The Electronic States of U(4+) in U(PO4)Cl: An Example for Angular Overlap Modeling of 5f(n) Systems

AOMadillo: A program for fitting angular overlap model parameters

The angular overlap model (AOM) is an established parameterization scheme within ligand field theory (LFT). In principle, its application is fairly straightforward, but can be tedious and involve a trial-and-error approach to identify and judge the best set of parameters. With the availability of quantum chemical methods to predict d-d transitions in transition metal complexes, a rich source of computational spectroscopic data with unambiguous assignments to electronic states is available. Herein, we present AOMadillo, a software package that is designed to interface the output of ab initio LFT calculations from the ORCA suite of programs and performs a least-squares fit for a chosen AOM parameterization. Many steps of the AOM parameterization are automated, so that scans of geometric parameters and evaluations of sets of similar complexes are convenient. The fitting routine is highly configurable, allowing the efficient evaluation of different parameter sets.

Thorium(IV) and Uranium(IV) Complexes with Cucurbit[5]uril

Tetravalent thorium and uranium complexes with cucurbit[5]uril (Q[5]) were investigated with eight new complexes being synthesized and structurally characterized. [Th(Q[5])(OH)(H₂O)₂]₆·18NO₃· nH₂O (1) has a hexagonal nanowheel structure with each of the six Th⁴⁺ ions being cap-coordinated by a Q[5] and monodentate-coordinated to the nearby Q[5]. [Th(Q[5])(HCOO)(H₂O)₄][Th(NO₃)₅(H₂O)₂]₂[Th(NO₃)₃(HCOO)(H₂O)₂]_0.5·NO₃· nH₂O (2) has a heteroleptic mononuclear structure with a Th⁴⁺ ion cap-coordinated on one side of the Q[5] portal and monodentate-coordinated to a formate anion inside the Q[5] cavity. [KTh_1.5(Q[5])Cl(NO₃)₃][Th(NO₃)₅(H₂O)₂]·2NO₃·2.5H₂O (3) has a heterometallic structure with both Th⁴⁺ and K⁺ ions each occupying one side of the two Q[5] portals forming a capsule. [CsTh(Q[5])Cl(NO₃)₂(H₂O)₃]·2NO₃· nH₂O (4) has a heterometallic 1D polymeric structure with both Th⁴⁺ and Cs⁺ ions each occupying one side of the two Q[5] portals, forming monomers which are linked together by sharing two water molecules and one carbonyl oxygen atom between Th⁴⁺ and Cs⁺ ions. [Th(Q[5])Cl(H₂O)][CdCl₃][CdCl₄]·0.5HCl·4H₂O (5), [Th(Q[5])Cl(H₂O)][Ru₂OCl₉(H₂O)]·0.5HCl·9.5H₂O (6), [Th(Q[5])Cl(H₂O)][IrCl₆]_1.5·3H₂O (7), and [U(Q[5])Cl(H₂O)][ZnCl₃(H₂O)][(ZnCl₄)]·8H₂O (8) have similar 1D polymeric structures with Th⁴⁺/U⁴⁺ ions cap-coordinated on one side of a Q[5] and bidentate coordinated to the nearby Q[5]. The transition metal chlorides act as anions for charge compensation as well as structure inducers via cation-anion interactions forming various anion patterns around the 1D polymers. Actinide contraction has been observed in the early actinide series.

[UCl4(HCN)4] – a hydrogen cyanide complex of uranium tetrachloride

The reaction of uranium tetrachloride with anhydrous liquid hydrogen cyanide yields a turquoise microcrystalline powder of tetrachloridotetraformonitrileuranium(iv), [UCl₄(HCN)₄].