Molecular Cocrystals of Carboxylic Acids.II. The Crystal Structure of the 1 : 2 Adduct of Phenoxyacetic Acid With 3,5-Dinitrobenzoic Acid

Abstract

The 1 : 2 molecular adduct between phenoxyacetic acid and 3,5-dinitrobenzoic acid, with formula [(C₆H₅OCH₂COOH)₂{3,5-(NO₂)₂C₆H₃COOH}₄(H₂O)₂], has been prepared and its structure determined by X-ray diffraction. Crystals are triclinic, space group Pī with two complex units in a cell with dimensions a 7.202(2), b 18.519(5), c 20.924(6)Ǻ, α 66.33(3),β 86.04(2),γ 89.32(2)°. The molecular repeating unit comprises two phenoxyacetic acid molecules [forming hydrogen-bonded cyclic dimers (O̷O, 2.71, 2.74 Ǻ)], four 3,5- dinitrobenzoic acid molecules [giving two unusual one-bond hydrogen bonds (O…O, 2.59, 2.64Ǻ)] and two water molecules. The waters are intimately involved in a hydrogen-bonding network with carboxylic acid oxygens.