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

Abstract

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@In 2 Bi 11 ] 4− (1) and its doubly μ-Bi-bridged analogue in the doubly4 1 and [K(crypt-222)] 4 2, respectively, achieved by reactions of [InMes 3 ] and [La(C 5 Me 4 H) 3 ] (Mes = mesityl, C 5 Me 4 H = tetramethylcyclopentadienyl) with K 10 Ga 3 Bi 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(C 5 Me 4 H) 3 ], the otherwise unchanged reactions afford the anions [Bi 6 (InMes)(InMes 2 )] 3− (3) and [Mes 3 In−InMes 3 ] 2− (4) instead, which can be isolated as their [K(crypt-222)] + salts [K(crypt-222)] 3 3 and [K(crypt-222)] 2 4•tol (tol = toluene), respectively. The {Bi 6 } 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.

Ligand–Metal Complementarity in Rare-Earth and Actinide Chemistry

“…For some of these, a dependence on both the reaction temperature and reaction stoichiometry is found, which shows that both kinetic and thermodynamic products can be accessed under appropriate conditions . Continuing the theme of using rare-earth cations to assemble p-block atoms, Dehnen and co-workers shift our focus from carbon, to the heavy Group 13 and 15 members indium and bismuth . While numerous examples of d-block ions encapsulated by Zintl phases are known, analogous rare-earth and actinide examples are rare.…”

“…When the same reaction was explored without [La­(C 5 Me 4 H) 3 ], the researchers isolated a smaller cage in [Bi 6 (InMes)­(InMes 2 )] 3– , and also [{InMes 3 } 2 ] 2– from the same reaction, both as their [K­(2.2.2-cryptand)] salts. This work demonstrates that the La III cation provides a significant stabilizing role in assembling larger cages …”