title: Synthesis, structure, and electrochemistry of the Ni-Au carbonyl cluster [Ni12Au(CO)24]3- and its relation to [Ni32Au6(CO)44]6-.
abstract: A detailed study of the reaction between [Ni(6)(CO)(12)](2-) and [AuCl(4)](-) afforded the isolation of the new Ni-Au cluster [Ni(12)Au(CO)(24)](3-) as well as identifying an improved synthesis for the previously reported [Ni(32)Au(6)(CO)(44)](6-). The new [Ni(12)Au(CO)(24)](3-) cluster is composed by two [Ni(6)(CO)(12)](2-) moieties coordinated to a central Au(I) ion, as determined by X-ray diffraction. It is noteworthy that the two [Ni(6)(CO)(12)](2-) fragments display different geometries, i.e., trigonal antiprismatic (distorted octahedral) and distorted trigonal prismatic (monocapped square pyramidal). The chemical reactivity of these clusters and their electrochemical behavior have been studied. [Ni(12)Au(CO)(24)](3-) is irreversibly transformed, upon electrochemical reduction, into Au(0) and [Ni(6)(CO)(12)](2-), followed by the reversible reduction of the latter homometallic cluster. Conversely, [Ni(32)Au(6)(CO)(44)](6-) displays five reductions, with apparent features of reversibility, confirming the ability of larger metal carbonyl clusters to reversibly accept and release electrons.
authors.affiliation: Dipartimento di Chimica Fisica e Inorganica, 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: Maria Carmela
authors.initials: MC
authors.lastname: Iapalucci
authors.forename: Giuliano
authors.initials: G
authors.lastname: Longoni
authors.forename: Stefano
authors.initials: S
authors.lastname: Zacchini
authors.forename: Serena
authors.initials: S
authors.lastname: Fedi
authors.forename: Fabrizia
authors.initials: F
authors.lastname: Fabrizi de Biani