Cationic transition-metal complexes. Part VI. The synthesis of dicarbene complexes of rhodium(III) and iron(II)

Abstract

Treatment of [RhR(CNBu^t)₄I][BF₄](R = Me or Et) with neat R′NH2 (R′= Me, Prⁿ, or Buⁿ) leads to the formation of the chelated dicarbene complexes [[graphic omitted](NHBu^t)}R(CNBu^t)₂I][BF₄]. An alternative route to the dicarbene complex where R = Me and R′= Prⁿ is reaction of [Rh{C(NHPrⁿ)(NHBu^t)}Me(CNBu^t)₃I][BF₄] with neat propylamine. Reaction of [RhMe(CNBu^t)₄I]+ with neat hydrazine affords a related dicarbene complex analogous to the Chugaveff salts. The use of neat amine as solvent in these reactions is extended to the synthesis of related 2.2′-bipyridyl and 1.10-phenanthroline iron (II) dicarbene complexes. The nature of the bonding and the mechanism of formation of these species is discussed.