From Small Metal Clusters to Molecular Nanoarchitectures with a Core-Shell Structure: the Synthesis, Redox Fingerprint, Theoretical Analysis, and Solid-State Structure of [Co38as12(co)50]4.

The cluster [Co38As12(CO)50]4- was obtained by pyrolysis of [Co6As(CO)16]-. The metal cage features a closed-packed core inside a Co/As shell that progressively deforms from a cubic face-centered symmetry. The redox and acid-base reactivities were determined by cyclic voltammetry and spectrophotometric titrations. The calculated electron density revealed the shell-constrained distribution of the atomic charges, induced by the presence of arsenic.