Derivate des Imidazols, XIX . Koordination oder Reduktion? Zur Reaktion von 1,3‐Diisopropyl‐4,5‐dimethylimidazol‐2‐yliden mit Schwefelhalogeniden und Schwefeloxidhalogeniden

Imidazole Derivatives, XIX Part XVIII: Ref. [1] . — Coordination or reduction? On the Reaction of 1,3‐Diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene with Sulfur Halides and Sulfur Oxygen Halides Herrn Professor Max Herberhold zum 60. Geburtstag gewidmet. 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 coordination ( 1 ) or reduction ( 2 ) process in respect to the sulfur centre. With SCl 2 and SOCl 2 the hypervalent sulfur compounds Im · SCl 2 ( 5 ) and Im · S(O)Cl 2 ( 13 ) are obtained. The SF 2 adduct Im · SF 2 ( 11 ) is formed on treatment of 5 with AgF. 13 is alkylated by methyl iodide to give the Im · S(Me)OCl 2 cation ( 15 ). Surprisingly, reduction of the sulfur centre ( 2 ) occurs on treatment of 4 with SF 4 to form the ImF + SF 3 − salt 18 containing the new SF 3 anion. As expected, the same type of reaction occurs with the sulfuryl halides SO 2 ClF and SO 2 F 2 to give the fluorosulfites ImCl + ‐SO 2 F − ( 21 ) and ImF + SO 2 F − ( 23 ). The X‐ray structures of 5 , 13 and 23 are reported.