[UO₂ Cl₂ (phen)₂ ], a Simple Uranium(VI) Compound with a Significantly Bent Uranyl Unit (phen=1,10-phenanthroline)

A simple synthesis based on UO₂ Cl₂ ⋅n H₂ O and 1,10-phenanthroline (phen) resulted in the formation of a new uranyl(VI) complex [UO₂ Cl₂ (phen)₂ ] (1), revealing a unique dodecadeltahedron coordination geometry around the uranium center with significant bending of the robust linear arrangement of the uranyl (O-U-O) unit. Quantum chemical calculations on complex 1 indicated that the weak but distinct interactions between the uranyl oxygens and the adjacent hydrogens of phen molecules play an important role in forming the dodecadeltahedron geometry that fits to the crystal structure of 1, resulting in the bending the uranyl unit. The uranyl oxygens in 1 are anticipated to be activated as compared with those in other linear uranyl(VI) compounds.