Electronic Structure Studies on the Whole Keplerate Family: Predicting New Members

A comprehensive study of the electronic structure of nanoscale molecular oxide capsules of the type [{MVI(MVI)5O21}12{M′V2O2(μ‐X)(μ‐Y)(Ln−)}30](12+n)− is presented, where M,M′=Mo,W, and the bridging ligands X,Y=O,S, carried out by means of density functional theory. Discussion of the electronic structure of these derivatives is focused on the thermodynamic stability of each of the structures, the one having the highest HOMO‐LUMO gap being M=W, M′=Mo, X=Y=S. For the most well‐known structure M=M′=Mo, X=Y=O, [Mo132O372]12−, the chemical bonding of several ligands to the {MoV2O2(μ‐O)2} linker moiety produces negligible effects on its stability, which is evidence of a strong ionic component in these bonds. The existence of a hitherto unknown species, namely W132 with both bridging alternatives, is discussed and put into context. Which one is next? The electronic structure of metal oxide molecular nanocapsules known as Keplerates was described at the DFT level. This study, which considered several combinations of the metal atoms (Mo/W), of the bridging atoms (O/S), and also of internal ligands, discusses stability trends and predicts the stability of not yet synthesized species: [W132O312(μ‐S)60]12− is the most promising candidate to be synthesized next.