Recurrence of carboxylic acid-pyridine supramolecular synthon in the crystal structures of some pyrazinecarboxylic acids

Vishweshwar, Peddy ; Nangia, Ashwini ; Lynch, Vincent M. (2002) Recurrence of carboxylic acid-pyridine supramolecular synthon in the crystal structures of some pyrazinecarboxylic acids Journal of Organic Chemistry, 67 (2). pp. 556-565. ISSN 0022-3263

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Official URL: http://pubs.acs.org/doi/abs/10.1021/jo0162484

Related URL: http://dx.doi.org/10.1021/jo0162484

Abstract

X-ray crystal structures of pyrazinic acid 1 and isomeric methylpyrazine carboxylic acids 2-4 are analyzed to examine the occurrence of carboxylic acid-pyridine supramolecular synthon V in these heterocyclic acids. Synthon V, assembled by (carboxyl)O-H···N(pyridine) and (pyridine)C-H···O(carbonyl) hydrogen bonds, controls self-assembly in the crystal structures of pyridine and pyrazine monocarboxylic acids. The recurrence of acid-pyridine heterodimer V compared to the more common acid-acid homodimer I in the crystal structures of pyridine and pyrazine monocarboxylic acids is explained by energy computations in the RHF 6-31G basis set. Both the O-H···N and the C-H···O hydrogen bonds in synthon V result from activated acidic donor and basic acceptor atoms in 1-4. Pyrazine 2,3- and 2,5-dicarboxylic acids 10 and 11 crystallize as dihydrates with a (carboxyl)O-H···O(water) hydrogen bond in synthon VII, a recurring pattern in the diacid structures. In summary, the carboxylic acid group forms an O-H···N hydrogen bond in pyrazine monocarboxylic acids and an O-H···O hydrogen bond in pyrazine dicarboxylic acids. This structural analysis correlates molecular features with supramolecular synthons in pyridine and pyrazine carboxylic acids for future crystal engineering strategies.

Item Type:Article
Source:Copyright of this article belongs to American Chemical Society.
ID Code:24554
Deposited On:29 Nov 2010 08:32
Last Modified:04 Mar 2011 05:44

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