Table 1. Selected Bond Lengths (in Å) of the Monomers and Dimers of Benzamide and Benzoic Acid as Well as Their Simple Ortho-Substituted Derivativesa.
| compd | C–Cring | C=Cring | Δr | C–O/Sring | C=O | C–O/Ninter |
|---|---|---|---|---|---|---|
| Monomers | ||||||
| benzamide | 1.502 | 1.394 | 0.108 | 1.214 | 1.368 | |
| benzoic acid | 1.487 | 1.394 | 0.093 | 1.204 | 1.347 | |
| salicylamide | 1.484 | 1.411 | 0.073 | 1.334 | 1.232 | 1.357 |
| 2-mercaptobenzamide | 1.501 | 1.406 | 0.095 | 1.774 | 1.219 | 1.362 |
| salicylic acid | 1.466 | 1.410 | 0.056 | 1.336 | 1.220 | 1.338 |
| thiosalicylic acid | 1.483 | 1.411 | 0.072 | 1.767 | 1.212 | 1.345 |
| salicylamide | 1.505 | 1.399 | 0.106 | 1.353 | 1.210 | 1.367 |
| 2-mercaptobenzamide | 1.498 | 1.404 | 0.094 | 1.778 | 1.214 | 1.368 |
| salicylic acid | 1.485 | 1.406 | 0.079 | 1.346 | 1.202 | 1.356 |
| thiosalicylic acid | 1.480 | 1.407 | 0.073 | 1.774 | 1.206 | 1.347 |
| Dimers | ||||||
| benzamide | 1.502 | 1.394 | 0.108 | 1.230 | 1.345 | |
| benzoic acid | 1.486 | 1.394 | 0.092 | 1.224 | 1.313 | |
| salicylamide | 1.484 | 1.411 | 0.073 | 1.336 | 1.248 | 1.338 |
| 2-mercaptobenzamide | 1.500 | 1.406 | 0.094 | 1.775 | 1.234 | 1.342 |
| salicylic acid | 1.465 | 1.411 | 0.054 | 1.336 | 1.240 | 1.309 |
| thiosalicylic acid | 1.483 | 1.411 | 0.072 | 1.768 | 1.230 | 1.314 |
| salicylamide | 1.504 | 1.399 | 0.105 | 1.354 | 1.226 | 1.345 |
| 2-mercaptobenzamide | 1.498 | 1.403 | 0.095 | 1.779 | 1.229 | 1.344 |
| salicylic acid | 1.486 | 1.406 | 0.080 | 1.348 | 1.220 | 1.319 |
| thiosalicylic acid | 1.480 | 1.407 | 0.073 | 1.774 | 1.225 | 1.314 |
a
Results for systems with closed ring by intramolecular hydrogen bond (cis conformations) are bolded. Results for systems without intramolecular hydrogen bond (trans conformations) are presented in the normal mode. The Δr parameter is included that is defined as the difference between bond lengths (C–Cring – C=Cring).