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.

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 (C2C2ImT) with Nd(NO3)3·6H2O and UO2Cl2·3H2O led to the isolation of the anhydrous thione complexes Nd(NO3)3(C2C2ImT)3 and UO2Cl2(C2C2ImT)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 C2C2ImT 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 [UO2]2+ complex, indicative of a stronger interaction. The reactivity of C2C2ImT 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.

Nonstoichiometric, Protic Azolium Azolate Ionic Liquids Provide Unique Environments for N-Donor Coordination Chemistry.

Here we demonstrate that neat reactions of amphoteric azoles with more basic azoles give a family of finely tunable, nonstoichiometric liquids which are useful for N-donor coordination chemistry. Reacting 4,5-dicyanoimidazole (4,5-DCNIm) with 1-methylimidazole (1-mim) gives new compounds with composition-dependent speciation. Two crystalline compounds, a 1:1 protic salt, [H(1-mim)][4,5-DCNIm], and a 1:2 salt co-crystal, [H(1-mim)][4,5-DCNIm]⋅4,5-DCNIm, were isolated and structurally characterized, while differential scanning calorimetry revealed both suppression of crystallization and the presence of neutral and anionic species in the melt. Reactions of Cu(NO3 )2 ⋅2.5 H2 O, CuO, and ZnO with the neat 2:1 1-mim/4,5-DCNIm melt resulted in the isolation of entirely N-donor ligated complexes of the formula M(4,5-DCNIm)2 (1-mim)4 (M=Cu, Zn).