Table 3. Selected geometric parameters (Å, °) for 3 .
| C1—C2 | 1.504 (5) | C15—C16 | 1.510 (5) |
| C2—O1 | 1.246 (4) | C16—O3 | 1.236 (4) |
| C2—C3 | 1.453 (4) | C16—C17 | 1.455 (4) |
| C3—C6 | 1.399 (4) | C17—C20 | 1.396 (4) |
| C3—C4 | 1.472 (5) | C17—C18 | 1.468 (4) |
| C4—O2 | 1.224 (4) | C18—O4 | 1.228 (4) |
| C4—C5 | 1.517 (5) | C18—C19 | 1.518 (5) |
| C6—N1 | 1.311 (4) | C20—N2 | 1.321 (4) |
| C7—N1 | 1.470 (4) | C21—N2 | 1.463 (4) |
| C7—C8 | 1.522 (4) | C21—C28 | 1.524 (5) |
| C7—C14 | 1.527 (5) | C21—C22 | 1.534 (4) |
| C8—C7—N1—C6 | −119.2 (3) | C22—C21—N2—C20 | −112.8 (3) |
| C14—C7—N1—C6 | 115.5 (4) | C28—C21—N2—C20 | 122.4 (3) |