gamma -Deprotonation of bridging vinyliminium ligands: New route to aminobutadienylidene diiron and diruthenium complexes

The SPh-functionalized vinyliminium complexes [M2{μ- η1:η3-C(R)=C(SPh)C=N(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] [M = Fe, R = Xyl, R = Me, 2a; M = Fe, R = Me, R = Me, 2b; M = Fe, R = 4-C6H4OMe, R = Me, 2c; M = Ru, R = Xyl, R = Me, 2d; M = Fe, R = Xyl, R = CH2OH, 2e; M = Fe, R = Me, R = CH2OH, 2f; Xyl = 2,6-Me2C6H3] react upon treatment with NaH in thf solution. Species 2a and 2c afford the dinuclear butadienylidene complexes [Fe2{μ-η1:η3-CN(R)- (Me)=C(SPh)C=CH2}(μ-CO)(CO)(Cp)2] (R = Xyl, 4; R = 4- C6H4OMe, 8), respectively. The transformation of 2c into 8 is selective, whereas 2a produces 4 together with the metallacycle [Fe(CO)(Cp){CN(Xyl)(Me)C(SPh)C(Me)C(O)}] (3). A very similar metallacycle [Fe(CO)(Cp){CN(Me)2C(SPh)- C(Me)C(O)}] (7) is obtained, as a single product, from 2b. Di-ruthenium complex 2d, upon treatment with NaH, affords the dinuclear butadienylidene complex [Ru2{μ-η2:η3-CN(Me)- (Xyl)=C(SPh)C=CH2}(CO)2(Cp)2] (9), which is very similar to diiron species 4 and 8, but it exhibits a different bridging coordination mode, as evidenced by X-ray diffraction. Complexes 2d and 2f upon treatment with NaH undergo deprotonation of the OH group, which consequently gives rise to an intramolecular nucleophilic addition to the CO group to yield the complexes [Fe2{μ-η1:η3-C{CH2OC(O)}=C(SPh)- C=N(Me)(R)}(μ-CO)(Cp)2] (R = Xyl, 10a; R = Me, 10b). This transformation is reversed upon treatment with HSO3CF3. The molecular structures of 8, 9, and 10a·0.33CH2Cl2·were determined by X ray diffraction studies