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

Investigating the interactions of f-block metal ions with p-block polyanions in multinary cluster compounds is becoming increasingly attractive but remains a challenge in terms of both the synthetic approach and the control of the structures that are formed during the syntheses. So far, two types of reactions were dominant for the formation of corresponding clusters: the reaction of binary anions of p-block elements in 1,2-diamino-ethane (en) solutions or the reaction of organobismuth compounds with corresponding f-block metal complexes in THF. Herein, we report the synthesis of [La@In₂Bi₁₁]^4- (1) and its doubly μ-Bi-bridged analogue in the doubly [K(crypt-222)]⁺-coordinated {[K(crypt-222)]₂[La@In₂Bi₁₁](μ-Bi)₂[La@In₂Bi₁₁]}^4- (2) as their [K(crypt-222)]⁺ salts [K(crypt-222)]₄1 and [K(crypt-222)]₄2, respectively, achieved by reactions of [InMes₃] and [La(C₅Me₄H)₃] (Mes = mesityl, C₅Me₄H = tetramethylcyclopentadienyl) with K₁₀Ga₃Bi_6.65/crypt-222 (crypt-222 = 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) in en. In the absence of [La(C₅Me₄H)₃], the otherwise unchanged reactions afford the anions [Bi₆(InMes)(InMes₂)]^3- (3) and [Mes₃In-InMes₃]^2- (4) instead, which can be isolated as their [K(crypt-222)]⁺ salts [K(crypt-222)]₃3 and [K(crypt-222)]₂4·tol (tol = toluene), respectively. The {Bi₆} fragment observed in anion 3 is assumed to be one of the key intermediates not only toward the formation of 1 and 2 but also on the way to more general bismuth rich compounds.