Table 4.
Selected experimental and calculated (B3LYP/6-31G(d), gas phase) bond distances in 4a,b and 5 (Å)
| Bond | 4a (X-ray) | 4b (DFT) | 4b (X-ray) | 5 (DFT) | 5 (X-ray) |
|---|---|---|---|---|---|
| N1–C2 | 1.320(3), 1.328(3) | 1.3442 | 1.3255(9) | 1.4878 | 1.4979(16) |
| N1–C8a | 1.346(3), 1.335(3) | 1.3336 | 1.3289(10) | 1.3430 | 1.3365(16) |
| C2–C3 | 1.416(3), 1.415(3) | 1.4673 | 1.4658(10) | 1.6027 | 1.5847(16) |
| C3–N4 | 1.325(3), 1.328(3) | 1.3480 | 1.3288(9) | 1.2923 | 1.2882(16) |
| N4–N5 | 1.342(3) | 1.3395 | 1.3314(8) | 1.3521 | 1.3574(14) |
| N5–C6 | 1.391(3), 1.390(3) | 1.3992 | 1.3931(9) | 1.4317 | 1.4240(16) |
| N5–C8a | 1.388(3), 1.396(3) | 1.4052 | 1.3733(10) | 1.3509 | 1.3460(15) |
| C6–C7 | 1.406(3), 1.411(3) | 1.4265 | 1.4120(10) | 1.4007 | 1.3859(17) |
| C7–C8 | 1.421(3), 1.419(3) | 1.4292 | 1.4168(11) | 1.4409 | 1.4343(17) |
| C8–C8a | 1.397(3) | 1.4050 | 1.4009(10) | 1.4014 | 1.4076(17) |
| C8–CN | 1.414(3) | 1.4065 | 1.4110(11) | 1.4074 | 1.4094(17) |
| C7–NH2 | 1.345(3) | 1.3506 | 1.3500(10) | 1.3541 | 1.3626(17) |
| C2–O, Ct-Bu | - | 1.5596 | 1.5510(11) | 1.6230, 1.6358 | 1.6080(18), 1.6168(17) |
| C6–CO | 1.457(3), 1.449(3) | 1.4411 | 1.4478(11) | 1.4376 | 1.4372(17) |