σ-Aromaticity-Induced Stabilization of Heterometallic Supertetrahedral Clusters [Zn6Ge16]4− and [Cd6Ge16]4−
Angewandte Chemie International Edition
Wiley-VCH Verlag GmbH & Co. KGaA
NSF, Division of Chemistry (CHE) 1664379
NSF, Division of Chemistry (CHE)
In this work, the largest heterometallic supertetrahedral clusters, [Zn6Ge16]4− and [Cd6Ge16]4−, were directly self-assembled through highly-charged [Ge4]4− units and transition metal cations, in which 3-center–2-electron σ bonding in Ge2Zn or Ge2Cd triangles plays a vital role in the stabilization of the whole structure. The cluster structures have an open framework with a large central cavity of diameter 4.6 Å for Zn and 5.0 Å for Cd, respectively. Time-dependent HRESI-MS spectra show that the larger clusters grow from smaller components with a single [Ge4]4− and ZnMes2 units. Calculations performed at the DFT level indicate a very large HOMO–LUMO energy gap in [M6Ge16]4− (2.22 eV), suggesting high kinetic stability that may offer opportunities in materials science. These observations offer a new strategy for the assembly of heterometallic clusters with high symmetry.
H.-L. Xu, I. A. Popov, N. V. Tkachenko, Z.-C. Wang, A. Muñoz-Castro, A. I. Boldyrev, Z.-M. Sun, Angew. Chem. Int. Ed. 2020, 59, 17286.