Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1403538 | Journal of Molecular Structure | 2012 | 9 Pages |
Very few investigations concerning the crystal structure and chemical properties of dioxamic acids have been related in the literature. This work describes the chemical properties of ortho-phenylenebis(oxamic acid) (2) and its new derivative, hydrogeno ortho-phenylenebis(oxamato) benzimidazolium (3) using experimental (FT-IR, NMR, and X-ray single crystal diffraction) and theoretical (HF/3-21G* and B3LYP/6-31G* calculations) methodologies. Compound 2 displays intramolecular hydrogen bonding between the hydrogen of an amide group and the oxygen atom of another amide group present in the structure. Compound 3 was prepared by a newly developed synthetic route involving decomposition of the dioxamic acid in solution without the presence of metallic ions. Thermodynamic calculations indicate a process via two successive hydrolyzes of the amide groups of 2, followed by condensation with formic acid and finally dehydration. The structure of 3 was solved by X-ray single-crystal diffraction and it consists of meso-helical chains stabilized by intra and intermolecular hydrogen bonds and π–π stacking interactions.
► Synthesis of ortho-phenylene(oxamic) acid. ► A new synthetic route involving decomposition of the dioxamic acid. ► Structural characterization of the hydrogeno ortho-phenylenebis(oxamato) benzimidazolium. ► Helical structure stabilized by intra and intermolecular hydrogen bonds and π–π stacking interactions.