Table 3. Selected geometric details (Å, °) for N,N′-bis(pyridin-4-ylmethyl)ethanediamide molecules and protonated formsa .
| Coformer | C4N2O2/N-ring | C(=O)—C(=O) | Refcodeb | Ref. |
|---|---|---|---|---|
| –c,d | 74.90 (4) | 1.532 (2) | CICYOD01 | Lee (2010 ▸) |
| –e | 68.83 (4); 70.89 (5) | 1.541 (3) | CICYOD | Lee & Wang (2007 ▸) |
| 80.46 (5); 83.35 (6) | 1.541 (3) | |||
| CF_5c,f | 87.37 (4) | 1.534 (2) | NAXMEG | Arman, Kaulgud et al. (2012 ▸) |
| CF_6c,f | 79.86 (4) | 1.542 (2) | AJEZEV | Arman et al. (2009 ▸) |
| CF_7g | 70.50 (4); 76.89 (4) | 1.52 (2) | CAJRAH | Nguyen et al. (2001 ▸) |
| CF_8c,g,h | 73.38 (11) | 1.523 (7) | SEPSIP | Nguyen et al. (1998 ▸) |
| CF_8c,g,i | 72.87 (9) | 1.514 (5) | SEPSIP01 | Nguyen et al. (2001 ▸) |
| CF_9c,f | 75.83 (5) | 1.543 (3) | TIPGUW | Arman et al. (2013 ▸) |
| 2-Methylbenzoic acid | 88.66 (4) | 1.5356 (19) | – | This work |
Notes: (a) Refer to Scheme 3 for the chemical structures of coformers, CF_5–CF_9; (b) Groom & Allen (2014 ▸); (c) molecule/dianion is centrosymmetric; (d) form I; (e) form II (two independent molecules); (f) 2:1 carboxylic acid/carboxylate diamide co-crystal/salt; (g) 1:1 dicarboxylic acid diamide co-crystal; (h) form I; (i) form II.