Unprecedented synthesis of iron-NHC complexes by C-H activation of imidazolium salts. Mild catalysts for reduction of sulfoxides.

A direct synthesis of bidentate cyclopentadienyl-functionalised NHC-iron(II) complexes by using imidazolium salts and commercially available Fe(3)(CO)(12) is developed. These well-defined iron-NHC complexes efficiently catalyse the reduction of sulfoxides under mild conditions. Radical scavenging experiments indicate the presence of free radicals in the catalytic reaction.