Table 2.
Comparisons of geometrical parameters and inclusion structures of four 2° amine TCAs embedded in the β-CD cavity, PRT (1), MPL (2), NRT (i), and DPM (ii) a.
| PRT (1) | MPL (2) | NRT (i) b | DPM (ii) c | |
|---|---|---|---|---|
| (1) Geometrical parameters | ||||
| (6-7/6-6)-Tricyclic core | ||||
| Butterfly angle ε (°) d | 131.4(4) | 118.6(3) | 116.7(3) | 120.0(3) |
| Annellation angle η (°) e | 26.1(1) | 2.5(3) | 24.5(3) | 28.9(3) |
| Twist angle τ (°) f | –178.3(4) | 1.7(3) | 4.7(4) | –8.1(5) |
| C15–C10–C11–C12 torsion angle (°) | 1.4(19) | – | 44.1(16) | –53.7(12) |
| A-ring-centroid–B-ring-centroid distance dAB (Å) | 4.978 | 4.483 | 4.814 | 4.757 |
| Side-chain at N5/C5 | ||||
| C13–N5/C5–C16–C17 torsion angle (°) | 59.1(10) | –167.4(7) | 174.4(5) | –64.3(7) |
| N5/C5–C16–C17–C18 torsion angle (°) | 179.3(8) | –172.1(10) | 140.0(6) | –171.9(5) |
| N5’–A-ring centroid distance dNA (Å) | 5.928(9) | 7.619(8) | 7.441(6) | 6.564(6) |
| N5’–B-ring centroid distance dNB (Å) | 7.543(8) | 6.111(8) | 6.055(6) | 6.136(6) |
| dNA/dNB ratio | 0.786 | 1.247 | 1.229 | 1.070 |
| (2) Inclusion structure | ||||
| Interplanar angle (°) | ||||
| A-ring vs. β-CD O4 plane | 41.8(3) | 85.4(2) | 88.4(2) | 83.7(2) |
| B-ring vs. β-CD O4 plane | 89.7(2) | 34.0(2) | 25.1(1) | 25.8(1) |
| Rings embedded in the β-CD cavity | B, C | A, C | A, C | A, C |
| Distance from TCA to β-CD (Å) | ||||
| A/B-ring centroid to O4 centroid (diagonal) g | 1.384 | 0.549 | 0.822 | 0.467 |
| A/B-ring centroid to O4 plane (vertical) | 1.384 | 0.551 | 0.822 | 0.464 |
| C-ring centroid to O4 centroid | –1.286 | –1.927 | –1.819 | –2.295 |
| B/A-ring centroid to O4 centroid | –3.741 | –4.127 | –4.111 | –4.475 |
a All TCAs are in HCl form. b β-CD inclusion complexes with NRT [23]. c β-CD inclusion complexes with DPM [28]. d–f Interplanar angle of the A and B rings; Angle between C13–C12 and C14–C15; C13–C12–C15–C14 torsion angle (see atom numbering in Scheme 1). g When the β-CD O6-side points upwards, the positive (negative) values indicate that the TCA A/B/C-ring centroid is above (beneath) the β-CD O4-plane.