Reaction of bis(morpholinothiocarbonyl) disulphide with iodine. Existence of a 1 : 1 charge-transfer precursory adduct in an oxidation reaction. Isolation and crystal structure of bis[3,5-di(N-morpholinio)-1,2,4-trithiolane] hexadecaiodide

Abstract

The reaction of bis(morpholinothiocarbonyl) disulphide, S₂[C(S)NC₄H₈O]₂, with iodine in ratios ranging between 1 : 1 and 1 : 10 has been investigated in CH₂Cl₂, by spectrophotometric measurements. The immediate production of the known 1 : 1 charge-transfer complex between the reagents is observed. This species evolves according to a first-order rate law to give a brown compound which has been isolated from concentrated CH₂Cl₂ solutions of I₂+ S₂[C(S)NC₄H₈O]₂ mixtures. An X-ray crystal structure analysis of this compound indicated that the crystals are triclinic, space group P, with a= 7.834(2), b= 7.959(2), c= 24.142(4)Å, α= 86.80(1), β= 88.55(1), γ= 70.86(1)°, and Z= 2. The structure consists of bis[3,5-di(N-morpholinio)-1,2,4-trithiolane] cations, [C₁₀H₁₆N₂O₂S₃]²⁺, and of discrete polyiodide anions I₁₆ ^4–.