4,5-ethylenedithio-1,3-diselenol-2-one synthesis

triethyl phosphite

toluene (refluxed over potassium, degassed)

Triethyl phosphite (10 ml) was added dropwise over 15 min to a solution of 4,5-ethylenedithio-1,3-diselenol-2-one (0.3 g, 0.99 mmol) in dry toluene (30 ml) under argon. The mixture was heated to reflux for 2 h and then allowed to cool. The product was collected by filtration and recrystallised from hot anhydrous carbon disulfide under argon (CAUTION - CS₂ has a very low flash point and is highly inflammable). Yield 0.15 g (52%).

BETS is really insoluble - CS₂ was the best solvent we found for recrystallisation, it also dissolves sparingly in chloroform.

This procedure has been published in outline by Kato et al. and Courcet et al., to our knowledge however this is the first detailed synthetic procedure for this reaction. The coupling procedure was adapted from Imakubo et al.

Elemental analysis found (calculated for C₁₀H₈S₄Se₄) %: C 21.10 (20.99), H 1.20 (1.41)

¹H NMR (400 MHz, 298K, CDCl₃) δ_H 1.56 (s, 8H, CH₂)

¹³C NMR, - no data obtained even on 700MHz and 16k scans - due to very low solubility

T. Courcet, I. Malfant, K. Pokhodnia and P. Cassoux, New J. Chem., 1998, 22, 585-589.

T. Imakubo, M. Kibune, H. Yoshino, T. Shirahata and K. Yoza, J. Mater. Chem., 2006, 16, 4110-4116.