title: A niobium-necked cluster [As3Nb(As3Sn3)](3-) with aromatic Sn3(2-) .
abstract: We describe here the synthesis and characterization of a ternary cluster compound [As3Nb(As3Sn3)](3-) (1), in which a niobium(v) atom is coordinated by an As3(3-) triangle and a bowl-type As3Sn3(5-) ligand. Cluster 1 was synthesized by dissolving K8NbSnAs5 (2) in the presence of [2.2.2]crypt in ethylenediamine solution, filtered and layered with toluene, then crystallized in the form of [K([2.2.2]crypt)]3[As3Nb(As3Sn3)]·en·tol. The flower-vase shaped compound 1 features a new structure type, rather different from the known Zintl phases. The stability and bonding of 1 are elucidated via extensive bonding analyses. The Sn3 ring is found to have σ-aromaticity featuring a delocalized Sn-Sn-Sn σ bond. Electronic structure calculations confirm the Nb(v) oxidation state and weak Nb-Sn and Sn-Sn bonding, in addition to the normal Nb-As and As-As bonds.
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China. szm@ciac.ac.cn.
authors.forename: Fu-Xing
authors.initials: FX
authors.lastname: Pan
authors.forename: Cong-Qiao
authors.initials: CQ
authors.lastname: Xu
authors.forename: Lei-Jiao
authors.initials: LJ
authors.lastname: Li
authors.forename: Xue
authors.initials: X
authors.lastname: Min
authors.forename: Jian-Qiang
authors.initials: JQ
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Hua-Jin
authors.initials: HJ
authors.lastname: Zhai
authors.forename: Zhong-Ming
authors.initials: ZM
authors.lastname: Sun