We used density functional theory calculations at the B3LYP/6-311G** level for a theoretical study on the complex formed when uranium(IV) coordinates with N, N'-bis(3-allyl salicylidene)-o-phenylenediamine (BASPDA), i.e., U(BASPDA)_2. The results indicated that the coordination complex of U(BASPDA)_2 could form two different structures with a ratio of 1:2. One was a parallel dislocation structure (PDS-U), in which the two BASPDAs' middle benzene rings adopted a parallel dislocation with an angle of 56.64°, and the other was a staggered finger ...