Condensation of fluoroalkyl-containing 1,2,3-trione 2-arylhydrazones with methylamine

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 (R_F = 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 (R_F = 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.     

Kinetics of oxidation of water by Mn(IV) sulfate in acid media

Kinetics of the Mn(IV)Mn(III) transition in the oxidation of watet to O₂ was investigated at 60–100°C in 6–15 M H₂SO₄. The reaction is approximately 2-nd order in Mn(IV) concentration in the process of oxidation and 1-st order in initial Mn(IV) concentration. The kinetics is interpreted by the existence of dimeric forms Mn(IV)·Mn(IV), Mn(IV)·Mn(III) and Mn(III)·Mn(III). The suggested mechanism includes O₂ formation directly in the coordination sphere of the Mn(IV)·Mn(IV) dimer in a polyelectronic process.

---

Mn (IV)»Mn (III) O₂ 60–100°C 6–15 M H₂SO₄. Mn (IV) I- Mn (IV). [Mn (IV)]₂; [Mn(III)]₂ Mn(IV)·Mn (III). , [Mn (IV)]₂

     

Singularity of proton transport in salts of orthoperiodic and orthotellurium acids: theoretical modeling using density functional calculations

Density functional B3LYP calculations have been performed to investigate proton transport in orthoperiodic and orthotellurium acids, their salts MIO(6)H(4)(M = Li, Rb, Cs) and CsH(5)TeO(6), dimers of the salt*acid type MIO(6)H(4)*H(5)IO(6)(M = Rb, Cs), CsIO(6)H(4)*H(6)TeO(6), CsHSO(4)*H(6)TeO(6), Cs(2)SO(4)*H(6)TeO(6), and also in double-substituted and binary salts Rb(2)H(3)IO(6) and Rb(4)H(2)I(2)O(10). It has been shown that the energy of salt dimerization is 33-35 kcal mol(-1) and the activation barrier for proton migration between the neighboring octahedrons of the salt*acid --> acid*salt type is calculated to be 3-13 kcal mol(-1). The activation energy of the proton migration along the octahedron, 20-30 kcal mol(-1), is comparable with the barrier for water molecule separation. Quantum-chemical calculations correlate with the results of X-ray and electrochemical studies.     

1-Benzyl-3,3,5′,6′-tetramethylspiro[indoline-2,2′-[2<Emphasis Type="Italic">H</Emphasis>]pyrano[3,2-<Emphasis Type="Italic">b</Emphasis>]-pyridinium] iodide,its hydrate,and a neutral precursor of the salts: synthesis,crystal structure,photochromic transformations in solutions and in crystals

A new 1-benzyl-3,3,5′,6′-tetramethylspiro[indoline-2,2′-[2H]pyrano[3,2-b]pyridinium] iodide, photochromic in the crystal state, was obtained. X-ray diffraction analysis was used for determination of crystal structures of the salt, its hydrate, and a neutral precursor. It was found that a replacement of the substituent in the indoline fragment leads to a considerable change in the crystal structure of both the neutral spiropyran and the salts as compared to the analogs studied earlier. Effects of crystal structure on photochromic properties were studied.     

Simulation of the kinetics of adenosine 5′-triphosphate hydrolysis catalyzed by the Cu2+ ion: The role of conformation and the catalytic effect of the OH− ion

The hydrolysis kinetics of the dimeric complex (CuATP^2? · OH₂)₂ {D} up to ≈40% ATP conversion at 25°C, pH 5.7–7.8, and [Cu · ATP]₀ = (2.07 ± 0.03) × 10^?3 mol/l is analyzed by numerical simulation. CuADP^? + P_i (P_i is an inorganic phosphate) form from DOH^?, and the latter forms rapidly from D. The abstraction of H⁺ from the coordinated H₂O molecule is an irreversible reaction involving an OH^? ion from the medium. The maximum possible DOH^? concentration at a given pH is reached at the initial stage of hydrolysis (0.3–6.0 min after the initiation of hydrolysis). CuADP^? + P_i form from D via two consecutive irreversible steps. The ADP buildup rate in the process is determined by the reversible conformational transformation of DOH^? resulting in a pentacovalent intermediate (IntK). OH^? ions from the medium are involved both in IntK formation and in the reverse reaction and are a hydrolysis inhibitor. AMP forms from the intermediate IntK₃, which forms reversibly from DOH^?, OH^? ions from the medium being involved in the forward and reverse reactions. This is followed by irreversible (AMPH)^? formation involving H₃O⁺ ions from the medium. The rate and equilibrium constants are determined for the formation and decomposition of hydrolysis intermediates. The concentrations of the intermediates are plotted versus time for various pH values. The structures of the intermediates are suggested. The causes of a peak appearing in the initial ADP formation rate versus pH curve are analyzed.     

Structural characteristics of different types of nanoparticles synthesised in mesomorphic metal alkanoates

The class of thermotropic ionic liquid crystals (LCs) of the metal alkanoates possesses a number of unique properties, such as intrinsic ionic conductivity, high dissolving ability and ability to form time-stable mesomorphic glasses. These ionic LCs can be used as nanoreactors for the synthesis and stabilisation of different types of nanoparticles (NPs). Thus, some semiconductors, metals and core/shell NPs were chemically synthesised in the thermotropic ionic liquid crystalline phase (smectic A) of the cadmium octanoate (CdC₈) and of the cobalt octanoate (CoC₈). By applying the scanning electron microscopy, the cadmium and cobalt octanoate composites containing CdS, Au, Ag and core/shell Au/CdS NPs have been studied. NPs’ sizes and dispersion distribution of the NPs’ size in the nanocomposites have been obtained.