjusting the preheating temperature, the difference of thermal stability between CH₃O^– and H⁺ could be obviously derived in Au deposition. After a large amount of H⁺ was separated, the isolation characteristic of CH₃O^– was discussed in the case of Fe deposition. In the process of building a new metal-CH₃O^–-H⁺ model, the dual characteristics of CH₃OH were synthetically verified in Sn deposition. CH₃O^– adsorption is prone to influencing the interaction between the metal deposition and substrate surface in the vertical direction, while H⁺ adsorption determines the horizontal behavior of metal atoms. These investigations lead one to believe that, to a certain extent, the formation of regular metal atomic structures on the Si (111)-7 × 7-CH₃OH surface is promoted, especially according to the dual characteristics and adsorption models we explored.     

Structure and stability of closo-hexaboranes and their heteroanalogs

The molecular and electronic structures of closo-hexaboranes B₆H₆ ^2–, B₆H₇ ^–, and B₆H₈ and closo-heterohexaboranes XYB₄H₄ (X = Y = CH, N; X = BH, Y = CH^–, N^–, NH, O) were studed by the ab initio (MP2(full)/6-311+G**) and density functional (B3LYP/6-311+G**) methods. The bridging H atoms in closo-hexaboranes B₆H₇ ^– and B₆H₈ can undergo facile low-barrier migrations around the boron cage (the barrier heights are about 10—15 kcal mol^–1). All heteroboranes having octahedron-like structures with hypercoordinated N and O atoms are rather stable and can be the subject of synthetic research efforts.     

Comparison of Ca2+ and Mg2+ binding to calmodulin. An enthalpy,entropy, and gibbs free energy analysis

A consistent set of G _B , H _B , and S _B parameters have been determined from ion specific electrode, calorimetric, and spectrophotometric studies for the binding of Ca²⁺ and Mg²⁺ to bovine calmodulin at pH=7.0 and an ionic strength I of 0.113M. A non-linear least squares analysis of calcium specific ion electrode data yields, on a molar basis, four calcium dissociation constants: 10^–7 for the first site, 10^–5 for the fourth site, and two constants between these values. Both calorimetric experiments and an indicator method provide evidence that Mg²⁺ binds to calmodulin, probably at the same sites as Ca²⁺, but with affinities about 100 times smaller: 4×10^–5 for the first site and 2×10^–3 for the fourth. Calorimetric titrations on Ca²⁺ binding to calmodulin in three buffers are consistent with 0.46 protons released upon binding at all four sites and yield an average H _B per site of 5.6 and 7.9 kJ-mol^–1 for Ca²⁺ and Mg²⁺, respectively. The entropy of the system increases by 524 and 361 J-K^–1-mol^–1 when Ca²⁺ and Mg²⁺, respectively, bind to four sites on calmodulin, i.e., the selectivity of calmodulin for Ca²⁺ is primarily derived from entropy effects. Further analysis based on elimination of the entropy term for the metal ions demonstrates that calmodulin bound to Ca²⁺ has a larger entropy than the unbound calmodulin; the opposite is true for calmodulin bound to Mg²⁺. These analyses are consistent with the hypothesis that Ca²⁺ forms tight complexes at all sites on calmodulin and that release of waters of hydration upon binding is the source of the increase of entropy in the system.     

Lithiated γ-O-functionalized propyl phenyl sulfides and sulfones of the type Li[CH(SOxPh)CH2CH2OR] (x = 0, 2). [Li{CH(SPh)CH2CH2Ot-Bu}(tmeda)] – A structurally characterized organolithium inner complex

Lithiation of O-functionalized alkyl phenyl sulfides PhSCH₂CH₂CH₂OR (R = Me, 1a; i-Pr, 1b; t-Bu, 1c; CPh₃, 1d) with n-BuLi/tmeda in n-pentane resulted in the formation of α- and ortho-lithiated compounds [Li{CH(SPh)CH₂CH₂OR}(tmeda)] (α-2a–d) and [Li{o-C₆H₄SCH₂CH₂CH₂OR)(tmeda)] (o-2a–d), respectively, which has been proved by subsequent reaction with n-Bu₃SnCl yielding the requisite stannylated γ-OR-functionalized propyl phenyl sulfides n-Bu₃SnCH(SPh)CH₂CH₂OR (α-3a–d) and n-Bu₃Sn(o-C₆H₄SCH₂CH₂CH₂OR) (o-3a–d). The α/ortho ratios were found to be dependent on the sterical demand of the substituent R. Stannylated alkyl phenyl sulfides α-3a–c were found to react with n-BuLi/tmeda and n-BuLi yielding the pure α-lithiated compounds α-2a–c and [Li{CH(SPh)CH₂CH₂OR}] (α-4a–b), respectively, as white to yellowish powders. Single-crystal X-ray diffraction analysis of [Li{CH(SPh)CH₂CH₂Ot-Bu}(tmeda)] (α-2c) exhibited a distorted tetrahedral coordination of lithium having a chelating tmeda ligand and a C,O coordinated organyl ligand. Thus, α-2c is a typical organolithium inner complex.Lithiation of O-functionalized alkyl phenyl sulfones PhSO₂CH₂CH₂CH₂OR (R = Me, 5a; i-Pr, 5b; CPh₃, 5c) with n-BuLi resulted in the exclusive formation of the α-lithiated products Li[CH(SO₂Ph)CH₂CH₂OR] (6a–c) that were found to react with n-Bu₃SnCl yielding the requisite α-stannylated compounds n-Bu₃SnCH(SO₂Ph)CH₂CH₂OR (7a–c). The identities of all lithium and tin compounds have been unambiguously proved by NMR spectroscopy (¹H, ¹³C, ¹¹⁹Sn).     

Preparation of new dinuclear half-titanocene complexes with ortho- and meta-xylene linkages and investigation of styrene polymerization

Half-titanocene is well-known as an excellent catalyst for the preparation of SPS (syndiotactic polystyrene) when activated with methylaluminoxane (MAO). Dinuclear half-sandwich complexes of titanium bearing a xylene bridge, (TiCl₂L)₂{(μ-η⁵, η⁵-C₅H₄-ortho-(CH₂–C₆H₄–CH₂)C₅H₄}, (4 (L = Cl), 7 (L = O-2,6-iPr₂C₆H₃)) and (TiCl₂L)₂{(μ-η⁵, η⁵-C₅H₄-meta-(CH₂–C₆H₄–CH₂)C₅H₄} (5 (L = Cl), 8(L = O-2,6-iPr₂C₆H₃)), have been successfully synthesized and introduced for styrene polymerization. The catalysts were characterized by ¹H- and ¹³C NMR, and elemental analysis. These catalysts were found to be effective in forming SPS in combination with MAO. The activities of the catalysts with rigid ortho- and meta-xylene bridges were higher than those of catalysts with flexible pentamethylene bridges. The catalytic activity of four dinuclear half-titanocenes increased in the order of 4 < 5 < 7 < 8. This result displays that the meta-xylene bridged catalyst is more active than the ortho-xylene bridged and that the aryloxo group at the titanium center is more effective at promoting catalyst activity compared to the chloride group at the titanium center. Temperature and ratio of [Al]:[Ti] had significant effects on catalytic activity. Polymerizations were conducted at three different temperatures (25, 40, and 70 °C) with variation in the [Al]:[Ti] ratio from 2000 to 4000. It was observed that activity of the catalysts increased with increasing temperature, as well as higher [Al]:[Ti]. Different xylene linkage patterns (ortho and meta) were recognized to be a principal factor leading to the characteristics of the dinuclear catalyst due to its different spatial arrangement, causing dissimilar intramolecular interactions between the two active sites.     

A theoretical study of the reaction of Ti+ with propane

Detailed quartet and doublet potential energy surfaces for the Ti⁺ + C₃H₈ → TiC₃H₆⁺ + H₂ and Ti⁺ + C₃H₈ → TiC₂H₄⁺ + CH₄ elimination reactions have been studied using density functional theory with B3LYP functional and ab initio coupled cluster CCSD(T) methods. Several H₂ elimination and CH₄ elimination reaction paths have been examined including the IRC following. In particular, the mechanisms involving, respectively, the H₂TiC₃H₆⁺ and CH₃TiHC₂H₄⁺ intermediates have been studied. Contribution to the Mark S. Gordon 65th Birthday Festschrift Issue.     

Tunable Diode Laser Absorption Studies of Hydrocarbons in RF Plasmas Containing Hexamethyldisiloxane

Tunable infrared diode laser absorption spectroscopy has been used to detect the methyl radical and three stable molecules, CH₄, C₂H₂ and C₂H₆, in radio frequency plasmas (f=13.56 MHz) containing hexamethyldisiloxane (HMDSO). The methyl radical concentration and the concentration of the stable hydrocarbons, produced in the plasma, have been measured in pure HMDSO discharges and with admixtures of Ar, while discharge power (P=20–200 W), total gas pressure (p=0.08–0.6 mbar), gas mixture and total gas flow rate (=1–10 sccm) were varied. The methyl radical concentration was found to be in the range of 10¹³ molecules cm^-3, while methane and ethane are the dominant hydrocarbons with concentrations of 10¹⁴–10¹⁵ mol cm^-3. Conversion rates to the measured stable hydrocarbons (RC(C_xH_y): 2×10¹²–2×10¹⁶ molecules J^-1 s^-1) could be estimated in dependence on power, flow, mixture and pressure. Under the used experimental conditions a maximum deposition rate of polymer layers of about 400 nm min^-1 has been found.     

Analysis of effect of specific C-H ...X interaction on the direct13C-1H spin-spin coupling constants based onab initio quantum-chemical calculations

Anab initio quantum-chemical calculation of the direct^13C–¹H spin-spin coupling constants in the CH₄–H₂O system was carried out and experimental data obtained for a series ofN-vinyl compounds were analyzed. The specific C-H ....X (X = O, N) intramolecular interactions result in increasing the direct¹³C–¹H spin-spin coupling constant of the hydrogen involved in bonding and decreasing the direct¹³C-¹H spin-spin coupling constant for the hydrogen atom that takes no part in the interaction.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1362–1365, Tune, 1996.     

Isotopic substitution effects on the volumetric and viscosimetric properties of water-dimethylsulfoxide mixtures at 25°C

Densities and viscosities of binary mixtures (H₂O or D₂O) (1) + (DMSO or DMSO-D6)(2) have been measured over the entire mole fraction range; and the excess volumes, excess viscosities, and excess partial molar volumes Vf of the components have been obtained. All systems show negative excess volume V^e at all compositions, values for mixtures containing D₂O being more negative than those with H₂O byca. 0.03 cm³-mol^-1 at x₁, = 0.6, where a minimum is observed. The difference between DMSO and DMSO-D6 containing mixtures is negligible. The excess viscosity η^e is always positive and shows a maximum at x₁ = 0.65; at this composition, the substitution of H₂O with D₂O causes an excess viscosity increment ofca. 0.35 mPa-s, while deuteration of DMSO brings about a smaller increase,ca. 0.1 mPa-s. The trend of V ₂ ^E with concentration shows the characteristic features of moderately hydrophobic solutes in water (negative values and a minimum in the water-rich region), features that are slightly but significantly more marked in D₂O than in H₂O. The V ₂ ^E values in the water-diluted region and at x₁, =0 are more negative for D₂O than for H₂O.     

Speed of Sound, Isentropic Compressibilities, and Excess Molar Volumes of Binary Mixtures Containing p-Dioxane

The speed of sound u in and densities of eight binary mixtures of p-dioxane (p-C₄H₈O₂) with methylcyclohexane (c-C₆H₁₁CH₃), 1-chlorohexane (C₆H₁₃C1), 1-bromohexane (C₆H₁₃Br), p-xylene [C₆H₄(CH₃)₂], propylbenzene (C₆H₅C₃H₇), methyl acetate CH₃COOCH₃), butyl acetate (CH₃COOC₄H₉), and amyl acetate (CH₃COOC₅H₁₁) were measured over the whole composition range at 30°C. Isentropic compressibilities (K _S), Rao's molar sound functions (R), excess molar volumes (V ^E), excess isentropic compressibilities (K _S ^E ) together with relative change in volume V/₁₂ values, have been obtained for all measured mole fractions. The excess partial molar volume (V₁-V ₁ ⁰ ) of p-dioxane in different solvents have also been estimated. The experimental results have been analyzed in terms of the Prigogine–Flory–Patterson theory of solutions.     

Nucleophilic addition of bifunctional sulfimidosulfides to platinum(<Emphasis Type="SmallCaps">IV</Emphasis>)-coordinated nitriles

Reactions of the platinum(IV) nitrile complexes [PtCl₄(RCN)₂] (R = Me, CH₂Ph, Ph) with 1,2- and 1,4-PhS(=NH)C₆H₄SPh in CH₂Cl₂ afforded addition products of sulfimides and coordinated nitriles, viz., the [PtCl₄{NH=C(R)N=S(Ph)(C₆H₄SPh)}₂] complexes. The latter were isolated in 75—90% yields and characterized by elemental analysis, positive-ion FAB mass spectrometry, IR spectroscopy, and ¹H and ¹³C¹H NMR spectroscopy. The temperature dependence of the ¹H NMR spectra of the model [PtCl₄{NH=C(R)N=SPh₂}₂] complexes (R = Me, Et) in CD₂Cl₂ studied in a temperature range from +40 to -70 °C demonstrated that E—Z isomerization of the ligands is a dynamic process in a range from +40 to -10 °C. The activation free energy of this process was calculated.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1618–1622, August, 2004.