Inorganic Chemistry最新文献

Varying the electronic structure of topological materials through aliovalent substitution is a primary approach to tuning their physical properties. Unlike substitution, metal site deficiency intrinsic to some structure types, including HfCuSi₂-type, has rarely been employed for controlling the properties of topological phases. In this report, we describe the synthesis and characterization of two new series of compounds, UCo_xBi₂ and UNi_xBi₂, which demonstrate the variation of transition metal content through synthetic conditions. Magnetic measurements reveal the dependence between the extent of transition metal incorporation and the magnetism of the resulting phase. DFT calculations demonstrated the ability to model their formation and predict the stability ranges of transition metal-site deficient compounds.

We report the first inverse-sandwich complexes containing rare earth (RE^III) metal ions that captured a toluene dianion between them. Toluene-bridged complexes [{(Me₃Si)₂NC(NⁱPr)₂}₂RE]₂(μ-η⁶:η⁶-C₆H₅Me) (RE = Y (1), Dy (2), and Er (3)) were synthesized via chemical reductions of chloride-bridged RE complexes in which each tripositive metal is stabilized by two guanidinate ligands. Compounds 1-3 were unambiguously characterized by crystallography, NMR, UV-vis, and IR spectroscopy, magnetometry, and computations. The bond metrics from single-crystal X-ray diffraction analysis revealed a planar, cyclohexadienediide-like structure for the ligated arene, indicative of a dianionic toluene. The ¹H NMR spectrum of 1 exhibits upfield-shifted resonances representing increased shielding from excess electrons, further validating its dianionic nature. DFT calculations afforded similar bond metrics, and natural bond orbital (NBO) analysis uncovered ionic bonding interactions between the bridging toluene and the yttrium centers, supporting the assignment of a -2 charge to the toluene. UV-vis spectroscopy highlighted that the electronic excitations primarily stem from toluene- and guanidinate-based orbitals. The Dy and Er congeners were further probed by SQUID magnetometry, with 3 revealing weak magnetic exchange coupling between the Er^III centers. These findings highlight the ability of reduced arenes to serve as bridging ligands in multimetallic rare earth architectures.

The ionic transport properties of Li₃PO₄ under high pressure up to 20.0 GPa were systematically studied with alternating-current impedance spectra measurements and first-principles calculations. Li₃PO₄ underwent a change in the transport mechanism from mixed ionic-electronic conduction to predominantly ionic conduction at approximately 7.1 GPa without a structural phase transition. It then reverted to mixed ionic-electronic conduction at approximately 11.8 GPa due to a pressure-induced structural phase transition from the Pmn2₁ phase to the Pnma phase. The conductivity of Li₃PO₄ increased by 2 orders of magnitude after structural phase transition, primarily due to the enhanced Li⁺ ion migration rate. Vacancy migration barriers increased with pressure in all crystallographic directions, but interstitial barriers decreased in Li₃PO₄. Li⁺ ions exhibited a stronger interstitial migration capability under high pressure. The reduced charge density within the interstitial position provided supporting evidence for an absence of the electronic conduction mechanism over the pressure range of 7.1 to 11.8 GPa in Li₃PO₄. These findings could be utilized to propose innovative strategies for enhancing the ionic conductivity of solid electrolytes.