Torsion angles shifts

Torsion angles in chain 0.3-0.9nm Conformation dependent chemical shifts (s-NMR)... 

Metal-Phosphorus Bono Lengths, Torsion Angles between the Metal and Phosphorus Coordination Planes, Sums of Angles at Phosphorus, and 3IP NMR Chemical Shifts for Three-Coordinate Aluminum, Gallium, and Indium Phosphides... 

For platinum(O) complexes, [42] analysis of the 1H chemical shifts and coupling constants as well as results of ID selective ROE experiments has allowed determination of the torsional angles j/ and

[Pg.169]

The molecular structure of the amyloid fibrils formed by fragment 105-115 of transthyretin (TTR10sns, YTIAALLSPTS) has been characterized by solid-state NMR. The fibril backbone structure was first established based on the TALOS analysis of the 15N and 13C chemical shifts [89]. Using the correlation experiments of Hn(0-N(0—CV-H0 , Ha(0-Ca(0-N(i.+1)-HN(i+1), and N -Tco-N, a total of 41 constraints on 19 backbone torsion angles have been obtained in a... 

Steric hindrance due to alkyl substituents increases the torsion angle between phenylene units, which results in an additional (unwanted) increase of the band gap. The emission band shifts into the violet region of the spectrum (APL 400 nm) [583]. The hypsochromic shift... 

Torsion Angle Constraints from Chemical Shifts... 

E. Relationship of Aromatic Nitro Group Torsion Angles with 170 Chemical Shifts... 

The apparent relationship between torsion angle and 170 chemical shift has been explored further by examination of the data for several ortho alkyl-substituted nitrobenzenes and dinitrobenzenes (Table 23). The deshielding values of the shifts reflect increasing nitrogen-oxygen double bond character, which is expected as the nitro group is rotated from the plane of the aromatic ring. 

Figure 6 shows a good correlation between torsional angle and 170 chemical shift. The empirical equation 7 has been established by Boykin and Balakrishnan110, between nitro group torsion angles (q in degrees) and the chemical shifts of the 170 resonance of the... 

FIGURE 6. Plot of torsional angle between aromatic rings and nitro groups vs the 170 chemical shift (ppm) data. Reprinted with permission from D. J. Craik, G. C. Levy and R. T. C. Brownlee,. /. Org. Chem., 48, 1601 (1983). Copyright (1983) American Chemical Society... 

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