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Reaction of thiopyrano[4,3-b]indole-3(5H)-thiones and dimethyl acetylenedicarboxylate (DMAD) proceeds via two competing cascade pathways. Initially, both the pathways begin from thiocarbonyl sulfur and acetylene carbon atoms interaction. Then two parallel processes take place: an alkyne–thiocarbonyl metathesis and a (3 + 2) cycloaddition. In the next stages, in both cases, thiophene ring formation and thiopyran ring opening proceed. Finally, (4 + 2) cycloaddition reactions of intermediate thioketones and a second equivalent of DMAD leads to the resulting thiopyrano[4,3-b]indole derivatives bearing thienyl substituent. The kinetic and thermodynamic characteristics of both pathways were compared on the basis of DFT and ab initio 6-311++G(d,p) quantum chemical calculations.

Dihydroquercetin (DHQ) is a promising antioxidant for medical applications. The poor water solubility of this flavanonol at ambient conditions inhibits its implementation in clinical practice as an injectable dosage form. Thus, increasing water solubility is a critical step toward solving this problem. Herein we attempted to deal with this problem via DHQ phase modification while at the same time adhering to the principles of green chemistry as much as possible. Lyophilization is an appropriate method to achieve phase modification in an environment-friendly way. This method was employed to generate new phase modifications of DHQ that were then characterized. Mixtures of water with ethanol or acetonitrile were used as solvents for the preparation of the lyophilizates, DHQE, and DHQA, respectively. The results of dissolution testing of the obtained DHQE and DHQA demonstrated that the lyophilization increased water solubility at least 30-fold times. These new DHQ modifications were studied by scanning electron microscopy, mass-spectrometry, nuclear magnetic resonance spectroscopy, infrared spectroscopy, X-ray powder diffraction, and thermal analysis. Their solid-state phases were confirmed to differ from the initial DHQ substance without any changes in the molecular structure. Both DHQE and DHQA showed as high antioxidant activity as the initial DHQ. These data demonstrate the potential of DHQE and DHQA as active pharmaceutical ingredients for injectable dosage forms.

All-inorganic lead halide perovskites, for example, CsPbI3, are becoming more attractive for applications as light absorbers in perovskite solar cells because of higher thermal and photochemical st...

Cyclic oxoammonium salts and DMSO are known as important reagents for their diverse and unique reactivity. In the present work, we have studied the reaction of six- and five-membered oxoammonium salts with DMSO. The reaction includes ∼100% selective transfer of the O atom from the >N+═O group to the S atom of DMSO and structural rearrangement of the remaining cationic framework, leading to the formation of hydrolytically unstable iminium salts. The logarithms of the bimolecular rate constants k of the reaction correlated linearly with the reduction potentials E>N+═O/>N-O•, a relationship known for other electrophile-nucleophile combinations. The kinetic data and results of the DFT calculations allow for the suggestion that the studied process proceeds via the prereactive charge-transfer complex >N+═O···S (O)Me2 and its direct concerted rearrangement to the iminium salts. An alternative mechanism that includes intermediate steps with discrete nitrenium cations can be ruled out on the basis of product analysis and DFT computations. The obtained results allow a deeper understanding of the redox chemistry of a pair of nitroxide radicals-oxoammonium cations.

Stable crystalline complexes of Co(II) acetylacetonate [Co(II)(acac)2], trifluoacetylacetonate [Co(II)(tfac)2] and hexafluoroacetylacetonate [Co(II)(hfac)2] with triphenodioxazines (TPDOs) were synthesized and their structures studied using X-ray crystallography. In the crystal, complexes [Co(II)(tfac)2]TPDO and [Co(II)(hfac)2]TPDO form infinite ⋯N⋯Co⋯N⋯ chains featuring 1D coordination polymeric structures, whereas in the [Co(II)(acac)2]TPDO complex, the Co(acac)2 units fill only half of the possible crystallographic positions. The electron accepting trifluoro substituents in the diketonate moieties significantly enhance the thermal stability of the complexes with TPDO. Of all the complexes, only [Co(II)(hfac)2]TPDO does not dissociate into the components in solution. In all studied complexes, the Co(II) atom is in a high-spin state and has distorted octahedral surroundings. Distortion of the octahedral polyhedrons appears as axial stretching of the octahedrons along the Co–N bonds; it is due to the specific features of the crystalline structure of the metal polymeric chain in the compounds.

A layered organic conductor θ-(ET)4CdI4(PhCl) has been synthesized and characterized (ET is bis(ethylenedithio)tetrathia-fulvalene). It belongs to the family of dual-layered conductors θ-(ET)4MBr4(C6H6−nXn) and for the first time includes the iodine-containing anion [CdI4]2−. It exhibits metallic conductivity within the plane of organic ET molecules down to 206 K, and semiconductor properties in the perpendicular direction. The temperature dependence of in-plane resistivity for the compound shows changes in the conductive properties at 199 K and below 164 K. Structural phase transitions have been revealed at these temperatures. Crystal structures determined at 220, 185, and 100 K are attributed to tetragonal, monoclinic, and triclinic crystal systems, respectively. As a result of the structural phase transition at 199 K, equivalent ET layers become nonequivalent, the dihedral angles between ET molecules of neighboring stacks change, and ordering of terminal ethylene groups of ET molecules occurs in a half of radical cation layers. At 100 K, the difference between neighboring radical cation layers increases as compared with the monoclinic phase and the ordering of terminal ethylene groups in all ET molecules has been found. The solvent molecule PhCl remains disordered in all these structures.

All-inorganic lead halide perovskites, for example, CsPbI

A row of dimeric diisobutylaluminum aryloxides bearing different sterically crowded substituents in ortho-positions of the aryl ligand [(ArO)AliBu2]2 (ArO = 2-tBu-C6H4O (AlTBP), 2-Me,6-tBu-C6H3O (AlMTBP), 2,6-iPr2-C6H3O (AlDIPP), 2-Ph-C6H4O (AlPP), 2,6-Ph2-C6H3O (AlDPP), 1-C10H7O (AlN-1)) was synthesized. The Molecular structures of AlMTBP, AlDIPP, AlPP, AlDPP, and AlN-1 have been determined by X-ray crystallography. All dimeric diisobutylaluminum aryloxides were tested as activators of rac-Et (2-MeInd)2ZrMe2 in homopolymerization of ethylene, propylene, copolymerization of ethylene with propylene and terpolymerization of ethylene/propylene/5-ethylidene-2-norbornene. It was shown that only AlMTBP and AlDPP work as effective activators in all polymerization processes, with activity of AlMTBP system being significantly higher than that of AlDPP. The evaluation of dimerization energies of synthesized aryloxides by means of DFT calculations have shown AlMTBP and AlDPP to form the least stable dimers. The activation of rac-Et (2-MeInd)2ZrMe2 was modeled as bonding of diisobutylaluminum aryloxide with zirconocene followed by the first insertion of ethylene into Zr+–Me bond. As per that model, DFT calculations demonstrated the process to be the most favorable for AlMTBP and AlDPP which well corresponds to experimental observations.

We report the first highly conducting single-molecule magnet, (BEDO)4[ReF6]·6H2O [1; BEDO = bis(ethylenedioxo)tetrathiafulvalene], whose conductivity and single-molecule magnetism coexist in the same temperature range. The compound was synthesized by BEDO electrocrystallization in the presence of (Ph4P)2[ReF6]·2H2O and characterized by crystallography and measurements of the conductivity and alternating-current magnetic susceptibility.

The effect of the calcination temperature on the structure and properties of acidic ammonium salt (NH4)2HPW12O40 was studied. The absence of the influence of the calcination temperature of the samples on their particle size distribution, thermal stability and water content was shown. In the investigated range from 300 to 450 ​°C, a nonmonotonic change in the specific surface area and proton-conducting properties is observed depending on the calcination temperature. Calcination at a temperature other than optimal leads to a decrease in the specific surface area and proton conducting properties. A lower temperature is probably not enough for a complete redistribution of protons and ammonium ions; and an increase in the calcination temperature above optimal one entails the compaction of the salt crystallites.

Three new compounds of formulas [Fe(SC(NH2)2)2(NO)2]2(Cl)(ClO4)·H2O (I), [Fe(SC(NH2)2)2(NO)2]ClO4 (II) and [Fe(SC(NHCH3)2)2(NO)2]BF4 (III), which are members of the cationic dinitrosyl iron complexes family (DNICs) with S-donor ligands, have been presented. DNICs I–III were synthesized by direct nitrosylation of acidic solutions of a ferrous salt and thiocarbamide derivatives. The structure and properties of the novel DNICs in the solid state were studied by X-ray analysis, IR, Mossbauer, and EPR spectroscopy. The DNICs with unsubstituted thiourea were studied, and their structural and physical–chemical features were shown to be independent on the counterion type. However, introduction of electron-donating substituents to the thiourea molecule results in a small shift of νNO in the IR spectra, slight increase of δFe, and averaging the g-factor anisotropy. As compared to other DNIC types, cationic DNICs with thiocarbamide derivatives are characterized by the increase in the positive charge on the NO group and higher electrophilic activity and nitrosylating ability, this being the evidence that cationic DNICs are highly effective NO donors.

This work explores new catalytic systems for the synthesis of ethylene-propylene (EPM) and ethylene-propylene-diene (EPDM) copolymers. We present the results on ethylene/propylene copolymerization and terpolymerization of ethylene/propylene/5-ethylidene-2-norbornene with different metallocenes activated by (2,6-tBu2PhO-)AliBu2. Metallocenes employed are EtInd2TiMe2, rac-EtInd2ZrMe2, rac-EtInd2HfMe2, rac-Et(2-MeInd)2ZrMe2, rac-Me2Si(2-MeInd)2ZrMe2. The data encompasses catalytic performance of the systems and copolymers properties: composition, molecular weight, thermo-physical, and mechanical characteristics. The highest copolymerization activities were observed for zirconocenes, the lowest — for rac-EtInd2HfMe2. On the other hand, rac-EtInd2HfMe2 shows the best incorporation of both propylene and 5-ethylidene-2-norbornene, yielding polymers with high molecular weights, low crystallinities and melting points. This catalyst system demonstrated the possibility of producing terpolymers with propylene content up to 39 wt % and 5-ethylidene-2-norbornene up to 18 wt %. Copolymers of ethylene with propylene with the highest tensile strength and elongation at break are obtained on rac-Me2Si(2-MeInd)2ZrMe2, while terpolymer with good elastic properties is formed on rac-EtInd2ZrMe2 and rac-EtInd2HfMe2. Copolymers with the best relaxation properties were synthesized on rac-EtInd2HfMe2.

Pycnometric method, powder X-ray diffraction analysis, and IR spectroscopy were used to study the fundamental aspects of how the density of energy-rich compound furazano[3,4-e]tetrazine-4,6-dioxide varies during its prolonged storage. It was shown that the density grows during the first stage with length of up to 14 days due to the recrystallization. In further storage during eight years, the density gradually falls due to the buildup of stresses in the crystal lattice, created by thermal decomposition products. The degree of decomposition at 22°C during 8 years, evaluated by extrapolation of the Arrhenius dependence, is 0.24%. The observed decrease in the density is attributed to the anomalously weak hampering effect of the crystal lattice.

Triclinic and monoclinic polymorph modifications of the complex [Co(qu)2Br2] were obtained, and its molecular and crystal structures were determined by single crystal X-ray analysis. The magnetic anisotropy parameter D and g-tensor were estimated by SQUID measurements and ab initio (SA-CASSCF/NEVPT2) quantum-chemical calculations. The ligand field effect and magnetostructural correlations in the family of complexes [Co(qu)2X2] (qu = quinoline and X = NCS−, Cl−, Br− and I−) were analyzed. A correlation between the ligand field and the energies of the molecule excited states was revealed.

A new representative of calix[4]arene-containing tetranuclear manganese complexes of [Mn2IIIMn2II] type with 2,2′-dipyridyl bidentate ligand coordinated in the equatorial plane of the complex (II) has been obtained. The complex is crystallized in monoclinic space group P21/c (a = 14.9402(7) A, b = 32.816(1) A, c = 21.595(1) A, β = 106.888(4)). Its magnetic properties have been studied by the method of SQUID magnetometry. The substitution of a peripheral ligand was shown to influence substantially on the structure of the central fragment of the metal complex, and, hence, on the magnetic properties. Quantum-chemical calculations were performed for this complex and for the similar calix[4]arene-containing manganese complex with pyridine ligand (I). The influence of peripheral environment on the magnetic properties of tetranuclear manganese skeleton was elucidated for both complexes.

Novel nitrosyl iron complexes [Fe(SC(NH2)2)2(NO)2]2SO4·H2O(I) and [Fe(SC(NH2)2)2(NO)2]2[Fe2(S2O3)2(NO)4](II) have been synthesized via the reactions of FeSO4 and Na2[Fe2(S2O3)2(NO)4], respectively, with acidic solutions of thiocarbamide in water. The structure and properties of I and II were studied using X-ray analysis, Mossbauer, IR, and EPR spectroscopy and amperometry. Both complexes are characterized by a prolonged NO generation without additional activation in aqueous anaerobic solutions, similar to the organic NO donor diethylene triamine; however, they are more effective: at pH 7 the NO amount is ∼32.6 and ∼31.8 nM mol−1 of the complex for I and II, respectively. The obtained results show feasibility for the synthesis of water-soluble hybrid nitrosyl NO-generating complexes, which contain the NO groups both in the cationic and anionic sublattices and provide the control of the NO release kinetics.

A new cationic dinitrosyl iron complex (DNIC) with thiourea of the formula [Fe(SС(NH 2 ) 2 ) 2 (NO) 2 ]Cl·H 2 O ( I ) has been obtained in the reaction of aqueous solutions of salts Na 2 [Fe 2 (S 2 O 3 ) 2 (NO) 4 ]·4H 2 O and Na 2 S 2 O 3 ·5H 2 O in the presence of SC(NH 2 ) 2 in acidic medium for the first time. Structure and properties of I have been studied by X-ray analysis, Mossbauer, IR- and EPR spectroscopy and amperometry. Complex I generates NO in aqueous anaerobic solutions (at T = 25 °C) without additional activation; NO amount at pH 7 and 8 is ~ 36 nM, at pH 9 a smaller (~ 24 nM) but more prolonged release of NO was observed, thus suggesting the potential of this method for synthesis of a new class of DNIC for medicine.

The new tetranitrosyl binuclear iron complex [Fe 2 (SС 5 H 5 O) 2 (NO) 4 ] ( I ) has been synthesized by the reaction of aqueous solutions of anionic salts [Fе(S 2 O 3 ) 2 (NO) 2 ] 3 − and [SС 5 H 5 O] − . The latter one has been obtained by the reduction of methyl furfuryl disulfide by hydrazine hydrate in ethanol at T = 25 °C. The molecular and crystalline structure of I has been determined by X-ray method. The complex has binuclear structure of “μ-S” type with the distance between the iron atoms ∼2.70 A. In the crystalline structure shortened intermolecular contacts of the nitrosyl groups of the adjacent molecules are observed. The maximum amount of NO generated by I in 1% aqueous solution of dimethylsulfoxide (DMSO) is ∼5 nM, and it reduces to zero in 8 min after decomposition starts in anaerobic conditions at Т = 25 °С, pH 6.5. As follows from the method of natural bond orbital analysis (NBO analysis), complex I has rather strong Fe NO bond, as compared to other NO donors. Using CVA method, the values of reduction potentials for I in an aprotic solvent have been determined, and the scheme for its reduction has been suggested.

Newly synthesized layered organic conductors θ-(ET)4MnBr4(1,2-C6H4Cl2) (1) and θ-(ET)4MnBr4(C6H5Cl) (2) show metal-like conductivity along conducting layers down to 4.3 and 60 K, respectively, while showing semiconducting properties in the perpendicular direction. Phase transitions driven by ordering in anion layers in 1 and ordering in a half of cation layers in 2 were found to occur at 297 and ~240 K, respectively. Crystal structures above and below the phase transitions were determined for 1 at 260 and 333 K and for 2 at 260 and 220 K. In the above-transition phases of both compounds, attributed to the tetragonal crystal system, all ET layers are similar in structure. In the below-transition phases, attributed to triclinic and monoclinic crystal systems, the neighboring ET layers of each phase differ in periods along the stacks and in dihedral angles θ between radical cations of the adjacent stacks.

Genuine organic anion-radical salt (N-Me-2,6-di-Me–Py)(TCNQ) 2 with pyridine-based cation was synthesized and its crystal structure was resolved. The DC magnetic susceptibility was measured in temperature range from 2 K to 300 K in magnetic fields 10 mT, 100 mT and 1 T. Zero field cooling (ZFC) and field cooling (FC) modes were used. The results were studied in terms of one-dimensional magnetic models and we have found that the most suitable of them is an antiferromagnetic linear Heisenberg S = 1/2 system with small amount of free spins. An additional peak observed at low temperatures can be explained by an interchain coupling between free chain-end spins.

New tetranitrosyl binuclear iron complex [Fe 2 (SС 7 H 5 N 4 ) 2 (NO) 4 ] ( I ) has been synthesized by interaction of aqueous solutions of anionic salts [Fе(S 2 O 3 ) 2 (NO) 2 ] 3− and [SС 7 H 5 N 4 ] − . The latter one was synthesized by reduction of bis -(1-phenyl-1H-tetrazole-5-yl) disulfide with hydrazine hydrate in ethanol at T = 25 °C. Molecular and crystalline structure of I was determined by X-ray analysis; the complex has binuclear structure of “μ-SCN” type with ∼4.02 A between the iron atoms. Shortened О⋯О contacts (2.81 A) between the NO groups of similar type are observed. Parameters of Mossbauer spectrum for I are: isomer shift δ Fe = 0.311(1) mm/s, quadrupole splitting Δ E Q = 1.044(1) mm/s, line width Γ = 0.267(1) mm/s at 85 K. From SQUID magnetometry data, the temperature and field dependences of the magnetic moment of I are well described in the frame of a simple model of binuclear iron complex with magnetic centers S 1 = S 2 = ½. In solution, binuclear structure of the complex remains, though the NO groups are non-equivalent. For solutions of I five-line hyperfine structure of spectrum (HFS) is observed, g-factor = 2.03. For polycrystals of I , no HFS was observed due to averaged exchange interaction between the electron spins of adjacent complexes. In polycrystals of I , the number of spins per one binuclear complex is I in 1% dimethylsulfoxide (DMSO) aqueous solution is ∼13.8 nM, it halves in 8 min after decomposition starts, and reaches ∼3.8 nM in anaerobic conditions at Т = 25 °С, pH 7.0. This is due, according to quantum-chemical calculations, to the presence of a more stable Fe NO bond in I than in its isostructural analog – nitrosyl iron complex with 1-methyltetrazole-5-yl ( II ).

Regioselective cyclocondensation of glycine hydroxamic and dl-alanine hydroxamic acids with 1-methylpiperidin-4-one gave 1-hydroxy-8-methyl-1,4,8-triazaspiro[4.5]decan-2-one (5) and (±)-1-hydroxy-3,8-dimethyl-1,4,8-triazaspiro[4.5]decan-2-one (6), respectively. The X-ray diffraction data showed that acid 6 formed racemic crystals with two independent molecules, whose structure was studied and compared with the analog obtained earlier. The in vivo tests on the leukemia P388 and L1210 models showed that the low-toxic spirocyclic hydroxamic acids 5 and 6 were the adjuvants of clinic cytostatics cisplatin and cyclophosphamide. Chemotherapy of the leukemias P388 and L1210 was more efficient with the combination of acid 6 with cisplatin and cyclophosphamide, respectively.

Acid-catalyzed reaction of 6,10a-dihydroxy-3,4a,7,9-tetra(tert-butyl)-1,2,4a,10a-tetrahydrodibenzo-[b,e][1,4]dioxine-1,2-dione with 4-chloro-2,7,8-trimethylquinoline gave previously unknown 3,6,8-tri-tert-butyl-3-[2-tert-butyl-5-(4-chloro-7,8-dimethylquinolin-2-yl)-4-hydroxy-3-oxopenta-1,4-dien-1-yl]-5-hydroxy-1,4-benzodioxin-2-one whose structure was determined by X-ray analysis. The energy and structure parameters of possible isomers of the product in the gas phase and in solution were estimated by PBE0/6-31G** quantum-chemical calculations.

A new analog of the active site of mononuclear dinitrosyl [1Fe–2S] proteins, [C3N2H8SFe(NO)2Cl][Fe(NO)2(C3N2H8S)2]+Cl− (I), has been synthesized by reacting NO with an aqueous mixture of iron(II) sulfate and N-ethylthiourea in acidic medium. The structure and properties of the complex were studied by X-ray diffraction, IR, Mössbauer, and EPR spectroscopy, in addition to quantum chemical calculations. Complex I spontaneously generates NO in protic media. The cytotoxicity of I was investigated against human cervical carcinoma (HeLa), breast cancer (MCF7), and non-immortalized (FetMCS) cell lines. The cytotoxicity of I against HeLa is similar to that of anticancer agents currently used clinically (platinum complexes), but I is 10 times less toxic in normal cells. The cytotoxicity of MCF7 cells to I is low.

By the XRD analysis the structure was established of 1-(7,8-dimethyl-4-chloroquinolin-2-yl)-2-[3,5-di(tert-butyl)-6-oxo-6H-pyran-2-yl]ethane-1,2-dione formed as a result of the oxidation of 3,5-di(tert-butyl)-6-[(Z)-2-(quinolin-2-yl)-1-hydroxyethen-1-yl]pyran-2-ones. By the cyclic voltammetry the oxidation of 1-(quinolin-2-yl)-2-(pyran-2-yl)ethane-1,2-dione derivatives was shown to proceed in two stages.

The reactions of 3-cyanotetrafluoropyridine and tetrachloro-3-trifluoromethylpyridine with sodium azide lead to the corresponding 2,4,6-triazido-5-cyano-3-fluoropyridine and 2,4,6-triazido-5-chloro-3-trifluoromethylpyridine. With the aid of comparative X-ray structural analysis of 2,4,6-triazido-5-cyano-3-fluoropyridine and its previously known 3-chloro-substituted derivative it was established that the geometric parameters and reactivity of the azide groups in the asymmetric 2,4,6-triazi-dopyridines depend not only on the position of these groups in the pyridine ring but also on their mutual orientation in space.

The molecular structures of 9,11-di-tert-butyl-2,4-dimethyl-7H-12-oxa-3,7-diazapleiadene and 7-acetyl-9,11-di-tert-butyl-2,4,6-trimethyl-7H-12-oxa-3,7-diazapleiadene were determined by X-ray analysis.

Substituted imidazoles (substituents are Me, Et, i-Bu, n-Hexyl, (CH2)2S–Bu-n, Ph, Bn) react smoothly (room temperature, without catalyst and solvent) with cyanoacetylenes (3-phenyl-2-propynenitrile and 4-(1-butoxyethoxy)-4-methyl-2-pentynenitrile) and aromatic or heteroaromatic aldehydes (benzaldehyde, 4-CN-benzaldehyde, pyridine-3-aldehyde) to give 3-(2-imidazolyl)-3-aryl-2-acylpropanenitriles, a hitherto unknown family of functionalized imidazole derivatives, in up to 62% yield. This three-component manifold represents a novel C(2)-functionalization of the imidazole nucleus involving zwitterionic, carbene and enol ether intermediates. Unlike the analogous reaction with aliphatic aldehydes, which gives enol ethers, in this case the latter undergo the further rearrangement to 3-(2-imidazolyl)-3-aryl-2-acylpropanenitriles.

2,2-Bis(alkoxy-NNO-azoxy)propane-1,3-diols reacted with thionyl chloride to give previously unknown 5,5-bis(methoxy-NNO-azoxy)- and 5,5-bis(ethoxy-NNO-azoxy)-1,3,2-dioxathiane 2-oxides. Replacement of the hydroxy groups by chlorine is a minor reaction path. According to the X-ray diffraction data, the heteroring in the molecule of 5,5-bis(methoxy-NNO-azoxy)-1,3,2-dioxathiane 2-oxide adopts a chair conformation with axial orientation of the S=O bond.

The molecular geometries and electronic structures of 2,4,6-tris(nitromethyl)-1,3,5-triazine isomers were investigated by the density functional method DFT/B3LYP/6-311++G** to elucidate the structural factors responsible for the stability of these systems. It was shown that a characteristic feature of the nitromethyl tautomer (1) of 2,4,6-tris (nitromethyl)-1,3,5-triazine consists in nonvalence interactions between an oxygen atom of nitro group and a carbon atom of triazine ring, which are probably due to Coulomb attraction between them. The tautomer with the 2,4,6-tris (nitromethylene)-hexahyrdo-1,3,5-triazine structure (2) is stabilized trough direct polar conjugation between the amino and nitro groups at the double bond. Structural strain of the molecule with the 2,4,6-tris(aci-nitromethyl)-1,3,5-triazine structure (3) is the reason for its thermodynamic instability. X-ray data indicate that the compound under study exists in the triazine tautomeric form 1 and the distances between oxygen atoms of nitro group and carbon atom of the triazine ring are shortened. NMR data suggest the existence of triazine in the nitromethyl form 1 in acetonitrile and acetone and a tautomeric equilibrium between the nitromethyl and nitromethylene forms in a more polar solvent (DMSO). The results obtained suggest a Coulomb-type stabilization of the 2,4,6-tris(nitromethyl)-1,3,5-triazine molecule in the gas phase, in the crystal, and in nonpolar solvents.

3-Phenylamino-5-phenylimino-1,2,4-dithiazole reacted with 1-acyl-2-phenylacetylenes in ethanol or toluene on heating (78–80°C, 1 h) in chemo- and regioselective fashion to give previously unknown N-[5-acyl-3,4-diphenyl-1,3-thiazol-2(3H)-ylidene]-N′-phenylthioureas (yield 57–60%). The structure of N-[5-benzoyl-3,4-diphenyl-1,3-thiazol-2(3H)-ylidene]-N′-phenylthiourea was proved by X-ray analysis.

Photocatalyst powders were synthesized from nanosized titanium dioxide crystals modified by sintering with thiourea (TU). The powders contained anatase crystals of various sizes. TU-TiO2 powders absorbed visible light to produce an oxidizer (oxidizing iodide) and a reducing agent (reducing tetranitromethane). The activity of TU-TiO2 correlated with the size of nanocrystals. The photocatalytic activity of TU-TiO2 was suggested to be related to impurity states appearing during modification in the forbidden band of TiO2.

The reaction of α,β-acetylenic γ-hydroxy nitriles with thiosemicarbazide, under mild conditions (rt, no catalyst, in 1:1 aqueous ethanol, 4–14 h), proceeds chemo-, regio- and stereoselectively to give atypically so far inaccessible tri-functionalized (amino, hydroxyl and thioamide groups) pyrazoles in 53–91% yields. The hydroxyl function is easily protected by using the corresponding acetals of the starting acetylenic hydroxy nitriles.

A reaction of 2,2-bis(methoxy-NNO-azoxy)ethyl methanesulfonate with ethyl(diisopropyl)amine afforded 1,1-bis(methoxy-NNO-azoxy)ethene (3). Compound 3 was examined by X-ray diffraction analysis.

The salt of cobalt hexacyanide with the photochromic mononitrosyl cation [RuNO(NH3)5]3+ with the composition [RuNO(NH3)5][Co(CN)6] was synthesized. Single crystals of the salt were grown, and the crystal structure was solved. The photochromic properties were studied by differential scanning calorimetry (DSC).

Fluoroalkyl-containing 1,2,3-trione 2-arylhydrazones react with methylamine in different ways, depending on the substrate structure. Arylhydrazones having a short fluoroalkyl substituent (RF = CF3, HCF2CF2) react at the carbonyl group adjacent to the nonfluorinated substituent to give 3-alkyl(aryl)-2-aryldiazenyl-3-methylamino-1-polyfluoroalkylprop-2-en-1-ones. Arylhydrazones with a long-chain fluoroalkyl group (RF = C3F7 and longer) and a bulky nonfluorinated group take up methylamine molecule at the carbonyl group linked to the fluorinated substituent, and the subsequent haloform reaction yields N-methyl-2-arylhydrazono-3-oxobutanamides. Both types of products are formed in reactions of methylamine with 1,2,3-triketone 2-arylhydrazones having a long fluoroalkyl group and methyl group at the other carbonyl group. Template condensation of fluoroalkyl-containing 1,2,3-trione 2-arylhydrazones with methylamine over Ni(II) template gives bis[3-alkyl(aryl)-1-polyfluoroalkyl-3-methylamino-2-aryldiazenylprop-2-en-1-onato-N,N′]-nickel(II), regardless of the size of the fluoroalkyl substituent. The same complexes and their copper analogs can be obtained by treatment of 3-alkyl(aryl)-2-aryldiazenyl-3-methylamino-1-polyfluoroalkylprop-2-en-1-ones with the corresponding metal salts.

Condensation of ethyl 3-polyfluoroalkyl-3-oxopropionates with excess triethyl orthoformate gave ethyl 3-polyfluoroalkyl-2-ethoxymethylidene-3-oxopropionates which reacted with primary aliphatic, aromatic, and heterocyclic amines to form ethyl 2-alkyl(aryl, hetaryl)aminomethylidene-3-polyfluoroalkyl-3-oxopropionates. According to the X-ray diffraction and IR data, the latter exist in the crystalline state as the corresponding E isomers, while in solution (NMR data), as mixtures of Z and E isomers. Condensation of ethyl 2-ethoxymethylidene-3-oxopropionates with secondary heterocyclic amines (morpholine and pyrrolidine) led to the formation of 2-morpholino(pyrrolidin-1-yl)methylidene-3-fluoroalkyl-3-oxopropionates which were shown to exist as Z isomers both in the crystalline state and in solution.

1-Substituted benzimidazoles are readily annelated regio- and stereoselectively with α,β-acetylenic γ-hydroxyacidnitriles under mild conditions (20–25 °C, no catalyst, no solvent) to form new polyfunctional condensed systems, 4-cyanomethylene-1,3-oxazolobenzimidazoles (30–88 % yield). Unexpectedly, the latter, when chromatographed on neutral Al2O3 at room temperature, undergo a complex multi-position hydrolytic rearrangement involving the cleavage of the imidazole ring to aminophenyl N-substituted formamides with an aminodihydrofuran moiety in the aminophenylsubstituent, N-(2-{[5-amino-2,2-dialkyl-3(2H)-furanylidene]amino}phenyl)-N-substituted formamides, a novel class of highly functionalized pharmacophoric compounds. The results contribute to the basic benzimidazole chemistry and provide for prospective families of drug candidates.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

The crystal structure of 9-azidoacridine (9AA) was determined by X-ray structure analysis (the compound crystallizes in the rhombic system). The crystallographically independent fragment of the structure of 9AA was found to contain two molecules. Both molecules were nonplanar, and the azido group was displaced out of the acridine nucleus plane by 34.6° (molecule A) and 28.6° (molecule B). The barriers to azido group rotations about the C-N bond were calculated by the semiempirical PM3 and nonempirical DFT B3LYP quantum-chemical methods. According to the B3LYP/6-31G* calculations, the structures with the azido group situated in the acridine nucleus plane and perpendicularly to this plane are 0.21 and 1.66 kcal/mol, respectively, higher in energy than the completely optimized structure, in which the dihedral angle between the azido group and acridine nucleus planes is 32°. The PM3 method overestimates the steric strain energy of 9AA and underestimates the energy of azido group conjugation with the acridine nucleus compared with B3LYP calculations.