Acta Crystallographica Section C

Crystal Structure Communications

Volume 60, Part 6 (June 2004)

fg1747 scheme

Acta Cryst. (2004). C60, o444-o448 [doi:10.1107/S010827010400976X]

Hydrogen-bonding adducts of benzenepolycarboxylic acids with N,N-dimethylformamide: benzene-1,4-dicarboxylic acid N,N-dimethylformamide disolvate, benzene-1,2,4,5-tetracarboxylic acid N,N-dimethylformamide tetrasolvate and benzene-1,2,3-tricarboxylic acid N,N-dimethylformamide disolvate monohydrate

S. H. Dale and M. R. J. Elsegood

Abstract: The N,N-dimethylformamide (DMF) solvates of terephthalic acid, H₂TA·2DMF (C₈H₆O₆·2C₃H₇NO), pyromellitic acid, H₄PMA·4DMF (C₁₀H₆O₈·4C₃H₇NO), and hemimellitic acid, H₃HMA·2DMF·H₂O (C₉H₆O₆·2C₃H₇NO·H₂O), are reported. The DMF solvate of terephthalic acid is centrosymmetric, containing one complete formula unit in the asymmetric unit. Both carboxylic acid groups hydrogen bond to a DMF molecule via an (7) O-HO/C-HO motif. Discrete H₂TA·2DMF units are observed. The DMF solvate of pyromellitic acid is centrosymmetric and the asymmetric unit contains half a formula unit. One of the unique carboxylic acid groups forms an (7) motif with a DMF molecule, while the other forms a linear O-HO hydrogen bond to the second unique DMF molecule. Discrete H₄PMA·4DMF units are observed. The DMF solvate of hemimellitic acid is non-centrosymmetric and includes a molecule of water per formula unit. Both DMF molecules form an (7) motif with the two outer carboxylic acid groups of HMA. A one-dimensional ladder structure is formed via hydrogen bonding between the central carboxylic acid group and the water molecules. The carboxylic acid (8) head-to-tail motif is not observed in any of these examples. The inclusion of DMF thereby has the effect of limiting the dimensionality of the structures.

Formula: C₈H₆O₄·2C₃H₇NO, C₁₀H₆O₈·4C₃H₇NO and C₉H₆O₆·2C₃H₇NO·H₂O

Online 31 May 2004


	Structure factor file (CIF format) (175.5 kbytes) Contains datablock I

	Structure factor file (CIF format) (157.7 kbytes) Contains datablock II

	Structure factor file (CIF format) (127.4 kbytes) Contains datablock III

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