The triangular clusters [Zn3Cp*3](+) and [Zn2CuCp*3] were obtained by addition of the in situ generated, electrophilic, and isolobal species [ZnCp*](+) and [CuCp*] to Carmona's compound, [Cp*Zn-ZnCp*], without splitting the ZnZn bond. The choice of non-coordinating fluoroaromatic solvents was crucial. The bonding situations of the all-hydrocarbon-ligand-protected clusters were investigated by quantum chemical calculations revealing a high degree of σ-aromaticity similar to the triatomic hydrogen ion [H3](+). The new species serve as molecular building units of Cu(n)Zn(m) nanobrass clusters as indicated by LIFDI mass spectrometry.

The first example of ligand protected Cu-Zn clusters is described. Reaction of [CpCu(CN(t)Bu)] with [Zn2Cp*2] yields [(CuCN(t)Bu)4(ZnCp*)4] (1a) and [(CuCN(t)Bu)4(ZnCp*)3(ZnCp)] (1b). According to DFT calculations, the [Cu4Zn4] unit fulfils the unified superatom model for cluster valence shell closing.

Zn-Cp* bond cleavage reactions leading to novel monovalent cationic zinc species are presented (Cp* = pentamethylcyclopentadienyl). The treatment of [Zn2Cp*2] with two equiv. of [H(Et2O)2][BAr4(F)] (BAr4(F) = B{C6H3(CF3)2}4) yields the triple-decker complex [Cp*3Zn4(Et2O)2][BAr4(F)] (1) via protolytic removal of a Cp* ligand as Cp*H, whereas the reaction with an equimolar amount of [FeCp2][BAr4(F)] (Cp = cyclopentadienyl) results in the formation of [Cp*Zn2(Et2O)3][BAr4(F)] (2) under oxidative cleavage of a Cp* ring giving decamethylfulvalene, (Cp*)2, and [FeCp2] as by-products. The molecular structures of compounds 1 and 2 are established by single-crystal X-ray diffraction studies. A new synthetic pathway for the formation of [Zn2Cp*2] based on the reductive elimination of Cp*H from in situ formed Cp*ZnH is presented.

The isoelectronic M7 clusters [Cu3Zn4](Cp*)5 and {[Cu2Zn5](Cp*)5}+ were isolated as unique species pushing the boundaries of the Wade–Mingos rules.

The bottom-up synthesis of organometallic zinc clusters is described. The cation {[Zn10](Cp*)6 Me}(+) (1) is obtained by reacting [Zn2 Cp*2] with [FeCp2][BAr4 (F)] in the presence of ZnMe2. In the presence of suitable ligands, the high reactivity of 1 enables the controlled abstraction of single Zn units, providing access to the lower-nuclearity clusters {[Zn9 ](Cp*)6} (2) and {[Zn8 ](Cp*)5 ((t) BuNC)3}(+) (3). According to DFT calculations, 1 and 2 can be described as closed-shell species that are electron-deficient in terms of the Wade-Mingos rules because the apical ZnCp* units that constitute the cluster cage do not have three, but only one, frontier orbitals available for cluster bonding. Zinc behaves flexibly in building the skeletal metal-metal bonds, sometimes providing one major frontier orbital (like Group 11 metals) and sometimes providing three frontier orbitals (like Group 13 elements).