Silver aggregation caused by Stanna-closo-dodecaborate coordination: syntheses, solid-state structures and theoretical studies.
Silver aggregation caused by Stanna-closo-dodecaborate coordination: syntheses, solid-state structures and theoretical studies.
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由锡-近十二硼酸配位引起的银聚集：合成、固态结构和理论研究。
DOI：
10.1002/chin.200744018
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发表时间：
2007
影响因子：
4.6
通讯作者：
L. Wesemann
中科院分区：
文献类型：
--
作者：
Siegbert Hagen;H. Schubert;C. Maichle‐Mössmer;I. Pantenburg;F. Weigend;L. Wesemann
邻十二硼酸锡 [SnB11H11]2- 作为亲核试剂与各种银亲电子试剂（[Ag(PMe3)]+、[Ag(PEt3)]+、[Ag(PPh3)]+ 和 Ag+）反应形成银-锡键。根据配位膦的大小，发现了两个、三个或四个单位的 [{Ag(SnB11H11)(PR3)}n]n- (PPh3，n = 2；PEt3，n = 3；PMe3，n = 4) 的聚集。通过单晶X射线衍射确定了固态银-锡簇的结构。在这些膦银配位化合物中，锡配体与银原子表现出微2-和微3-配位。通过与硝酸银的反应，分离出八阴离子锡-近十二硼酸配位化合物[Et4N]8[Ag4(SnB11H11)6]。在这个蝴蝶状排列的簇中，锡硼酸盐在四个银原子处显示出各种配位模式。在已报道的银-锡配合物中，银-银原子间距离在2.6326(10)-3.1424(6) A范围内。银-锡原子间距离在2.6416(5)和3.1460(6) A之间。通过密度泛函理论计算的分子轨道分析表明，不含[SnB11H11]2-单元的核心化合物的LUMO始终为Ag 原子（主要是）s 轨道的完全对称组合。该核心充满了 [SnB11H11]2- 单元 HOMO 的电子，通过这种方式形成稳定的化合物。
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 the coordinating phosphine. The structures of the silver-tin clusters in the solid state were determined by single-crystal X-ray diffraction. In these phosphine silver coordination compounds, the tin ligand exhibits micro2- and micro3-coordination with the silver atoms. From the reaction with silver nitrate, an octaanionic stanna-closo-dodecaborate coordination compound, [Et4N]8[Ag4(SnB11H11)6], was isolated. In this cluster, arranged as butterfly, the stannaborate shows various coordination modes at four silver atoms. In the reported silver-tin complexes, the silver-silver interatomic distances are in a range of 2.6326(10)-3.1424(6) A. Silver-tin distances were found between 2.6416(5) and 3.1460(6) A. Analysis of the molecular orbitals calculated by means of density functional theory shows that the LUMO of the core compound without [SnB11H11]2- units is always a totally symmetric combination of (mainly) s-orbitals of Ag atoms. This core is filled with electrons of the HOMOs of the [SnB11H11]2- units and is leading, in this way, to a stable compound.