2-(2,5-Dichlorophenylhydrazono)glutaric acid and 2-(3,5-dichlorophenylhydrazono)-glutaric acid

The title compounds, C₁₁H₁₀Cl₂N₂O₄, are constitutional isomers which exhibit similar molecular geometry. The configuration about the N=C bond is E in both molecules. The same packing pattern was found in both structures. Hydrogen-bonded dimers, formed around the inversion centres via O - H⋯O interactions of carboxyl groups, are connected into infinite chains. The intramolecular N - H⋯Cl hydrogen bond observed only in the 2,5-dichlorophenyl derivative contributes to the planarity of the molecule.