Table 4.
Sizes of trisubstituted-silylethynyl groups in 8.
| intermolecular close contacts | |||||||
| radius (Å)a | radius (Å)b | contact | distance (Å) | dc | θd | ||
| n-alkyl symmetric | 8a | 2.69 | – | – | – | 6.366 | 57.2 |
| 8b | 4.06 | – | – | – | 6.439 | 57.5 | |
| 8c | 5.26 | – | – | – | 8.239 | 65.4 | |
| symmetric | 8a | 2.69 | – | – | – | 6.366 | 57.2 |
| 8b | 4.06 | – | – | – | 6.439 | 57.5 | |
| 8d | 4.09 | – | – | – | 9.550, 7.419e | 69.6, 62.7e | |
| 8c | 5.26 | – | – | – | 8.239 | 65.4 | |
| 8e | 5.28 | – | C9···C2 C6···C3 C6···C6 |
3.407 3.562 3.524 |
6.134 | 56.4 | |
| 8f | 5.89 | – | C10···C10 C17···C4 |
3.188 3.369 |
10.984 | 74.7 | |
| asymmetric | 8i | 2.73 | 3.99 | C7···C3 | 3.348 | 6.356 | 58.0 |
| 8h | 2.68 | 5.26 | C9···C2 C10···C3 |
3.437 3.409 |
5.976 | 55.3 | |
| 8g | 2.67 | 5.74 | C6···C10 C3···C17 |
3.361 3.361 |
6.096 | 56.5 | |
| 8j | 2.68 | 5.94 | – | – | 6.292 | 57.3 | |
aSi···X distance where X is the farthest atom from Si with the covalent radii of X added to the distance [30]. bRadius for other axis of lower symmetry trialkylsilanes. cDistance between the centroid of two molecules in the 1-D stack. dAngle between the centroid of each of two molecules of the π stack and the normal to the average plane. eThere are two symmetrically independent 1-D stacks.