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排序方式: 共有526条查询结果,搜索用时 171 毫秒
1.
Vytautas Getautis Albina Stanisauskaite Tadas Malinauskas Jolanta Stumbraite Valentas Gaidelis Vygintas Jankauskas 《Monatshefte für Chemie / Chemical Monthly》2006,23(12):1401-1409
Hydrazones containing 1-phenyl-1,2,3,4-tetrahydroquinoline units were synthesized starting from diphenylamine. These compounds
were found to constitute novel hole transporting materials and were characterized by the time of flight method. The hole drift
mobility in these compounds exceeds 10−6 cm2 V−1 s−1 at an electric field of 106 V cm−1. 相似文献
2.
3.
Marchán V Cieślak J Livengood V Beaucage SL 《Journal of the American Chemical Society》2004,126(31):9601-9610
Several nitrogen-sulfur reagents have been investigated as potential 5'-hydroxyl protecting groups for deoxyribonucleoside phosphoramidites to improve the synthesis of oligonucleotides on glass microarrays. Out of the nitrogen-sulfur-based protecting groups so far investigated, the 2,2,5,5-tetramethylpyrrolidin-3-one-1-sulfinyl group exhibited near optimal properties for 5'-hydroxyl protection by virtue of the mildness of its deprotection conditions. Specifically, the iterative cleavage of a terminal 5'-sulfamidite group in the synthesis of 5'-d(ATCCGTAGCCAAGGTCATGT) on controlled-pore glass is efficiently accomplished by treatment with iodine in the presence of an acidic salt. Hydrolysis of the oligonucleotide to its 2'-deoxyribonucleosides upon exposure to snake venom phosphodiesterase and bacterial alkaline phosphatase did not reveal the formation of any nucleobase adducts or other modifications. These findings indicate that the 2,2,5,5-tetramethylpyrrolidin-3-one-1-sulfinyl group for 5'-hydroxyl protection of phosphoramidites, such as 10a-d, may lead to the production of oligonucleotide microarrays exhibiting enhanced specificity and sensitivity in the detection of nucleic acid targets. 相似文献
4.
Summary. Phenoxyacetic acid distribution in two-phase systems n-aliphatic hydrocarbon (C5–C8) – water and its dimerization in organic phase were investigated. The values of distribution coefficient (D
HR), distribution constant (K
D), and dimerization constant (K
dim) of acid were obtained. The empirical correlations of these quantities with Hildebrand solubility parameter of organic solvents were established. The influence of pH of the aqueous phase as well as the polarity of the applied organic solvents on phenoxyacetic acid physical chemistry in
the two-phase systems was described. 相似文献
5.
A vinyl bis-sulfone Michael type approach towards heteroatom vinylation was applied on nitrogen derivatives. Cyclic thionocarbamates--mainly 1,3-oxazolidine-2-thiones--were converted into their N-vinyl counterparts; the procedure proved particularly efficient in the case of carbohydrate-derived complex structures. 相似文献
6.
Adach Anna Cieślak-Golonka Maria Maciejewska Gabriela 《Transition Metal Chemistry》2003,28(3):247-253
The reduction of CrO3 with an excess of L-cysteine and its interaction with DNA fragments (adenine, adenosine) and ATP nucleotide was studied by analysis of the isolated solid products. The precipitates were characterised by elemental analyses, FAB mass spectral data, spectroscopic methods (u.v.–vis., f.i.r., i.r.) and magnetic measurements. The CrIII complexes obtained appear to be various CrIII cysteinate and adenine or ATP (but not adenosine) ternary species of the addition type bound through the hydrogen bonding network. 相似文献
7.
Jolanta Obniska Krzysztof Kaminski Agnieszka Dzierzawska-Majewska 《Journal of fluorine chemistry》2006,127(3):417-425
A series of N-phenyl- and N-benzyl-2-azaspiro[4.4]nonane- and [4.5]decane-1,3-diones containing a fluoro or trifluoromethyl substituents at the aryl ring was synthesized and tested for their anticonvulsant activity in the maximal electroshock (MES) and subcutaneous metrazole (sc.Met) tests. Among them, the most active were N-benzyl derivatives with fluoro and trifluoromethyl substituents especially at position-2 of the aryl moiety. The introduction of the phenyl ring at the imide nitrogen atom resulted in less active compounds. The results obtained showed that incorporation of fluoro or trifluoromethyl substituents increased the anticonvulsant activity in comparison to respective chloro, methoxy or methyl analogues. Crystallographically obtained conformation for one active and two inactive derivatives with trifluoromethyl substituents at position-2 or -3 of phenyl ring were initially used for molecular electrostatic potentials (MEP) calculation. The MEP distribution at carbonyl oxygen atoms was different for active and inactive molecules. 相似文献
8.
Jolanta Olkowska‐Oetzel Dieter Fenske Petra Scheer Andreas Eichhfer 《无机化学与普通化学杂志》2003,629(3):415-420
Syntheses and Thermal Properties of Cluster Molecules, formed from Groups 11‐13‐16 Elements In the presence of PPh3, CuX (X = Cl, CH3COO) or AgOC(O)C6H5 and GaCl3 react in THF with S(SiMe3)2 or Se(SiMe3)2 to yield [Cu6Ga8Cl4S13(PPh3)6] ( 1 ), [Cu6Ga8Cl4Se13(PPh3)6] ( 2 ), [Ag6Ga8Cl4S13(PPh3)6] ( 4 ) and [Ag6Ga8Cl4Se13(PPh3)6] ( 5 ). The use of PnPr2Ph instead of PPh3 and subsequent layering with n‐hexane leads to the formation of the cluster [Cu6Ga8Cl4Se13(PnPr2Ph)12] ( 3a , 3b ). Reaction of CuCl, GaCl3 and PnPr3 with Se(SiMe3)2 in THF results in the crystallisation of the ionic cluster (HPnPr3)2[Cu2Ga4Cl4Se6(PnPr3)4] ( 6 ). The structures of 1 — 6 were determined by X‐ray single crystal structure analysis. Thermogravimetric measurements of the cluster molecules and powder diffraction patterns of the remaining powders reveal the potential use of them as single source precursor compounds for the synthesis of the related ternary solid state materials. 相似文献
9.
Alumina-silica possessing various Al2O3/SiO2 ratios was used as a carrier of surface titanium complexes. The systems obtained were examined as models for the investigation of the macroligand (inorganic gel) influence on the physicochemical properties of supported transition metal complexes. The titanium complexes were prepared first by the reaction of CpTiCl3, with the hydroxyl groups of the gel and then reduced by an excess of BuLi. The influence was established of the basic gel properties on: (a) the amount of titanium(IV) and titanium(III) complexes on the alumina-silica gel surfaces; (b) the symmetry of the surface TiIII surface complexes; (c) the electron density around the surface-TiIII ions, ionic or covalent bonds character in a complex; and (d) the catalytic activity in olefin hydrogenation. 相似文献
10.
Marek Daszkiewicz Zbigniew Staszak Adam Pietraszko Wiesława Bronowska Maria Cieślak-Golonka 《Structural chemistry》2006,17(6):599-608
Two polymeric complexes: catena(μ-CrO4-O,O′)[Co(HIm)3H2O] (1) and catena(μ-CrO4-O,O′)[Co0.43Ni0.57(HIm)3H2O] (2) (where HIm=imidazole) with a cis-bridging coordination mode of the CrO4
2− anion have been synthesized and characterized by X-ray and spectroscopic methods. These crystals were isolated from nine
systems of varying reagent molar ratios and three excluding anions: Cl−, NO3
− and SO4
2− exclusively as mer [M(HIm)3O3]-type isomers. The unit cell of these isostructural complexes (monoclinic crystal system P21
/n) contains two independent helixes, left- and right handed, stabilized by intrahelical and interhelical hydrogen bonding and
π–π interaction between pairs of the imidazole rings from neighbouring helixes. The Raman spectra at 77 K of 1 and 2 deconvoluted into lorentzian components revealed the block-type polymeric structure of the complexes. Moreover, the solution
studies at millimolar concentrations of 1 and 2 indicated their complete decomposition in water. Four K electronic spectral analysis of the crystals (band deconvolution
into gaussian components) enhanced with the data obtained in the polarized light allowed for assignment of the bands to the
respective d–d transition (D4h symmetry). It was found that the metallic centres are independently absorbing species, which supports the suggestion of a
block-type structure of the polymers. The respective crystal field parameters for Co and Ni were calculated. 相似文献