CRYSTAL-STRUCTURE OF UM[BIS(PHENYLSULPHONYL)]-METHYLSULPHONYLMETHYLIDE, C28H21IO6S3

The crystal and molecular structure of the title compound (BPIS hereaf ter) has been determined from three-dimensional X-ray data, measured o n a computer-controlled STOE AED 2 diffractometer. The structure is tr iclinic Space group P1BAR, with a = 8.325(6) angstrom, b = 11.809(6) a ngstrom, c = 13.618(7) angstrom, alpha = 105.06(4)degrees, beta = 104. 46(5)degrees, gamma = 99.57(5)degrees, V = 1212.99 angstrom3, and Z = 2. The structure was solved by Patterson and Fourier syntheses and ref ined by least-squares calculations to a final R = 0.039 (R(w) = 0.039) Two I-C(ar) bonds and two I ... O secondary bonds to different sulpho nyl groups form a distorted planar tetragonal coordination around the I atom. The structural unit is a dimer formed by two centrosymmetrical ly related formula units bridged by secondary I ... O bonds. A twelve- membered pseudo ring is formed around an inversion centre. Another fea ture of interest is the delocalization occurring in the carbanion and its planarity.