Equilibrium Chemistry in $${\text {BCl}}_3$$ BCl 3 – $${\text {H}}_2$$ H 2 –Ar Plasma

Plasma Chemistry and Plasma Processing - The approach, which was developed earlier for modeling chemical reactions in laser induced plasmas, is applied to radio-frequency discharge plasmas. The...     

Electrochemistry of Interaction Between Flavin Mononucleotide (FMN) and PM-17 as Antitumoral ε-Keggin Core Compound, \left[ {{\text{H}}_{ 2} {\text{Mo}}_{ 1 2}^{\text{V}} {\text{O}}_{ 2 8} \left( {\text{OH}} \right)_{ 1 2} \left( {{\text{Mo}}^{\text{VI}} {\text{O}}_{ 3} } \right)_{ 4} } \right]^{ 6- } at pH 7.5

In order to obtain a clue to the antitumor mechanism of $\left[ {{\text{Me}}_{ 3} {\text{NH}}} \right]_{ 6} \left[ {{\text{H}}_{ 2} {\text{Mo}}_{ 1 2}^{\text{V}} {\text{O}}_{ 2 8} \left( {\text{OH}} \right)_{ 1 2} \left( {{\text{Mo}}^{\text{VI}} {\text{O}}_{ 3} } \right)_{ 4} } \right]$ ·2H₂O (PM-17), the interaction of PM-17 with flavin mononucleotide (FMN) as a prosthetic group of the flavoprotein has been investigated by both polarographic analysis and isothermal titration calorimetry (ITC) technique at the physiological solution pH (7.5). The half-wave potential (?0.50 V vs. Ag/AgCl) of the d.c. polarogram for the quasi-reversible one-electron reduction of FMN was shifted by PM-17 toward a more positive potential with a resultant deviation from one-electron reduction to formally more than one-electron reduction waves. The PM-17 effect on the d.c. polarogram could be explained by a variety of FMN···(PM-17)_n (n > 0) aggregates with multiple conformations which was supported by the thermodynamic parameters (ΔH = ?29.7 kJ mol^?1, ΔS = ?28.2 J mol^?1 K^?1, ΔG = ?21.5 kJ mol^?1, and number of FMN in the binding with PM-17 (N) = 0.053 at 20 °C) estimated by the ITC technique. A large conformational change of the FMN domain by the FMN···(PM-17)_n aggregates is suggested to prevent the movement of the FMN centers into close proximity with nicotinamide adenine dinucleotide (NADH) with a resultant depression of the electron transport in NADH dehydrogenase.     

Intramolecular Nonvalent Interactions in the $${\text{Eu}}_{{\text{2}}}^{{{\text{II}}}}$$ EuIII(μ-ORF)2(μ2-ORF)3(μ3-ORF)2(DME)2 Complex

Russian Journal of Coordination Chemistry - A quantum chemical study of fluorinated europium alcoholate $${\text{Eu}}_{{\text{2}}}^{{{\text{II}}}}$$...     

MHD mixed convection of $$ {\text{Al}}_{2} {\text{O}}_{3} $$ Al 2 O 3 –Cu–water hybrid nanofluid in a wavy channel with incorporated fixed cylinder

Journal of Thermal Analysis and Calorimetry - This study deals with mixed convection of $$ {\text{Al}}_{2} {\text{O}}_{3} $$ –Cu–water hybrid nanofluid in a wavy channel having a...     

Mixed-Ligand Complexes Zn(2,2′-Bipy)(ROCS2)2 with Mono- and Bidentate Ligands {\text{ROCS}}_{\text{2}}^ - (R = i-Pr, i-Bu)

The mixed-ligand complexes Zn(2, -Bipy)(i-PrOCS₂)₂ (I) and Zn(2, -Bipy)(i-BuOCS₂)₂ (II) were synthesized. Their structures were solved using the X-ray diffraction data (CAD-4 diffractometer, MoK radiation, 1873 and 1948 F _hkl , R = 0.0357 and 0.0338). The crystals are triclinic with unit cell dimensions a = 10.002(2), b = 11.080(2), c = 11.756(2) , = 78.46(3), = 75.49(3), = 63.50(3)°, V = 1122.9(4) ³, Z = 2, space group (for complex I) and a = 8.760(2), b = 12.520(3), c = 13.252(3) , = 63.93(3), = 71.10(3), = 88.01(3)°, V = 1225.2(5) ³, Z = 2, space group (for II). The structures are based on discrete monomeric molecules. The polyhedra of Zn atoms are tetragonal pyramids (ZnN₂S₃, c.n. 4+1, both bidentate and monodentate ligands coordinated to the Zn atom). The packing of molecules and the character of their interaction in the structures are considered.     

Direct chemiluminescence determination of fenbufen by the enhancement of the {\text{Ru}}\left( {{\text{phen}}} \right)_3^{2 + } –cerium(IV) system

A method is described for determination of fenbufen that is based on the chemiluminescence (CL) reaction of the ${\text{Ru}}\left( {{\text{phen}}} \right)_3^{2 + } $ –cerium(IV)–fenbufen system. An enhanced CL reaction was developed, and optimum conditions for CL were investigated. The CL was linearly dependent on fenbufen concentration in the range 4.0?×?10^?8–9.0?×?10^?6 mol L^?1. The detection limit was 2.0?×?10^?8 mol L^?1. The relative standard deviation (RSD) was 2.8% for eleven measurements of 6.0?×?10^?7 mol L^?1 fenbufen standard solution. The new method enables simple, sensitive, and rapid determination of fenbufen and has been used for determination of fenbufen in pharmaceutical preparations in capsule, spiked serum and urine samples.     

Application of the Molecular Invariom Model for the Study of Interactions Involving Fluorine Atoms in the { $${\text{Yb}}_{{\text{2}}}^{{{\text{II}}}}$$ (μ2-OCH(CF3)2)3(μ3-OCH(CF3)2)2YbIII(OCH(CF3)2)2(THF)(Et2O)} Complex

Russian Journal of Coordination Chemistry - The electron density distributions obtained by the quantum-chemical (density functional theory) calculations and molecular invariom model in the trimeric...     

Electrical properties of the protonic conductor 1 mol% Y-doped $$ {\hbox{BaZr}}{{\hbox{O}}_{{3 - \delta }}} $$

Much attention has been paid to barium zirconates because their high protonic conductivity and chemical stability are excellent properties for solid electrolytes. However, most studies have focused on highly doped materials such as 10 or 20 mol% Y-doped barium zirconates. In this study, the bulk and the grain boundary electrical properties of 1 mol% Y-doped barium zirconate are investigated as a function of temperature, water partial pressure, and oxygen partial pressure. At low temperatures and in wet atmospheres, the bulk of the barium zirconate predominantly conducts protonic defects, whereas, at high temperatures and in dry conditions, it is mixed oxygen ionic and electron-hole conducting. In the grain boundary, the protonic conductivity is a few orders of magnitude lower than the protonic conductivity in the bulk. In this study, possible causes for the low protonic conduction at the grain boundaries are considered.     

Vibratio nal assig nme nts,co nformatio nal a nalysis,a nd molecular structures of $$\left[ {\text{C}_{\text{ n}} \text{mim}} \right]\left[ {\text{NTF}_{\text{2}} } \right]$$C nmimNTF2 ( n = 2, 4, 6, a nd 8) imidazolium-based io nic liquids: a combi ned experime ntal a nd qua ntum chemical approach

This work is aimed at providing physical insights about the interactions of cations, anion, and ion pairs of four imidazolium-based ionic liquids of \(\left[ {{\text{C}}_{\text{n}} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\) with varying alkyl chain lengths (n = 2, 4, 6, and 8) using both DFT calculations and vibrational spectroscopic measurements (IR absorption and Raman scattering) in the mid- and far regions. The calculated Mulliken charge distributions of \(\left[ {{\text{C}}_{\text{n}} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\) ion pairs indicate that hydrogen-bonding interactions between oxygen and nitrogen atoms (more negative charge) on \(\left[ {{\text{NTF}}_{2} } \right]^{ - }\) anion and the hydrogen atoms (more positive charge) on the imidazolium ring play a dominating role in the formation of ion pair. Thirteen stable conformers of \(\left[ {{\text{C}}_{2} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\) were optimized. According to our results, the strongest and weakest hydrogen bonds were existing in \(\left[ {{\text{C}}_{2} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\) and \(\left[ {{\text{C}}_{8} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\), respectively. A redshift of 290, 262, 258, and 257 cm^?1 has been observed for cations involving \(\left[ {{\text{C}}_{2} {\text{mim}}} \right]^{ + }\), \(\left[ {{\text{C}}_{4} {\text{mim}}} \right]^{ + }\),\(\left[ {{\text{C}}_{6} {\text{mim}}} \right]^{ + }\), and stretching vibrations of \({\text{C}}12{-}{\text{H}}3\), respectively. By increasing the chain length, the strength of hydrogen bonds decreases as a result of \({\text{C}}12{-}{\text{H}}3\) bond elongation and less changes are observed in stretching vibrations of \({\text{C}}12{-}{\text{H}}3\) compared to the free cations. To the best of our knowledge, this research is the first work which reports the far-IR of \(\left[ {{\text{C}}_{4} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\), \(\left[ {{\text{C}}_{6} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\), and \(\left[ {{\text{C}}_{8} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\) and the mid-IR of \(\left[ {{\text{C}}_{8} {\text{mim}}} \right]\left[ {{\text{NTF}}_{2} } \right]\).     

SYNTHESIS AND STRUCTURE OF SALTS OF THE N,N′,N″-TRIS(4-(PHENYLDIAZENYL)PHENYL) IMIDOSULFITE ANION – AN ORGANIC ANALOGUE OF $$\mathbf{SO}_{\mathbf{3}}^{\mathbf{2}-}$$

Journal of Structural Chemistry - Reduction of 4,4′-bis-(phenyl azo)-diphenyl thiodiimide S(=N–C6H4–N=N–C6H5)2 (1) in tetrahydrofuran (ТHF) with potassium-intercalated...     

Preparation,Structure, and Reactivity of ≡Si– $${\text{N}}^ \cdot$$ –H Radicals

A method is developed for the synthesis of Si– –H radicals on a silica surface and information is obtained by ESR and quantum chemical calculations of model systems on their structure and spectral (radiospectroscopic) characteristics. The reactivity of these radicals toward CO, H₂, and H₂=H₂ molecules is studied. The structure of the Si–HN– =O radical is analyzed, which is the product of CO addition. The kinetic and thermochemical characteristics of processes with the participation of synthesized radicals are determined.     

Schrödinger equations on $${\mathbb{R}^3 \times \mathcal{M}}$$ with non-separable potential

We consider the problem of defining the Schrödinger equation for a hydrogen atom on \({\mathbb{R}^3 \times \mathcal{M}}\) where \({\mathcal{M}}\) denotes an m dimensional compact manifold. In the present study, we discuss a method of taking non-separable potentials into account, so that both the non-compact standard dimensions and the compact extra dimensions contribute to the potential energy analogously to the radial dependence in the case of only non-compact standard dimensions. While the hydrogen atom in a space of the form \({\mathbb{R}^3 \times \mathcal{M}}\) , where \({\mathcal{M}}\) may be a generalized manifold obeying certain properties, was studied by Van Gorder (J Math Phys 51:122104, 2010), that study was restricted to cases in which the potential taken permitted a clean separation between the variables over \({\mathbb{R}^3}\) and \({\mathcal{M}}\) . Furthermore, though there have been studies on the Coulomb problems over various manifolds, such studies do not consider the case where some of the dimensions are non-compact and others are compact. In the presence of non-separable potential energy, and unlike the case of completely separable potential, a complete knowledge of the former case does not imply a knowledge of the latter.     

Inclusion complexes of $$\hbox{cholesteryl-(}\varepsilon\hbox{-caprolactone})_{\overline{10}}$$ functionalized polymer with γ-cyclodextrin

An inclusion complex (IC) of γ-cyclodextrin with biodegradable \(\hbox{cholesteryl-(}\varepsilon\hbox{-caprolactone})_{\overline{10}}\) \(\hbox{(Chol-(CL)}_{\overline{10}})\) functionalized polymer was prepared by using a general method of mixing solution. The formation of \(\gamma \hbox{-CD-Chol-(CL)}_{\overline{10}}\) IC was determined by Fourier transform infrared (FTIR),¹H-NMR, differential scanning calorimetry (DSC), and wide angle X-ray diffraction (WAXD), respectively. The results indicated that the \(\hbox{oligo}(\varepsilon\hbox{-CL})_{\overline{10}}\) blocks as well as the end cholesteryl moiety of the functionalized polymer were included and covered by γ-CD in a single-stranded mode in the \(\gamma \hbox{-CD-Chol-(CL)}_{\overline{10}}\) ICs. Moreover, the \(\gamma \hbox{-CD-Chol-(CL)}_{\overline{10}}\) ICs had a channel-type crystalline structure similar to that formed between the poly(propylene glycol) (PPG) and γ-CD. Finally, TGA revealed that the ICs had better thermal stability than their free components due to the inclusion complexation.     

Coating of $$\hbox {C}_{60}$$ by para-$$\hbox {H}_2$$H2 and ortho-$$\hbox {D}_2$$D2: revisiting the solvation shell—CMMSE

The solvation of Buckminsterfullerene \(\hbox {C}_{60}\) by para-hydrogen and ortho-deuterium clusters has been modeled using a dedicated potential and path-integral molecular dynamics simulations at low temperature (2 K). The solvation shell obtained from the distribution of radial distances is found to be complete near 50 molecules, in agreement with recent mass spectrometry measurements. Deuteration increases the shell size by one, indicating a denser shell owing to less prominent vibrational delocalization for this heavier isotope.     

Thermodynamic Model for BiPO4(cr) and Bi(OH)3(am) Solubility in the Aqueous Na+–H+–\mathrm{H}_{2}\mathrm{PO}_{4}^{-}–\mathrm{HPO}_{4}^{2-}–\mathrm{PO}_{4}^{3-}–OH−–Cl−–H2O System

Prior to this study no data for the solubility product of BiPO₄(cr) or the complexation constants of Bi with phosphate were available. The solubility of BiPO₄(cr) was studied at 23±2?°C from both the over- and under-saturation directions as functions of a wide range in time (6–309 days), pH values (0–15), and phosphate concentrations (reaching as high as 1.0 mol?kg^?1). HCl or NaOH were used to obtain a range in pH values. Steady state concentrations and equilibrium were reached in <6 days. The data were interpreted using the SIT model. These extensive data provided a solubility product value for BiPO₄(cr) and an upper limit value for the formation of BiPO₄(aq). Because the aqueous system in this study involved relatively high concentrations of chloride, reliable values for the complexation constants of Bi with chloride were required to accurately interpret the solubility data. Therefore as a part of this investigation, existing Bi–Cl data were critically reviewed and used to obtain values of equilibrium constants for various Bi–Cl complexes at zero ionic strength along with the values for various SIT ion interaction parameters. Predictions based on these thermodynamic quantities agreed closely with our experimental data, the chloride concentrations of which ranged as high as 0.7 mol?kg^?1. The study showed that BiPO₄(cr) is stable at pH values <9.0. At pH values >9.0, Bi(OH)₃(am) is the solubility controlling phase. Reliable values for the Bi(OH)₃(am) solubility reactions involving Bi(OH)₃(aq) and $\mathrm{Bi}(\mathrm{OH})_{4}^{-}$ and the formation constants of these aqueous species are also reported.     

Unimolecular reactions of \documentclass{article}\pagestyle{empty}\begin{document}$ ^ \cdot {\rm CH}_2 {\rm CH}_2 \mathop {\rm O}\limits^ + {\rm HCH}_2 {\rm CH}_2 {\rm CH}_3 $\end{document} β?distonic ion

The β-distonic ion $ ^ \cdot {\rm CH}_2 {\rm CH}_2 \mathop {\rm O}\limits^ + {\rm HCH}_2 {\rm CH}_2 {\rm CH}_3 $ has been shown previously to be an intermediate in the fragmentation of ionized ethyl propyl ether. The reactions of this ion (generated by fragmentation in the ion source of alkyl propyl ethers of glycol) were studied in this work. Labelling showed that this ion undergoes competing hydrogen transfers leading to a series of isomeric distonic ions. Each of them was submitted to an isotope effect.     

Synthesis and Structure of Ruthenium Complexes $$\rm[{Ph_{3}PR]_2^+[RuCl_6]^{2-}}$$ (R = C2H5, CH=CHCH3, CH2CH=CHCH3, CH2OCH3), and $$\rm[{Ph_{3}PCH_2CH=CHCH_2{PPh_3}]_2^{2+}[Ru_2Cl_{10}O]^{4-}}$$[Ph3PCH2CH=CHCH2PPh3]22+[Ru2Cl10O]4−· 4H2O

Complexes \(\rm[{Ph_{3}PR]_2^+[RuCl_6]^{2-}}\), where R = C₂H₅ (I), CH=CHCH₃ (II), CH₂CH=CHCH₃ (III), and CH₂OCH₃ (IV), have been prepared by the reaction between ruthenium(III) chloride hydrate and triphenylorganylphosphonium chlorides in dimethylsulfoxide in the presence of hydrochloric acid. A hydrochloric acid solution of ruthenium(III) chloride hydrate when mixed with an aqueous solution of 2-butylene-1,4- bis(triphenylphosphonium dichloride) followed by recrystallization from dimethylsulfoxide results in complex \(\rm[{Ph_{3}PCH_2CH=CHCH_2{PPh_3}]_2^{2+}[Ru_2Cl_{10}O]^{4-}}\)· 4H₂O (V). According to X-ray diffraction data, phosphorus atoms in mono- and binuclear cations have slightly distorted tetrahedral coordination (CPC 105.54(13)°?113.00(8)°, P?C 1.758(9)?1.839(7) Å). In slightly distorted octahedral anions [RuCl₆]^2? of complexes I–IV, the Ru?Cl bond lengths vary in the range 2.3222(6)?2.340(2) Å; the cis-ClRuCl and trans-ClRuCl angles are 89.133(18)°–90.867(18)° and 179.53(13)°–180°, respectively. In the binuclear [(RuCl₅)₂O]^4? anion of complex V, RuCl₅ fragments are bonded by a bridging oxygen atom. The Ru–Cl bond lengths fall in the range 2.3375(8)?2.3957(8) Å; the Ru–O bond length is 1.7832(2) Å. The cis-ClRuCl, trans-ClRuCl, cis-ORuCl, and trans-ORuCl angles are 86.67(3)°?91.28(3)°, 174.60(3)°?174.83(3)°, 91.49(2)°?93.65(2)°, and 178.39(2)°, respectively. In crystals I–V, interionic hydrogen bonds Cl···H_cation (2.63?2.95 Å), Cl··· \({\rm{H}_{{H_2}O}}\) (2.35?2.79 Å), and H_cation···\({\rm{O}_{{H_2}O}}\) (1.72?1.93 Å) (for V) are found.     

Acid–Base Properties of the \mathrm{Fe}(\mathrm{CN})_{6}^{3-}/\mathrm{Fe}(\mathrm{CN})_{6}^{4-} Redox Couple in the Presence of Various Background Mineral Acids and Salts

The acid?Cbase behavior of $\mathrm{Fe}(\mathrm{CN})_{6}^{4-}$ was investigated by measuring the formal potentials of the $\mathrm{Fe}(\mathrm{CN})_{6}^{3-}$ / $\mathrm{Fe}(\mathrm{CN})_{6}^{4-}$ couple over a wide range of acidic and neutral solution compositions. The experimental data were fitted to a model taking into account the protonated forms of $\mathrm{Fe}(\mathrm{CN})_{6}^{4-}$ and using values of the activities of species in solution, calculated with a simple solution model and a series of binary data available in the literature. The fitting needed to take account of the protonated species $\mathrm{HFe}(\mathrm{CN})_{6}^{3-}$ and $\mathrm{H}_{2}\mathrm{Fe}(\mathrm{CN})_{6}^{2-}$ , already described in the literature, but also the species $\mathrm{H}_{3}\mathrm{Fe}(\mathrm{CN})_{6}^{-}$ (associated with the acid?Cbase equilibrium $\mathrm{H}_{3}\mathrm{Fe}(\mathrm{CN})_{6}^{-}\rightleftharpoons \mathrm{H}_{2}\mathrm{Fe}(\mathrm{CN})_{6}^{2-} + \mathrm{H}^{+}$ ). The acidic dissociation constants of $\mathrm{HFe}(\mathrm{CN})_{6}^{3-}$ , $\mathrm{H}_{2}\mathrm{Fe}(\mathrm{CN})_{6}^{2-}$ and $\mathrm{H}_{3}\mathrm{Fe}(\mathrm{CN})_{6}^{-}$ were found to be $\mathrm{p}K^{\mathrm{II}}_{1}= 3.9\pm0.1$ , $\mathrm{p}K^{\mathrm{II}}_{2} = 2.0\pm0.1$ , and $\mathrm{p}K^{\mathrm{II}}_{3} = 0.0\pm0.1$ , respectively. These constants were determined by taking into account that the activities of the species are independent of the ionic strength.     

Theoretical Study on the Stable Structures and Aromaticities for Pnictogen Dianionic Sb4^2-, Bi4^2-, and （SbBi）2^2- Clusters

Through the theoretical calculation of structural optimization, vibrational frequencies and atomization energies with one method of density functional theory （B3LYP） and two post- Hartree-Fock approaches （MP2, CCSD（T））, several stable isomers for new three pnictogen dianionic Sb4^2-, Bi4^2-, and （SbBi）2^2- species were determined. For two homoatomic Sb4^2- and Bi4^2- species, there are three stable isomers： square （D4h）, roof-shaped （C2v-1）, and C2v-2 structure with the square isomer being the ground state. For the heteroatomic dian- ionic （SbBi）2^2- species, there are also three stable isomers： rhombus （D2h）, roof-shaped （C1）, and C2v structures with the rhombic isomer being the ground state. The calculated NICS values show that nucleus-independent chemical shifts （NICS） values of roof-shaped isomers for Sb4^2-, Bi4^2-, and （SbBi）2^2- species are all negative, consequently indicating that these roof-shaped isomers possess aromaticities. NICS values for the planar ring isomers are all positive, suggesting that these three planar ring isomers have antiaromatic characters. The aromaticity for the two stable roof-shaped and square isomers are preliminarily explained and discussed with MO analysis.