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

Abstract

The 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 provides the second coordination compound at all reported for Bi73–.

Effect of La3+ on the Formation of Endohedral Zintl Clusters Featuring In/Bi Shells

“…36 The coordination of the extra-cyclic In atom, on the other hand, is reminiscent of recent coordination compounds of the Bi 7 3− anion, [(Bi 7 )M-(Bi 7 )] 4− (M = Zn, Cd), that were formed in similar reactions. 36,37 Cluster 3 therefore indicates the dominance of this structural motif also upon the combination of the ternary solid with a p-block organometallic.…”

“…The structural arrangement not only refers to the famous nortricyclane-type Zintl clusters Pn 7 3– of all group 15 elements (Pn = P–Bi) but also is reminiscent of the recently reported multinary Zintl cluster [(Bi 6 )­Zn 3 (TlBi 5 )] 4– with the same underlying {Bi 6 } subunit, which was formed in a reaction of [K­(crypt-222)] 2 (TlBi 3 )·en with [ZnPh 2 ] . The coordination of the extra-cyclic In atom, on the other hand, is reminiscent of recent coordination compounds of the Bi 7 3– anion, [(Bi 7 )­M­(Bi 7 )] 4– (M = Zn, Cd), that were formed in similar reactions. , Cluster 3 therefore indicates the dominance of this structural motif also upon the combination of the ternary solid with a p-block organometallic.…”