Table 3.
Detail of lone pair-π contacts in compounds 1–4 (shortest contact for each crystal structure)
| Ligand | N-O … C Angle (deg) | C-NO2 Torsion (deg) | NO … C Distance (Å) | dplane (Å) | doffseta (Å) | dcentroid (Å) | |||
|---|---|---|---|---|---|---|---|---|---|
| L1 | N5-O5 … C6 | 145.0(1) | C7C8N5O5 | −42.3(2) | O5 … C6 | 2.891(2) | 2.886 | 1.151 | 3.107 |
| L2 | N7-O5 … C8 | 111.6(3) | C15C16N7O5 | 78.3(4) | O5 … C8 | 2.975(5) | 2.893 | 1.876 | 3.448 |
| L3 | N6-O8 … center | 118.58 | C9C14N6O8 | −126.6(2) | O8 … center | 2.915 | 2.897 | 0.323 | 2.915 |
| L4 | N8-O6 … C9 | 99.51(9) | C20C19N8O6 | −7.7(2) | O6 … C9 | 2.936(2) | 2.889 | 1.751 | 3.378 |
a
To provide proper context: an offset of 0 Å corresponds to perfectly centered anion-π interaction; C and N atoms in s-tetrazine are 1.28 and 1.38 Å apart from the ring centroid, respectively.