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91.
Several reactions of 2-naphthol with 2-alkyl-2-hydroxymethylaldehydes have been investigated. Novel synthesis of 14-(hydroxymethyl)alkyldibenzo[a,j]xanthenes and 3,3-dimethyl-4-(2-hydroxy-1-naphthyl)benzo[f]chroman has been realized. 相似文献
92.
We report highly convenient Pd catalysts for the aerobic oxidation of alcohols, which are generated in situ by combining commercially available catalyst precursors. Systematic optimizations of the L- and X-type ligand environment and the employed additive allow the use of air as the sole oxidant without formation of Pd black. The resulting novel protocol provides quantitative yields of a broad variety of ketones and aldehydes. 相似文献
93.
Two polynuclear complexes, a dimer and a tetramer, involving sulfate and hydroxo bridges and ligating ascorbate were isolated from aqueous solutions. Structural formulae are proposed on the basis of microanalytical and thermal analysis results, i.r., 13C-n.m.r., mass spectral data and magnetic measurements. 相似文献
94.
High-resolution 17O NMR spectra have been collected for crystalline samples of lanthanum new phase, La3Si8N11O4. In conjunction with previously published 29Si and 15N spectra obtained for this phase, and in the light of the high-quality crystal structure data reported recently, a more detailed interpretation of the NMR spectra is presented than was possible in previous studies. The non-bridging oxygens in the structure are responsible for the single sharp peak seen in the 17O spectrum at 188 ppm; the remaining oxygens, occupying bridging sites shared with nitrogen, show up only weakly on the 17O spectrum as a broad diffuse band centered around zero ppm. The peak at −57.3 ppm on the 29Si spectrum is believed to correspond to an overlap of [SiN4] and [SiON3] environments, with the −68.2 ppm peak corresponding to an [SiO2N2] environment. 相似文献
95.
Nagihan Saglam Ahmet Colak Kerim Serbest Serdar Karab?cek Saadettin Güner 《Monatshefte für Chemie / Chemical Monthly》2004,15(4):1023-1031
Nucleolytic activities of novel mononuclear Cu(II), homo- and heterodinuclear Cu(II)–Ni(II) complexes with two diester-type ligands were investigated on pCYTEXP by neutral agarose gel electrophoresis. The analyses of the cleavage products obtained electrophoretically indicate that the examined complexes induce very similar conformational changes on supercoiled DNA by converting supercoiled form to nicked form. At concentrations greater than 100M, the complexes possessed effective nucleolytic activities for 10min of incubation time. However, their nucleolytic activities did not increase significantly with longer periods of incubation. The pH-nucleolytic activity profiles of the complexes differed significantly. Metal complex induced DNA cleavage was also tested for inhibition by various radical scavengers. It could be proposed from the data that diffusible intermediate oxidants are not involved in these reactions or they are not necessary for DNA cleavage since none of antioxidants inhibited DNA cleaving activities of the complexes. 相似文献
96.
In this study, a rapid pre-concentration procedure, which employs powdered activated carbon as a clean-up and pre-concentration material, is described for the gas chromatographic analysis of N-nitrosodiethylamine (NDEA) and N-nitrosodimethylamine (NDMA) in aqueous solutions. It was found that powdered activated carbon is suitable for the adsorption of volatile N-nitrosamine compounds from aqueous solutions. Adsorption efficiency with spiked beer samples (alcohol content 5% v/v) was found to be 80.5% (NDMA) and 89.4% (NDEA) and recovery of extraction from activated carbon was calculated as 82.1% (NDMA) and 89.7% (NDEA), respectively. The effect of 100µgmL–1 of tannic acid on the adsorption was also studied, and no significant effect on the adsorption and extraction of volatile N-nitrosamine compounds was found. 相似文献
97.
Cem Cüneyt Ersanl idem Albayrak Mustafa Odabaolu Carsten Thne Ahmet Erdnmez 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(2):o133-o135
The structure of the title compound, C18H20ClN3O5, displays the characteristic features of azobenzene derivatives. Intramolecular N—H⋯O, weak intramolecular C—H⋯O, and intermolecular O—H⋯O and C—H⋯O interactions influence the conformation of the molecules and the crystal packing. Intermolecular hydrogen bonds link the molecules into infinite chains, and the title compound adopts the keto–amine tautomeric form. The azobenzene moiety of the molecule has a trans configuration. The molecule is not planar, and the dihedral angle between the two phenyl rings is 35.6 (2)°. 相似文献
98.
Cem Cüneyt Ersanl igdem Albayrak Mustafa Odabaog
lu Canan Kazak Ahmet Erdnmez 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(6):o455-o457
The two title molecules, both C15H14N2O3, are roughly planar and display a trans conformation with respect to the –N=N– double bond, as found for other diazene derivatives. In both compounds, there are intramolecular O—H⋯O hydrogen bonds and the crystal packing is governed by weak intermolecular C—H⋯O hydrogen bonds and π–π stacking. 相似文献
99.
Ahmet Karadag Ahmet Bulut Orhan Büyükgüngr 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(8):m402-m404
The crystal structure of the title compound, [Ni(NCS)2(C4H12N2O)2], has two crystallographically independent half‐molecules in the asymmetric unit, with each Ni atom residing on a centre of symmetry. The two molecules exhibit similar coordination geometry but display differences with regard to other structural features. Each NiII centre is octahedrally coordinated by two mutually trans chelating hydroxyethylethylenediamine ligands and two mutually trans isothiocyanate ions. The two independent molecules form chains through different types of non‐covalent interactions. In the case of one of the molecules, only NCS and free OH groups participate in hydrogen bonding, while in the chain based on the second molecule, the NCS, NH, NH2 and free OH groups are involved in intermolecular hydrogen bonding. The two chains interact with one another through hydrogen bonding, forming planar sheets. The third packing direction is mediated only by van der Waals interactions. 相似文献
100.
Ahmet Bulut brahim Uar Okan Zafer Yeilel Hasan budak Halis
lmez Orhan Büyükgüngr 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(10):m526-m528
The title mononuclear [Cu(sq)(phen)2]·3H2O complex [sq is squarate (C4O4) and phen is 1,10‐phenanthroline (C12H8N2)] has been synthesized and the structure consists of a neutral mononuclear [Cu(sq)(phen)2] unit and three solvate water molecules. The CuII ion has distorted square‐pyramidal coordination geometry, comprised of one carboxylate O atom from a monodentate squarate ligand and four N atoms from two chelating phen ligands. An extensive three‐dimensional network of OW—H⋯O/OW hydrogen bonds, face‐to‐face π–π interactions between the 1,10‐phenanthroline aromatic rings and a weak π–ring interaction are responsible for crystal stabilization. 相似文献