Molecular and crystal structure of C.I. Pigment Yellow 1. 11680, N-PhenyI-2-(4-methyl-2-nitro-phenylhydrazono)- 3-oxo-butyramide (Hansagelb G)

Abstract

Hansagelb G has the structure formula N-Phenyl-2-(4-methyl-2nitro-phenylhydrazono)-3-oxo-butyramide. Like other "azo"-pigments the molecule prefers -at least in solid state -the hydrazono -to the azotautomeric form. It crystallizes in the monoclinic space group P2Jn with 4 molecules in the unit cell. It could be shown that the cell constants given in the literature are wrong. The molecules are crystallizing in layers built by endless tapes joined together like staircases. Brought to you by | New York University Bobst Library Technical Service Authenticated Download Date | 7/23/15 7:38 PM 66 Ε. F. Paulus: Hansagelb G Experimental To get fairly good crystals we used ethylene glycolmonomethylether suggested as solvent in the literature (Mez, 1968). We also got very bad faulty crystals. The crystals from chlorbenzene, however, proved to be excellent. One of them (0.4 χ 0.26 χ 0.13 mm 3 ) was sealed in a Mark tube and fixed to a goniometer head. The cell determination and the intensity measurements were done on a four circle single crystal Nicolet diffractometer with MoKa-radiation, 23/3scan, scan speed of 2 to 20°/min depending on the strength of the special reflexion and a 3 max of 28°. An absorption correction was not necessary (μ = 0.97 cm -1 ). The extinction correction consisted of leaving 7 larger reflexions. Of the 3878 unique reflexions to be measured 3043 had intensities larger than their standard deviation according to the counting statistics and only these were used in the structure determination. These counting statistics Ε. F. Paulus: Hansagelb G 67 were also the basis for the weighting scheme in the least-squares refinement of the structure parameters [φ = l/a 2 (F)]. The following cell parameters were found: a = 7.598(1), 0 = 20.375(2), c = 10.440(1)A; 0 = 98.18(1)°; V= 1599.8 Ä; Ζ = 4; Q X = 1.413gem" 3 ; ρ"ρ (in aqueous K2HgJ4-sol.) = 1.41 gem" 3 ; P2Jn. Formula: C17H16N404; M.W.: 340.34. The given standard deviations resulted from 12 independent measurements.