Synthesis and Characterization of Homoleptic Zintl Anions [(Pn7)M(Pn7)]4− (M/Pn=Pb/As, Zn/Bi)

Abstract

AbstractThe formation and follow‐up chemistry of P73− has been intensely studied in the recent decades. In contrast, corresponding investigations of its heavier polycyclic polypnictide congeners Pn73− (Pn=As, Sb, Bi), especially Bi73−, have been done to a much lesser extent. In our report, we add to these rare studies, by reporting new coordination compounds with As73− and Bi73−, respectively. Addition of PbI2 to a solution of K3As7 in ethane‐1,2‐diamine (en) afforded the heterometallic cluster anion [(As7)Pb(As7)]4− (with an 8 % co‐crystallization of [PbAs15]3− on the same site), in compound [K3.92(crypt‐222)4][(As7)Pb(As7)]0.92[PbAs15]0.08 ⋅ 3en (1). A similar reaction of [ZnPh2] with a pyridine (py) solution of the ternary solid ‘K5Ga2Bi4’, which was previously shown to release Ga and polybismuthide units in situ under certain reaction conditions, resulted in the formation of [K(crypt‐222)]4[(Bi7)Zn(Bi7)] ⋅ 2.5py (2), comprising the related heterometallic anion [(Bi7)Zn(Bi7)]4−. The former represents the first Pb−As binary Zintl anions obtained via solution chemistry, and the latter adds one more piece to the remarkably rare coordination compounds reported for Bi73−.