Novel organoiron compounds resulting from the attempted syntheses of dibenzofulvalene complexes

Abstract

Thermal reaction of 2,2′-biindenyl with Fe(CO) 5 generates (η 4-2,2′-biindenyl)Fe(CO) 3 and a ferrole isomer of (μ,η 3:η 3-dibenzo[b,e]fulvalene)Fe 2(CO) 6. Reaction of the dianion of dibenzo[b,e]fulvalene with iron carbonyls produced a novel cyclized acyliron complex, whose structure was proven by X-ray crystallography; a mechanism is proposed for its formation. Reaction of the same dianion with (η 5-cyclopentadienyl)Fe(CO) 2Br generated another novel cyclic compound (C 18H 12)Fe(CO) 2(C 5H 4), probably via intramolecular radical attack on the η 5-bound cyclopentadienyl ring. Treatment of dibenzo[a,d]fulvalene with Fe 2(CO) 9 generates (η 2-dibenzo[a,d]fulvalene)Fe(CO) 4, (μ,η 2:η 2-dibenzo[a,d]fulvalene)Fe 2(CO) 8, and two compounds with bis(η 5) structures. These appear to have CO and Fe(CO) 4 groups inserted into the reactive Fe–Fe bond of (μ,η 5:η 5-dibenzo[a,d]fulvalene)Fe 2(CO) 4.