Interplanar angle

Table 22. Shape of hosts 26 and 41 in their crystal inclusions, or in the free state, as characterized by inclination angles of some planes. Attached drawing explains definition of the interplanar angles (degf...

As already demonstrated (see Sect. 4.5.1), 1 displays a characteristic shape in its inclusions even with respect to the inclination angle of the carboxyl groups to their naphthyl planes. Coplanarity of these moieties depends partly on the bulkiness of the substrate molecule, however, the interplanar angle usually does not exceed 30° [mean value 11.9(8.3)°, Table 20). 

Assiuning a 001 crystal surface, we use the formula for interplanar angles in tetragonal crystals to obtain... 

In 3-bromo-7-methoxy-2-tetrahydropyran-2-ylpyrazolo[l,5-( ]pyrimidine 66, the pyrimidine and pyrazole rings make a dihedral angle of 3.8°. The tetrahydropyran ring is in a chair conformation and its mean plane makes an interplanar angle of 52.5° with the pyrazole ring. There is a short Br- -O intramolecular contact of 2.994 A <2004JSTC356>. 

Interplanar Angles and Diameters Characterizing Empty Cyclodextrin... 

Figure 4 Definition of a and ji interplanar angles of Table 4. The positive sign refers to a counterclockwise rotation...

The tin-119m Mossbauer spectra of some stannocenes were recorded by Zuckerman s group (221,222). The observed isomer shifts are compatible with the presence of divalent tin, while the dependence of the quadrupole splitting on the interplanar angle in these complexes is still unknown. 

Fig. 16. van der Waals stereodrawings of interacting benzene rings positioned in four enthalpically optimal geometric arrangements for r = 5.5 A, using the coordinate system defined in Fig. 8. (A) = 0°, interplanar angle = 90° (B) = 30°, interplanar angle = 55° (C) 0 = 50°, interplanar angle = 20° (D) 0 = 90°, interplanar angle = 90°.

Substitution in the ortho positions of the heteroaromatic ring progressively increases the interplanar angle between the heterocycle and the carbonyl plane and thus gives rise, with sufficient substitution, to a steric barrier around the heteroaromatic amide bond similar to that encountered in biphenyls. The transition state to rotation around this bond may be even higher than that for rotation around the C—N bond (vide infra Section III,C,2) (Scheme 77). 

---