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261.
262.
Solid solutions NaCl—CdCl2 were studied in an interval of CdCl2 concentrations of 0.05—3 mol.% by Raman spectroscopy. The molecular form Na2CdCl4 decomposes: Na2CdCl4 2Na+ + Cd2+ + 2Cl2
– + 2e–; 2Na + 2e– 2Na0. Free sodium atoms form color centers of crystal (F centers) in the region of jumpwise changing the partition coefficient of CdCl2 in NaCl (K jump). 相似文献
263.
Z. Stec 《Monatshefte für Chemie / Chemical Monthly》1993,124(3):331-332
Summary 2-Acetoxy- and 2-Hydroxy-2,3-dihydronaphtho[1,8-bc]pyranes were synthesized by decomposition of 1-hydroperoxy-1,2-dihydroacenaphthylene in acetic acid in the presence of perchloric acid.
Synthese von 2-Acetoxy- und 2-Hydroxy-2,3-dihydronaphtho[1,8-bc]pyran
Zusammenfassung 2-Acetoxy- und 2-Hydroxy-2,3-dihydronaphtho[1,8-bc]pyrane konnten durch Zersetzung von 1-Hydroperoxy-1,2-dihydroacenaphthylen in Essigsäure in Anwesenheit von Perchlorsäure synthetisiert werden.相似文献
264.
The reactions of [RuHCl(CO)(PPh3)3] and [(C6H6)RuCl2]2 with 2-benzoylpyridine have been examined, and two novel ruthenium(II) complexes – [RuCl(CO)(PPh3)2(C5H4NCOO)] and [RuCl2(C12H9NO)2] – have been obtained. The compounds have been studied by IR and UV–Vis spectroscopy, and X-ray crystallography. The molecular orbital diagrams of the complexes have been calculated with the density functional theory (DFT) method. The spin-allowed singlet–singlet electronic transitions of the compounds have been calculated with the time-dependent DFT method, and the UV–Vis spectra of the compounds have been discussed on this basis. 相似文献
265.
2-Trifluoromethyl-4H-thiochromene-4-thione obtained from 2-trifluoromethyl-4H-thiochromen-4-one and P2S5 reacts with aromatic amines, hydrazine hydrate, phenylhydrazine, and hydroxylamine at the C(4) atom of the chromene ring
to give the corresponding anils, azine, hydrazones, and oxime of thiochromone. 2-Trifluoromethyl-4H-thiochromen-4-one is oxidized by hydrogen peroxide in AcOH into 4-oxo-2-trifluoromethyl-4H-thiochromene 1,1-dioxide and reduced by NaBH4 to 2-trifluoromethyl-4H-thiochromen-4-ol or cis-2-(trifluoromethyl)thiochroman-4-ol. When treated with hydrazine hydrate, thiochromen-4-one gives 3(5)-(2-mercaptophenyl)-5(3)-trifluoromethylpyrazole.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 504–509, March, 2006. 相似文献
266.
Gataullin R. R. Afonkin I. S. Fatykhov A. A. Spirikhin L. V. Tal"vinskii E. V. Abdrakhmanov I. B. 《Russian Chemical Bulletin》2001,50(4):659-664
Electrophilic addition of HCl or Br2 to N-acyl-2-(alk-2-enyl)anilines is accompanied by intramolecular cyclization of these amides to give 3,1-benzooxazine hydrochlorides or hydrobromides in high yields. 相似文献
267.
Four 2-(α-hydroxyalkyl)-2-oxazolines and a 2-(α-hydroxy-α,α-diphenyl)-2-benzooxazole were synthesized from β-amimoalcohols and α-hydroxy carboxylic acids under microwave irradiation in the absence of a solvent. 相似文献
268.
The reaction of a rhodanine derivative (=(Z)-5-benzylidene-3-phenyl-2-thioxo-1,3-thiazolidin-4-one; 1) with (S)-2-methyloxirane (2) in the presence of SiO2 in dry CH2Cl2 for 10 days led to two diastereoisomeric spirocyclic 1,3-oxathiolanes 3 and 4 with the Me group at C(2) (Scheme 2). The analogous reaction of 1 with (R)-2-phenyloxirane (5) afforded also two diastereoisomeric spirocyclic 1,3-oxathiolanes 6 and 7 bearing the Ph group at C(3) (Scheme 3). The structures of 3, 4, 6, and 7 were confirmed by X-ray crystallography (Figs. 1 and 2). These results show that oxiranes react selectively with the thiocarbonyl group (CS) in 1. Furthermore, the nucleophilic attack of the thiocarbonyl S-atom at the SiO2-activated oxirane ring proceeds with high regio- and stereoselectivity via an SN2-type mechanism. 相似文献
269.
Alkylidynephosphanes and -arsanes. I [P ≡ C? S]?[Li(dme)3]+ – Synthesis and Structure O,O′-Diethyl thiocarbonate and bis(tetrahydrofuran)-lithium bis(trimethylsilyl)phosphanide dissolved in 1,2-dimethoxyethane, react below 0°C to give ethoxy trimethylsilane and tris(1,2-dimethoxyethane-O,O′)lithium 2λ3-phosphaethynylsulfanide – [P≡C? S]? [Li(dme)3]+ – ( 1a ). Apart from bis(trimethylsilyl)sulfane or carbon oxide sulfide, dark red concentrated solutions of λ3-phosphaalkyne 1 are also obtained from reactions of carbon disulfide with bis(tetrahydrofuran)-lithium bis(trimethylsilyl)phosphanide or with the homologous lithoxy-methylidynephosphane ( 2 ) [1]. The ir spectrum shows two absorptions at 1762 and 747 cm?1 characteristic for the P≡C and C? S stretching vibrations. The nmr parameters {δ(31P) ? 121.3; δ(13C) 190.8 ppm; 1JCP 18.2 Hz} resemble much more values of diorganylamino-2λ3-phosphaalkynes than those of bis(1,2-dimethoxyethane-O,O′)lithoxy-methylidyne-phosphane ( 2a ). As found by an X-ray structure analysis (P21/c; a = 1192.6(16); b = 1239.1(19); c = 1414.8(26) pm; β = 105.91(13)° at ?100 ± 3°C; Z = 4 formula units; wR = 0.064) of pale yellow crystals (mp. + 16°C) isolated from the reaction with O,O′-diethyl thiocarbonate, the solid is built up of separate [P≡C? S]? and [Li(dme)3]+ ions. Typical bond lengths and angles are: P≡C 155.5(11); C? S 162.0(11); Li? O 206.4(17) to 220.3(20) pm; P≡C? S 178.9(7)°. 相似文献
270.
An improved version of the disposable multichannel immunochemical biosensor for the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) based on a screen-printed amperometric transducer and monoclonal antibodies (MAb) against 2,4-D is reported. Entrapment within a thin Nafion film was used for the direct immobilization of MAb at the electrode surface. The amount of the tracer (2,4-D conjugated to acetylcholinesterase) bound in a competitive immunochemical reaction was determined amperometrically using acetylthiocholine iodide as substrate. The measuring procedure (times of incubation with tracer and substrate, pH, tracer concentration) was optimized. The sensor was able to detect less than 0.01 μg/L of free 2,4-D in water. One analysis (8 samples) was completed in 30 min (20 min for immunochemical reaction, 5 min incubation with substrate, 5 min measurement). The performance of the immunosensor (two configurations) was evaluated on real samples (tap water) with added 2,4-D. The determined amounts (mean values 0.097 to 0.105 and 0.89 to 1.13) corresponded well with the added contents of 2,4-D (0.100 and 1.00 μg/L, respectively). 相似文献