Table 3. IR spectral assignments of the wavenumbers for iz4h4m2p and its cocrystals to the carboxylic acid functional and/or the hydroxyl and carbonyl functional groups.
| Sample | C=O stretch (cm− 1) | O—H stretch (cm−1) | C—O stretch (cm−1) | O—H bend in-plane (cm−1) | O—H bend out-plane (cm−1) |
|---|---|---|---|---|---|
| i4h4m2p (form I) | 1660 | 2969 | 1273 | 1407 | 932 |
| i4h4m2p (form II) | 1673 | 2971 | 1271 | 1404 | 919 |
| iz4h4m2p + 2c4n | 1662 | 2980 | 1309 | 1408 | 924 |
| iz4h4m2p + 3hba | 1674 | 2964 | 1292 | 1412 | 924 |
| iz4h4m2p + 4nba | 1662 | 2982 | 1285 | 1410 | 925 |
| iz4h4m2p + ca | 1667 | 2975 | 1281 | 1409 | 927 |
| iz4h4m2p + sa | 1662 | 2968 | 1309 | 1407 | 925 |
| iz4h4m2p + dnba | 1655 | 2976 | 1286 | 1412 | 912 |
| iz4h4m2p + 4hba | 1651 | 2962 | 1271 | 1415 | 926 |
| iz4h4m2p + 2,5-dhba | 1673 | 2972 | 1305 | 1413 | 928 |