n -Butane represents the simplest case (Fig. 16.1). The central torsion or dihedral angle determines the relative orientation of the two bonds to the methyl groups to one another. If n -butane is rotated out of the arrangement with the two bonds to the methyl groups in 180° orientation ...
organic compounds/ conformational analysisn-alkanesdensity functional theoryab initio calculationsrelative conformational energiesn-butanen-pentaneRelative conformational energies of n-butane, n-pentane and n-hexane were calculated by the DFT method (Becke's exchange and Lee, Yang and Parr's correlation ...
Zero-order normal coordinate calculations were made for the five conformers of each compound that have all the carbon atoms coplanar. Comparison of the observed and calculated wavenumbers led to the conclusion that all five conformers of Cl(CH 2) 4I are present in the liquid and solid states...
This observation leads us to conclude that the higher conductance of the A-form is due to the large difference in the DoS in the central bridge region. Finally, we note that all of the analysis we have performed indicates that A-form should be higher in conductance than B-form in ...
nomenclatureblackburnconformationalconformationssynthesisbutane Alkanes Nomenclature,ConformationalAnalysis,andanIntroductiontoSynthesis Alkanes saturatedaliphatichydrocarbons paraffins generalformulaCnH2n+2 acyclichydrocarbons Sourcesofmethane majorconstituentofnaturalgas(97%) “firedamp”ofcoalmines “marshgas” productofan...
The fractional population of the s-trans conformer is estimated as 0.65 ± 0.l0 at 300 K, in reasonable agreement with molecular mechanics and INDO MO computations of the energies of the gauche and trans forms.The conformational preference of this molecule is similar to that in n-butane and...
By analogy with mono-substituted cyclo- butanes (47), azetidine should exist in two con- formations with lone pair orientations that are 5 Lone pair "axial" (two trans CH/lone pair interactions) high frequency vNII(3387 cm-') 6 Lone pair "equatorial" (no trans CH/lone pair interaction...
Thermodynamie parameters involved in the rotation of the partial C-N double bond in a series of 5-membered heteroaromatic N,N-dimethyl-carbamides and -thiocarbamides have been measured by total line shape (TLS) analysis of their NMR. Lan... F Bernardi,L Lunazzi,P Zanirato,... - 《Tetrah...
To understand the possible impacts of chalcogen bonding interactions, we examined two other sulfoxide substrates (1aaand1ab) by placing the positions of aldehyde moieties which are far away from the sulfoxides sulfur center (Fig.4a). From analysis on the X–ray structure of1aa, the remote ald...
Pin1 and its homologues are the only enzymes known so far that can specifically isomerize pSer/Thr-Pro bonds with high efficiency (Ranganathan et al., “Structural and Functional Analysis of the Mitotic Rotamase Pin1 Suggests Substrate Recognition Is Phosphorylation Dependent,” Cell 89:875-886 ...