Synthesis, Characterization, and Density Functional Theory Investigation of the Solid-State [UO₂Cl₄(H₂O)]^2- Complex.

ABSTRACT: A significant number of solid-state [UO₂Cl₄]^2- coordination compounds have been synthesized and structurally characterized. Yet, despite their purposive relative abundance in aqueous solutions, characterization of aquachlorouranium(VI) complexes remain rare. In the current study, a solid-state uranyl aqua chloro complex ((C₄H₁₂N₂)₂[UO₂Cl₄(H₂O)]Cl₂) was synthesized using piperazinium as a charge-balancing ligand, and the structure was determined using single-crystal X-ray diffraction. Using periodic density functional theory, the electronic structure of the [UO₂Cl₄(H₂O)]^2- complex was compared to [UO₂Cl₄]^2- to uncover the strengthening of the U═O bond in [UO₂Cl₄(H₂O)]^2-. Changes in the strength of the U═O bond were validated further with Raman and IR spectroscopy, where uranyl symmetrical (ν₁) and asymmetrical (ν₃) stretches were blue-shifted compared to the reference [UO₂Cl₄]^2- complex. Furthermore, the formation energy of the solid-state (C₄H₁₂N₂)₂[UO₂Cl₄(H₂O)]Cl₂ complex was calculated to be -287.60 ± 1.75 kJ mol^-1 using isothermal acid calorimetry. The demonstrated higher stability relative to the related [UO₂Cl₄]^2- complex was related to the relative stoichiometry of the counterions.

SUBMITTER: Rajapaksha H 

PROVIDER: S-EPMC10481372 | biostudies-literature | 2023 Sep

REPOSITORIES: biostudies-literature