Dihedral angle dependence

Although the origin of the PM transition remains obscure, the differences in potential energy curves and main-chain stiffness between 16 and 17 may be critical. Figure 4.14 shows the main-chain dihedral angle dependence on the... 

Figure 4.14 Results of molecular mechanics calculation. Main-chain dihedral angle dependence on the potential energy of (a) it- and si-(S)-3,7-dimethyloctyl-3-methylbutylsilane 31 repeat units with hydrogen termini (20), and (b) it- and si-(S)-3,7-dimethyloctyl-2-methyl-propylsilane 31 repeat units with hydrogen termini (21).

FIGURE 2. The dihedral angle dependence of the p effect of silicon... 

Eq. (8.7), which provides the scalar coupling constant due to the interaction between nuclei, is analogous to Eq. (2.29), used to describe the dihedral angle dependence of the contact coupling constant due to the interaction between nuclei and electrons. 

Fig. 24 Dihedral angle dependence of the potential energy for it-27 model molecules with 31 repeating units and hydrogen termini (oligo-27)...

Figure 4. The dihedral angle dependence of the p-effect of silicon. Reprinted from J. B. Lambert, X. Zhao, J. Organomet. Chem. 1996,521,203, with permission from Elsevier Science, Kidlington, UK.

The a-helix and /1-sheet are common components of the structures of proteins, and such secondary structures are defined by two dihedral angles, 1j/ and . Again, it is expected that 170 NMR tensors are related to the changes in the angles. To investigate dihedral angle dependence, a theoretical model of an isolated... 

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