[As3M(As3Pb3)]3− (M = Nb, Ta): Ternary Heterometallic Clusters with Early Transition Metal Atoms and Aromatic [Pb3]2−

Abstract

Two ternary clusters, [As3Nb(As3Pb3)]3− 1 and [As3Ta(As3Pb3)]3− 2, were directly extracted from “K8NbPbAs5” and “K8TaPbAs5” intermetallic solid in the presence of ethylenediamine and 2.2.2-crypt, respectively. Both 1 and 2, comprising an electron-poor early transition metal-atom Nb or Ta coordinated to a As3 triangle and a bowl-like As3Pb3, were characterized by single crystal X-ray diffraction, energy dispersive X-ray (EDX) and electrospray ionization mass-spectrometry (ESI-MS). They also represent the first examples of the Pb-As hybrid in solution-based Zintl anion chemistry and DFT calculations revealed a σ-aromaticity of the [Pb3]2− unit.