Adduct formation between (Ph3SbI)2O and I2

Article abstract of DOI:10.1016/0022-328X(96)06304-8

The compound 4[(Ph₃SbI)₂O] · I₂ (1) has been obtained by the addition of an I₂ solution in acetonitrile containing ca. 5% water to a solution of triphenylantimony in the same solvent. 1 crystallises in the rhombohedral crystal system. The unit cell contains 12 molecules of (Ph₃SbI)₂O and four diiodine molecules. The I₂ molecules link IPh₃SbOSbPh₃I molecules to form a one-dimensional chain, while the remaining molecules of IPh₃SbOSbPh₃I are not coordinated to I₂. The geometry of the IPh₃SbOSbPh₃I unit, in which the Sb-O-Sb bridge is linear, is relatively little perturbed upon coordination, but the I₂ unit shows a significant lengthening of the I-I bond compared with free diiodine. This bond lengthening is reflected in the Raman spectrum of 1 which displays v(I-I) at 174 cm^-1, representing a decrease of 40 cm^-1 from the position of the fundamental vibration of the free diatomic molecule.