Хуудас 1 -аас 140 үр дүн
The geometry and energetics of the N-H…O=C hydrogen bond (H-bond) are important to understand the stability and flexibility of biomolecules, such as protein and DNA. Jet-cooled pyrrole-cyclopentanone (Py-Cp) binary clusters are appropriate models to investigate the N-H…O=C H-bond from a microscopic
A new "super-extended cavity" tetraacetylcalix[4]pyrrole derivative was synthesized and characterized, and X-ray crystal structures of complexes bound to fluoride and acetonitrile were obtained. The binding behavior of this receptor was investigated by NMR titration, and the complex was found to
N-H···π hydrogen-bonded (H-bonded) structures were studied by applying vibrational spectroscopy to self-aggregate clusters of 2,5-dimethylpyrrole (DMPy) and its binary clusters with pyrrole (Py). The NH stretching vibrations of jet-cooled clusters were observed by IR cavity ringdown spectroscopy. A
We report what to our knowledge is the smallest bis-calix[4]pyrrole (2). It proved capable of trapping fluoride anions exclusively relative to other anions (Cl-, Br-, SCN-, NO3-, H2PO4-,
The hydrogen-bonded structures of pyrrole-solvent (H(2)O,CH(3)OH,C(2)H(5)OH) binary clusters were studied by the combination of experimental and theoretical techniques. Infrared cavity ringdown spectroscopy was applied to observe the NH and OH stretching vibrations of the clusters. The structures,
The IR spectra for various sizes of pyrrole clusters were measured in the NH stretching vibration region by infrared cavity ringdown spectroscopy. The hydrogen-bonded structures and normal modes of the pyrrole clusters were analyzed by a density functional theory calculation of the
A double-cavity calix[4]pyrrole derivative, meso-tetramethyl-tetra[N-(2-phenoxyethyl)-N'-phenylurea]calix[4]pyrrole, 1, with enhanced hosting ability for the fluoride anion has been designed and characterized. Its interaction with anions (fluoride, chloride, bromide, iodide, dihydrogen phosphate,
We report the synthesis of a novel, water-soluble aryl-extended calix[4]pyrrole receptor. The water-solubilising groups are placed at the lower rim of the receptor, leaving the binding pocket unperturbed and open for modification. Binding studies were performed with a series of pyridine N-oxides.
A novel class of dinucleating ligands has been introduced into manganese chemistry to study the reactivity of this metal towards dioxygen under strictly controlled conditions. Such N4 ligands combine some of the major peculiarities of tetradentate Schiff bases and the porphyrin skeleton. They are
Trihalogenated compounds act as effective and selective templates in the template-assisted synthesis of meso-hexaphenyl-calix[6]pyrrole.
The pathway by which HIV-1 enters host cells is a prime target for novel drug discovery because of its critical role in the life cycle of HIV-1. The HIV-1 envelope glycoprotein gp120 plays an important role in initiating virus entry by targeting the primary cell receptor CD4. We explored the
The binding studies of calix[4]pyrroles (1-6) with fluoro, chloro, bromo, iodo and sulphato anions generated from normal-tetrabutylammoniumfluoride, normal-tetrabutylammoniumchloride, normal-tetrabutylammoniumbromide, normal-tetrabutylammoniumiodide, and normal-tetrabutylammoniumsulphate
Calix[4]pyrrole-chloride interactions are affected not only by the choice of countercation in halogenated solvents, but show a specific dependence on the way in which these cations are bound within the electron rich, bowl-like calix[4]pyrrole cavity formed upon chloride anion complexation. In
Gold nanoparticles decorated with a double-armed, deep-cavity calix[4]pyrrole were prepared and fully characterized. Transmission electron microscopy imaging revealed that the average diameter of the particles was approximately 4 nm both before and after attachment of the receptor to the surface.
Calix[4]pyrroles having extended aromatic cavities have been functionalized with 4 ureas in the para position of their meso phenyl substituents. This elaboration of the upper rim was completed in 2 synthetic steps starting from the alpha,alpha,alpha,alpha-tetranitro isomer of the calix[4]pyrrole