CRYSTAL STRUCTURES OF A SOLVATED AND UNSOLVATED SULFONE CYCLIC OLIGOMER. P. J. Cahill, L. N. Venkateshwaran, J. A. Kaduk, Amoco Corporation, P.O. Box 3011 MC F-9, Naperville IL 60566

The material causing slight cloudiness in a polysulfone was isolated, and its powder diffraction pattern could be indexed on a primitive monoclinic unit cell having a = 9.5703(15), b = 18.7582(18), c = 13.3945(12) Å, and ß = 92.684(11)deg.. Single crystals as large as 80 x 80 x 10 um could be grown from boiling dimethylsulfoxide. The single crystal had a primitive monoclinic cell with a = 9.561(3), b = 18.728(5), c = 13.382(4) Å, and ß = 92.66(3)deg.. Both forms crystallize in P2₁/c, with Z = 2. The structure of the DMSO solvate was solved and refined using the single crystal data, and the structure of the unsolvated form was refined using powder data.

The crystal structure consists of discrete centrosymmetric cyclic oligomers, containing two of each of the diphenylsulfone and bisphenol A monomers. At the center of each macrocycle in the solvated form is a single disordered DMSO molecule. The torsion angles at the sulfone and isopropylidine linkages between the phenyl rings differ by less than 6deg. in the solvated and unsolvated forms. The torsion angles involving the ether oxygens differ by as much as 30deg.. The conformational differences are discussed in light of observed distributions of the torsion angles in diphenylsulfones, diphenylisopropylidines, and diphenyl ethers, as well as the distributions expected from conformational analyses. These structures provide valuable experimental measurements of the torsion angles in polysulfones.