2 (CO) 6 ] (18). Analogous iron-sulfur cluster bridging carbene complexes [Fe 2 (µ-CO)(µ-CAr)(CO) 2 (η 5 -C 5 H 5 ) 2 -(µ-S)(µ-SC 6 H 5 )Fe 2 (CO) 6 ] (19, Ar ) C 6 H 5 ; 20, Ar ) p-CH 3 C 6 H 4 ) can also be obtained by the reactions of diiron cationic carbyne complexes [Fe 2 (µ-CO)(µ-CAr)(CO) 2 (η 5 -C 5 H 5 ) 2 ]BBr 4 (7, Ar ) C 6 H 5 ; 8, Ar ) p-CH 3 C 6 H 4 ) with [(µ-SLi)(µ-SC 6 H 5 )Fe 2 (CO) 6 ]. The structures of complexes 9, 13, 16, and 18 have been established by X-ray crystallography.

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.

The reactions of cationic carbyne complexes of manganese and rhenium, [η-C 5 H 5 (CO) 2 Mt CC 6 H 5 ]BBr 4 (1, M ) Mn; 2, M ) Re), with diiron anionic compoundsComplexes 1 and 2 also react with [MgBr][Fe 2 (µ-CO)(µ-SeC 2 H 5 )(CO) 6 ] (5) to produce [Fe 2 -(µ-SeC 2 H 5 ) 2 (CO) 6 ] (15) and dimetal bridging carbene complexes [MnFe{µ-C(SeC 2 H 5 )C 6 H 5 }-(CO) 5 (η-C 5 H 5 )] ( 17) and [ReFe{µ-C(SeC 2 H 5 )C 6 H 5 }(CO) 5 (η-C 5 H 5 )] ( 18), respectively. 2 reacts similarly with 16) and a Re-Fe bridging carbene complex [ReFe{µ-C(SeC 4 H 9 -n)C 6 H 5 }(CO) 5 (η-C 5 H 5 )] ( 19), while the analogous reaction of 1 with 6 produced an unexpected trimetal bridging carbyne complex [MnFe 2 (µ-H)(µ-CO) 2 (µ 3 -CC 6 H 5 )CO) 6 (η-C 5 H 5 )] (20). The structures of complexes 9, 10, 13, 18, and 20 have been established by X-ray diffraction studies.