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The crystal structure of C.I. Pigment Yellow 3, α -(1-hydroxyethylidene)-2-chloro-acetanilide- α -azo-(4′-chloro-2′-nitrobenzene)

1983; De Gruyter; Volume: 163; Issue: 1-2 Linguagem: Inglês

10.1524/zkri.1983.163.1-2.19

2196-7105

Dye analysis and toxicity

Abstract The crystal structure of C.I. Pigment Yellow 3, α -(1-hydroxyethylidene)-2-chloro-acetanilide- α -azo-(4′-chloro-2′-nitrobenzene) has been determined by single-crystal X-ray diffraction techniques. It crystallises in the orthorhombic system with cell parameters a = 13.240 ± 0.073 Å, b = 30.206 ± 0.118 Å, c = 8.333 ± 0.025 Å. The space group is Pbca and there are eight molecules per unit cell. The structure was solved using direct methods and least-squares refinement has been completed on three-dimensional data, 1191 reflections (Cu Kα radiation). The hydrogen atoms have been found and included, but only those associated with the methyl group have been refined. The final residual is 7.2%. The molecule exists as the hydrazone tautomer and intramolecular hydrogen bonds keept the molecule approximately planar. The molecules are packed in planar chains parallel to the c axis with the molecules linked by hydrogen bonds, alternatively they may be thought of as packed in columns parallel to the a axis with alternate molecules antiparallel but with the molecules linked by van der Waals forces.