Hydrogen-bonding in the structures of the 1 : 1 salts of isonipecotamide with a set of four polyfunctional monocyclic heteroaromatic carboxylic acids

✍ Scribed by Smith, Graham; Wermuth, Urs D.

• Book ID: 115513825
• Publisher: Oldenbourg Wissenschaftsverlag
• Year: 2012
• Tongue: English
• Weight: 503 KB
• Volume: 227
• Category: Article
• ISSN: 2194-4946
• DOI: 10.1524/zkri.2012.1543

✦ Synopsis

The crystal structures of the 1 : 1 proton-transfer compounds of isonipecotamide (piperidine-4-carboxamide) with the monocyclic heteroaromatic carboxylic acids, isonicotinic acid, picolinic acid, dipicolinic acid and pyrazine-2,3dicarboxylic acid have been determined at 200 K and their hydrogen-bonding patterns examined. The compounds are respectively anhydrous 4-carbamoylpiperidinium pyridine-4-carboxylate (1), the partial hydrate 4-carbamoylpiperidinium pyridine-2-carboxylate 0.25 water (2), the solvate 4carbamoylpiperidinium 6-carboxypyridine-2-carboxylate methanol monosolvate (3), and anhydrous 4-carbamoylpiperidinium 3-carboxypyrazine-2-carboxylate (4).

In compounds 1 and 3, hydrogen-bonding interactions give two-dimensional sheet structures which feature enlarged cyclic ring systems, while in compounds 2 and 4, three-dimensional structures are found. The previously described cyclic R 2 2 (8) hydrogen-bonded amide-amide dimer is present in 2 and 3. The hydrogen-bonding in 2 involves the partial-occupancy water molecule while the structure of 4 is based on inter-linked homomolecular hydrogen-bonded cation-cation and anion-anion associated chains comprising head-to-tail interactions. This work further demonstrates the utility of the isonipecotamide cation in the generation of chemically stable hydrogenbonded systems, particularly with aromatic carboxylate anions, providing crystalline solids.