A relativistic DFT probe of polypyrrolic macrocyclic diuranium(III) complexes with terminal solvents and iodines

Relativistic density functional theory finds that two isomers of a diuranium(III) complex of a polypyrrolic macrocycle (H 4 L) feature active sites on uranium moieties, allowing for their potential application in activating industrially and economically important small molecules. To address this, a series of adducts [(X) n U 2 (L)] (2–m)+ (X = THF, I − and HI; n = 1 and 2; m = 0, 1 and 2) have been examined. The coordination from X to the exposed uranium(s) changes the general geometry and electronic structure slightly. Thermodynamic calculations reveal that iodine termination is energetically favored over THF/HI coordination. Graphical abstract Scalar and spin-orbit coupling relativistic DFT calculation reveals that the active sites on the uranium moieties of [U 2 (L)] 2+ lead to formation of adducts [(THF) n U 2 (L)] 2+ , [I n U 2 (L)] (2–n)+ and [(HI) n U 2 (L)] 2+ (n = 1 and 2). Coordination to the exposed uranium(s) changes geometrical and electronic properties slightly, but iodine termination is the most energetically favored.