Cationic (eta(6)-arene)tricarbonylmanganese linked to ferrocene complexes

Palladium-catalyzed Sonogashira coupling reactions of the neutral [eta(5)(1-5)-(1-chloro-4-methoxycyclohexa-2,4-dienyl)]tricarbonylmangane se(l) (2) and 2-bromo-5-{[eta(5)(1-5)-(4-methoxycyclohexa-2,4-dienylltricarbonylmangan ese(I)}thiophene (13) with the ethynylferrocene derivative 5 give the dinuclear complexes 1-(ferrocenylethynyl)[eta(5)(1-5)-(4-methoxycyclohexa2,4-dienyl)]tricarb onylmanganese(I) (6) and 2-(ferrocenylethynyl)-5-[eta(5)(1-5)-(4-methoxycyclohexa-2,4-dienyl)tric arbonylmanganese]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 eta(6)-arene cations 7, 11, and 20. The structure of one of them, 1-(ferrocenylethynyl)[eta(6)(1-6)-(4-methoxybenzene)]tricarbonylmanganes e(I) tetrafluoroborate (7), has been investigated by X-ray diffraction.