Conformation winged

The preferred conformation of the unsubstituted calixarene shown in Fig. 1 (X = CH2) is 1,3-alternating, whereby two opposite rings are perpendicular to the plane formed by the four methylene groups and the other two are parallel to the same plane [11]. In the case of calix[6]arenes the conformational mobility is enhanced and 1,3,5-alternating or 1,4-alternating winged conformations have been identified as the preferred ones [9]. Very few heteratom-... 

Liskov91] Liskov, B., and J. Wing. 1991. Type conformance. In Proceedings ECOOP 91. New York Springer. 

Coming back to the molecular structures of SOAz (I), SOAz (II A) and SOAz (IIB), it is noticeable that the conformations of their aziridinyl ligands differ drastically from one allotropic form to the other. In other words, the molecule of SOAz appears to be a versatile molecule with respect to its aziridinyl groups. There is, at the moment, no ready explanation for the adoption of either the one or the other conformation when the synthesis is repeated under exactly the same experimental conditions. However, the SOAz molecule seems to be extremely flexible with regard to the orientation of its wings , even more flexible than that of N3P3AZg 3 15>... 

Thus, we may conclude at this stage that there exists some direct connection through the rotation of one wing only between SOAz(IIA) and MYKO-XYL, SOAz(lIB) and MYKO-CgHg, SOAz(IIB) and SOAz(I) M respectively. For these three pairs, the six or sevendimensional conformational problem could be then reduced to a monodimensional one. 

The micro-computer-assisted approach we have developed shows that the 6-dimen-sional E = f(a, P, y, 8, e) conformational problem within the set of SOAz geometries can be actually reduced to a monodimensional one. In other words, the passage from SOAz(I) to SOAz(II B) can be then simulated upon rotation of the Az group linked to the sulphur, the four other wings staying unchanged, in first approximation at least. 

The determination of relative configurations in saturated four-membered ring systems requires a conformational analysis because they exist in noncoplanar wing-shaped conformations461,462, meaning that experimental NMR parameters may be weighted averages. 

The X-ray crystal structure of chiral dihydrodibenzo[ /]thiepine 26 was reported <1999TL813>. The results showed that thiepine 26 does not adopt a Cz symmetrical conformation in the crystalline state. The two benzene rings are twisted about the y-axis like the wings of a butterfly. The X-ray structure of its corresponding sulfoxide has also been reported <20060BC2218>. 

Montreuil has proposed the terms T -, Y -, bird and broken wing shape for the description of the conformations of AT-type oligosaccharides [154, 155]. These terms, although illustrative, highly simplify the conformational orientation of the different parts of the molecule with respect to the others. The more elaborate characterization of the molecule via its dihedral angles is required to describe the conformers at the glycoside bonds adequately, because within each of the families of conforma-... 

Spectra of samples in the liquid state (Fig. 2.6-lB) are given by molecules which may have any orientation with respect to the beam of the spectrometer. Like in gases, flexible molecules in a liquid may assume any of the possible conformations. Some bands are broad, since they are the sum of spectra due to different complexes of interacting molecules. In the low frequency region spectra often show wings due to hindered translational and rotational motions of randomly oriented molecules in associates. These are analogous to the lattice vibrations in molecular crystals, which, however, give rise to sharp and well-defined bands. The depolarization ratio p of a Raman spectrum of molecules in the liquid state (Eqs. 2.4-11... 13) characterizes the symmetry of the vibrations, i.e., it allows to differ between totally symmetric and all other vibrations (see Sec. 2.7.3.4). 

To demonstrate the application of these butterfly wing SERS substrates to the problem of protein-binding detection, Garrett et al. devised a protein-binding assay. There are a variety of methods for binding proteins to a metal surface, some of which depend on the amino acid composition of the protein, others of which do not. Direct adsorption via covalent bonds between sulfur groups in proteins and metal surfaces has been used with some success [43] however, this method is unsuitable for use in Raman spectroscopy-based assays, as nonspecific binding may result in a wide variety of conformational orientations of the molecules with respect to the metal s surface. This can lead to Raman spectra that are difficult to reproduce. Not only that, but the analyte may bind to the metal as well as the antibody, which can lead to noisy spectra. 

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