E5 M7+ (E=C-Pb, M=Li-Cs): A Source of Viable Star-Shaped Clusters.

Herein we report the systematic exploration of the potential energy surfaces of a series of clusters with formula E5 M7+ (E=C-Pb and M=Li-Cs). Fifteen of these combinations adopt a D5h three-dimensional seven-pointed star-like structure in a singlet state, where M atoms interact electrostatically with the E5 ring. The determining factors in the relative preference of having the D5h structure over the most competitive isomer or vice-versa are analyzed. These star-shaped systems satisfy the 4n+2 Hückel's rule and exhibit a strong diatropic (σ and π) response to an external magnetic field.