Synthesis of iron complexes [(η5-indenyl)FeL3]+ from the readily available[(η5-indenyl)Fe(η6-indene)]+

The iron complex [(η5-indenyl)Fe(η6-indene)]+ (1) was prepared via one-pot procedure in 25% yield by reaction of FeCl3 with indenyl lithium giving Fe(η5-indenyl)2 and its subsequent protonation with CF3COOH. Cation 1 reacts with 2e ligands L (L = tBuNC, P(OMe)3, P(OEt)3, PMe(OEt)2) under visible light irradiation giving the half-sandwich complexes [(η5-indenyl)FeL3]+ in 50–80% yields. Protonation of the related ruthenium complex Ru(η5-indenyl)2 gives cation [(η5-indenyl)Ru(η6-indene)]+ (23% yield). The structures of [1]BF4 and [(η5-indenyl)Fe(tBuNC)3]PF6 were determined by X-ray diffraction.