Novel Reactions of Cationic Carbyne Complexes of Manganese and Rhenium with Polymetal Carbonyl Anions. An Approach to Trimetal Bridging Carbyne Complexes

The reaction of a cationic carbyne complex of manganese, [(η-C 5 H 5 )(CO) 2 Mn⋮CC 6 H 5 ]BBr 4 ( 1 ), with [(Ph 3 P) 2 N] 2 [Ru 3 (CO) 11 ] ( 3 ) in THF at low temperature gave the heteronuclear trimetal bridging carbyne complex [MnRu 2 (μ-H)(μ-CO) 2 (μ 3 -CC 6 H 5 )(CO) 6 (η-C 5 H 5 )] ( 7 ). A cationic carbyne complex of rhenium, [(η-C 5 H 5 )(CO) 2 Re⋮CC 6 H 5 ]BBr 4 ( 2 ), reacts similarly with 3, affording the corresponding bridging carbyne complex [ReRu 2 (μ-H)(μ-CO) 2 (μ 3 -CC 6 H 5 )(CO) 6 (η-C 5 H 5 )] ( 8 ) and neutral Re−carbyne dimer [Re(CO) 2 (η-C 5 H 5 )(μ-CC 6 H 5 )] 2 ( 9 ). The compound [(Ph 3 P) 2 N] 2 [Os 3 (CO) 11 ] ( 4 ) only reacts with 1 to give the trimetal bridging carbyne complex [MnOs 2 (μ-H)(μ-CO) 2 (μ 3 -CC 6 H 5 )(CO) 6 (η-C 5 H 5 )] ( 10 ) and neutral Mn−carbyne dimer [Mn(CO) 2 (η-C 5 H 5 )(μ-CC 6 H 5 )] 2 ( 11 ). [(Ph 3 P) 2 N] 2 [Fe 4 (CO) 13 ] ( 5 ) also reacts with cationic carbyne complexes 1 and 2 to give the trimetal bridging carbyne complexes [MnFe 2 (μ-H)(μ-CO) 2 (μ 3 -CC 6 H 5 )(CO) 6 (η-C 5 H 5 )] ( 12 ) and [ReFe 2 (μ-H)(μ-CO) 2 (μ 3 -CC 6 H 5 )(CO) 6 (η-C 5 H 5 )] ( 13 ), respectively. Product 13, when treated with an excess of PPh 3, gave the PPh 3 -substituted bridging carbyne complex [ReFe 2 (μ-H)(μ-CO) 2 (μ 3 -CC 6 H 5 )(CO) 5 (PPh 3 )(η-C 5 H 5 )] ( 14 ). In contrast to carbonylmetal anions 3 − 5, [Mo(η-C 5 H 5 ) 2 (H)CO][Mn 3 (CO) 9 (μ-SC 6 H 5 ) 4 ] ( 6 ) reacts with 1 to produce not the analogous bridging carbyne complexes but rather the mercapto−carbene complex [(η-C 5 H 5 )(CO) 2 Mn C(SC 6 H 5 )C 6 H 5 ] ( 15 ) and the thiolato-bridged Mo−Mn carbonyl complex [Mo(η-C 5 H 5 )(CO) 2 (μ-SC 6 H 5 ) 2 Mn(CO) 3 ] ( 16 ), while the analogous reaction of 2 with 6 yields the mercaptocarbene complex [(η-C 5 H 5 )(CO) 2 Re C(SC 6 H 5 )C 6 H 5 ] ( 17 ) and phenylcarbene complex [(η-C 5 H 5 )(CO) 2 Re C(H)C 6 H 5 ] ( 18 ). The structures of 7, 9, 13, 14, and 16 have been established by X-ray diffraction studies.