The reaction of 1,2,3-thiadiazoles and 1,2,3-selenadiazoles with nonacarbonyldi-iron

Abstract

Carbene complexes [µ-(thiophenacylidene)-bis(tricarbonyliron)(Fe–Fe) derivatives (9) and the seleno-analogues (10)] are obtained by the reaction of phenyl-substituted 1,2,3-thiadiazoles and 1,2,3-selenadiazoles with nonacarbonyldi-iron. When the substituents at positions 4 and 5 of the thiadiazoles and selenadiazoles are different, two isomeric carbene complexes are produced, the minor isomer in each case being a rearrangement product. Evidence is presented that this rearrangement occurs before the carbene complexes are formed, and may involve antiaromatic thiirens and selenirens as the symmetrical intermediates.