Bi-Zn Bond Formation in Liquid Ammonia Solution: [Bi-Zn-Bi]4-, a Linear Polyanion that is Iso(valence)-electronic to CO2

Reactions of the zinc (I) complex [Zn-2(Mesnacnac)(2)] (Mesnacnac = [(2,4,6-Me3C6H2)NC(Me)J(2)CH) with solid K3Bi2 dissolved in liquid ammonia yield crystals of the compound K-4[ZnBi2]center dot(NH3)(12) (1), which contains the molecular, linear heteroatomic [Bi-Zn-Bi](4-) polyanion (1a). This anion represents the first example of a three-atomic molecular ion of metal atoms being iso(valence)-electronic to CO2 and being synthesized in solution. The analogy of the discrete [Bi-Zn-Bi](4-) anion and the polymeric (1)(infinity)[(ZnBi4/2)(4-)] unit to monomeric CO2 and polymeric SiS2 is rationalized.