Syntheses, structures and reactivities of diindenyl-coordinated diiron bridging carbene complexes

Abstract

Compound [Fe 2(μ-CO) 2(CO) 2(η 5-C 9H 7) 2] ( 1) reacts with aryllithium reagents, ArLi (Ar = C 6H 5, p-CH 3C 6H 4, p-CF 3C 6H 4) followed by alkylation with Et 3OBF 4 to give the diindenyl-coordinated diiron bridging alkoxycarbene complexes [Fe 2{μ-C(OC 2H 5)Ar}(μ-CO)(CO) 2(η 5-C 9H 7) 2] ( 2, Ar = C 6H 5; 3, Ar = p-CH 3C 6H 4, 4, Ar = p-CF 3C 6H 4). Complex 4 reacts with HBF 4 · Et 2O at low temperature to yield cationic bridging carbyne complex [Fe 2(μ-CC 6H 4CF 3- p)(μ-CO)(CO) 2(η 5-C 9H 7) 2]BF 4 ( 5). Cationic 5 reacts with NaBH 4 in THF at low temperature to afford diiron bridging arylcarbene complex [Fe 2{μ-C(H)C 6H 4CF 3- p}(μ-CO)(CO) 2(η 5-C 9H 7) 2] ( 6). The reaction of 5 with NaSC 6H 4CH 3- p under the similar conditions gave the bridging arylthiocarbene complex [Fe 2{μ-C(C 6H 4CF 3- p)SC 6H 4CH 3- p}(μ-CO)(CO) 2(η 5-C 9H 7) 2] ( 7). Complex 5 can also react with carbonylmetal anionic compounds Na[M(CO) 5(CN)] (M = Cr, Mo, W) to produce the diiron bridging aryl(penta-carbonylcyanometal)carbene complexes [Fe 2{μ-C(C 6H 4CF 3- p)NCM(CO) 5}(μ-CO)(CO) 2(η 5-C 9H 7) 2] ( 8, M = Cr; 9, M = Mo; 10, M = W). The structures of complexes 4, 6, 7, and 10 have been established by X-ray diffraction studies.