IMIDAZOLE DERIVATIVES .19. COORDINATION O R REDUCTION - ON THE REACTION OF 1,3-DIISOPROPYL-4,5-DIMETHYLIMIDAZOL-2-YLIDENE WITH SULFUR HALIDES AND SULFUR OXYGEN HALIDES

The reaction of 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (4, Im) with sulfur halides and sulfur oxygen halides may be described as a c oordination (1) or reduction (2) process in respect to the sulfur cent re. With SCl2 and SOCl2 the hypervalent sulfur compounds Im . SCl2 (5) and Im . S(O)Cl-2 (13) are obtained. The SF2 adduct Im . SF2 (11) is formed on treatment of 5 with AgF. 13 is alkylated by methyl iodide to give the Im . S(Me)OCl2 cation (15). Surprisingly, reduction of the s ulfur centre (2) occurs on treatment of 4 with SF4 to form the ImF(+)S F(3)(-) salt 18 containing the new SF3 anion. As expected, the same ty pe of reaction occurs with the sulfuryl halides SO2ClF and SO2F2 to gi ve the fluorosulfites ImCl(+)SO(2)F(-) (21) and ImF(+)SO(2)F(-) (23). The X-ray structures of 5, 13 and 23 are reported.