title: The redox chemistry of [Co6C(CO)15](2-): a synthetic route to new co-carbide carbonyl clusters.
abstract: The oxidation and reduction reactions of [Co6C(CO)15](2-) have been studied in detail, leading to the isolation of several new Co-carbide carbonyl clusters. Thus, [Co6C(CO)15](2-) reacts in tetrahydrofuran (THF) with oxidants such as HBF4·Et2O and [Cp2Fe][PF6], resulting first in the formation of the previously reported [Co6C(CO)14](-); then, in CH2Cl2, the new dicarbide [Co11C2(CO)23](2-) is formed. The latter may be further oxidized, yielding the isostructural monoanion [Co11C2(CO)23](-), whereas its reduction with (cyclopentadienyl)2Co affords the unstable trianion [Co11C2(CO)23](3-), which decomposes during workup. Oxidation of [Co6C(CO)15](2-) in CH3CN with [C7H7][BF4] affords the same major products, and besides, the new monoacetylide [Co10(C2)(CO)21](2-) was obtained as side-product. Conversely, the reduction of [Co6C(CO)15](2-) in THF with increasing amounts of Na/naphthalene results in the following species: [Co6C(CO)13](2-), [Co11(C2)(CO)22](3-), [Co7C(CO)15](3-), [Co8C(CO)17](4-), [Co6C(CO)12](3-), and [Co(CO)4](-). The new [Co11C2(CO)23](-), [Co11C2(CO)23](2-), [Co10(C2)(CO)21](2-), [Co8C(CO)17](4-), [Co6C(CO)12](3-), and [Co7C(CO)15](3-) clusters were structurally characterized. Moreover, the paramagnetic species [Co11C2(CO)23](2-) and [Co6C(CO)12](3-) were investigated by means of electron paramagnetic resonance spectroscopy. Finally, electrochemical studies were performed on [Co11C2(CO)23](n-) (n = 1-3).
authors.affiliation: Dipartimento di Chimica Industriale "Toso Montanari", Università di Bologna , Viale Risorgimento 4 - 40136 Bologna, Italy.
authors.forename: Iacopo
authors.initials: I
authors.lastname: Ciabatti
authors.forename: Cristina
authors.initials: C
authors.lastname: Femoni
authors.forename: Mohammad
authors.initials: M
authors.lastname: Hayatifar
authors.forename: Maria Carmela
authors.initials: MC
authors.lastname: Iapalucci
authors.forename: Giuliano
authors.initials: G
authors.lastname: Longoni
authors.forename: Calogero
authors.initials: C
authors.lastname: Pinzino
authors.forename: Matilde Valeria
authors.initials: MV
authors.lastname: Solmi
authors.forename: Stefano
authors.initials: S
authors.lastname: Zacchini