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991.
A gas-phase electron-diffraction study of the product of rearrangement of N,N-dichloro-perfluoroaniline has assisted in establishing it to be the N-chloroimine, I, rather than the azepine, II. The molecule is found to be planar apart from atoms Cl13 and F14. The detailed dimensions shown in Fig. 2 were obtained by least-squares refinements in which several structural constraints were applied to reduce the total number of independent parameters. Of particular interest is the evidence for overcrowding around the CN bond: ∠N7C1C2 = 128°, ∠C18N7C1 = 126°, ∠N7C1C6 = 118° ; the distance C18 β F9 is 2.73 Å. 相似文献
992.
1,2-Bis-(triphenylphosphorane-ylidene-amino)ethane as a Bidentate Ligand in Transition Metal Complexes The reactions of Ph3P?N? C2H4? N?PPh3 with transition metal halogenides MX2 give according to eq. (1) novel bisiminophosphorane complexes of the type M(Ph3PNC2H4 NPPh3)X2 (M ? Co, X ? Cl 1 a , Br 1 b , J 1 c ; M ? Ni, X ? Cl 2 a , Br 2 b , J 2 c , M ? Hg, X ? Cl 3 , M ? Cd, X ? Cl 4 ). The preparation, properties, magnetic moments, and structure of the new complexes are reported 相似文献
993.
1-Hydrazino-2-propanol reacts with aliphatic carbonyl compounds to form the corresponding (2-hydroxypropyl)hydrazones. 1-(N-Alkylhydrazino)-2-propanols, on the other hand, give tautomeric mixtures of alkyl-substituted perhydro-1,3,4-oxadiazines and N-alkyl-N-(2-hydroxypropyl)hydrazones. As compared with derivatives of 2-(N-alkylhydrazino)ethanols, the position of the equilibrium in the investigated cases is shifted to favor the cyclic forms.See [1] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 301–308, March, 1971. 相似文献
994.
A. P. Kilimov M. A. Svechnikova V. I. Shevchenko V. V. Smirnov F. V. Kvasnyuk-Mudryi S. B. Zotov 《Chemistry of Heterocyclic Compounds》1967,3(2):467-471
Data for the characteristic bands of cyclic ethers are reviewed. The infrared spectra of a number of 2-mono- and 2, 5-di-substituted
derivatives of tetrahydrofuran are investigated. Absorption bands at about 900 cm−1 are related to pulsation vibrations, and those at about 1200 cm−1 to antisymmetric skeletal vibrations, of the tetrahydrofuran ring. It is shown that to confirm the presence of a tetrahydrofuran
ring in a molecule, it is necessary to take into account not only the band of valence antisymmetric vibrations of the group
C-O-C (ν
C-O-C
as
1075 cm−1), but also bands due to ring pulsation vibrations (ring symmetric valence vibrations ν
sk
s
∼ 900 cm1). 相似文献
995.
During research on model molecular compounds for synthetic polyamides, the crystal structure of N,N′ di n-hexyladipamide (NNDHA) has been determined by single crystal X-ray diffraction. The structure was solved by direct methods and refined to a final R value of 0.054. The molecule has an all-trans planar conformation. The packing consists of layers of molecules linked by hydrogen bonds in c direction. Molecular structure and packing resemble closely those reported for polyhexamethylenadipamide (nylon 6,6). 相似文献
996.
The effect of substituted hydroxybenzophenone, benzotriazole and organic metal complexes on the photooxidation of PP films has been studied. It has been established that NiDBTC added in 1.0 wt. % is the most effective photostabilizer.While in the case of other stabilizers there is a slight increase in the Co content even during the induction period, with the application of NiDBTC practically no oxidation can be observed before the stabilizer completely disappears. This means that NiDBTC inhibits the photooxidation of the polymer even in low concentration.
, - . , Ni, 1,0 . %. . , Ni , . , Ni .相似文献
997.
Summary This paper discusses the application of X-ray photoelectron spectroscopy to the determination of the chemical composition of sulfur and nitrogen species in air pollution particulates. Core electron chemical shift measurements are augmented by the determination of relative concentrations and volatility of particulate species.
Untersuchung von Verunreinigungsteilchen in der Luft durch Röntgenphotoelektronen-Spektroskopie
Zusammenfassung Die Anwendung der Röntgenphotoelektronen-Spektroskopie auf die Bestimmung der chemischen Zusammensetzung von Schwefel und Stickstoff enthaltenden Verunreinigungsteilchen in Luft wird diskutiert. Messungen der chemischen Verschiebung werden ergänzt durch die Bestimmung der relativen Konzentrationen und der Flüchtigkeit der Verbindungen.
Presented at the 6th Annual Symposium on Recent Advances in the Analytical Chemistry of Pollutants, April 21–23, 1976; Vienna, Austria. 相似文献
998.
Non-empirical SCF and CI calculations are reported for the HN2, free radical in various low-lying electronic states. The nature of the angular and N-N and N-H stretching potential curves of each of these species is investigated, including a study of the dissociative behavior of such states. The ground state is found to be only very slightly bound with respect to NH stretch, in contrast to what is observed for isoelectronic HCO, The vertical electronic spectrum of HN2, appears to be marked by a single long wavelength transition (1.95 eV) from the bent (124°) ‘A’ ground state to the linear 2Π excited species, but at least four other intra-valence and an additional n → 3s Rydberg species are indicated in the 5.5–8.0 eV absorbing region. 相似文献
999.
An investigation of the MECA behaviour of sulphate, sulphite, metabisulphite, peroxodisulphate, thiocyanate, thiosulphate and sulphide ions, has shown that ng amounts of these anions may be determined in samples of a few μl. Metal ion interferences in the determination of sulphate and sulphite are removed by addition of phosphoric acid. 相似文献
1000.
This paper discusses the problem of the thermal properties of flame retarding additives based on phosphazene derivatives and of the commercial agents TomflamB, FlammexT23P and StockhausenW-20949, as well as of flame resistant viscose fibers containing the above agents. Results of this investigation showed the action of FlammexT23P, StockhausenW-20949 and phosphazene derivatives at lower temperature. TomflamB acted within a much wider range of temperatures. The flame retardant additives applied to viscose fibers change the thermal properties of the fiber material. 相似文献