Highly correlated coupled cluster methods with single and double excitations (CSSD) and CCSD with perturbative triple excitations were used to predict molecular structures and harmonic vibrational frequencies for the electronic ground state X 1Sigma+, and for the 3Delta, 3Sigma+, 3Phi, 1 3Pi, 2 3Pi, 1Sigma+, 1Delta, and 1Pi excited states of NiCO. The X 1Sigma+ ground state's geometry is for the first time compared with the recently determined experimental structure. The adiabatic excitation energies, vertical excitation energies, and dissociation energies of these excited states are predicted. The importance of pi and sigma bonding for the Ni-C bond is discussed based on the structures of excited states. 相似文献
Fluoro-, chloro-, bromo-, and iodocyclopropane derivatives were obtained in 10–80% yields by the reaction of FCHI2, ClCHI2, BrCHI2, and CHI3, respectively, with Cu in the presence of olefins. The reaction was electrophilic, and proceeded stereospecifically, i.e., cis and trans olefins afforded cyclopropane derivatives whose configurations with respect to the substituents from original olefins were cis and trans, respectively. Since isomeric olefins were not detected in the reaction mixture which would be expected from the insertion of the corresponding free monohalocarbenes into C—H bonds, the reaction seemed to proceed via organocopper intermediates rather than free monohalocarbenes. With respect to the configuration of the halogen introduced by the new reaction, the cis or endo isomers were generally obtained predominantly over the corresponding trans or exo isomers. 相似文献
has been determined by gas electron diffraction (GED) combined with microwave (MW) spectroscopic data. Ab initio calculations at the HF/3–21G* level were carried out and used as structural constraints in the data analysis. The torsional vibration of the methyl group was treated as a large-amplitude motion. The structural parameters were determined to be: rg(S---C2) = 1.719(2) Å, rg(C2=C3) = 1.370(3) Å, rg(C3---C6) = 1.497(6) Å, rg(C2---H) = 1.101(5) Å, CSC = 91.6(2)°, SC2C3 = 113.3(5)°, SC5C4 = 111.3(3)°, C2C3C6 = 123.2(11)° and C3C6H = 112(2)°. The values of r(S---C2) − r(S---C5) and r(C2=C3) − r(C4=C5) were fixed at the 3–21G* value of 0.002Å. Parenthesized values are the estimated limits of error (3σ) referring to the last significant digit. 相似文献
The molecular structure of 3-methylthiophene
has been determined by gas electron diffraction (GED) combined with microwave (MW) spectroscopic data. Ab initio calculations at the HF/3–21G* level were carried out and used as structural constraints in the data analysis. The torsional vibration of the methyl group was treated as a large-amplitude motion. The structural parameters were determined to be: rg(S---C2) = 1.719(2) Å, rg(C2=C3) = 1.370(3) Å, rg(C3---C6) = 1.497(6) Å, rg(C2---H) = 1.101(5) Å, CSC = 91.6(2)°, SC2C3 = 113.3(5)°, SC5C4 = 111.3(3)°, C2C3C6 = 123.2(11)° and C3C6H = 112(2)°. The values of r(S---C2) - r(S=C5) and r(C2=C3)-r(C4 =C5) were fixed at the 3–21G* value of 0.002 Å. Parenthesized values are the estimated limits of error (3σ) referring to the last significant digit. 相似文献
The insertion and abstraction reactions are investigated on the basis of the Heisenberg model. These reactions are characterized as spin-symmetry forbidden and allowed reactions, respectively. It is pointed out that free radical reactions occur readily when there is no spin degeneracy in the course of these reactions. The rule obtained is discussed in relation to the orbital symmetry conservation rule for concerted reactions. 相似文献
A gas chromatographic method has been developed that permits the accurate and specific determination of a new psychotropic agent, PF-257, in plasma. PF-257 is extracted with ethyl acetate from alkaline plasma and, after a clean-up procedure, derivatized with heptafluorobutyric anhydride to form 3-[(5-n-heptafluoropropyl-1,2, 4-oxadiazol-3-yl)methyl]-1,2-benzisoxazole (HOMB). The HOMB is assayed on a gas chromatograph equipped with an electron-capture detector. Accurate determinations of PF-257 are possible in the concentration range from 1-40 ng/ml with a relative standard deviation of 6.8%. The minimum detectable concentration in plasma is 0.1 ng/ml. Plasma levels of PF-257 in rats receiving intravenous or oral dosing (10 mg/kg) were determined. 相似文献
The diethylstilbestrol-related compounds 3,3'-dihydroxy-alpha, beta-diethyldiphenylethane (I), diethylstilbestrol (II) and hexestrol (III) showed hypotensive effects on spontaneously hypertensive rats (SHR) and antifungal activities against all Fusarium oxysporum sp. tested. As previously reported, I had strong hypotensive action on normotensive rats at the dose of 10 mg/kg, while II and III showed weak hypotensive effects on these rats at the same dose. In this work, all three compounds also had hypotensive actions on SHR at the same dose. I showed the strongest hypotensive effect (-80.0 +/- 5.0 mmHg, 10 mg/kg, i.v.) on both SHR and normotensive rats. The three compounds also had antifungal activities against five kinds of Fusarium oxysporum sp. tested. Especially, II strongly inhibited the growth of Fusarium oxysporum f. sp. raphani IFO-9972 (minimum inhibitory concentration (MIC): 1.0 micrograms/ml). 相似文献
We prepared and characterized a grinding-induced equimolar complex of thiourea with ethenzamide. When thiourea and ethenzamide were co-ground at a molar ratio of 3 : 1, new powder X-ray diffraction (PXRD) peaks were observed in addition to PXRD peaks of thiourea crystals. The optimum stoichiometry of the new structure was confirmed as 1 : 1 mol/mol. Effect of grinding time on the thiourea-ethenzamide equimolar complex formation was investigated by using PXRD, differential scanning calorimetry and Fourier transform infrared spectroscopy. The equimolar crystal structure was confirmed by X-ray diffraction measurements of the single crystal which was recrystallized from ethanol. It was found that the intermolecular hydrogen bond formations between thiourea and ethenzamide molecules contributed to the equimolar complex formation. The complex formation was not observed in the cases where benzamide, salicylamide or 3-ethoxybenzamide was co-ground with thiourea. 2-Alcoxyl benzamide structures should be required for the grinding-induced equimolar complex formation with thiourea. 相似文献
Reactions of [(Cp*Ir)2(mu-dmpm)(mu-H)2]2+ (1) with NaOtBu in aromatic solvent at room temperature give [(Cp*Ir)(H)(mu-dmpm)(mu-H)(Cp*Ir)(Ar)]+ [Ar = Ph (3), p-Tol (4a), m-Tol (4b), 2-furanyl (5a), 3-furanyl (5b)] via intermolecular aromatic C-H activation. Treatment of [(Cp*Ir)2(mu-dppm)(mu-H)2]2+ (2) with base (Et2NH) results in intramolecular C-H activation of the phenyl group in the dppm ligand to give [(Cp*Ir)(H){mu-PPh(C6H4)CH2PPh2}(mu-H)(Cp*Ir)]+ (6). The structures of 3, 5a, and 6 have been determined by X-ray diffraction methods. 相似文献
Microwave spectra of thionyl chloride, SO35Cl2 and SO35Cl37Cl, in the frequency range 8–25 GHz have been analyzed. The rotational constants have been obtained from the low J transition frequencies. The rS coordinates of Cl atoms and the ro structure have been evaluated with some assumptions: r(S-O) = 1.435 ± 0.011± Å, r(S—Cl) = 2.072 0.005 Å, ∠ OSCl = 108.00 ± 0.06°, ∠ ClSCl = 97.15 ± 0.30°. Nuclear quadrupole coupling constants have been obtained for the SO35Cl2, species: xaa = ?25.02 ± 0.04 MHz, x(bb = ?0.25 ± 0.04 MHz, Xcc = 25.27 ± 0.08 MHz, and Xzz = ?96.75 MHz. The values obtained are compared with those of other workers. 相似文献