Cationic (η6-Arene)tricarbonylmanganese Linked to Ferrocene Complexes

Palladium-catalyzed Sonogashira coupling reactions of the neutral [η5(1−5)-(1-chloro-4-methoxycyclohexa-2,4-dienyl)]tricarbonylmanganese(I) (2) and 2-bromo-5-{[η5(1−5)-(4-methoxycyclohexa-2,4-dienyl]tricarbonylmanganese(I)}thiophene (13) with the ethynylferrocene derivative 5 give the dinuclear complexes 1-(ferrocenylethynyl)[η5(1−5)-(4-methoxycyclohexa-2,4-dienyl)]tricarbonylmanganese(I) (6) and 2-(ferrocenylethynyl)-5-[η5(1−5)-(4-methoxycyclohexa-2,4-dienyl)tricarbonylmanganese]thiophene (10). Similarly, condensation of 2 with 2-(ferrocenylethynyl)-5-ethynylthiophene (18) affords the dinuclear complex 19. These complexes are valuable precursors, upon hydride abstraction, of the corresponding η6-arene cations 7, 11, and 20. The structure of one of them, 1-(ferrocenylethynyl)[η6(1−6)-(4-methoxybenzene)]tricarbonylmanganese(I) tetrafluoroborate (7), has been investigated by X-ray diffraction.