Crystal structure, PIXEL calculations of inter-molecular inter-action energies and solid-state characterization of the herbicide isoxaflutole.

In the isoxaflutole mol-ecule {systematic name: (5-cyclo-propyl-1,2-oxazol-4-yl)[2-(methyl-sulfon-yl)-4-(tri-fluoro-meth-yl)phen-yl]methanone; CHFNOS}, the 1,2-oxazole and methanone fragments form an almost coplanar unit, whereas the methanone and phenyl mean planes are inclined by an angle of more than 60°. This conformation differs fundamentally from all other known examples of the 1,2-oxazol-4-yl(phen-yl)methanone fragment and is ascribed to the presence of the bulky methyl-sulfonyl substituent at the phenyl ring. PIXEL calculations reveal that the largest contributions to the stabilization of the crystal persist within a columnar arrangement of mol-ecules along the twofold screw axis and in inter-actions between adjacent columns related by an inversion operation.