نتایج جستجو برای: intermolecular hydrogen bonds
تعداد نتایج: 180813 فیلتر نتایج به سال:
270-MHz 1H NMR studies of the 11-21 suzukacillin fragment Boc-Gln-Aib-Leu-Aib-Gly-Leu-Aib-Pro-Val-Aib-Aib-OMe (11-G) and its analogue Boc-Ala-Aib-Leu-Aib-Gly-Leu-Aib-Pro-Val-Aib-Aib-OMe (11-A) have been carried out in CDCl3 and (CD3)2SO. The NH chemical shifts and their temperature coefficients have been measured as a function of peptide concentration in both solvents. It is established that re...
Intermolecular hydrogen bond librational modes in cyclic trimers and tetramers of methanol and t-butyl alcohol isolated at low temperature in pulsed supersonic jet expansions are observed by direct absorption spectroscopy in the far-infrared region. The large amplitude librational modes probe the strength and directionality of the intermolecular hydrogen bonds. In addition, their frequency and ...
The synthesis and X-ray diffraction analysis of a new acidic salt, [4-methyl-phenyl ammonium][(O-phenyl)(hydroxyl)phosphate], [4-CH3-C6H4NH3][(C6H5O)P(O)(O)(OH)], is reported. This compound crystallizes in the monoclinic system, with space group P21/c (a = 9.5147(4) Å, b = 23.2158(10) Å, c = 13.2740(6) Å and b = 111.244(4)°) with four independent components including two cations and two anions...
To study the early time hydrogen-bonding dynamics of chromophore in hydrogen-donating solvents upon photoexcitation, the infrared spectra of the hydrogen-bonded solute-solvent complexes in electronically excited states have been calculated using the time-dependent density functional theory (TDDFT) method. The hydrogen-bonding dynamics in electronically excited states can be widely monitored by ...
Control of intermolecular interactions is integral to harnessing self-assembly in nature. Here we demonstrate that control of the competition between hydrogen bonds and halogen bonds, the two most highly studied directional intermolecular interactions, can be exerted by choice of solvent (polarity) to direct the self-assembly of co-crystals. Competitive co-crystal formation has been investigate...
Our goal was to gain a better understanding of the contribution of the burial of polar groups and their hydrogen bonds to the conformational stability of proteins. We measured the change in stability, Δ(ΔG), for a series of hydrogen bonding mutants in four proteins: villin headpiece subdomain (VHP) containing 36 residues, a surface protein from Borrelia burgdorferi (VlsE) containing 341 residue...
Crystalline N-alkyl-N-arylthioureas with ortho hydroxyl and para or meta methyl substituents to the phenyl ring were studied by single crystal X-ray diffraction, IR and solid state C CP MAS NMR. Two different modes of association were found: i) intermolecular NH...S bonds and NH not involved in hydrogen bonding in N-methyl-N(2-hydroxy,5-methylphenyl)thiourea 1, ii) cyclic dimers with two NH...S...
In order to understand the nature and dynamics of interfacial water molecules on the surface of complex systems, large scale, fully atomistic molecular dynamics simulations of an aqueous micelle of cesium perfluorooctanoate (CsPFO) surfactant molecules have been carried out. The lifetime and the intermolecular vibrational frequencies of the hydrogen bonds that the water molecules form with the ...
In this study, two new salicylideneaniline derivative compounds which are an isomer of each other have been synthesized and characterized by X-Ray Diffraction (XRD) technique, IR spectroscopy, and theoretical method. While (E)-4-(dihydroxyamino)-2-(((4-fluorophenyl)imino) methyl)phenol (1), crystalizes triclinic P-1 space group, (E)-4-(dihydroxyamino)-2-(((3-fluorophenyl)im...
At 150 K, the title compound, C(9)H(11)NO(4)S, crystallizes in the orthorhombic form as a zwitterion and has a low gauche conformation [chi = -46.23 (16) degrees] for an acyclic cysteine derivative. A difference in bond length is observed for the alkyl C-S bond [1.8299 (15) A] and the aryl C-S bond [1.7760 (15) A]. The -NH(3)(+) group is involved in four hydrogen bonds, two of which are intermo...
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