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1.
The structure of novel phosphorus‐containing N‐vinylazoles prepared by action of phosphorus pentachloride has been studied by multinuclear 1H, 13C, 15N, 31P and two‐dimensional (2D) NMR spectroscopy. N‐vinyl‐substituted 1,2‐diazoles and 1,2,3‐triazoles have undergone phosphorylation, exclusively, on double bond. N‐vinylazoles‐based hexa‐coordinated phosphorus compounds have been synthesized for the first time. 31P NMR spectroscopy provides the most convenient and unambiguous method for the investigation of EZ‐isomeric structures of phosphorylated enamines. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
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Intermolecular coordination effects on the 31P NMR spectra of molecular complexes of N-vinylimidazole and 1-allyl-3,5-dimethylpyrazole with phosphorus pentachloride were studied by theoretical and experimental methods. The formation of intermolecular dative N→P bond was shown to be accompanied by upfield shift of the phosphorus resonance signal by more than 200 ppm. Appreciable contribution of relativistic effects to 31P NMR chemical shifts was revealed; the spin-orbital contribution to 31P shielding constant was estimated at >210 ppm. Consideration of solvent effect was found to be crucial while studying steric structure of molecular complexes of azoles with phosphorus pentachloride and intermolecular coordination effects on 31P NMR chemical shifts.  相似文献   
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A new method of synthesis of phosphonic and thiophosphonic chlorides is offered, based on treatment of acyclic and cyclic organylchlorophosphonium hexachlorophosphorates with dimethylformamide, dimethylacetamide, or dimethylthioacetamide. The method involves no formation of phosphoryl chloride and thiophosphoryl chloride, which facilitates isolation of the target products. The reactions of alkenylchlorophosphonium hexachlorophosphorates with amides and thioamides results in incorporation of the PCl6 - anion into an insoluble chloroiminium salt which is easily separated by filtration. Removal of the solvent leaves almost pure phosphonic or thiophosphonic chlorides.  相似文献   
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Phosphorylation of tertiary amines containing at least two ethyl groups at the nitrogen atom with phosphorus pentachloride was studied. New C-chlorophosphorylated enamines were characterized by NMR spectroscopy. A scheme was suggested for the phosphorylation reaction. It was found that the presence of two aryl substituents in the molecule of tertiary ethylamine deactivated the ethyl group to block phosphorylation. Phosphorylation of N,N-diethylaniline, besides phenyl-substituted phosphorus-containing enamines, also gave phosphorylated enamines chloro-substituted in the ring. Using N-ethyl-N-methylaniline as an example, a possibility of substitution for two chlorine atoms in the PCl5 molecule with alkenyl groups was demonstrated.  相似文献   
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Background: Fluorophore dyes are used extensively in biomedical research to sensitively assay cellular constituents and physiology. We have created, as proof of principle, fluorophore dye binding peptides that could have applications in fluorescent dye-based approaches in vitro and in vivo.Results: A panel of Texas red, Rhodamine red, Oregon green 514 and fluorescein binding peptides, termed here ‘fluorettes’, was selected via biopanning of a combinatorial library of 12-mer peptides fused to a minor coat plll protein of the filamentous bacteriophage M 13, The ‘best’ fluorette sequences from each of the groups were subjected to further mutagenesis, followed by a second biopanning to select a new generation of improved fluorettes. Phage were selected that had higher avidity for each fluorophore except Rhodamine red, Of these, peptides were characterized that could specifically and with high affinity bind at least one dye, Texas red, in solution, In addition, the binding of certain peptides to Texas red shifted the peak excitation and/or the emission spectra of the bound dye.Conclusions: Peptides in the context of phage display could readily be selected that could bind to small-molecule fluorophores. The affinities of selected mutant fluorettes could be increased by mutation and further selection, Only a subset of the free peptides could bind free dyes in solution, suggesting that phage context contributed to the selection and ability of certain peptidic regions to independently bind the dyes, Future screens might lead to the creation of other dye-binding peptides with novel characteristics or Texas red derivatives with cross-linking substituents might be designed to increase the utility of the system.  相似文献   
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