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71.
Jacques Bridet Sndor Fliszr Simone Odiot Robert Pick 《International journal of quantum chemistry》1983,24(6):687-695
Quasi-Wannier functions for the ammonia crystal have been determined from optimized ab initio calculations of the heptamer (NH3)7, thus accounting for all the first neighbor interactions. The calculated geometry and binding energy are in good agreement with their experimental counterparts. 相似文献
72.
Henri J.-M. Dou Maria Ludwikow Parina Hassanaly Jacky Kister Jacques Metzger 《Journal of heterocyclic chemistry》1980,17(2):393-395
A general study of the chemical behavior of heterocyclic anions, dianions and dianionic reagents under phase transfer catalysis conditions allowed us to synthesize various heterocyclic compounds such as imidazo[2,1-b]thiazole and derivatives; imidazo[2,1-b]thiazine and imidazo[2,1-b]benzothiazepine. Reaction conditions e.g., catalyst, solvent, temperature, etc., are indicated. 相似文献
73.
An inductively coupled plasma-atomic emission spectrometric method is reported for the determination of calcium, copper, iron, manganese, magnesium and zinc. Samples are introduced directly when a sheath gas device is used. An external calibration procedure is used. The standards are prepared in a matrix composed of 0.5% (w/v) albumin and 0.76% (w/v) sodium chloride. The procedure was evaluated with a standard reference material (NBS SRM 909 Human Serum); all the values obtained are in agreement with the certified values. Results obtained for the determination of zinc, calcium, magnesium, copper, iron and manganese in amniotic fluid samples are reported. 相似文献
74.
Hydroxylamine-O-sulfonic acid: a convenient reagent for the conversion of aldehydes into nitriles . Hydroxylamine-O-sulfonic acid (HAS) proved to be an excellent reagent for the conversion of aliphatic, aromatic and heteroatomic aldehydes into nitriles. There, aldehydes in the form of suspension in HAS water solution, react rapidely to give the corresponding nitriles in high yield. Only with formylpyridines could the intermediate oxime-O-sulfonic acids be isolated. 相似文献
75.
The products of decomposition of solutions of p-chlorobenzenediazonium tetrafluoroborate in aqueous buffer solutions (pH 9.0–10.3; ionic strength 0.1–0.5) at 20.0° have been analyzed quantitatively. Up to eleven low molecular weight compounds could be identified besides the major product, the complex polymeric diazo tar. The distribution of products is influenced by trace amounts of oxygen as well as by p-chlorophenol and the radical trapping reagent iodoacetic acid. Mechanisms of formation of the products are discussed. 相似文献
76.
Henri J.-M. Dou Parina Hassanaly Jacques Metzger 《Journal of heterocyclic chemistry》1977,14(2):321-323
Alkylation of ambident-anions derived from 2- and 4-pyridones yield by phase transfer catalysis, 80% of N-substitution and 20% of O-substitution. Change of salts, solvents, temperature and alkyl halide do not interfere very much with the N- and O-alkylation percentage of substitution. Overall yields range from 40 to 80% with primary or secondary alkyl halides. 相似文献
77.
An easily prepared and highly efficient monodentate phosphoramidite ligand derived from BINOL, (S)-2,2'-O,O-(1,1'-binaphthyl)-dioxo-N,N-diethylphospholidine, was examined in the hydrogenation of both enamides and alpha-dehydroamino acid derivatives. The catalyst provided remarkably high enantioselectivities (up to 99.6% ee for enamides and >99.9% ee for alpha-dehydroamino acid derivatives). 相似文献
78.
Sandrine Bouquillon Ulla Létinois-Halbes Jacques Muzart 《Journal of organometallic chemistry》2003,687(2):377-383
The reaction between palladium acetate, (−)-ephedrine and potassium acetate led to bis-chelate complex Pd[OCH(Ph)NH(Me)]2 whose the trans-structure is obtained from calculations. The use of this complex to catalyze either the 1,4-hydrogenation of (E)-2-benzyliden-1-tetralone or Heck reaction of phenyl iodide with 3-methyl-3-buten-2-ol led to a low enantiomeric excess. 相似文献
79.
Abstract— Results concerning Rose Bengal sensitized photoxidation of 2,7-dimethyl-2,6-octadiene (A) are discussed. This diolefin may be considered as a model molecule of polyisoprene of polymerization number two with 1,4-4,1 addition mode.
All the mono- and dihydroperoxides apt to occur are actually obtained. One of the occurring hydroperoxides, 2,7-dimethyl-dihydroperoxy-3,5-octadiene, which has the structure of a conjugated diene, does not lead to an endoperoxide. This is contrary to Kaplan and Kelleher's hypothesis. On the other hand, no trihydroperoxide forms as a result of further addition of singlet oxygen (1 O2 ).
A complete kinetic study has allowed us to determine the rate constants of all the reactions which take place. The reactivity of (A) is twice that of 2-methyl-2-pentene and the addition of1 O2 to one of the double bonds of (A) induces deactivation of the remaining double bond. 相似文献
All the mono- and dihydroperoxides apt to occur are actually obtained. One of the occurring hydroperoxides, 2,7-dimethyl-dihydroperoxy-3,5-octadiene, which has the structure of a conjugated diene, does not lead to an endoperoxide. This is contrary to Kaplan and Kelleher's hypothesis. On the other hand, no trihydroperoxide forms as a result of further addition of singlet oxygen (
A complete kinetic study has allowed us to determine the rate constants of all the reactions which take place. The reactivity of (A) is twice that of 2-methyl-2-pentene and the addition of
80.
The absorption spectra of Ru(2,2′-bipyridine)2 (2,2′-bipyridine-4,4′-dicarboxylic acid)2+ (I) and its diethyl ester (II) are closely related and are both significantly different from the spectra of the mono-protonated (Ia) and deprotonated (Ib) complexes. Luminescence polarization measurements show that for I and II the luminescent states have the transferred electron in the bipy-4,4′(COOH)2 and bipy-4,4′(COOEt)2 ligands, respectively, rather than in the unsubstituted bipy ligands. 相似文献