Crystal structures of 3,5,5′-trichloro-2,2′-bithiophene and 3,3′,5,5′-tetrachloro-2,2′-bithiophene

Abstract

The crystal structures of 3,5,5′-trichloro-2,2′-bithiophene (I) and 3,3′,5,5′-tetrachloro-2,2′-bithiophene (II) have been determined by single crystal X-ray diffraction techniques. Both I and II crystallize in the monoclinic crystal system. For I, a=3.895(2), b=11.928(2), c=10.701(2)Å, β=97.70(1)°, space group P21, Z=2 and for II, a=8.942(2), b=3.900(2), c=15.180(2)Å, β=92.30(1)°, space group P21/n, Z=2. The structures have been solved by direct methods and all nonhydrogen atoms refined with anisotropic thermal parameters. For I the final residual is 0.035 (all 1185 independent reflections, Mo Kα radiation) and for II, 0.034 (all 1209 independent reflections, Mo Kα radiation). Both I and II have the anti conformation but I has a torsion angle of 3.4(5)° between the two thiophene rings while II is completely planar. © 1993 Plenum Publishing Corporation.