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
Summary A pure silica gel (Pia Seed 5S-60-SIL), synthesized by the hydrolysis of pure tetraethoxysilane [Si(OCH2CH3)4], was applied as a cation-exchange stationary phase in ion chromatography with indirect photometric detection for common
mono-and divalent cations (Li+, Na+, NH4+, K+, Mg2+, and Ca2+) using various protonated aromatic monoamines (tyramine [4-(2-aminethyl) phenol], benzylamine, phenylethylamine, 2-methylpyridine
and 2,6-dimethylpyridine) as eluet ions. When using 0.75 mM tyramine-0.25 mM oxalic acid-1.5 mM 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane)
at pH 5.0 as the eluent, excellent simultaneous separation and highly sensitive detection at 275 nm for these mono-and divalent
cations were achieved on the Pia Seed 5S-60-SIL column (150×4.6 mm I.D.) in 20 min. 相似文献
It was found that [60]fullerene encapsulated in p-sulfonatocalix[8]arene and single-walled carbon nanotubes (SWNTs) solubilized by sodium dodecylsulfate can be readily deposited on the ITO electrode by electrochemical oxidative polymerization of ethylenedioxythiophene (EDOT) without chemical modification of these carbon clusters. The driving force for the deposition is an electrostatic interaction between the anionic complexes and the cationic charges of poly(EDOT) formed in the oxidative polymerization process. The surface morphology was thoroughly characterized by scanning electron micrograph: the [60]fullerene/poly(EDOT) film is covered by nano-particles with 20-100 nm diameters whereas the SWNTs/poly(EDOT) film is covered by nanorods with several microm length and ca. 100 nm diameter. The results indicate that the anionic complexes act as nuclei for the polymer growth in the oxidation polymerization. Interestingly, when these modified ITO electrodes were photoirradiated, the appearance of a photocurrent wave was observed. The action spectra showed that the photoexcited energy of [60]fullerene or SWNTs is efficiently collected by the electroconductive poly(EDOT) film and transferred to the ITO electrode. 相似文献
An enzyme reactor consisting of a 2.6-m-long silicon capillary with glucose oxidase immobilized on the inner surface was fabricated using micromachining techniques. A V-shaped groove of 100 μm width, formed by anisotropic etching, was anodically bonded to a glass plate to create the capillary. Glucose oxidase was covalently immobilized with 3-aminopropyltriethoxysilane and glutaraldehyde. The reactor was evaluated by connecting it to a Flow injection analysis system for glucose detection. Glucose concentrations were in the range of 10−3 to 5 × 10−2M with a volume of 0.2 μl of glucose solution. 相似文献
The 2,3-dihydro-1H-benz[f]indole-4,9-diones 3a–d , h were formed in a one-step reaction in 13–82% yield by an unprecedented [3 + 2] regioselective photoaddition of 2-amino-1,4-naphthoquinone ( 1 ) with various electronrich alkenes 2 (Scheme 1, Table). The [3 + 2] photoadducts derived from 1 with vinyl ethers and vinyl acetate gave 1H-benz[f]indole-4,9-diones 4e , f , i , in 33–72% yield, by spontaneous loss of the corresponding alcohol or AcOH from the resulting adducts; 4i has a kinamycin skeleton. The [3 + 2] photoaddition also took place on irradiation of the differently substituted amino-1,4-benzoquinones 6 , 7 , and 12 and excess alkenes 2 in benzene, giving 1H-indole-4,7-dione derivatives 13 and 14 (Scheme 3), 15a and 16 (Scheme 4), and 18 (Scheme 4), respectively. The initial products in these photoadditions were proved to be hydroquinones, the air oxidation of which yielded the heterocyclic quinones; 2,3-dihydro-2-methoxy-2-methyl-5-phenyl-1H-indole-1,4,7-triyl triacetate ( 19 ) was isolated after treatment of the crude photoaddition mixture obtained from 2-amino-5-phenyl-1,4-benzoquinone ( 7 ) and 2-methoxyprop-1-ene ( 2f ) with Ac2O and pyridine under N2. A pathway leading to the annelated hydroquinones involving ionic intermediates arising from an electron transfer in these photoadditions is proposed (Scheme 5). 相似文献
High-resolution solid-state magic angle spinning (73)Ge NMR spectra of some organogermanium compounds were measured. Most tetrasubstituted germanes with identical substituents exhibited signals except for one case. Tetrasubstituted germanes with two kinds of different but somewhat similar substituents exhibited broad peaks. Trisubstituted germanes failed to show signals, indicating the importance of symmetry around germanium. 相似文献
A palladium-assisted coupling reaction of aryl triflate with arene was investigated, and a novel Pd reagent prepared from equimolar Pd(OAc)2, 1,3-Bis[diphenylphosphino]propane (DPPP), and Bu3P was developed. This method is useful for intramolecular biaryl coupling reactions, not only between aryl triflate and arene (triflate-amide), but also between aryl halide and arene (halo-amide). 相似文献
pi-Allyl-nickel complexes initiated addition polymerisation of 2-phenyl-1-methylenecyclopropane to give a polymer with three-membered rings; the formed polymer showed a high Tg and negligible thermal decomposition up to 300 degrees C. 相似文献