A second triclinic polymorph of azimsulfuron

Abstract

The title compound, C13H16N10O5S (systematic name: 1-(4,6-dimethoxypyrimidin-2-yl)-3-{[1-methyl-4-(2-methyl-2H-tetrazol-5-yl)pyrazol-5-yl]sulfonyl}urea), is a second triclinic polymorph of this crystal [for the other, see: Jeon et al., (2015). Acta Cryst. E71, o470–o471]. There are two molecules, A and B, in the asymmetric unit; the dihedral angles between the pyrazole ring and the tetrazole and dimethoxypyrimidine ring planes are 72.84 (10) and 37.24 (14)°, respectively (molecule A) and 84.38 (9) and 26.09 (15)°, respectively (molecule B). Each molecule features an intramolecular N—H...N hydrogen bond. In the crystal, aromatic π–π stacking interactions [centroid–centroid separations = 3.9871 (16), 3.4487 (14) and 3.5455 (16) Å] link the molecules into [001] chains. In addition, N—H...N, N—H...O, C—H...O and C—H...N hydrogen bonds occur, forming a three-dimensional architecture. We propose that the dimorphism results from differences in conformations and packing owing to different intermolecular interactions, especially aromatic π–π stacking.

Keywords

• crystal structure
• sulfonylurea herbicide
• azimsulfuron
• dimorphism