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101.
DFT calculations have been performed to determine the isomer shift for a series of iron(II) clusters with nitrogen-containing ligands which serve as models of coordination units in Fe(II) complexes with 1,2,4-triazoles possessing a 1 A 1 ? 5 T 2 spin transition. Good agreement has been found between the theoretical and experimental values of the isomer shift for both low-and high-spin phases. Our calculations confirmed the hypothesis about relationship between the experimentally observed differences in the isomer shift for the low-spin phases of the complexes and variations of the Fe-N mean bond length. 相似文献
102.
Friedrich W. Vierhapper 《Monatshefte für Chemie / Chemical Monthly》1980,111(2):551-554
Conformations of six title compounds were determined by13C-NMR spectroscopy. Equilibration of the 2-methyl-compounds gives as main products the derivatives of the amines least abundant in the product mixture of the catalytic hydrogenation.
Konformation und Base-katalysierte Äquilibrierungen von N-Nitroso-decahydrochinolinen und N-Nitroso-2-methyl-decakydrochinolinen (Kurze Mitt.)
Zusammenfassung Die Konformationen der sechs Titelverbindungen wurden mittels13C-NMR Spektroskopie bestimmt. Äquilibrierung der 2-Methyl-verbindungen ergab als Hauptprodukte die Derivate der bei katalytischer Hydrierung in geringster Menge entstandenen Amine.相似文献
103.
γ-芳基取代烯丙醇菊酯的合成及杀虫活性陈亚娟,黄润秋,马军安(南开大学元素有机化学研究所,天津,300071)关键词γ-芳基取代烯丙醇,拟除虫菊酯,杀虫活性第一个人工合成除虫菊酯烯丙菊酯保留了天然除虫菊酯醇部分的环戊烯醇酮结构,至今仍广泛用作卫生杀虫... 相似文献
104.
The stereochemistry of substituted cyclopent-2-en-1-ones was studied by NMR. The existence of non-planar rings is indicated and conformational analysis, based principally upon examination of the coupling constants enables the conformational population to be estimated; trans dihalogeno derivatives, for example, occur predominantly in the diaxial form. 相似文献
105.
An explicit expression for the analytical first derivative of the Z-averaged perturbation theory taken to second order energy, due to Lee and Jayatilaka, is presented for application to high-spin
systems described by a restricted open-shell Hartree–Fock wavefunction. The use of frozen core orbitals is incorporated into
the derivation.
Received: 23 April 2001 / Accepted: 31 August 2001 / Published online: 9 January 2002 相似文献
106.
Mosstafa Kazemi 《合成通讯》2020,50(13):1899-1935
AbstractCatalysis research under magnetically recoverable nanocatalysts is a well-known topic in organic synthesis. In recent times, catalysis research has clearly experienced a renaissance in the area of utility of ferrite nanoparticles based on their ability to recovery and reusability. In this review, the focus is on the fabrication, characterization and of application the MFe2O4 (M=Co, Cu, and Ni) nanocatalysts in synthesis of heterocyclic structural scaffolds. 相似文献
107.
Rudolph Willem Ann Delmotte Inge De Borger Monique Biesemans Marcel Gielen Franois Kayser Edward R. T. Tiekink 《Journal of organometallic chemistry》1994,480(1-2):255-259
The synthesis of (Z)-2-methyl-3-triphenylstannyl-3-pentene-2-ol and its characterization by an X-ray diffraction study and multinuclear NMR are reported. The tin atom exhibits a distorted tetrahedral SnC4 geometry with the four Sn---C bond distances experimentally equivalent. The slight distortion from the ideal tetrahedral geometry is because of the presence of a weak intramolecular HO → Sn interaction of 3.012(3) Å which produces a loose four-membered ring. The title compound was characterized in solution by 1H, 13C and 119Sn NMR, and the persistence of the weak intramolecular HO → Sn coordination in solution was revealed by 13C and 119Sn secondary isotope multiplet of partially labelled entities (SIMPLE-NMR) experiments. 相似文献
108.
The effect of the addition of a second metals such as Zn and Ni on the calcinaton and reduction of alumina, magnesia and silicasupported iron catalysis with total iron loading of 5wt% is investigated by Mössbauer spectroscopy. It is shown that the reducibility of supported α-Fe2O3 is gradually increased by adding the second metal. The values of the magnetic hyperfine field obtained from Mössbauer spectra for the Zn or Ni-added α-Fe2O3 or Fe catalysts decreased with increasing second metal loading. 相似文献
109.
Anju Midha Rajender D. Verma K. Brown R. V. Parish 《Monatshefte für Chemie / Chemical Monthly》1983,114(6-7):661-667
Mixed dialkytin(IV) trifluoroacetates,Me EtSn(O2CCF3)2,Et Pr
n
Sn(O2CCF3)2 andPr
n
Bu
n
Sn(O2CCF3)2 have been prepared by metathetical reactions of the corresponding dialkyltin(IV) chlorides with silver trifluoroacetate in CH2Cl2. They are monomeric in benzene and nonconducting inMeNO2 andMeCN. Bidentate trifluoroacetate groups are indicated by their IR spectra.Mössbauer spectra confirmtrans-arrangement of theR-Sn-R moiety.1H,19F NMR and mass spectra are also discussed.
Gemischte Dialkylzinn(IV)-trifluoracetate
Zusammenfassung Die gemischten Dialkylzinn(IV)-trifluoroacetateMe EtSn(O2CCF3)2,Et Pr n Sn(O2CCF3)2 undPr n Bu n Sn(O2CCF3)2 wurden über Metathese-Reaktionen der entsprechenden Dialkylzinn(IV)-chloride mit Silbertrifluoracetat in CH2Cl2 dargestellt. Sie sind monomer in Benzol und nichtleitend inMeNO2 undMeCN. Die IR-Spektren zeigen zweizähnige Trifluoracetat-Gruppen an. DieMössbauer-Spektren bestätigen dietrans-Anordnung derR-Sn-R-Einheit. Die1H-,19F-NMR und die Massenspektren werden ebenfalls diskutiert.相似文献
110.
Cyclisation of the title compounds leads to mixtures of the expected 4H-cyclopental[b]pyrrol-4-ones (1), the corresponding 6-ones (3) by a single rearrangement, and the cyclopenta[c]pyrrol-4-ones (4) by a double rearrangement, the proportions depending upon the substituents.The 1H NMR spectra of 2-methyl-4H-cyctopenta[b]thiophen-6-one (3f) shows 6J long range coupling, but this is absent in the corresponding pyrroles (3c,d). The 13C spectra of 1 and 3 cannot be interpreted on the basis of substituent chemical shifts in pyrroles and thiophens, and are clearly -CH = CH-X (X = NMe, NPh, S) bridged derivatives of cyclopent-2-enone. 相似文献