Single crystal X-ray structure of C.I. Disperse Yellow 3

Crystals of C.I. Disperse Yellow 3, an aminoazobenzene derivative, were grown in an acetonitrile solution and its crystal structure was determined by single crystal X-ray diffraction analysis. It was found that the asymmetric unit consisted of two dye molecules (A and B) and one acetonitrile solvent. In each dye molecule, the aminoazobenzene framework was almost planar due to intramolecular H-bonds. The dye molecules are connected by weak intermolecular H-bonds to form a molecular pair in “head-to-tail” mode. The acetonitrile molecule is also bound to the dye molecule by H-bonding. In the packed structure, interlayer association occurs by further π–π stacking of the molecular pairs formed. Results from thermogravimetric analysis and X-ray powder diffraction studies of a crystalline sample of the title compound support the contribution of the solvent molecule to the formation of the crystal lattice.