Cu–S heteroadamantanes are of great interest owing to their relevance to bioproteins. New copper(I) thiolate compounds with additional N‐donor functions from phenanthroline ligands have been synthesised. These complexes feature heteroadamantane cage structures with minor deviations in their construction and, therefore, a strong structural relationship. Furthermore, a decanuclear copper–sulfur cluster complex was isolated and shows known structural motifs arranged in a new fashion. Metallothioneins are natural counterparts to these complexes due to their thiolate‐rich and polynuclear d10 character. In addition to the structural characterisation, theoretical studies with a triple‐zeta basis set have been performed to further understand the building patterns of the reported complexes and their relevance to copper‐rich metalloproteins. This includes a Wiberg bond analysis and a full orbital analysis of selected heteroadamantanes to highlight the bonding interactions that connect the copper–sulfur skeletons.

The electrochemical synthesis is an underestimated synthesis protocol, which can lead to unexpected results. We obtained an unusual CuI complex salt with a pentanuclear anion and a heptanuclear cation. The anion [Cu5(StBu)6]– features a trigonal prism coordination motif with a twisted arrangement. The cation [Cu7(StBu)6(bipy)3]+ is structurally almost identical to the anion and shares therefore basic building principles. These Cu–S skeletons with additional N donor functions in the cation have relevance to biological copper proteins. Besides structural discussion and analysis, a theoretical study was performed to determine stabilizing effects. This is accomplished by means of DFT with a triple‐zeta basis set and the TPSSh functional in order to highlight bonding interactions and to understand d10–d10 interactions, which are assigned a major stabilizing part. This is realized through Wiberg bond analysis and frontier orbital analysis of both ions.