CRYSTAL AND MOLECULAR-STRUCTURE OF METHYLSULFINYL DERIVATIVES OF FURAN AND THIOPHENE BY X-RAY-DIFFRACTION

An investigation of the solid-state conformational properties of 3-methylsulphinyl derivatives of furan and 2- and 3-methylsulphinyl derivatives of thiophene, which also contain halogen atoms in the heterocyclic ring, is reported. For 3-iodo-2-(methylsulphinyl)thiophene, compound 1, two crystallographically independent molecules were found in the unit cell, and in 2-bromo-4-iodo-3-(methylsulphinyl)thiophene, compound 5, a high degree of disorder is present. The sulphur atom of the methylsulphinyl group has a pyramidal structure. The methyl group is highly twisted with respect to the ring plane and the S-O bond adopts different orientations in the molecules examined. When only one halogen atom is present in the ring the S-O bond is directed to the opposite side of the ring with respect to this atom, yet the relative position of the substituents determines a different twist of this bond with respect to the heterocyclic plane.