نتایج جستجو برای: intramolecular hydrogen bond
تعداد نتایج: 210500 فیلتر نتایج به سال:
The quantum chemical calculations were performed to investigate the interplay between the anion˗π and intramolecular hydrogen bond (IMHB) interactions in the various complexes of 1,3,5-triamino-2,4,6-trinitrobenzene (ANB) with Hˉ, Fˉ, Clˉ and Brˉ anions. For better understanding the cooperative effects, the parent molecules (ANB) and the corresponding complexes of 1,3,5˗trinitrobenzene with the...
The effect of pressure on the crystal structure of salicylaldoxime has been investigated. The ambient-pressure phase (salicylaldoxime-I) consists of pairs of molecules interacting through oximic OH...O hydrogen bonds; taken with phenolic OH...N intramolecular hydrogen bonds, these dimers form a pseudo-macrocycle bounded by an R4 4(10) motif. The dimers interact principally via pi...pi stacking ...
Profiling of eight stereoisomeric T. cruzi growth inhibitors revealed vastly different in vitro properties such as solubility, lipophilicity, pKa, and cell permeability for two sets of four stereoisomers. Using computational chemistry and NMR spectroscopy, we identified the formation of an intramolecular NH→NR3 hydrogen bond in the set of stereoisomers displaying lower solubility, higher lipoph...
The Crystal Structure of Anhydrous Xanthosine Displays Intramolecular 0(2')H ... 0(3') Hydrogen Bond
From an equimolar dipeptide/xanthosine mixture in water/methanol, only the nucleoside crystallized in anhydrous form, space group P2,2,2, with a = 17.406 (5) A, 6 = 12.378 (4), c= 5.350 (2) A, Z = 4, C|0H 12O6N4, FW = 284.26, D x = 1.639 g • cm-3. The structure was deter mined by direct methods on the basis of 984 X-ray data and refined to an agreement index of R = 3.9%. Xanthosine occurs in t...
New guanidine-derived superbases with TBD-functionalized alkyl side chains have been developed using a computational DFT approach. Exploiting the high hydrogen bond basicity of TBD allowed access to systems with strong charge-assisted intramolecular hydrogen bonds in the protonated state. The enhanced stability of such guanidines is mirrored in their gas-phase basicities, which cover the range ...
The title compound, C(17)H(18)N(2)OS, adopts a trans-cis geometry of the thio-urea group which is stabilized by intra-molecular hydrogen bonds between the O atom of the carbonyl group and the H atom of the thio-amide group. A C-H⋯S intramolecular hydrogen bond is also present. In the crystal structure, mol-ecules are linked by inter-molecular N-H⋯S hydrogen bonds to form centrosymmetric dimers.
in 0.1 M ionic strength aqueous solution at 120 for the following: 2,4-dihydroxy4'-nitroazobenzene (I), 2,4-dihydroxy-4'-sulfonateazobenzene (II), and p-(2hydroxy-l-naphthylazo) benzenesulfonic acid (III). The reported values of k231 were 4O X 105, 3.6 X 105, and 3.6 X 106 M-1 sec-1. They attributed the much lower values of k23, for these acids than the value3 k23, 2 X 109 M-1 sec-1 kn,' for th...
In the crystal structure of the title compound, C(11)H(14)N(2)OS, the two N-H bonds are anti to each other. There is an intramolecular N-H⋯O hydrogen bond generating an S(6) ring motif.In the crystal, mol-ecules are linked via N-H⋯S hydrogen bonds with an R(2) (2)(8) motif and N-H⋯O hydrogen bonds with an R(2) (2)(12) motif into chains running along [1-10].
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