Vol 65, No 1 (2016)

A survey of publications concerning the properties of solids in relation to wetting phenomena is presented. Factors influencing the contact angle value as well as problems of objective approach to research into wetting phenomena are discussed. Peculiarities of the direct and reverse processes during the formation of the solid—liquid—vapor three-phase contact and the inevitability of contact angle hysteresis for polar solids and liquids are analyzed. It is suggested that contact angle hysteresis is due to high energy of the interaction between the liquid and the solid and hence a long relaxation time of the three-phase contact system. Specific features of the response of a solid surface to all surface processes (“chemomechanics”) is discussed. Cleaning of solid surfaces as well as surface preparation for repeated measurements is considered. It is shown that good reproducibility of results is possible if conditions for sample preparation are met. The results of determination of the activation energy for wetting of glass surface with water are presented. The influence of the structure of solids (their hardness) on the contact angle values is demonstrated. Inevitability of the presence of different-type active sites characterized by different dissociation constants (pK_a) on the surface of solids is discussed. The pK_a values and content of these surface sites obtained from potentiometric titration and wetting data are estimated. The estimates thus obtained are in reasonable agreement with each other and can thus be used in practical applications. However, potentiometric titration is currently inappropriate for evaluating the content of individual surface sites as well as the surface charge.

The combinatorial-topological modeling of 3D periodic packings of layers composed of T₁₂ polyhedral clusters (t-hpr tiles in the form of hexagonal prisms) was carried out. The T12 clusters are among the most abundant units in the crystal structures of zeolites. The layers were produced by decoration of the vertices of the square and hexagonal (graphite-like) nets with T₁₂ clusters. All combinatorially possible patterns of 3D frameworks, which were constructed based on packings of decorated square nets, correspond to known zeolite structures: CHA (mineral chabazite, Ca₆(H₂O)₄₀Al₁₂Si₂₄O₇₂), AEI (AlPO-18, Al₂₄P₂₄O₉₆), SAV ((C₁₈H₄₂N₆)₂(H₂O)₇Mg₅Al₁₉P₂₄O₉₆), and KFI (Na₃₀(H₂O)₉₈Al₃₀Si₆₆O₁₉₂). The modeling using the same scheme and a decorated hexagonal net gave rise to the frameworks of three known zeolites, GME (gmelinite, (Ca,Na)₄(H₂O)₂₄A_l8Si₁₆O₄₈), AFX (SAPO-56, H₃Al₂₃Si₅P₂₀O₉₆), and AFT (AlPO-52, Al₃₆P₃₆O₁₄₄), as well as of one previously unknown hypothetical zeolite ISC-2 with the unit cell parameters a = 13.90 Å, c = 30.00 Å, V = 5019.7 ų, sp. gr. \(P\bar 6m2\). Zeolite ISC-2 contains a cavity with a new t-isc-2 topology [4²¹.6².8¹⁵], which is responsible for its unique framework. An analysis of the specially created database of topological types of molecules (TTM collection) containing geometric and topological characteristics of more than 300000 different molecules suggested an organic structure-directing agent, which stabilizes the t-isc-2 cavity and which can be used for the synthesis of ISC-2.

The self-assembly of tetrathiacalix[4]arene and tetraoxacalix[4]arene molecules functionalized by hydrazide groups was studied by DFT calculations at B3LYP/6-31G(d,p) level. The calculations were performed for the cone and 1,3-alternate conformations. The associates of calix[4]arenes in the cone conformation are stabilized by multiple hydrogen bonds with inclusion of all hydrazide groups in the formation of the globule, which suppresses the formation of extended structures.

The theoretical study of the reactivity of catecholate and o-amidophenolate complexes of Sb^V in the reversible binding of molecular oxygen was performed. The evaluation of the strength of intramolecular interactions in pre-reaction complexes provides the assessment of the strength of oxygen binding in the coordination sphere of Sb. The initial complexes, their transition states, and final spiroendoperoxide complexes were modeled. The calculated activation energies of the reaction and ionization can serve as the energy criteria providing the explanation and prediction of interactions of these complexes with molecular oxygen.

The heat capacity and the temperatures and enthalpies of physical transformations of the alternating terpolymer of carbon monoxide, ethylene, and 1-butene (the content of butene units is 10.7 mol.%) were studied by adiabatic and differential scanning calorimetry in the temperature range from 6 to 520 K. The energy of terpolymer combustion was measured at 298.15 K on an calorimeter with an isothermal shell and static bomb. The standard thermodynamic functions C°_p(T), H°(T)–H°(0), S°(T)–S°(0), and G°(T)–H°(0) for the range from Т → 0 to 400 K, the standard enthalpy of combustion, and the thermodynamic parameters of formation of the partially crystalline CO—ethylene—1-butene terpolymer at 298.15 K, as well as the thermodynamic characteristics of its synthesis in the range from T → 0 to 400 K were calculated.

The β → γ polymorphic transformation (PT) in polycrystalline 1,1-diamino-2,2-dinitroethylene (DADNE) was studied by isothermal calorimetry. The kinetics of the β → γ PT, like that of the α → β process studied earlier, follows the first-order autocatalytic equation. The rate constants and activation energy of the process were determined. The kinetics of the reverse β → α and γ → α PTs in DADNE was studied by IR spectroscopy. The rates of the β → α and γ → α PTs follow first-order kinetics with the rate constants that depend on morphological features of the crystals. The general features of the kinetics of direct and reverse polymorphic transformations in molecular crystals of energetic compounds are discussed.

The thermodynamic characteristics for complex formation of molecules of the cage structure with β-cyclodextrin (β-CD) were determined using gas liquid chromatographic columns with glycerol and glycerol + β-CD as with stationary liquid phases assuming equilibrium conditions at infinitely low sorbate concentrations in the gas phase. The influence of the nature and number of substituents in the adamantane fragment on the stability of the formed complexes was shown. Unlike adamantanes, the series of n-decane derivatives shows a decrease in chromatographic retention after addition of β-CD to glycerol indicating the absence of strong interactions of the linear sorbates with β-CD molecules. The parameters were determined for the regression equations relating the values of specific retention volumes to molecular parameters of sorbates such as polarizability, molar volume, liphophilicity, and others. The parameters of the derived equations were used for the determination of the relative contribution of various molecular descriptors to chromatographic retention of the adamantane derivatives on the sorbents studied.

Deposition of Ni(OH)₂ from an aqueous solution of Ni(N₃)₂ onto highly porous carbon matrices of two types with different porous structure afforded high-purity nanostructured hydroxide—carbon composites with a regular spatial morphology, which are filled with Ni(OH)₂ nanocrystallites (up to 30.9 wt.%) and have high values of specific suface area (up to 1875 m² g^–1) and porosity (up to 2.65 cm³ g^–1). Largeand small-angle X-ray diffraction and low-temperature nitrogen absorption on composites showed that nanocrystallites with a brucite-type layered structure form as plates with a thickness of 2—4 nm and a size along the developed face (001) of 25—30 nm in mesopores and on the outer surface of matrices. The degree of mesopore filling with crystallites depends on the mesopore size and the composition of composites; the micropores remain mainly unfilled. The increase in the hydroxide content results in pore size redistribution: in general, the distribution curves shift in favor of smaller mesopore sizes; the portion of pores with sizes comparable with the thickness of filler nanoplates (3—6 nm), as well as the portion of mid-sized pores (20—30 nm) decrease significantly in favor of smaller pores (8—12 nm). Partial blocking (clogging) of pores with filler nanocrystallites was also observed.

Palladium was combined with porous silicon into catalytically active functional electrode nanocomposites. Palladium nanoparticles were examined by transmission electron microscopy and atomic force microscopy; their catalytic activity was estimated using cyclic voltammetry.

Supramolecular nanocontainers based on monocationic and gemini surfactants and oppositely charged polyelectrolytes (polyacrylic acid, polyethyleneimine) for the stabilization and enhancement of solubility of hydrophobic quantum dots CdSe/ZnS were formed. The size (from 2 to 70 nm depending on the type of nanocontainers) and shape of aggregates containing quantum dots were determined by transmission electron microscopy. It was shown that the nature of the stabilizing agent influences the morphology of aggregates. The increase in photostability of quantum dots in micellar solutions of gemini surfactants and the possibility of their preservation in the polyelectrolyte capsules are identified.

Two sonochemiluminescence mechanisms were established in peroxide solutions. The sonochemiluminescence intensity often exceeds the sonoluminescence intensity of solvents caused by inelastic collisions of cavitation bubbles in the gas phase. In solutions of peroxides, whose chemiluminescence decomposition proceeds via the monomolecular peroxide decomposition involving no radical intermediates with a high activation energy, in particular, for adamantylidenadamantane-1,2-dioxetane, the mechanism based on the total thermal ultrasonic action on the solution takes place. The initiation of chemiluminescence reactions of peroxide decomposition by radical products of solvent sonolysis is a source of sonochemiluminescence for peroxides decomposing via the radical mechanism, for example, for cumene peroxide.

Conditions for chemical assembly of new heterometallic trinuclear pivalates [Cd₂M(piv)₆L₂] (M = Mg, Ca, or Sr; piv is pivalate) were found. Reactions with the nonchelating ligand 2,4-lutidine (lut) gave the crystals of heterometallic complexes [Cd₂M(piv)₆(lut)₂] (M = Mg (1), Ca (2), and Sr (3)). With the chelating ligand 1,10-phenanthroline (phen), only the homometallic dimer [Cd₂(piv)₄(phen)₂] (4) was obtained under these conditions. Yet heterometallic trinuclear complexes with 1,10-phenanthroline ([Cd₂Mg(piv)₆(H₂O)(phen)₂] (5), [CaCd₂(piv)₆(phen)₂] (6), and [Cd₂Sr(piv)₆(phen)₂]∙2MeCN (7)) were synthesized by reactions of phen with complexes 1—3. For all the complexes obtained, the molecular and crystal structures as well as the details of their molecular architecture were determined. The thermal behavior of aqua complex 5 was studied by TG and DSC. The complex eliminated the water molecule between 130 and 180 °C with a high endothermic effect (Q = 101 kJ mol^–1) due to (1) intramolecular hydrogen bonds that stabilize its molecular architecture and (2) subsequent structural rearrangements.

A reaction of 7-alkyl-, 7-allyl-, 7-phenyl-1,3,5-cycloheptatrienes with 1,2-dienes in the presence of the two-component catalytic system Ti(acac)₂Cl₂—Et₂AlCl, which led to the formation of practically important substituted endo-bicyclo[4.2.1]nona-2,4-dienes in up to 90% yields, was accomplished for the first time.

1,2,3-Thiadiazolylureas containing amino acid residues were synthesized. These compounds were converted to 5-sulfanyl-1,2,3-triazol-1-ylaminocarboxylic acid sodium salts under alkaline conditions. These salts were found to inhibit the oxidation of ascorbic acid with air oxygen. In the presence of the equimolar amount of 5-sulfanyl-1,2,3-triazoles, the rate of diminution of ascorbic acid decreased by 1.5—3 times, whereas in the case of their two-fold excess by a factor of 5.

The Biginelli reaction between 5-R-salicylic aldehyde (R = H, Me, and Br), α-nitroacetophenone, and urea affords 8-R-11-nitro-2-phenyl-5,6-dihydro-2H-2,6-methanobenzo-[g][1,3,5]oxadiazocin-4(3Н)-ones as mixtures of two diastereomers. The ratio of diastereomers depends on the catalyst (HCl) concentration in the reaction medium. In DMSO and DMF, the resulting compounds undergo oxadiazocine ring opening with establishment of a three-component equilibrium between 4-(2-hydroxy-5-R-phenyl)-5-nitro-6-phenyl-3,4-dihydropyrimidin-2(1Н)-one as the major component and diastereomeric methanobenzoxadiazocines as two minor components. Dilution of these solutions with water favors the oxa-Michael reaction resulting in the reverse transformation of dihydropyrimidinones into the corresponding starting diastereomers.

Amino derivatives of methylenebisphosphonic acids were synthesized by phosphorylation of formamide, nitriles or hydrochlorides of alkyl imidates with H₃PO₃—PCl₃—(Me₃Si)₂NH.

The properties of the reaction products of hydrolytic lignin with nitric acid in water—dioxane medium were studied. The products are a mixture of nitrogen-containing oligomeric compounds with high degree of polydispersity.

Reactions of vanadyl sulfate (VOSO₄∙3H₂O) with dimethylmalonic (H₂Me₂mal = = C₃H₆(CO₂H)₂), cyclobutane-1,1-dicarboxylic (H₂cbdc = C₄H₆(CO₂H)₂), or butylmalonic acid (H₂Bumal = C₄H₁₀(CO₂H)₂) and Li₂CO₃ in a ratio of 1: 2: 2 afforded novel coordination polymers of similar compositions ([Li₂(VO)(Me₂mal)₂]_n (1), [Li₂(VO)(Me₂mal)₂(EtOH)-(H₂O)]_n (2), [Li₄(VO)₂(cbdc)₄(H₂O)₇]_n (3), and [Li₂(VO)(Bumal)₂(H₂O)_5.5]_n (4)) but different structures. The crystal structures of the compounds containing the Me₂mal^2– and Bumal^2– anions depend on the solvent nature.

The sizes (hydrodynamic diameter) and ζ potentials of sodium N-acryloyl-11-aminoundecanoate and poly(sodium N-acryloyl-11-aminoundecanoate) with molecular weights of 10 000, 100 000, and 250 000 were determined using dynamic light scattering. The particle size of the formed aggregates of the macromolecules depends on the molecular weight. The value of ζ potential of the aggregates increases with an increase in the molecular weight of the polymer. The influence of the systems based on the monomer and polymers on the alkaline hydrolysis of 4-nitrophenyl chloroethyl methylphosphonate was studied by spectrophotometry. The character and extent of effect of the system depend on the molecular weight of the polymer and type of the counterion. The strongest inhibition of the process (by 65 times) is observed in the case of poly(sodium N-acryloyl-11-aminoundecanoate) with the molecular weight 100 000.

Phthalocyanines of magnesium, aluminum, and zinc immobilized on nano-sized silica and poly-N-vinylpyrrolidone in aqueous solutions were synthesized. Photochemical activity of the immobilized metal complexes was assessed by generation of singlet oxygen. Nontoxic concentrations of the new photosensitizers were determined in vitro. A comparative analysis of the efficiency of photodynamic therapy (PDT) was performed for immobilized phthalocyanines using mesenchymal stromal cells as a cell model. Aluminum phthalocyanine immobilized on nano-sized silica displayed the highest cell tropism. Irradiation of phthalocyanine-loaded cells resulted in generation of active singlet oxygen and subsequent apoptotic cell death. The use of immobilized phthalocyanines allowed decreasing the effective concentration (dose) of photosensitizer and enhancing the PDT cytotoxicity.

The composition of gas evolved upon thermal decomposition of individual and carbamidemodified graphite nitrates was determined. The addition of carbamide was shown to result in the 2—4-fold decrease in the content of nitrogen oxides and the 2—5-fold increase in the content of carbon monoxide. The content of nitrogen oxides in the gas phase decreased when the HNO₃ : (NH₂)₂CO molar ratio was equal to 1 : (0.4—1). Combination of carbamide addition with catalytic afterburning provides the 5-fold decrease in the gas-phase amount of nitrogen oxides at the minimum CO content.

The Kabachnik—Fields methylphosphorylation of 1,3-diaminopropan-2-ol affords a mixture of 1,3-diamino-2-hydroxypropane-N,N,N′,N′-tetrakismethylphosphonic acid and its intramolecular cyclic ester. Subsequent heating of this mixture led to the thermal dehydration of the acid with the 1,4,2-oxazaphosphorinane ring closure and the formation of 6-[N,N-bis(dihydroxyphosphorylmethyl)amino]methyl-2-hydroxy-2-oxido-1,4,2-oxazaphosphorinane4-methylphosphonic acid. A predominant chair conformation of the formed six-membered heterocycle was inferred from the data of 2D homonuclear (¹H, ¹H; J-resolved) and heteronuclear (¹H, ¹³C; HSQC, HMBC) NMR correlation spectra.

An approach to the synthesis of selenium bicyclic structures of the 1-azabicyclo[4.4.0]decane series was developed, which included the condensation of aryl isoselenocyanates with 2-(2-bromoethyl)piperidine and subsequent intramolecular cyclization of selenoureas formed.