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1.
V. A. Kuz'min P. P. Levin Yu. E. Borisevich I. A. Degterev S. M. Smirnov 《Russian Chemical Bulletin》1988,37(7):1333-1337
| 1. | The energy of the triplet electronically excited state in 5-(4-R-1-quinolyl)-2-nitrofurans and 5-nitropyromucic acid is localized chiefly on the chain of -electron conjugation of the molecules. |
| 2. | With an increase in the length of the chain of -electron conjugation in nitrofuran derivatives their reduction potential in the triplet electronically excited state decreases; this, in turn, decreases the rate constant for interaction of the triplet state with electron donors — amines. |
| 3. | As a result of interation of the triplet states of the investigated nitrofuran derivatives with tertiary aromatic amines in dioxane one observes the formation of triplet exciplexes, the principal contribution to the structure of which is made by a state with complete charge transfer, whereas their deactivation is realized via reverse charge transfer as a result of decomposition of the nitrofuran anion radical. |
2.
| 1. | Paramagnetic species quench the triplet exciplexes of contact radical-ion pairs with a rate approaching the diffusion-controlled limit taking account of the spin statistical factor of 1/3. |
| 2. | The quenching mechanism lies in an acceleration in the transition of the radical pair between states with different multiplicity due to removal of the prohibition in the collision complex. |
3.
| 1. | A model of geminal recombination of radical pairs generated in the triplet state in micelles including triplet-singlet transitions in radical pairs, caused by isotropic and anisotropic hyperfine interactions with strong separation of radicals and spin-orbital interaction for contact radical pairs, was proposed. |
| 2. | The spin-orbital interaction determines the rate of recombination of triplet radical pairs in micelles of small radius in strong magnetic fields. The contribution of the spinorbital interaction increases on incorporation of heavy atoms in the radicals. |
4.
| 1. | In inhibition of oxidation of ethylbenzene and isopropyl alcohol by secondary aromatic amines, organic acids prevent transformation of diarylaminyl radicals into nitroxyl radicals. |
| 2. | An acid increases the efficiency and duration of the inhibiting effect of secondary aromatic amines on oxidation of isopropyl alcohol, since it causes formation of quinone imine, a product of transformation of the amine which has high inhibiting activity. |
5.
K. L. Rogozhin A. N. Rodionov S. G. Smirnov D. N. Shigorin O. P. Syutkina V. I. Lodochnikova K. A. Kocheshkov 《Russian Chemical Bulletin》1976,25(2):319-322
| 1. | There is a regular increase in the energy of the lowest singlet and triplet excited levels in the aromatic derivatives of the elements C, Si, Ge, Sn and N, P, As, Sb, Bi, which is consistent with the quantum-mechanical model of the mixing of the electronic states of the aromatic system with states involving p and s orbitals of the heteroatom with different energies and symmetries. |
| 2. | The yields of the radiative electronic transitions regularly decrease, and the probabilities of nonradiative intramolecular electronic transitions increase. |
| 3. | The temperature effects inthe 300–77°K range in the electronic absorption spectra have been found and are associated with a postulated change in the spatial configuration of the compounds investigated. |
6.
N. K. Tatarskaya M. A. Zhurav S. M. Smirnov I. A. Degterev V. F. Tarasov Yu. E. Borisevich G. E. Zaikov 《Russian Chemical Bulletin》1989,38(4):722-726
| 1. | The decomposition of khinifur in aqueous solutions proceeds according to two parallel paths: direct photodecomposition from the first singlet activated state (monomolecular path) and reaction of the molecule in the triplet state with a molecule in the initial state (bimolecular path). |
| 2. | The first path does not depend on the pressure of oxygen in the solution, while the second path is inhibited by oxygen. |
7.
V. A. Petrosyan A. A. Fainzil'berg M. E. Niyazymbetov V. N. Solkan 《Russian Chemical Bulletin》1989,38(5):985-989
| 1. | The MINDO/3 method has been used to calculate enthalpies in decomposition reactions of the dimethylsulfonium dinitromethylide cation radical in the gas phase; it has been shown that the most probable direction of decomposition leads to the formation of dinitrocarbene. |
| 2. | The MINDO/3 method has been used to calculate the geometric parameters and electronic structure of dinitrocarbene, and it has been shown that the singlet state is more favorable than the triplet state. It has been found that, in a series of singlet carbenes with electron-acceptor substituents, dinitrocarbene is the strongest electrophile. |
8.
Presently, a large variety of layered materials are synthesized that are able to intercalate neutral guest molecules or to exchange inorganic and organic ions for interlayer ions. Several of these materials are also found as minerals.The intracrystalline reactivity of a few selected compounds will be described and compared to clay minerals:
相似文献
| – | - intercalation into crystalline silicic acids; |
| – | - reactions of phosphates, arsenates, and sulfates; |
| – | - reactions of titanates, niobates, and molybdates with long chain alkylammonium ions, and |
| – | - anion exchange properties of double hydroxides. |
9.
P. P. Levin V. A. Kuz'min V. B. Ivanov V. V. Selikhov 《Russian Chemical Bulletin》1988,37(8):1552-1555
| 1. | Data on the kinetics of geminal and bulk recombination of radical pairs formed in transfer of a hydrogen atom from 2,4,6-trimethylphenol to the triplet state of benzophenone in polyvinyl chloride films were obtained with the method of laser photolysis. |
| 2. | Bulk recombinatin of low-molecular-weight radicals makes the fundamental contribution to the kinetics of their quenching in films containing 50% liquid plasticizer and is characterized by high values of the second-order rate constants, close to the value of the rate constant of a diffusion-controlled reaction in low-viscosity liquids. |
| 3. | Geminal recombination of low-molecular-weight radicals in polyvinyl chloride films is characterized by polychromatic kinetics and makes a marked contribution with a concentration of plasticizer 60%. |
10.
V. T. Varlamov 《Russian Chemical Bulletin》1989,38(3):482-490
| 1. | Secondary aromatic amines are catalysts in the reaction of sterically hindered aroxyl radicals with hydroperoxides. The rate of the catalytic reaction v is proportional to [ArO], [ROOH], [AmH], and inversely proportional to [ArOH]. |
| 2. | Values of kcat have been found for eleven aromatic amines in reaction with 2,4,6-tri-t-butylphenoxyl radical with cumyl hydroperoxide in CCl4 over the temperature range 298,2–341.6 K. The values of E and F fall with increasing electron-donor properties of the substituents on the aromatic ring of the amine. On the basis of the values of k which were obtained, several parameters have been estimated including the strength of the N-H bond in the amine molecule. |
| 3. | For diphenylamines with electron-donor substituents there is a linear relationship between log k and the + function. |
11.
B. M. Lerman Z. Ya. Aref'eva L. I. Umanskaya G. A. Tolstikov 《Russian Chemical Bulletin》1976,25(11):2353-2355
| 1. | The reaction between 1-chloro-1,3,5,7-tetramethyl-2,4,6,8-tetrathioprotoadamantane and mercapto-compounds or weakly basic amines produces sulfides and amine derivatives with the protostructure. When (II) reacts with strongly basic amines, dehydrochloridation takes place. |
| 2. | The reaction between 9-bromo-1,3,5,7-tetramethyl-2,4,6,8-tetrathioadamantane and thioacetic acid in ethanol in presence of alkali proceeds by regrouping, with the formation of the thiolacetate of 2,4,6,8-tetra-thioprotoadamantane. |
12.
B. A. Glazun R. N. Kurnosova M. M. Dubinin I. V. Zhilenkov S. S. Levchenko 《Russian Chemical Bulletin》1976,25(1):8-11
| 1. | In NaA zeolite a homocharge is formed by charges deposited on the surface of the zeolite from the gas gap between the electrode and the specimen. |
| 2. | The existence of thermoelectret effects has been found in the systems NaA-zeolite -air, NaA-helium, NaA-nitrogen, and NaA-oxygen. |
| 3. | The thermoelectret effects are caused by both the accumulation of charges in the specimen and the adsorption of molecules in the electric field. |
| 4. | A low mobility has been noted for adsorbed molecules in the electret state of the system. |
13.
| 1. | The rate constant for the destruction of radical pairs decreases with increase in the distance between the traps of the H atom. |
| 2. | A mechanism was proposed for the destruction of radical pairs, according to which the main channel for hydrogen transfer during annealing does not coincide with the channel for phototransfer when the RP are formed. |
| 3. | Based on a formally kinetic analysis for a stepwise rate, distribution parameters based on the activation energies were found for the deuterated and undeuterated samples. A superficial estimate was made of the change in the activation energy when the distance between the unpaired electrons in the radical pairs is changed by one unit of length. |
14.
| 1. | Following the CNDO/2 approximation to the SCF MO LCAO method, electronic parameters have been calculated for the molecules and ions of various nitro compounds. |
| 2. | Calculated values of the dipole moment and enthalpy of atomization proved to be in satisfactory agreement with the experimentally determined values, the maximum deviation between them amounting to 1.4% for the aromatic systems. |
| 3. | The nitro compound parameters most sensitive to change in the intramolecular interaction are the C-N bond energy and the charges on the carbon and halide atoms. |
15.
| 1. | For dyes the steric hindrance that is ereated when several hydrogen atoms are replaced by fluorine leads to a decrease of 1.5-2 times in the activation energy for the relaxation of the photoisomers and a decrease in the life span of the photoisomers by 3–4 orders of magnitude when compared with the unhindered photoisomers of the dyes. Despite the great steric hindrance, the radiationless degradation of the energy goes for the dyes by the path of cis—trans isomerization. |
| 2. | Isomerization from the triplet states of the dyes causes a rapid deactivation of the triplets in the ground state of the photoisomer. |
| 3. | Due to the high coefficient of converting the radiation and the photochemical stabilitys, 3,3'-diethyl-9-fluor othiacarbocyanine can be used successfully as an active medium for lasers. |
16.
L. D. Belyakova G. A. Gerasimova L. T. Zhuravlev G. V. Kudryavtsev G. V. Lisichkin N. S. Ovchinnikova N. P. Platonova T. I. Shevchenko 《Russian Chemical Bulletin》1989,38(5):885-891
| 1. | When silicas are modified with amines, not all surface silanol groups participate in the chemical reaction. |
| 2. | When amine-modified silica gels are heated, water is produced; the maximum rate of the formation of gas occurs at 625 and 750 K. Destruction of the modifying layer begins with the liberation of ammonia at T > 640 K. |
| 3. | Adsorption of SO2 and CO2 on aminated silicas is determined by the surface concentration of amino groups, by their nature, and by their mutual position. |
17.
B. K. Nefedov V. A. Petukhov N. S. Sergeeva Ya. T. Éidus 《Russian Chemical Bulletin》1976,25(7):1466-1469
| 1. | It was shown by the UV spectroscopy method that the active initiators of the Liquid-phase carbonylation of amines with CO are oxidizing agents that form charge-transfer complexes with the amines. |
| 2. | The carbonylation of piperidine with CO in the presence of I2 or KMnO4 is inhibited by excess initiator The addition of a second initiator to the reaction system retards the carbonylation due to a decrease in the rate of forming the complex of the first initiator with the amine. |
18.
B. A. Arbuzov O. Éxsner A. P. Timosheva V. E. Kataev S. G. Vul'fson A. N. Vereshchagin 《Russian Chemical Bulletin》1976,25(6):1206-1212
| 1. | The dipole moments of the two kinds of C-O bonds in acetals and their analogs are not identical. |
| 2. | In formal molecules and the dimethylketal of acetone the C-O-C-O -C chains have gauche-gauche conformation, with the methyl groups lying on different sides of the O-C-O plane. |
| 3. | The dimethylketal of tetrachlorocyclopentadienone is represented by a mixture of trans-gauche and gauche-gauche conformers. |
19.
Medvedeva A. S. Safronova L. P. Kalikhman I. D. Voronkov M. G. 《Russian Chemical Bulletin》1976,25(8):1695-1698
| 1. | The reaction of acetylenic -hydroxyaldehydes with secondary amines in a methanolic medium leads to the formation of 2-methoxy-4-dialkylamino-5,5-dialkyldihydrofurans. |
| 2. | Protection of the hydroxyl group in the acetylenic -hydroxyketones allows one to add diethylamine and obtain previously unknown enamines. |
20.
Yu. V. Kuznetsov L. G. Stolyarova V. P. Lezina L. D. Smirnov 《Russian Chemical Bulletin》1989,38(7):1494-1500
| 1. | New halogen derivatives of 1-ethyl-2-methyl-, 2-methyl- and 5-hydroxybenzimidazole were obtained. |
| 2. | A method for the chlorination of aromatic compounds by an alcoholic solution of hydrogen chloride in the presence of hydrogen peroxide was proposed, which enables carrying out the reaction with a high yield. |
| 3. | The reactivity of the series of 5(6)-hydroxybenzimidazole derivatives during the electrophilic substitution (halogenation) was shown to be as follows: 1-ethyl-2-methyl-5-hydroxybenzimidazole >5(6)-hydroxybenzimidazole 2-methyl-5-hydroxybenzimidazole. |