Showing papers in "Russian Chemical Bulletin in 1975"
TL;DR: In this article, the rate and equilibrium constants for acid disproportionation of 2,2,6,6-tetramethylpiperidino-1-oxyls were determined.
Abstract: 1.
The reactions of acid disproportionation of piperidinooxyls and the interaction of 1-oxo with 1-hydroxypiperidinium salts are reversible and proceed through an intermediate 1-hydroxypiperidmylium cation according to a general kinetic scheme.
2.
The rate and equilibrium constants were determined for the reaction of acid disproportionation of 2,2,6,6-tetramethylpiperidino-1-oxyl.
20 citations
TL;DR: Based on the 14N NQR data, the pπ − dπ interaction in dimethylaminosilanes is weaker than in the amides of phosphorus acids as discussed by the authors.
Abstract: Based on the14N NQR data, the pπ − dπ interaction in dimethylaminosilanes is weaker than in the amides of phosphorus acids.
14 citations
TL;DR: In this article, the cleavage rate of some C-substituted o-carboranes to the (3)-l,2-dicarbaunde-CARborate anion by treatment with amines was studied and it was established that the reaction is first order in both the ocarborane and the amine.
Abstract: When the cleavage rate of some C-substituted o-carboranes to the (3)-l,2-dicarbaunde-carborate anion by treatment with amines was studied it was established that the reaction is first order in both the o-carborane and the amine. The cleavage rate depends on the nature of the amine and the nature of the substituent in the o-carborane.
12 citations
TL;DR: In this article, the reaction of Al(BH4)3 with the unsolvated Ca(Bh4)2 gave the complex Ca(bH4)-2·Al(bh4)-3, which is stable at room temperature; its density and IR spectrum are given.
Abstract: 1.
The reaction of Al(BH4)3 with the unsolvated Ca(BH4)2 gave the complex Ca(BH4)2·Al(BH4)3, which is stable at room temperature; its density and IR spectrum are given.
2.
Ca(BH4)2·Al(BH4)3 decomposes completely into the component borohydrides when heated in vacuo or when treated with donor solvents. The complex apparently has the structure [CaBH4]+[Al(BH4)4]− after treatment with octane.
12 citations
TL;DR: It was shown spectrophotometrically that the acetyl and N-tert-butyloxycarbonylalanyl-imida-zolides are formed when diethyl phosphate imidazolide is reacted with acetic acid or with BOC-alanine in aqueous medium or in absolute isopropanol as mentioned in this paper.
Abstract: 1.
It was shown spectrophotometrically that the acetyl- and N-tert-butyloxycarbonylalanyl-imida-zolides are formed when diethyl phosphate imidazolide is reacted with acetic acid or with BOC-alanine in aqueous medium or in absolute isopropanol.
2.
It was shown that it is theoretically possible to use diethyl phosphate imidazolide as the activating agent for the synthesis of 3′(2′)-aminoacylnucleotides in aqueous medium.
9 citations
TL;DR: In this paper, the adsorption of xenon on NaX zeolite was measured in the range of pressures from ∼0.1 Pa to ∼1.4·104 kPa (eight orders of magnitude) and temperatures from 150 to 370 K. The results of the measurements were tabulated.
Abstract: 1.
The adsorption of xenon on NaX zeolite was measured in the range of pressures from ∼0.1 Pa to ∼1.4·104 kPa (eight orders of magnitude) and temperatures from 150 to 370‡K, i.e., from a temperature below the melting point of xenon to a temperature 80‡K above the critical point. The results of the measurements were tabulated.
2.
In the initial portion of all the isotherms, a Henry region was detected, extending to the adsorption of ∼0.15 mmole/g. The values of the Henry constants for all the temperatures were tabulated.
3.
The adsorption isosteres are linear within the entire range of pressures and temperature studied. Just as in the system CF3C1-NaX zeolite, the isosteres, terminating on the saturated vapor pressure curve of xenon, then continue in the region of temperatures above the critical point.
4.
The linearity of the isosteres permits a calculation of the adsorption equilibria at high pressures on the basis of the data characterizing the region of comparatively low pressures and temperatures.
8 citations
TL;DR: In this article, the thermal decomposition of titanium and iron hydroaluminates was studied, and possible schemes of their decomposition were proposed, and the results showed that Ti(AlH4)4 and Fe(H42)2 are formed at −110°C.
Abstract: 1.
In the interaction of titanium and iron halides with LiAlH4 at−110°C, the hydroaluminates Ti(AlH4)4 and Fe(AlH4)2 are formed.
2.
The thermal decomposition of titanium and iron hydroaluminates was studied, and possible schemes of their decomposition were proposed.
8 citations
TL;DR: In this paper, a general method has been developed for the calculation of the physical parameters of molecules of complexes and their stability constants on an electronic computer, permitting the use of a single program for the treatment of the experimental results, obtained by the methods of UV and NMR spectroscopy, dielectrometry, calorimetry, cryoscopy, etc., for which the property to be measured obeys the additivity law.
Abstract: 1.
A general method has been developed for the calculation of the physical parameters of molecules of complexes and their stability constants on an electronic computer, permitting the use of a single program for the treatment of the experimental results, obtained by the methods of UV and NMR spectroscopy, dielectrometry, calorimetry, cryoscopy, etc., for which the property to be measured obeys the additivity law, and the investigated solutions are close to ideal.
2.
A method is proposed for the evaluation of the significance of the results obtained.
3.
The potentialities of the method and its reliability were tested in an investigation of various types of molecular complexes of metal halides, organometallic compounds, and complexes with an intermolecular hydrogen bond.
8 citations
TL;DR: In this article, a scheme was proposed for the decomposition of trialkylaminalanes and a kinetic analysis of it was cited, as a result of which kinetic equations were obtained, reflecting the experimentally observed principles in the nature of the gas evolution.
Abstract: 1.
The decomposition of AlH3·NMe3 and AlH3·NEt3 under isothermal conditions above the melting point proceeds simultaneously both in the gas and in the condensed phase. Decomposition in the gas phase leads to the formation of hydrogen, metallic aluminum, and the corresponding amine. Decomposition in the condensed phase leads to the formation of an amine and a solvated polymer form of aluminum hydride,
2.
A scheme was proposed for the decomposition of trialkylaminalanes, and a kinetic analysis of it was cited, as a result of which kinetic equations were obtained, reflecting the experimentally observed principles in the nature of the gas evolution. The rate constants of the decomposition of AlH3 · NMe3 and AlH3 · NEt3 in the gas phase, as well as the effective rate constant of the decomposition of AlH3, were determined.
7 citations
TL;DR: In this paper, the PMR spectra of a number of derivatives of 1, 2, 5-orthobenzoyl-β-L-arabinofuranose were studied in detail.
Abstract: 1.
The PMR spectra of a number of derivatives of 1, 2, 5-orthobenzoyl-β-L-arabinofuranose were studied in detail. The assignment of the signals of all the protons were demonstrated with the aid of deuterated analogs and shifting reagents.
2.
On the basis of the independence of all the spin-spin interaction constants from the nature of the substituent at C3 of the arabinofuranose system, as well as on the nature of the solvent, it was concluded that the framework heterocyclic system lying at the basis of the structure of the orthoesters studied possesses high conformational rigidity.
6 citations
TL;DR: The rate constant of methanol with atomic oxygen was determined for the temperature 310-800°K, equal to k=7.1±0.12 · 10−12 exp(−2030±134/RT) cm3/molecule · sec as discussed by the authors.
Abstract: 1.
The rate constant of the reaction of methanol with atomic oxygen was determined for the temperature 310–800°K, equal to k=7.1±0.12 · 10−12 exp(−2030±134/RT) cm3/molecule · sec.
2.
A mechanism was proposed for the oxidation (combustion) of methanol, characterized by the presence of stable intermediate products: formaldehyde, hydrogen, hydrogen peroxide, and carbon monoxide.
TL;DR: In this article, the influence of the initial pressure, surface of the reaction vessel, and inhibitors of free radical processes on the rate of decomposition of nitrobenzene in the gas phase was investigated.
Abstract: The influence of the initial pressure, surface of the reaction vessel, and inhibitors of free radical processes on the rate of decomposition of nitrobenzene in the gas phase was investigated. Conditions were found under which the decomposition of nitrobenzene proceeds monomolecularly, and the kinetic characteristics of the step corresponding to cleavage of the Ph-NO2 bond were determined.
TL;DR: In this paper, a simple method was proposed for determining the relative stability of the chelate bond in the halide complexes of o-semiquinones, and the order of their stability in THF was given.
Abstract: 1.
The reaction of 3,6-di-tert-butyl-1,2-benzoquinone with the halides of the Group III elements leads to paramagnetic chelate complexes.
2.
A simple method was proposed for determining the relative stability of the chelate bond in the halide complexes of o-semiquinones, and the order of their stability in THF is given.
TL;DR: In this article, the spin-spin interaction constants (SSIC) between 1H and 13C nuclei were measured for N-methylacetamide and N-acetyl-L-alanine-N-methylamide.
Abstract: 1
The spin-spin interaction constants (SSIC) between1H and13C nuclei were measured for N-methylacetamide and N-acetyl-L-alanine-N-methylamide
2
The direct and geminal SSIC of13C1H were calculated for these compounds by a quantum chemical method The angular dependences of the SSIC found are evidence of the possibility of using them for the conformational analysis of peptide systems
3
A comparison of the measured and calculated SSIC gives a satisfactory qualitative agreement, which confirms the justification of theoretical calculations of the SSIC in peptide systems
4
From the experimental data we determined the dependence for the vicinal SSIC of13C'-NCα-1H in the peptide fragment on the torsional angle Φ of the N-Cα bond The use of this dependence together with the previously established angular dependence of the SSIC of H-NCα-H should give more unambiguous information on the three-dimensional structure of peptide systems
TL;DR: The reduction of the nitro group of p-nitrobenzoic acid and its salts on Pd-, Ru-, and Rh-catalysts is zero order with respect to the substrate, first order in respect to hydrogen, and is not inhibited by the reaction product.
Abstract: 1.
The reduction of the nitro group of p-nitrobenzoic acid and its salts on Pd-, Ru-, and Rh-catalysts is zero order with respect to the substrate, first order with respect to hydrogen, and is not inhibited by the reaction product.
2.
The activity of the catalysts in the reduction of the nitro group decreases in the series Pd≫Rh> Ru, while in the case of hydrogenation of the aromatic ring it decreases in the series Rh≥Ru≫Pd.
3.
The optimum condition of the catalytic synthesis of p-aminobenzoic acid are: 0.5% Pd/C, 90–120‡, 30 atm, aqueous suspension.
TL;DR: In this article, the authors studied the problem of synthesizing 3-D-gluean using a sequence of reac t ions that lead to 3-dimensional topyranose.
Abstract: According to [2, 3 ], 1 ,2-methylor thoaeetyl -4 ,6-O-benzyl idene-o~-D-glucopyranose (I) is easi ly cycl ized to the t r i m e r i e mac rocye l i c o r thoes t e r , the polymer iza t ion of which under the conditions of the o r thoes te r method of glycosylat ion leads to the regu la r /3-1 ~ 3-D-gluean. To study the possibi l i ty of synthesizing the /3-1 ~ 3-D-galae tan we undertook the below desc r ibed synthesis of the 1 ,2 -o r thoes te r s of 4 ,6-O-bensyl idenea -D-ga lae topyranose using a sequence of reac t ions s imi l a r to those that lead to o r thoes te r (I). O--CH~ CH.qOR . .,O'--CHt
TL;DR: In this article, it was shown that it is practical to use steam as the mobile phase in capillary chromatography, and it was also shown that steam can be used as a mobile phase of the capillary process.
Abstract: The capillary chromatography process was run in a current of steam and it was shown that it is practical to use steam as the mobile phase in capillary chromatography.
TL;DR: The dissociation rate of perchloric acid to give per chloric anhydride increases rapidly at temperatures above −30°C as mentioned in this paper, which is the temperature at which the monohydrate decomposes.
Abstract: 1.
Pure anhydrous perchloric acid melts without decomposition to perchloric anhydride and the monohydrate.
2.
The dissociation rate of perchloric acid to give perchloric anhydride increases rapidly at temperatures above −30‡.
TL;DR: The paramagnetic derivatives of diethylenimino-S-triazine, pentaethyleniminocyclotriphospha-zatriene, and p-N-di-(β-chloroethyl)aminophenylacetic acid were synthesized.
Abstract: 1.
The paramagnetic derivatives of diethylenimino-S-triazine, pentaethyleniminocyclotriphospha-zatriene, and p-N-di-(β-chloroethyl)aminophenylacetic acid were synthesized.
2.
The 4-aminomethyl- and 4-(β-aminoethyl)-2, 2, 6,6-tetramethylpiperidine-1-oxyls were synthesized.
3.
A study was made of the reaction of the new spin-labeled compounds with DNA, synthetic polynucleotides, and albumin.
4.
A study was made of the τsec of the spin-labeled polynucleotides as a function of the action of deoxyribonuclease, temperature, and the formation of purine-pyrimidine complexes.
5.
The paramagnetic ethers of cellulose were obtained by the condensation of alkali cellulose with the paramagnetic derivatives of dichloro- and diethyleniminotriazine, and also of pentaethyleniminocyclo-triphosphazatriene.
TL;DR: The relative stability of the adducts of N-phenyltrifluoromethylcarbalkoxyketenimines at the C=N bond with alcohols and hydrogen fluoride is caused by the presence of an intramolecular hydrogen bond as discussed by the authors.
Abstract: 1.
Some N-phenyltrifluoromethylcarbalkoxyketenimines were synthesized.
2.
The relative stability of the adducts of N-phenyltrifluoromethylcarbalkoxyketenimines at the C=N bond with alcohols and hydrogen fluoride is caused by the presence of an intramolecular hydrogen bond.
TL;DR: In this paper, the acid-base properties of the phosphine oxides were studied by the method of potentiometric titration in nitromethane, and a linear correlation was obtained between the values of pK a (CH3NO2) and the σσϕ constants of the substituents at the phosphorus atom.
Abstract: 1.
The acid-base properties of the phosphine oxides were studied by the method of potentiometric titration in nitromethane. The titration curve has two potential jumps at the points of 50% and 100% neutralization, which is due to the formation of complexes of the BHB+ type at the first stages of protonation.
2.
A linear correlation was obtained between the values of pK a (CH3NO2) and the σσϕ constants of the substituents at the phosphorus atom, which permitted a calculation of the σϕ constants of the -CH2OR and -CH2COOH groups.
3.
Aminomethylphosphine oxides are titrated as nitrogen bases. Substantial differences in the values of pK a (CH3+NO2) of different degrees of protonation of the molecules of these compounds are probably due to the formation of intramolecular hydrogen bonds (of the type N+-H ... N) and the inductive effect of the protonated dialkylaminomethyl group.
TL;DR: In this article, a series of donors for complexes of diethylzinc with THF, propylene oxide (PO), and propylene sulfide (PS) were studied, based on an estimate of the equilibrium constants of the reaction of complex formation and the spectroscopic effect.
Abstract: 1.
Complexes of diethylzinc with THF, diethyl ether (DEE), propylene oxide (PO), and propylene sulfide (PS) are appreciably dissociated in solutions of cyclohexane, and in the case of dilution, the degree of dissociation increases, which is manifested in the PMR spectra.
2.
On the basis of an estimate of the equilibrium constants of the reaction of complex formation and the spectroscopic effect, the donors studied are arranged in the following series according to decreasing strength of their complexes with diethylzinc: THF>PO>PS ≥DEE.
TL;DR: In this article, the regeneration of the radicals from their radiolysis products was examined and a possible mechanism for the regeneration process was examined in the irradiation of hydrocarbon solutions of iminoxy radicals in the presence of oxygen.
Abstract: In the irradiation of hydrocarbon solutions of iminoxy radicals in the presence of oxygen, regeneration of the radicals from their radiolysis products is observed. A possible mechanism for the regeneration process was examined.
TL;DR: In this article, the parameters of the 13C NMR spectra of the exo and endo-isomers of hydrocarbons of the tricyclo[5.1.2.
Abstract: 1.
A study was made of the parameters of the13C NMR spectra of the exo- and endo-isomers of hydrocarbons of the tricyclo[5.2.1.02,6]decane series and related compounds.
2.
The spatial arrangement of the cyclopentane ring in tricyclo[5.2.1.02,6]decane exerts the strongest influence on the chemical shift of the bridge carbon of the norbornane part of the molecule.
TL;DR: In this article, it was shown by the method of IR spectroscopy and x-ray powder patterns that magnesium borohydride hexaammine and beryllium borhydride tetraammine have a salt-like structure, and their crystal lattices are constructed from the ions [Mg(NH3)6]2+, [Be(NH 3)4]2+ and BH4−.
Abstract: 1.
It was shown by the method of IR spectroscopy and x-ray powder patterns that magnesium borohydride hexaammine and beryllium borohydride tetraammine have a “salt-like” structure, and their crystal lattices are constructed from the ions [Mg(NH3)6]2+, [Be(NH3)4]2+, and BH4−.
2.
The parameters of the rhombic cells of [Mg(NH3)6](BH4)2 and [Be(NH3)4](BH4)2 were determined.
3.
In the approximation of a “diatomic model” the valence force constants of the Be-N and Mg-N bonds were calculated, and the interatomic distances Be-N and Mg-N in the cations [Be(NH3)4]2+ and [Mg(NH3)6]2+ were determined.
TL;DR: In this paper, the NMR-13C spectra of a number of vinyl alkyl sulfides was studied and it was shown that weak p-π conjugation of the heteroatom with the multiple bond operates in these compounds.
Abstract: 1.
The NMR-13C spectra of a number of vinyl alkyl sulfides was studied. An analysis of the chemical shifts of the carbons of the multiple bond gives unambiguous evidence that weak p-π conjugation of the heteroatom with the multiple bond, the intensity of which is three times lower than in vinyl alkyl ethers, operates in these compounds.
2.
The chemical shifts of13Cβ in the series of vinyl alkyl sulfides and ethers show that in both cases the degree of p-π conjugation is determined by the steric inhibition of resonance, which is more pronounced in the series of sulfides.
TL;DR: In this article, it was shown that Ni(acacac)2+AlEt3 has a high reactivity in the hydrosilylation of conjugated dienes by phenylsilane.
Abstract: It was established that the catalytic system Ni(acac)2+AlEt3 has a high reactivity in the hydrosilylation of conjugated dienes by phenylsilane.