Crystal and molecular structure of 4,4′-dichlorodiphenyl sulphone, 4,4′-dibromodiphenyl sulphone and 4,4′-diiododiphenyl sulphone

The crystal and molecular structure of 4,4-dichloro-diphenyl sulphone (A), 4,4-dibromodiphenyl sulphone (B) and 4,4-diiododiphenyl sulphone (C) have been determined from three-dimensional MoK. diffractometer data. These structures are isomorphous in the monoclinic space groupI2/a, with four molecules per unit-cell. The cell dimensions ofA,B andC area = 20.216 (4),b = 5.004(1),c = 12.248(2) Å, = 90 °34(1);a = 20.813(10),b = 5.055(3),c = 12.421(9) Å, = 92 °46(2) anda = 19.762(8),b = 4.947(2),c = 14.480(5) Å, =103 ° 18(1), respectively. Least-squares refinements converged toR-factors of 6.0% over 925 reflections, 6.8% over 1273 reflections and 3.8% over 995 reflections forA,B andC, respectively.The S—O bond lengths are 1.432(3), 1.453(5) and 1.445(7) Å and the S—C bond lengths 1.766(4), 1.764(6) and 1.756(7) Å inA,B andC, respectively. The C—Cl, C—Br and H—-I bond lengths are 1.748(5), 1.905(6) and 2.103(7) Å, respectively. The dihedral angle between the plane of each aromatic ring and the C—S—C plane is 84.6 ° inA, 83.8 ° inB and 86.9 ° inC. Intermolecular BrBr and II contacts of 3.65 and 3.90 Å are considerably shorter than the van der Waals contacts given by Pauling.