Theoretical insight into the open‐shell singlet diradical character of single molecular solvated dielectron e₂@C_nF_n (n = 20, 28, 36, 50, 60, and 80)

Abstract

Can there exist an open‐shell (OS) singlet diradical in the electronic ground state of the solvated dielectron? Here, we presented a comparison study by different cage‐shaped e2@CnFn (n = 20, 28, 36, 50, 60, and 80) at unrestricted broken spin‐symmetry density functional theory. It is found that both the stability and the singlet diradical character of the molecule increase with increasing excess electron encapsulation space (size of the cage). For the e2@CnFn (n = 50, 60, and 80), the electronic ground states have obvious special OS singlet diradical characters. Among these OS e2@CnFn (n = 50, 60, and 80), the e2@C50F50 with intermediate diradical character (0.658) is the most stable. The two semispheres in each highest occupied molecular orbital (α and β) of these diradicals suggest that the two excess electrons are simultaneously encapsulated inside the different regions of the cage, respectively, to form special broken s‐type 3excess electron pair.