Hydrogen bonding in 1,2-diazine-chloranilic acid (2/1) and 1,4-diazine-chloranilic acid (2/1) determined at 110 K

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

The crystal structures of the isomeric title compounds [systematic names: pyridazine-2,5-dichloro-3,6-dihydr-oxy-p-benzoquinone (2/1), (I), and pyrazine-2,5-dichloro-3,6-dihy-droxy-p-benzoquinone (2/1), (II)], 2C 4H4N2·C6H2Cl 2O4, have been re-determined at 110 K. The H atom in the inter-molecular O⋯H⋯N hydrogen bond in each compound was revealed to be disordered; the relative occupancies at the O and N sites are 0.33 (3) and 0.67 (3), respectively, for (I), and 0.56 (4) and 0.44 (4) for (II). The formal charges of the chloranilic acid in (I) and (II) estimated from the occupancy factors are ca -1.3 and -0.8, respectively. The geometries of the centrosymmetric chloranilic acid molecule in (I) and (II) are compared with the neutral, monoanionic and dianionic forms of chloranilic acid optimized by density functional theory (DFT) at the B3LYP/6-311+G(3df,2p) level. The result implies that the chloranilic acid molecule in (I) is close to the monoanionic state, while that in (II) is between neutral and monoanionic, consistent with the result derived from the H-atom occupancies.

Original languageEnglish
Pages (from-to)o550-o553
JournalActa Crystallographica Section C: Crystal Structure Communications
Volume64
Issue number10
DOIs
Publication statusPublished - Oct 13 2008

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

Fingerprint Dive into the research topics of 'Hydrogen bonding in 1,2-diazine-chloranilic acid (2/1) and 1,4-diazine-chloranilic acid (2/1) determined at 110 K'. Together they form a unique fingerprint.

Cite this