5 Search Results

A series of compounds of the form [HAr]2[UO2X4] is reported here, wherein Ar is systematically varied between pyridine (1-X), quinoline (2-X), acridine (3-X), 2,5-dimethylpyrazine (4-X), quinoxaline (5-X), and phenazine (6-X), and X = Cl or Br. With greater conjugation in the organic cation, a larger quenching in uranyl luminescence is observed in the solid state. Supporting our luminescence experiments with computation, we map out the potential energy diagrams for the singlet and triplet states of both the [HAr]+ cations and [UO2Cl4]2– anion in the crystalline state, and of the assembly. The distinct energy transfer pathways in each compound are discussed.

Here, we report a set of three new mixed-valent Au^I Au^III iodides: (ClPy)₃[AuI₂]₂[AuI₄] [1], (BrPy)₃[AuI₂]₂[AuI₄] [2], and (ClPy)₂[AuI₂][AuI₄] [3], as well as three new monovalent Au^III iodides: (XPy)₂[AuI₄][I₃] (Py = 4-X-pyridinium X = Cl, Br, and I) [4–6]. Two of these mixed-valent compounds (1 and 2) incorporate both monovalent Au^I···Au^I (aurophilic bonding) and mixed-valent Au^II···Au^IIII couples (Au–I halogen bonding), to the best of our knowledge an unprecedented structural feature. These same two mixed-valent compounds also exhibit a rare low-dimensional molecular architecture with respect to second sphere Au···I interactions, namely, 1D chains of Au···I interactions, extending along a single crystallographic axis.more » All compounds were synthesized with the assistance of the I^–/I₃^– redox couple and tacit manipulation of the polyiodide content during synthesis. Air-free synthesis was used to influence the redox process of I^–/I₃^–, resulting in better selection for mixed-valent products. Compounds 1–2 and 4–5 exhibit a characteristically narrow bandgap (1.04–1.25 eV), as measured via diffuse reflectance spectroscopy (DRS). Computational analyses were used to rationalize the specific assembly modes of [AuI₂]^– and [AuI₄]^– species, and they show that the Au^I···I interaction type is favored over the Au^III···I.« less

Here, we report here the oxidation of dimethyl sulfoxide in the presence of uranyl salts at temperatures typically considered ‘safe’ for its handling. Uranyl salts, even in the absence of light, appear to accelerate the well-known oxidative decomposition of DMSO in air. Sulfate, a product of the decomposition, was captured in the crystalline state as the uranyl sulfate phase, UO₂(DMSO)₂(SO₄).

A family of zero dimensional tellurium( iv ) iodide perovskite derivatives, which demonstrate the presence of polyiodides (I ₂ or I ₃ ⁻ ) strongly affects the bandgap of these materials.

Uranium tris(imido) species have been synthesized using different imido groups in the axial and equatorial positions by treating [( ^Mes PDI ^Me )U(THF)] ₂ ( 1-THF ) – a uranium( iv ) dimer supported by ^Mes PDI ^Me tetraanions – with mixed organoazide solutions.