Reactivity of fluoro-substituted bis(thiocarbonyl) donors with diiodine: an XRD, FT-Raman, and DFT investigation

The reactions of 1,3,8,10-tetrakis( 4’-fluorophenyl)-4,5,6,7-tetrathiocino[ 1,2-b:3,4-b’]diimidazolyl-2,9-dithione (4) and molecular diiodine afforded spoke adducts with stoichiometries 4·I2 and 4·3I2, isolated in the compound 4·3I2·xCH2Cl2·ACHTUNGTRENUNG(1 x)I2 (x=0.70), and characterized by single-crystal XRD and FT–Raman spectroscopy. The nature of the reaction products was investigated under the prism of theoretical calculations carried out at the DFT level. The structural data, FT–Raman spectroscopy, and quantum mechanical calculations agree in indicating that the introduction of fluorophenyl substituents results in a lowering of the Lewis basicity of this class of bis(thiocarbonyl) donors compared with alkyl-substituted tetrathiocino donors and fluorine allows for extended interactions that are responsible for solid-state crystal packing.