Synthesis and characterization of new diiron and diruthenium MU-aminocarbyne complexes containing S, P and C-ligands

The diiron aminocarbyne complexes [Fe2{µ-CN(Me)(R)}(µ-CO)(CO)(NCMe)(Cp)2][SO3CF3] (R = Xyl, 1a; R = Me, 1b; R =CH2Ph, 1c; Xyl = 2,6-Me2C6H3) undergo replacement of the coordinated nitrile by halides, diethyldithiocarbamate, and dicyanomethanide to give [Fe2{µ-CN(Me)(R)}(µ-CO)(CO)(X)(Cp)2] complexes (R = Me, X = Br, 4a; R = Me, X = I, 4b; R =CH2Ph, X =Cl, 4c; R =CH2Ph, X = Br, 4d; R =CH2Ph, X = I, 4e; R = Xyl, X = SC(S)NEt2, 5a; R = Me, X = SC(S)NEt2, 5b; R = Xyl, X = CH(CN)2, 7), in good yields. The molecular structure of 5a shows an unusual η1 coordination mode of the dithiocarbamate ligand. Similarly, treatment of [M2{µ-CN(Me) (R)}(µ-CO)(CO)(NCMe)(Cp)2][SO3CF3] (M = Fe, R = Xyl, 1a; M = Fe, R = Me, 1b; M = Ru, R = Xyl, 2a; M = Ru, R = Me, 2b) with a series of phosphanes generates the cationic complexes [M2{µ-CN(Me)(R)}(µ-CO)(CO)(P)(Cp)2][SO3CF3] (M = Fe, R = Xyl, P = PPh2H, 6a; M = Fe, R = Xyl, P = PPh3, 6b; M = Fe, R = Xyl, P = PMe3, 6c; M = Fe, R = Me, P = PMe2Ph, 6d; M = Fe, R = Me, P = PPh3, 6e; M = Fe, R = Me, P = PMePh2, 6f; M = Ru, R = Xyl, P = PPh2H, 6g; M = Ru, R = Me, P = PPh2H, 6h), in high yields. The molecular structure of 6a has been elucidated by an X-ray diffraction study. The reactions of [Fe2{µ-CN(Me)(Xyl)}(µ-CO)(CO)(NCR )(Cp)2][SO3CF3] [R =Me, 1a; R = tBu, 3] with PhLi and PPh2Li yield [Fe2{µ-CN(Me)(Xyl)}(µ-CO)(CO)(Ph)(Cp)2] (8) and [Fe2{µ-CN(Me)(Xyl)}(µ-CO)(CO)(PPh2)(Cp)2] (9), respectively. The molecular structure of 8 has been ascertained by X-ray diffraction. Conversely, the reaction of 1a with MeLi generates the aminoalkylidene compound [Fe2{C(Me)N(Me)(Xyl)}(µ-CO)2(CO)(Cp)2] (10). Finally, the acetone complex [Fe2{µ-CN(Me)(Xyl)}(µ-CO)(CO)(OCMe2)(Cp)2][SO3CF3] (12) reacts with lithium acetylides to give complexes [Fe2{µ-CN(Me)(Xyl)}(µ-CO)(CO)(C≡CR)(Cp)2] (R = p-C6H4Me, 11a; R = Ph, 11b; R = SiMe3, 11c), in high yields. Filtration through alumina of a solution of 11a in CH2Cl2 results in hydration of the acetylide group and C–Si bond cleavage, affording [Fe2{µ-CN(Me)(Xyl)}(µ-CO)(CO){C(O)Me}(Cp)2] (12).