FEATURES OF COMPONENT INTERACTION IN LIQUID ALLOYS OF TERNARY Al-Ge-3d-Me (Me = Mn, Fe, Ni, Cu) SYSTEMS

The features of the component interaction in liquid alloys of ternary Al-Ge-3d-Me systems (Me = Mn, Fe, Ni, Cu) are described. A joint analysis of the concentration dependences of the enthalpies of mixing of liquid alloys previously obtained by the authors via high-temperature calorimetry, and also of the phase diagrams of the constituent binary systems was carried out. The relationship between the enthalpy values and the type of short-range ordering in liquid alloys of the studied systems was established. The visual similarity of the topology of the projections of ΔmH isolines of the Al-Ge-Fe (Ni, Cu) liquid alloys and a completely different course of the isolines of the enthalpies of mixing for the liquid Al-Ge-Mn alloys are established. The changes in the absolute values of the ΔmHmin from system to system are observed. The enthalpies are approximately the same for the Al-Ge-Mn and Al-Ge-Fe systems (about -20 kJ⋅mol-1), they increase significantly from Al-Ge-Fe to Al-Ge-Ni (-50 kJ⋅mol-1), and then decrease substantially towards the Al-Ge-Cu system (-15 kJ⋅mol-1). For the Al-Ge-Mn (Fe, Ni, Cu) liquid alloys the lines of extreme interaction are located near the 3d-corner of the concentration triangle. These lines connect the compositions of the most stable intermetallic compounds in binary Al(Ge)-Mn(Fe, Ni, Cu) systems. It has been shown that the thermodynamic properties of Al-Ge-Fe (Ni, Cu) liquid alloys are mainly determined by the pair interaction of the components of the constituent binary Al-Fe(Ni, Cu) and Ge-Fe(Ni, Cu) systems, the influence of Al-Fe(Ni, Cu) systems being prevailed. For the Al-Ge-Mn system, the interaction of components in the Ge-Mn binary system gives the main contribution to the thermodynamic properties of the ternary system. The Al-Ge-Mn (Fe, Cu) systems are characterized by significantly lower absolute values of the heats of alloy formation compared to the Al-Ge-Ni one. The specified characteristics of component interaction in the ternary systems under consideration and different values of the enthalpies of mixing are determined by the peculiarities and regular changes of the electronic structure of 3d metals across the 3d series from Mn to Cu.

SYNTHESIS OF A 1,2,3-TRIAZOLE-CONTAINING MACROCYCLE BASED ON THE "CLICK CHEMISTRY" REACTION AND ANALYSIS OF ITS PLANAR CHIRALITY USING NMR AND DFT CALCULATIONS

Macrocycles represent previously unexplored promising drug candidates, that can be useful for treating protein-protein interactions. Atropoisomerism is an inherent feature of the natural macrocyclic peptides that is significant for their activity and selectivity, and, therefore, should be introduced into newly synthesized macrocycles. Synthesis of the libraries of artificial macrocycles faces many challenges due to their structure and size. Herein we report on the preparation of a 16-membered macrocycle containing 1,2,3-triazole ring, spiro-piperidine, and phenyl moieties, as well as a chiral carbon atom. Our approach to the macrocycle was inspired by the "build/couple/pair" (B/C/P) strategy, a part of diversity-oriented synthesis methodology. We have employed readily accessible starting materials and robust synthetic procedures which allowed us to obtain the target macrocycle in a high yield. Standard methods of amide bond formation were used for the coupling of macrocycle building blocks. Click chemistry azide-alkyne cycloaddition was exploited at the final ring closure step. The assignment of signals in 1H and 13C NMR spectra of the macrocycle was performed using a series of 2D NMR techniques. The macrocycle displayed planar chirality, which, in a combination with a stereocenter with the known configuration, was sufficient to propose possible structures of diastereomers. The diastereomers could differ by the relative position of triazole ring. Their racemization could occur through a "rope skipping" motion involving the cyclic chain crossing the plane of 1,2,3-triazole ring. The supposed structures of diastereomers were corroborated by means of a various NMR spectroscopy techniques and DFT calculations. Analysis of the amide NH chemical shift temperature coefficients coupled with the data on optimized geometries obtained by DFT convincingly demonstrated that the intramolecular hydrogen bonds play a major role in stabilization of the diastereomer structures. According to the variable temperature NMR experiment, the interconversion of two diastereomers did not occur even at heating up to 70 °C.

STRUCTURAL AND SPECTRAL STUDIES OF THE MIXED-LIGAND CATION COMPLEX OF LANTHANUM [Lа(L)2bipy2]BPh4 WITH CARBACYLAMIDOPHOSPHATE (CAPH) TYPE LIGAND AND 2,2'-BIPYRIDINE

A new cationic mixed-ligand complex [Lа(L)2bipy2]BPh4 (where L-= bis(N,N'-diethylamide)(N'-trichloroacetyl)-triamidophosphate anion, bipy = 2,2'-bipyridine) has been synthesized and studied by the means of IR, 1H NMR spectroscopy, thermogravimetric and X-ray structural analyses. Low-frequency shifts of the absorption bands of the carbonyl and phosphoryl groups of phosphorylated ligand in the IR spectra of the complex compared with similar absorption bands in the spectrum of "free" CAPh ligand are Δν(C = O) = 117 cm–1 and Δν(P = O) = 137 cm–1. The analysis of integral signal intensity in the investigated NMR spectra of coordination compounds [Lа(L)2bipy2]BPh4 indicates the molar ratio of ligand : bipyridine : tetraphenylborate anion as a 2:2:1, which corresponds to the proposed structure of the complexes. The compound has been obtained in monocrystalline form. The structure of the complex has been determined by X-ray structural analysis, its ionic structure was proved, and the coordination of two CAPh ligands through the oxygen atoms of the carbonyl and phosphoryl groups was confirmed. Based on the structural data, it was determined that the La3+ ion is octocoordinated (surrounded by four oxygen atoms from two chelated phosphoryl ligands and four nitrogen atoms from two 2,2'-bipyridine molecules). The coordination polyhedron of central ion is interpreted as a square antiprism. Complex cations and tetraphenylborate anions are connected both by electrostatic interaction and by weak intermolecular C – H ∙∙∙ π-contacts between phenyl substituents of BPh4- and molecules of 2,2'-bipyridine. It was established by thermogravimetric analysis that the complex [Lа(L)2bipy2]BPh4 obtained is thermally stable up to a temperature of 150 °C. Significant decomposition of the complex begins at a temperature of 150 °C, occurs in one stage and most intensively continues up to 300 °C. The total weight loss is 78 %.

A DEVELOPMENT OF AN EFFECTIVE METHOD FOR THE SYNTHESIS OF 2-(5-OXO-4,5-DIHYDRO-1,2,4-OXADIAZOL-3-YL)BENZOIC ACID

2-(5-Oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid was synthesized using a new effective method – thermal heterocyclization of 3-(hydroxyimino)isoindolin-1-one, which occurs as a result of its interaction with 1,1'-carbonyldiimidazole (CDI) and subsequent base-promoted cycleopening of the obtained intermediate 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione. Direct cyclization of 3-(hydroxyimino)isoindolin-1-one by the reaction with diethyl carbonate in the presence of sodium ethylate in ethanol at room temperature and under heating was unsuccessful. The same result was observed when using triphosgene in the presence of triethylamine in dichloromethane. Treating 3-(hydroxyimino)isoindolin-1-one with methyl chloroformate gave 3-(((methoxycarbonyl)oxy)-imino)isoindolin-1-one which was thermally stable and was not cyclized into the desired acid by boiling in toluene and o-xylene for 24 hours. The reflux of the excess of CDI with 3-(hydroxyimino)isoindolin-1-one in anhydrous ethyl acetate and subsequent alkaline hydrolysis gave the desired 2-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid in a total yield of 90%. An attempt to stop the process at the stage of formation of the intermediate 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione by carrying out the reaction in the absence of a base failed. Its partial hydrolysis took place during the reaction, and especially at the stage of isolation, and as a result a mixture of 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione and 2-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid was formed in a ratio of about 2:3. The obtained substance after mixing with aqueousmethanolic NaOH solution and subsequent acidification with 1M HCl was quantitatively converted into the pure desired acid. The developed method allows the use of 3-(hydroxyimino)isoindolin-1-ones as convenient starting materials for the preparation of vic-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)aromatic acids and subsequently related compounds, in particular isomeric vic-carbamimidoyl(hetero)aromatic carboxylic acids, which cannot be obtained by other currently known methods. All the compounds obtained during the development of the method were studied by means of NMR spectroscopy.

FLUORESCENCE CHARACTERISTICS OF FLUORESCEIN AND EOSIN Y SOLUTIONS IN WATER-MICELLAR SURFACTANT MEDIA

The effect of cationic, anionic and nonionic surfactants on the fluorescence properties of fluorescein and eosin Y aqueous solutions has been investigated. It has been found that sodium dodecyl sulfate does not affect the position of the maximum wavelengths of solutions of fluorescein and eosin Y in the study of the effect of an anionic surfactant on the fluorescence emission intensity of dyes. The intensity of the signal of the dye solutions when changing the concentration of anionic surfactant changes little. As the concentration of non-ionic surfactant increases, the fluorescence emission intensity of the fluorescein solutions decreases. In contrast, with increasing concentration of Triton X-100, there is an increase in the signal intensity of solutions of more hydrophobic eosin Y with subsequent access to the "plateau" at СТХ-100≥5.1·10–2 mol/L. The position of the maxima fluorescence emission wavelengths for the fluorescein solutions in the 0-1.0·10–5 mol/L range of concentrations of cationic surfactant cetylpyridinium chloride remain unchanged. The position of the maxima shifts to the long-wavelength region of the spectrum at higher concentrations of CPC. The nature of the position dependence of the fluorescence emission maxima of eosin Y solutions in the presence of cationic surfactants is similar. The effect of fluorescence quenching has also been shown in the study of the influence of organic substances of cationic nature on the signal intensity of fluorescein solutions. It has been shown that the concentration dependence is linear in the (0.1–4.0)·10–1 mol/L range of isoniazid molecule concentrations. The data obtained can be implemented in the development of conditions and methods for the determination of pharmacologically active substances of cationic nature by reaction with fluorescein in medicines.

CATECHOLASE ACTIVITY OF A COPPER(II) COMPLEX WITH THE 2-(5-(1,2,4)TRIAZOLE-1-ILMETHYL-1H-(1,2,4)-TRIAZOLE-3-IL)-PYRIDYL

Methods of the synthesis of 2-(5-(1,2,4)triazol-1-ylmethyl-1H-(1,2,4)-triazol-3-yl)-pyridine and a binuclear copper complex are described. The structure of the complex is established by X-ray structural analysis. The complex is a centrosymmetric [Cu2(L)2(NO3)2·2H2O]·H2O dimer. The Cu-Cu distance is 4.0408 (3) Å. In the complex the ligand is in a deprotonated state. Due to this, the triazole fragment acts as a bridge between the two metal centers. Copper ions are in an octahedral environment. The equatorial plane is formed by three triazole nitrogen atoms and one pyridyl nitrogen atom. The axial positions are occupied by a water molecule and a nitrate ion. Isotropic patterns corresponding to binuclear copper particles of the [Cu2L2-H]+ composition were registered in the ESI mass spectra of the solution of the [Cu2(L)2(NO3)2(H2O)2]·H2O complex. These data confirm the presence of a binuclear complex in solution. The catecholoxidase activity of the binuclear copper (II) complex based on 2-(5-(1,2,4)triazol-1-ylmethyl-1H-(1,2,4)-triazol-3-yl)-pyridine was studied. The kinetics of model reactions of the catecholase type were investigated by the method of initial velocities using a model substrate of 3,5-di-tert-butyl catechol (3,5-DTBK). At low concentrations of 3,5-DTBK, the dependence of the initial oxidation rate on the concentration of the substrate is linear, which corresponds to the first order of the reaction on the substrate. However, the dependence graph at higher concentrations of 3,5-DTBK is nonlinear and indicates the saturation of the catalyst with the substrate. The form of the dependence of the initial reaction rate on the substrate concentration is explained within the framework of the Michaelis-Menten model, which well describes the behavior of natural metaloenzymes.

OPTICAL AND PHOTOCHEMICAL PROPERTIES OF POLYMERS BASED ON 2-(4-METHACRYOXYSTYRYL)QUINOLINE

The design and synthesis of new polymer materials with controlled and predictable properties is still a challenge. Photoactive chromophore can be incorporated into a polymer in several different ways: guest-host systems, main chain polymers and side chain polymers. While none of these options are not perfect and each has its advantages and disadvantages. However, the chromophore functionalized polymers were found to be more effective due to: high concentration of the chromophores can be introduced; polymers with chromophore moiety show increased stability of poling induced SHG activity and decrease of the orientation relaxation process; absence of phase separation lessens the scattering losses; such techniques as plasma etching, optically induced index changes, laser ablation, electrical poling can be applied; multilayer phormation assists in easy integration with electronic and optical components. The principles of design of various molecular photoswitches and logical devices, in particular, those based on the photoisomerization reaction of diarylethylenes have been actively investigated in recent years. Azasubstituted diarylethylenes (DAE) styrylquinolines containing a central double bond and an endocyclic nitrogen atom, have become the subject of interest due to their ability to reversible transformations (photoisomerization and protonation). In this work, photosensitive polymers were synthesized by radical polymerization of corresponding styrylquinoline derivatives with comonomers methyl methacrylate (MMA) using asobisisobutyronitrile (AIBN) as radical initiator. We present results obtained for thin films of the methacrylic polymers incorporating styrylquinoline side-group as optically active molecule. Synthesis of 2-(4-methacryloxystyryl)quinolone and 2-(4-methacryloxystyryl)-6-methoxyquinoline was described. The polymers were obtained by free radical polymerization of methacrylic monomers in dimethylformamide with azobisisobutyronitrile as initiator. The products of polymerization were characterized and evaluated by 1HNMR, UV spectroscopy. Glass transition temperatures were characterized by DSC method. It was found 133°C, 110°C, 130°C, 112°C for P1, P1MMA, P2, P2MMA respectively. Their optical and photochemical properties as well as temperature dependence of the photoluminescence of diarylethylenes have been investigated.

STRUCTURE OF THE ZINC COMPLEX WITH CYCLOHEXYL AСETOACETATE

Binuclear complex of Zn(II) with cyclohexyl acetoacetate was obtained and structurally characterized for the first time. According to structural data, the crystal system is triclinic, space group P-1; a = 7.6530(4), b = 12.2412(8), c = 12.9102(9) Å; α = 90.198(5), β = 101.071(5), γ = 96.937(5) deg. The molecular structure corresponds to the formula [Zn2(C10H15O3)4(C2H5OH)2]. The complex is located in a special position to the symmetry center of the unit cell. The coordination polyhedrons of the Zn atoms are the same distorted octahedrons formed by six oxygen atoms. Each formed by 4 oxygen atoms in the equatorial position, which belong to three ligand molecules: terminal ligand (2 oxygen atoms) and bridged ligand (1 oxygen atom) which chelate the zinc atom of the named polyhedron and 1 oxygen atom belong to a bridged ligand that chelates the other nucleus and monodentantly coordinated to mentioned one. Two oxygen atoms occupy an axial position, one of which belongs to the terminal ligand, mentioned above and the other to the coordinated ethanol molecule. The bond between the complex nuclei is stabilized by two hydrogen bonds formed by the hydrogen atoms from hydroxyl groups of ethanol molecules and the enol oxygen atoms of the terminal ligands of the other nucleus. The compound was also characterized by IR-spectroscopy, characteristic bands (сm-1) are: ν(C–H) - 2936, 2860, ν(C=O) & ν(C=C) – 1612, ν(C=O) + δ(C–H) – 1532, ν(C=C) & ν(C-CH3)– 1252, δ(C–H) – 1172, π(C–H) – 784, ν(M–O) – 456, 416. IR spectroscopy data confirm the bidentate coordination of cyclohexyl acetoacetate to zinc atoms in deprotonated form with the formation of chelated metallocycles. The structure of the complex is similar to the structures of cobalt and nickel complexes with cyclohexyl acetoacetate. Analysis of XRD-data (which are supplemented with this work) for Co(II), Ni(II) and Zn(II) complexes with acetoacetic acid esters shows that their structure, in particular the number of metal centers in the structures, regardless of the nature of the central atom or the alcohol fragment, but determined the presence of components capable of complementing the coordination sphere of the metal in reaction media.

REACTION OF 2-HETARYL-2-(DIHYDROFURAN-2(3H)-ILIDEN)ACETONITRILES WITH AROMATIC AMINES

This article reports on the reaction of 2-hetaryl-2-(furanyl-2-ylidene)acetonitriles with aromatic amines as N-nucleophiles. 2-Hetaryl-2-(furanyl-2-ylidene)acetonitriles represent versatile building blocks in syntheses of ω-(N-aryl)alkyl substituted heterocycles due to the presence of 1,3-bielectrophilic acrylonitrile fragment functionalized with unsaturated heterocyclic ring and nucleophilic azaheterocyclic moiety. The carbonyl group masked within the N-arylpyrrolidinylidene fragment which undergoes a ring opening through the reaction with nucleophiles. So, a method for the synthesis of 2-hetaryl-6-hydroxy-3-(arylamino)hex-2-enenitriles and 2-hetaryl-2-(N-arylpyrrolidin-2-ylidene)acetonitriles has been developed by us. The proposed scheme is based on the available reagents using. As a result of Michael addition, the aromatic amines to 2-hetaryl-2-(furanyl-2-ylidene)acetonitriles followed by ring transformations has formed two types of products, depending on the reaction conditions. The reaction of substituted furanylylideneacetonitriles with aromatic amines proceeds in good to high yields affording the corresponding 3-(arylamino)hex-2-enenitriles and 2-(N-arylpyrrolidin-2-ylidene)acetonitriles derivatives. The stereochemistry of the ring-opening reaction follows the rules of a classical SN2 mechanism. The resulting linear products can be cyclized to 2-hetaryl-2-(furanyl-2-ylidene)acetonitriles in high yields by treatment with the catalytic amount of acid or the equimolar amount of aromatic amines. Under these conditions 2-hetaryl-6-hydroxy-3-(arylamino)hex-2-enenitriles arising from reaction gives the ring closure. Since both ring-opening and cyclisation occur with fixed stereochemistry the reaction appears a valuable modification to the preparation of acetonitriles derivatives.

THE ROLE OF COMBINED MOLTEN SALTS IN SODIUM-CERIUM (III) ORTHOPHOSPHATE CRYSTALLIZATION

The efficient crystallization conditions for high temperature synthesis of sodium-cerium(III) orthophosphate from binary molten salts have been investigated in a light of influence of the inert reaction media addition. Taking into consideration NaF and Na2MoO4 as an addictives to a convention phosphate melt the crystallization regions of CePO4 and Na3Ce(PO4)2 have been identified by means of IR spectroscopy and powder X-Ray diffraction methods. The initial Na/P ratio in the melt has been shown to play the key role in pure Na3Ce(PO4)2 phase formation. The concentration of NaF has been chosen as 20–60 mol. % and MoO3 in a range of 30–60 mol. %, while the cerium(III) content has been maintained equal to 10 mol. %. Additional application of NaF or Na2MoO4 lowers the temperature from 1400 in comparison to Na4P2O7 flux to 1000°C and homogenization time from 12 to 1h., respectively. Thus, the optimal conditions for the high-temperature growth has been found to be Na/P = 1.67 and NaF content equal to 30–45% mol. in case of fluoride-containing systems, and Na/P> 4,00 with MoO3 content of 25–36% mol for a molybdate one. In case of both fluoride and molybdate addition the crystallization region of the target compound has been bordered by a wide area of CePO4 phase. Three crystallization regions has been estimated during crystallization process: CePO4, Na3Ce(PO4)2 and a wide field of their co-crystallization. With Na/P ratio in the binary melt there is a simultaneous change in the solids structure prepared. Thus, when CePO4 possesses highly condensed CeO8 polyhadra in the framework and crystallizes at lower Na/P ratio, Na3Ce(PO4)2 corresponds to isolated CeO8 moieties that are stabilized under higher Na/P values. Within the synthetic conditions investigated, the melts have shown to play a depolymerizing role for the phosphate chains found in the melt, leading to crystallization temperature lowering in initial melt. The approach proposed for the of Na3Ce(PO4)2 synthesis allows to expand the temperature range of its formation and to carry out its uniform doping with fluorescent activators to modify its characteristic spectrum for the needs of modern inorganic LEDs.