Σ‐Aromaticity‐Induced Stabilization of Heterometallic Supertetrahedral Clusters [Zn6Ge16]4− and [Cd6Ge16]4−. (13th August 2020)

• Record Type: Journal Article
• Authors: Xu, Hong‐Lei; Popov, Ivan A.; Tkachenko, Nikolay V.; Wang, Zi‐Chuan; Muñoz‐Castro, Alvaro; Boldyrev, Alexander I.; Sun, Zhong‐Ming
• Is Part Of: Angewandte Chemie. Volume 132:Number 39(2020)
• Page Start: 17439
• Page End: 17443
• Publication Date: 2020-08-13
• Subjects: planar tetracoordinate Zn/Cd -- supertetrahedron -- Td symmetry -- Zintl clusters -- σ-aromaticity; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202008276
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: In this work, the largest heterometallic supertetrahedral clusters, [Zn6 Ge16 ] 4− and [Cd6 Ge16 ] 4−, were directly self‐assembled through highly‐charged [Ge4 ] 4− units and transition metal cations, in which 3‐center–2‐electron σ bonding in Ge2 Zn or Ge2 Cd 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 [M6 Ge16 ] 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. Abstract : Driven by strong 3c–2e Zn–Ge–Ge or Cd–Ge–Ge interactions, two unprecedented supertetrahedral clusters [Zn6 Ge16 ] 4− and [Cd6 Ge16 ] 4− were synthesized through the assembly of [Ge4 ] 4− and transition metal precursors. This strategy provides not only a new method to obtain large heterometallic clusters, but also a new conceptual understanding of how σ‐aromaticity induces the stabilization of high‐symmetry clusters.