The Crystal and Molecular Structure of the 1:1 Adduct Hydrate of Pyrazine-2,3-dicarboxylic Acid with 1,1-Diethylurea

Abstract

The adduct hydrate of 1,1-diethylurea with pyrazine-2,3-dicarboxylic acid, [(C₆H₄N₂O₄)(C₅H₁₂N₂O)].H₂O has been prepared and characterized using low-temperature single-crystal X-ray diffraction methods. A primary asymmetric cyclic hydrogen-bonding interaction, similar to those found in other adducts of 1,1-diethylurea with the nitro-substituted aromatic acids, was found between the amide group of the substituted urea and one carboxylic acid group of the acid. Further peripheral hydrogen-bonding associations involving both the f irst and the second carboxylic acid groups, urea and the lattice water molecule result in a ribbon polymer structure.