Structural characterization of a seven-coordinated organotin(IV) complex: Tris(dimethyl sulphoxide)nitratodiphenyltin(IV) nitrate

A seven-coordinated organotin(IV) compound has been obtained and its IR spectroscopic properties and X-ray crystal structure are reported. Crystals are monoclinic (p2₁/c) with unit-cell dimensions: a 16.017(9), b 10.365(5), c 15.994(8) Å, β 96.1(1)°, Z = 4. The structure has been determined from diffractometer data (Cu-K_a radiation) by conventional Patterson and Fourier techniques and refined by block-diagonal least-squares procedure to an R value of 0.093 for 4298 independent reflections. The structure consists of monomeric seven-coordinated cations Sn(C₆H₅)₂NO₃{(CH₃)₂SO}₃] and NO₃- anions. Coordination around tin is pentagonal bipyramidaI with the bidentate nitrate group and the three dimethyl sulphoxide molecules in the equatorial positions and the two phenyl rings at the apices. Literature on seven-coordinated tin(IV) compounds and nitratotin(IV) complexes is quoted and discussed.