Synthesis and Characterizations of a Plutonium(III) Crown Ether Inclusion Complex.

We report the synthesis, single-crystal structure, solid-state ultraviolet-visible-near-infrared spectroscopy, and theoretical calculations on the first trivalent plutonium crown ether inclusion complex, [(HO)(18-crown-6)]Pu(HO)(18-crown-6)·2(HO) (denoted as Pu-18C6). Single-crystal X-ray diffraction reveals that Pu-18C6 crystallizes in the orthorhombic space group of , which is assembled by independent ionic pairs including [Pu(HO)(18-crown-6)], [(HO)(18-crown-6)], and perchlorate anions. The plutonium atom is fully encapsulated within the cavity of the 18-crown-6, generating a distorted bicapped square antiprism geometry. The theoretical evaluation confirms that weak Pu-O dative bond is involved between Pu ions with 18-crown-6. This work may deepen the understanding of the host-guest interactions between trivalent transuranic and macrocyclic ligands.