Selenium-77 nuclear magnetic resonance identification of seven-membered selenium sulfide ring molecules

Abstract

Seven-membered heterocyclic selenium sulfides were prepared from a mixture of [Ti(C₅H₅)₂Se_xS_5–x] species (Se : S = 3 : 2)1 upon treatment with S₂Cl₂ and Se₂Cl₂, and the products identified with ⁷⁷Se NMR spectroscopy. The assignment of the spectra was based on the known chemical shifts, and on the well established trends in the chemical shifts. The reaction of 1 with S₂Cl₂ produced 1,2,3,4,5-Se₅S₂, 1,2,3,4-Se₄S₃, 1,2,3-Se₃S₄ and 1,2-Se₂S₅, and that with Se₂Cl₂ produced Se₇, 1,2,3,4,5,6-Se₆S, 1,2,3,4,5-Se₅S₂, 1,2,3,5,6-Se₅S₂ and 1,2,4,5-Se₄S₃. A comparison of the predicted product distribution from the known composition of the starting [Ti(C₅H₅)₂Se_xS_5–x] mixture to that determined semiquantitatively from the peak intensities supports the spectral assignment.