Reactions of Cationic Bridging Carbyne Complexes of Bis(η-cyclopentadienyl)diiron Tricarbonyl with Nucleophiles. A Route to Diiron Bridging Carbene Complexes

Abstract

The reactions of the cationic carbyne complex of diiron, [Fe2(μ-CO)(μ-CPh)(CO)2(η-C5H5)2]BBr4 (3), with NaSMe, NaSEt, NaSPh, NaSC6H4Me-p, and NaSC6H4NO2-p in THF at low temperature afforded diiron bridging thiocarbene complexes [Fe2(μ-CO){μ-C(SR)Ph}(CO)2(η-C5H5)2] (5, R = Me; 6, R = Et; 7, R = Ph; 8, R = p-MeC6H4; 9, R = p-NO2C6H4). Complex [Fe2(μ-CO)(μ-CC6H4Me-p)(CO)2(η-C5H5)2]BBr4 (4) reacted similarly with NaSPh and NaSC6H4Me-p to give corresponding bridging carbene complexes [Fe2(μ-CO){μ-C(SR)C6H4Me-p}(CO)2-(η-C5H5)2] (10, R = Ph; 11, R = p-MeC6H4). Complex 3 also reacted with NaOPh and NaN(SiMe3)2 to yield bridging carbene complexes [Fe2(μ-CO){μ-C(OPh)Ph}(CO)2(η-C5H5)2] (12) and [Fe2(μ-CO){μ-C(N(SiMe3)2)Ph}(CO)2(η-C5H5)2] (13), respectively. Complexes 3 and 4 reacted with reactive salt [Et3NH][Fe2(μ-CO)(μ-SBun)(CO)6] to yield the bridging mercaptocarbene complex [Fe2(μ-CO){μ-C(SH)Ph}(CO)2(η-C5H5)2] (14) and the bridging butylthiocarbene complex [Fe2(μ-CO){μ-C(SBun)C6H4Me-p}(CO)2(η-C5H5)2] (15), respectively. The analogous reactions of [Et3NH][Fe2(μ-CO)(μ-SPh)(CO)6] with 3 and 4 afforded the thiolato-bridged iron carbonyl compound [Fe2(μ-SPh)2(CO)6] (16) and the bridging arylcarbene complexes [Fe2(μ-CO){μ-C(H)Ar}(CO)2(η-C5H5)2] (17, Ar = Ph; 18, Ar = p-MeC6H4), while [Et3NH][Fe2(μ-CO)(μ-SC6H4Me-p)(CO)6] reacted with 3 to yield 17 and [Fe2(μ-SC6H4Me-p)2(CO)6] (19). The reaction of metal carbonyl anion compounds Na2W(CO)5 and Na2Fe(CO)4 with 3 gave the same product, 17. The structures of 6, 7, 15, and 17 have been established by X-ray diffraction studies.