A co-crystalline adduct consisting of a phosphinine selenide and an organohalide was obtained by slow evaporation of the solvent from a mixture of 2,6-bis(trimethylsilyl)phosphinine selenide and 1,4-diiodotetrafluorobenzene (1,4-TFDIB). The crystallographic characterization of the product shows π-π stacking, F⋅⋅⋅H hydrogen bonding between 1,4-TFDIB and the phosphinine selenide, as well as F⋅⋅⋅F interactions between 1,4-TFDIB molecules. Moreover, the phosphorus heterocycle could be crystallized with diiodine to form a 1 : 1 adduct. The d(I−I) distance in this compound is 2.8475(3) Å, which is shorter than the corresponding one in triphenylphosphine selenide diiodide, reflecting the weaker net-donor power of the phosphinine selenide towards diiodine. The phosphinine selenide could also be used as a selenium transfer reagent to generate KSeCN from KCN.
