Transformation of Distinct Superatoms to Superalkalis by Successive Ligation of Thymine Nucleobases.

The ligation strategy has been widely used in the chemical synthesis of atomically precise clusters. A series of thymine (T)-ligated Al₁₂M-T_n (M = Be, Al, C; n = 1-5) complexes have been studied to reveal the effect of DNA nucleobase ligands on the electronic structures of different superatoms in the present work. In addition to its protective role, the successive attachment of thymine ligands significantly lowers the adiabatic ionization energies (AIEs) of the studied Al₁₂M superatoms with filled and unfilled electronic shells. The continuous decrease in the AIEs of Al₁₂M-T_n is derived from the gradually raised highest occupied molecular orbital (HOMO) levels upon the addition of ligands. Interestingly, the lowering degree of AIEs for such nucleobase-protected superatoms is independent of the distinct shell fillings of Al₁₂M superatoms but is significantly related to the types of nucleobases. Moreover, the obtained Al₁₂M-T₅ superalkalis not only exhibit excellent performance in activating the stable CO₂ and O₂ molecules but also have considerable nonlinear optical (NLO) responses. We, therefore, hope that this study could provide a viable strategy for synthesizing novel nucleobase-ligated superatom clusters with excellent reducing capability to enrich the family of multifunctional nanoclusters.