Clusterification of reactive species generated through chemical reduction of metallocenes: synthesis and stereochemical characterization of a new hexameric series of metal-cyclopentadienyl clusters, [Ni6(.eta.5-C5H5)6]n (n = 0, + 1)

The Magnetic Behaviour of [NnBu4]4[Ni16Pd16(CO)40]: An Even‐Electron Homoleptic Carbonyl–Metal Cluster Anion Displaying aJ=2 Ground State

“…Among the latter, there are known species that undergo singlet-triplet equilibria or feature two unpaired electrons, such as the 50-or 46-electron Cp-and Cp*-stabilised triangular clusters (e.g., [Co 3 (Cp) 3 S 2 ], [7] [Co 3 (Cp*) 3 (CO) 2 ] [17,18] and [IrCo 2 (Cp) 2 (Cp*)(CO) 2 ] [19] ). To our knowledge, the ascertained maximum spin system is 3/2 for the odd-electron [Ni 4 (Cp) 4 H 3 ] [20] and [Ni 6 (Cp) 6 ] + species, [21] and 2 for the even-electron [Cr 2 FeX 2 (CO) 10 ] 2À (X = Se, Te) derivative. [22] It may be conjectured that a progressive tightening of the frontier energy levels as a function of size of the carbonylated metal clusters could trigger magnetism in an increasing number of compounds, regardless of even or odd numbers of electrons.…”

New insights into the reaction of nickelocene with methyllithium: the isolation and crystal structure of (NiCp)3(μ3-CH)

“…1 To the best of our knowledge, only one hexameric cyclopentadienylnickel cluster, i.e. (NiCp) 6 , has been characterised by X-ray diffraction so far [20].…”

Novel tetrahedral tetranickel cluster with alkylidyne ligand (NiCp)4(μ3-CR)

“…The tetrahedral [1,2], square planar [12] and octahedral [6] cyclopentadienylnickel clusters, (NiCp) n (n = 4; 6), are stable only when they possess more than so-called ''magic numbers'' of valence electrons, and each nickel atom has on average more than 18 valence electrons. Clusters of the type (NiCp) 4 may achieve this by adopting additional ligands.…”

“…Hexanickel cluster (NiCp) 6 was also synthesised [6]. In fact it has 90 valence electrons (4 more than ''magic number'') and all nickel atoms do not fulfil 18 valence electron rule.…”