Dehydration of UO₂Cl₂·3H₂O and Nd(NO₃)₃·6H₂O with a Soft Donor Ligand and Comparison of Their Interactions through X-ray Diffraction and Theoretical Investigation

Abstract

We investigated whether the relatively Lewis basic imidazole-2-thiones could be used to substitute water ligands bound to f-element cations and generate f-element soft donor complexes. Reactions of 1,3-diethylimidazole-2-thione (C 2 C 2 ImT) with Nd(NO 3 ) 3 •6H 2 O and UO 2 Cl 2 •3H 2 O led to the isolation of the anhydrous thione complexes Nd(NO 3 ) 3 (C 2 C 2 ImT) 3 and UO 2 Cl 2 (C 2 C 2 ImT) 2 , characterized by single crystal X-ray diffraction. Differences in the strength of metal−thione interactions have been examined by means of the crystal structure analysis and density functional theory (DFT) calculations. The C 2 C 2 ImT ligands were found to be affected by both coordination and noncovalent interactions, making it impossible to deconvolute the effects of one from the other. Calculated partial atomic charges indicated greater ligand-to-metal charge transfer in the [UO 2 ] 2+ complex, indicative of a stronger interaction. The reactivity of C 2 C 2 ImT demonstrates its usefulness in the preparation of f-element soft donor complexes from readily available hydrates that could be useful intermediates for promoting the coordination and studying the effects of soft donor anions.

Sandwiched Kagomé Lattices in a Coordination Polymer Based on Mixed-Valent Uranium

“…The oxidation of [C 2 mim]­[OAc] by elemental chalcogens is also known, including a metal-catalyzed oxidation by O 2 to form an imidazol-2-one . We have also observed the oxidation of a normally stable dialkylimidazole-2-thione to an imidazole-2-thione-3,4-dione in the presence of [UO 2 ] 2+ , lending support to the notion that these normally stable heterocycles can be photoxidized by [UO 2 ] 2+ under certain conditions. Such partial reduction of U­(+VI) to U­(+V) by means of glutathione in a neutral medium has recently been reported .…”

Covalency of Trivalent Actinide Ions with Different Donor Ligands: Do Density Functional and Multiconfigurational Wavefunction Calculations Corroborate the Observed “Breaks”?

“…Actinide–ligand bonding can be probed by a variety of spectroscopic tools, e.g., X-ray diffraction, − X-ray absorption, ,− Mössbauer spectroscopy, ,− or magnetic measurements. ,,− Quantum chemical calculations play a particularly important role in actinide chemistry research. From a theoretical viewpoint, an An complex is likely to exhibit a complicated multiconfigurational ground state (GS) because of the open 5f shell.…”

Uranium Going the Soft Way: Low-Valent Uranium(III) Coordinated to an Arene-Anchored Tris-Thiophenolate Ligand

“…While uranium complexes with hard-donor ligands such as alkoxides, aryloxides, and amides have experienced a development boom in the past few decades, , with numerous examples of small molecule activations − and few catalytic applications, − the coordination chemistry of uranium with the softer chalcogenide sulfur trailed behind with only a fraction of publications, relatively. , Examples of low-valent U­(III) thiolate complexes are still exceedingly rare, − and even more than half of the reported U­(IV)–U­(VI) compounds with thiophenolate ligands are the result of reactivity studies with relatively simple thiophenols, their salts, or their diphenyl disulfide precursors. ,− Sulfur-based ligand design efforts still focus mainly on aspects of lanthanide–actinide separation in nuclear fuel reprocessing, − by exploiting the different degrees of covalency for 4f and 5f metal–ligand bonds. − …”