Date Published: August 01, 2009
Publisher: International Union of Crystallography
Author(s): Bing-Yu Zhang, Jing-Jing Nie, Duan-Jun Xu.
In the molecule of the title CoII complex, [Co(C6H4NO3)2(C3H4N2)2], the CoII atom is located on a twofold rotation axis and chelated by two oxidopyridiniumcarboxylate anions and further cis-coordinated by two imidazole ligands in a distorted octahedral geometry. The shorter C—O bond distance of 1.260 (2) Å suggests electron delocalization between the oxido group and the pyridinium ring. The uncoordinated carboxylate O atom links with the imidazole and pyridinium rings of adjacent molecules via N—H⋯O hydrogen bonding. Weak C—H⋯O hydrogen bonding is also present in the crystal structure.
For the isostructural NiII complex, see: Zhang et al. (2009 ▶). For the shorter C—O bond distance between the pyridine ring and the hydroxy-O atom in 2-oxidopyridinium-3-carboxylate complexes and in 2-hydroxypyridinecarboxylate complexes, see: Yao et al. (2004 ▶); Yan & Hu (2007a ▶,b ▶); Wen & Liu (2007 ▶); Quintal et al. (2002 ▶). For the corresponding C—O bond distances in 2-hydroxybenzencarboxylic acid and in metal complexes of 2-hydroxybenzencarboxylate, see: Munshi & Guru Row (2006 ▶); Su & Xu (2005 ▶); Li et al. (2005 ▶).