Xu HL, Tkachenko NV, Muñoz-Castro A, Boldyrev AI, Sun ZM. [Sn
8 ]
6- -Bridged Mixed-Valence Zn
I /Zn
II in {[K
2 ZnSn
8 (ZnMes)]
2 }
4- Inverse Sandwich-Type Cluster Supported by a Zn
I -Zn
I Bond.
Angew Chem Int Ed Engl 2021;
60:9990-9995. [PMID:
33682237 DOI:
10.1002/anie.202102578]
[Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Indexed: 11/08/2022]
Abstract
Since [Sn8 ]6- was discovered from the solid-state phase in 2000, its solution chemistry has been elusive due to the high charges and chemical activity. Herein, we report the synthesis and characterization of an inverse sandwich-type cluster dimer {[K2 ZnSn8 (ZnMes)]2 }4- (1 a), in which the highly charged [Sn8 ]6- is captured by mixed-valence ZnI /ZnII to form the dimer {closo-[Zn2 Sn8 ]}2 moieties bridged by a Zn-Zn bond. Such Zn-Sn cluster not only exhibits a novel example of mixed-valence ZnI /ZnII for stabilizing highly active anion species, but also indicates the [Sn8 ]6- cluster can act as a novel bridging ligand, like arene, with a η4 :η4 -fashion. Theoretical calculations indicate that a significant delocalization of electrons over Zn atoms plays a vital role in the stabilization of the [Sn8 ]6- species. The AdNDP and magnetic response analyses clearly showed the presence of local σ-aromaticity in three cluster fragments: two ZnSn4 caps and Sn8 square antiprism.
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