Doping the cage. Re@AuPt and Ta@AuHg, as novel 18-ve trimetallic superatoms displaying a doped icosahedral golden cage.

Expanding the versatility of well defined clusters is a major concern in the design of building blocks towards functional nanostructures. W@Au is a prototypical binary bare superatomic cluster involving an icosahedral symmetry, which has been discussed in the literature, precluding the proposal of several endohedral d-block and f-block element structures within a golden cage. Here we pursue the construction of related trimetallic clusters, which has been explored to a lesser extent. Our results expose the great advantages of involving heterocages in the superatom approach, unraveling Re@AuPt and Ta@AuHg as novel trimetallic candidates. Re@AuPt exhibits an electron-deficient element in the cage, and an endohedral atom with an extra electron. In contrast, Ta@AuHg is conceived as having an icosahedral cage with an extra electron, and an electron-deficient endohedral element. These new clusters follow the eighteen valence electron principle, with similar characteristics to their W@Au parent. This leads to stable clusters with an electronic structure formally described by the 1s1p1d closing shell order, showing an interesting approach to design ternary superatoms, where the variation of valence electrons occurs in both cage and endohedral sites. Moreover, the cage doping appears as a useful approach to further evaluate the formation of magnetic superatoms, and also the construction of larger clusters by fusing different icosahedral structures.