Silver Aggregation Caused by Stanna-closo-dodecaborate Coordination: Syntheses, Solid-State Structures and Theoretical Studies
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- 作者：Siegbert Hagen ; Hartmut Schubert ; Cä ; cilia Maichle-Mö ; ssmer ; Ingo Pantenburg ; Florian Weigend ; Lars Wesemann
- 刊名：Inorganic Chemistry
- 出版年：2007
- 出版时间：August 6, 2007
- 年：2007
- 卷：46
- 期：16
- 页码：6775 - 6784
- 全文大小：830K
- 年卷期：v.46,no.16(August 6, 2007)
- ISSN：1520-510X
文摘
Stanna-closo-dodecaborate [SnB11H11]2- reacts as a nucleophile with various silver electrophiles ([Ag(PMe3)]+, [Ag(PEt3)]+, [Ag(PPh3)]+, and Ag+) to form silver-tin bonds. Aggregation of two, three, or four units of[{Ag(SnB11H11)(PR3)}n]n- (PPh3, n = 2; PEt3, n = 3; PMe3, n = 4) was found, depending on the size of thecoordinating phosphine. The structures of the silver-tin clusters in the solid state were determined by single-crystalX-ray diffraction. In these phosphine silver coordination compounds, the tin ligand exhibits 
2- and 3-coordinationwith the silver atoms. From the reaction with silver nitrate, an octaanionic stanna-closo-dodecaborate coordinationcompound, [Et4N]8[Ag4(SnB11H11)6], was isolated. In this cluster, arranged as butterfly, the stannaborate showsvarious coordination modes at four silver atoms. In the reported silver-tin complexes, the silver-silver interatomicdistances are in a range of 2.6326(10)-3.1424(6) Å. Silver-tin distances were found between 2.6416(5) and 3.1460(6) Å. Analysis of the molecular orbitals calculated by means of density functional theory shows that the LUMO ofthe core compound without [SnB11H11]2- units is always a totally symmetric combination of (mainly) s-orbitals of Agatoms. This core is filled with electrons of the HOMOs of the [SnB11H11]2- units and is leading, in this way, to astable compound.
2- and 3-coordinationwith the silver atoms. From the reaction with silver nitrate, an octaanionic stanna-closo-dodecaborate coordinationcompound, [Et4N]8[Ag4(SnB11H11)6], was isolated. In this cluster, arranged as butterfly, the stannaborate showsvarious coordination modes at four silver atoms. In the reported silver-tin complexes, the silver-silver interatomicdistances are in a range of 2.6326(10)-3.1424(6) Å. Silver-tin distances were found between 2.6416(5) and 3.1460(6) Å. Analysis of the molecular orbitals calculated by means of density functional theory shows that the LUMO ofthe core compound without [SnB11H11]2- units is always a totally symmetric combination of (mainly) s-orbitals of Agatoms. This core is filled with electrons of the HOMOs of the [SnB11H11]2- units and is leading, in this way, to astable compound.