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, [(H3O)(18-crown-6)][Pu(H2O)(4)(18-crown-6)](ClO4)(4)center dot 2(H2O) (denoted as Pu-III-18C6). Single-crystal X-ray diffraction reveals that Pu-III-18C6 crystallizes in the orthorhombic space group of Pccn, which is assembled by independent ionic pairs including [Pu(H2O)(4)(18-crown-6)](3+), [(H3O)(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-III ions with 18-crown-6. This work may deepen the understanding of the host-guest interactions between trivalent transuranic and macrocyclic ligands.

Automated summary

The study presented the synthesis, crystal structure, spectroscopic analyses, and theoretical calculations of the first trivalent plutonium crown ether inclusion complex Pu-III-18C6. It was found that the plutonium atom is completely encapsulated within the cavity of the 18-crown-6, forming a distorted geometric structure, with weak Pu-O dative bond confirmed by theoretical evaluation. This work may enhance the understanding of host-guest interactions between trivalent transuranic elements and macrocyclic ligands.