223 Search Results

Synthetic variables can have an outsized influence on the crystal structure and magnetic properties of a material, particularly those of quantum materials. In this work, we investigate the impact of synthesis under a magnetic field (magnetosynthesis) on the crystal structure and magnetic properties of several Cu²⁺ (S = 1/2)-based materials with antiferromagnetic interactions and varying levels of magnetic frustration, from simple antiferromagnets to a quantum spin liquid. Here, we develop methods to apply small (0.09–0.37 T) magnetic fields during low-temperature hydrothermal, evaporative, and rehydration syntheses of the simple antiferromagnet CuCl₂·2H₂O, the canted antiferromagnet (Cu,Zn)₃Cl₄(OH)₂·2H₂O, the frustrated and canted antiferromagnet atacamitemore » Cu₂(OH)₃Cl, and the highly frustrated quantum spin liquid herbertsmithite Cu₃Zn(OH)₆Cl₂. We report the first single-crystal X-ray structural determination of the Cu₃Cl₄(OH)₂·2H₂O structure type and probe the stability of this phase both experimentally and computationally. Atacamite Cu₂(OH)₃Cl synthesized under a 0.19 T field experiences a 0.15 K (∼3%) decrease in its Néel transition temperature. This result suggests that magnetosynthesis with small applied fields may have a very subtle influence upon the magnetic properties of moderately magnetically frustrated 3d materials.« less

Argyrodites are a compositionally diverse family of materials that exhibit remarkable ion transport properties. While the average crystal structures of argyrodites have been extensively studied, ion transport in these materials is governed by a confluence of dynamic processes spanning the cation, anion, and polyanionic sublattices. This Perspective synthesizes recent advances in understanding the role of dynamics in structural behavior and ion transport properties. We examine the compositional and structural motifs that govern order−disorder transitions within the argyrodite family and further explore how ion hopping is facilitated by lattice dynamics, from long-range phonons to local rotational dynamics of polyanionic species. Throughmore » the lens of dynamics spanning multiple time and length scales, we establish guiding principles that govern transport phenomena and highlight avenues of future study for the argyrodite family of ion conductors.« less

The 23S rRNA methylating enzyme Cfr, found in pathogens including Staphylococcus aureus, Clostridium difficile, Escherichia coli, and Klebsiella pneumoniae, confers resistance to phenicols, lincosamides, oxazolidinones (including linezolid), pleuromutilins, and streptogramins A (the PhLOPS_A phenotype). Cfr catalyzes methylation of the C8 position of the A2503 base in 23S rRNA, the recognition site of the above antibiotic classes. Along with the RlmN housekeeping enzyme, Cfr can also promote methylation of the C2 position of the same base. The molecular and structural basis of Cfr’s dual substrate specificity is not known, which hinders our ability to design Cfr-targeting inhibitors necessary to curb PhLOPS_Amore » resistance. Here, we present the first crystal structure of Cfr and a detailed analysis of its possible interactions with rRNA. Using structure-guided mutagenesis, mass spectrometry analysis of in cellulo 23S rRNA methylated species, and in cellulo resistance studies, we identify the key amino acids essential for Cfr methylation and multidrug resistance activity. In particular, we found that Cfr’s Q329 residue is important for C8- specific methylation. These data provide a framework for further studies of the biochemistry, structure, and inhibition of this important resistance determinant.« less

The development of reversible metal anodes is a key challenge for advancing aqueous battery technologies, particularly for scalable and safe stationary energy storage applications. Here, in this study, we demonstrate a strategy to realize epitaxial electrodeposition of iron (Fe) on single-crystal copper (Cu) substrates in aqueous electrolytes. We compare the electrodeposition behavior of Fe on polycrystalline and single-crystalline Cu substrates, revealing that the latter enables highly uniform, dense, and crystallographically aligned Fe growth. Comprehensive electron backscatter diffraction (EBSD) and X-ray diffraction (XRD) analysis confirms the formation of Fe with specific out-of-plane and in-plane orientations, including well-defined rotational variants. Our findingsmore » highlight that epitaxial electrodeposition of Fe can suppress dendritic growth and significantly enhance Coulombic efficiency during plating/stripping cycles. This approach bridges fundamental crystallography with practical electrochemical performance, providing a pathway toward high-efficiency aqueous batteries utilizing Earth-abundant materials.« less

Nominally weakly coordinating anions are useful for modulating the solubility and chemical properties of metal complexes, but identification and analysis of the systematics of the interactions of anions with cationic metal complexes has not received the attention it deserves. Here, a chemical informatics approach is demonstrated for identifying and quantitatively analyzing the ways that the bis(trifluoromethylsulfonyl)imide anion (TFSI) can interact with metal-containing species. An open access computer program (PyCIFTer) was developed to facilitate large-scale structural analysis of TFSI-containing species by utilization of experimental atomic coordinate data from single-crystal X-ray diffraction (XRD) studies obtained from the Cambridge Structural Database (CSD). PyCIFTermore » establishes a three-dimensional vector space from the raw atomic coordinates, generating acyclic, undirected graphs that are used to rapidly analyze the structural properties (bond lengths and angles) of TFSI in individual structures in sequential/batch fashion. The structures are sorted by PyCIFTer into groups based on pre-set and chemically sensible criteria, affording a comprehensive and systematic view of TFSI structural chemistry. This approach avoids tedious one-at-a-time interrogation of structures, a prospect unreasonable in this case, and many others of contemporary chemical relevance; there were over 1500 structures in the CSD containing TFSI as of November 2024. The results demonstrate that TFSI only rarely binds to cations in the solid state, favoring the formation of species in which TFSI is found in cations’ outer coordination spheres. The prospect of applying PyCIFTer to other moieties is also discussed. PyCIFTer is also schematically compared to the commercial CSD Python application programming interface (API). Taken together, this work demonstrates the usefulness of modular workflows for sequential/batch analysis of structural data from XRD, an approach that appears poised to accelerate the translation of legacy structural results into new chemical insights and hypotheses.« less

Dithiophosphinic acids undergo radiolytic degradation during the extraction of actinides in used nuclear fuel. These will degrade into monothiophosphinic acids and then to phosphinic acids. To elucidate how the complexes that are formed during these radioactive separations change as the ligand degrades, the mixed donor ligand O,O′- diethylmonothiophosphate is chosen as an analog for the monothiophosphinic intermediate. Herein, the monothiophosphate complexes Ln₂(OPS(OEt)₂)₆(H₂O)₈ (Ln = La) (La₂L₆H₂O), Ln₂(OPS(OEt)₂)₆(EtOH)₄ (Ln = La) (La₂L₆EtOH), K₂[Ln(OPS(OEt)₂)₅(H₂O)₂]·H₂O·CH₂Cl₂, (Ln = Ce) (CeL₅-α), K₂[Ln(OPS(OEt)₂)₅(H₂O)₂]·H₂O·CH₂Cl₂, (Ln = Pr) (PrL₅-β), K[Ln(OPS(OEt)₂)₄(H₂O)₃], (Ln = Pr, Sm-Er) (ML₄), and K₃[Ln(OPS(OEt)₂)₆], (Ln = Dy) (DyL₆) were synthesized and characterized using single-crystal X-raymore » diffraction and optical spectroscopy. Although the lanthanides contract in a nearly linear fashion, the structural changes observed as the f-block is traversed in these compounds are not necessarily a hard line but more so a blend of different structure types possible for each f-element. Furthermore, comparison of the Ln−O bond lengths shows a nearly linear contraction, but the Ln−S bond lengths do not monotonically decrease because of the hard Lewis acidity of the Ln³⁺ cations.« less

Eu(II)-containing chalcogenides are an emerging class of materials that are of great interest due to their high optical activity and intriguing magnetism. Here, we synthesized Eu₂SiSe₄ as red-colored single crystals and characterized its structure with single-crystal X-ray diffraction, confirming the reported chiral monoclinic P2₁ symmetry at room temperature. The crystal structure of Eu₂SiSe₄ comprises distorted SiSe₄ tetrahedral units and charge-balancing Eu(II) cations. Here, we develop a two-step solid-state synthesis method for Eu₂SiSe₄ and compare it to the known boron chalcogenide method. We find the second-harmonic generation (SHG) activity of polycrystalline Eu₂SiSe₄ to be ∼7 × AgGaS₂, placing it among themore » highest-known SHG-active chalcogenides. No symmetry lowering is observed down to 100 K in single-crystal X-ray diffraction, although an anomalous expansion in the b-axis lattice parameter occurs and may be correlated to lattice modes of the SiSe₄ tetrahedra. We investigate the physical properties of Eu₂SiSe₄ using magnetometry and heat capacity measurements and find a transition to an antiferromagnetic ground state at T_N ≈ 5.5 K. The low-temperature transition releases less entropy than expected, which may be due to the complex crystal electric field effects of Eu(II).« less

Here, we report the synthesis of five new examples of ladder cyclohexasilanes, possessing up to three consecutive fused rings and differing in relative ring fusion configuration and side chain structure. By coupling a 1,4-dipotassiooligosilyl dianion to a cyclohexasilane, we obtained bi- and tricyclic ladder cyclohexasilanes. Combined experimental and theoretical studies suggested that annulation could favor the cis configuration under kinetic control, while the trans configuration predominates under thermodynamic control. Computational studies show that with each additional ring in the trans-diastereomeric series, the predicted onset of light absorption shifts to longer wavelengths.

This work evaluates the compositional standard currently developed for Ti-5553 powder and explores the metastable β region for sensitivity to martensitic formation during rapid quenching from the melt. Ti-5553 is a beta-stabilized titanium alloy that is increasingly being used in additive manufacturing applications. A series of alloys within the Ti-5553 compositional space was processed using two-piston spat quenching to perform rapid solidification and quenching for each of these alloy compositions. Typical empirical models such as molybdenum equivalency are not able to fully separate the retained BCC and martensitic compositions. Further, the use of thermodynamic data to estimate the transformation energymore » needed to form martensite can differentiate the alloys and provide a metric to further develop compositional limits for metastable beta titanium alloy development.« less

Understanding the interplay between crystal engineering and the coupled electronic-ionic charge transport properties of metal halide perovskites remains a critical issue in the field. In this work, we developed an experimental approach to tune the crystallite orientation of methylammonium lead iodide (CH₃NH₃PbI₃) while maintaining their overall crystal structure. This approach allows us to selectively manipulate crystallite orientations to control out-ofplane ion migration and mitigate voltage bias stress effects in CH₃NH₃PbI₃ thin films. By employing advanced diffraction and spectroscopic techniques, we achieved a comprehensive characterization of the anisotropic crystallite properties in CH₃NH₃PbI₃ thin films with distinct preferred orientations. Our findings revealmore » that specific crystallite orientations, particularly those that limit halide ion migration pathways along the (200) crystallographic plane, significantly suppress out-of-plane ion migration. This suppression reduces hysteresis and alleviates voltage bias stress effects in CH₃NH₃PbI₃ solar cells, ultimately enhancing device stability and performance. These insights not only deepen our understanding of the relationship between crystallite orientation and device functionality but also highlight a promising strategy for regulating ion migration in MHP-based devices. This approach holds significant potential for advancing the stability and efficiency of perovskite solar cells and extending its applicability to other optoelectronic devices.« less