Growing single crystals of molybdenum disulfide at scale
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Unusual Li2O sublimation promotes single-crystal growth and sintering
Li2O is rarely used for cathode material synthesis due to its high melting point (1,438 °C). Here we discover that Li2O can sublimate at 800–1,000 °C under ambient pressure, opening new possibilities for cathode synthesis. We propose a mechanism that enables synthesis of single crystals—such as LiNi0.8Mn0.1Co0.1O2 (NMC811) or LiNi0.9Mn0.05Co0.05O2 (NMC90)—without direct contact with Li2O salts. We show that Li2O vapour successfully converts spent polycrystalline NMC811 into segregated single crystals without milling or post-treatment. The Li2O vapour, derived from Li2O solids, diffuses rapidly and reacts with precursors, mimicking a molten-salt environment, which facilitates single-crystal growth. The chemical lithiation process continuously drives Li2O sublimation, sintering the crystals. Single crystals derived from Li2O and fresh precursors or spent polycrystals exhibit outstanding cycling after 1,000 cycles in full cells. The demonstrated Li2O sublimation and its universal role in promoting single-crystal growth provides an effective approach for single-crystal synthesis, scale-up and recycling.
Site-specific activation of the proton pump inhibitor rabeprazole by tetrathiolate zinc centres
Proton pump inhibitors have become top-selling drugs worldwide. Serendipitously discovered as prodrugs that are activated by protonation in acidic environments, proton pump inhibitors inhibit stomach acid secretion by covalently modifying the gastric proton pump. Despite their widespread use, alternative activation mechanisms and potential target proteins in non-acidic environments remain poorly understood. Employing a chemoproteomic approach, we found that the proton pump inhibitor rabeprazole selectively forms covalent conjugates with zinc-binding proteins. Focusing on DENR, a protein with a C4 zinc cluster (that is, zinc coordinated by four cysteines), we show that rabeprazole is activated by the zinc ion and subsequently conjugated to zinc-coordinating cysteines. Our results suggest that drug binding, activation and conjugation take place rapidly within the zinc coordination sphere. Finally, we provide evidence that other proton pump inhibitors can be activated in the same way. We conclude that zinc acts as a Lewis acid, obviating the need for low pH, to promote the activation and conjugation of proton pump inhibitors in non-acidic environments.
Microscopic crystallographic analysis of dislocations in molecular crystals
Organic molecular crystals encompass a vast range of materials from pharmaceuticals to organic optoelectronics, proteins and waxes in biological and industrial settings. Crystal defects from grain boundaries to dislocations are known to play key roles in mechanisms of growth1,2 and in the functional properties of molecular crystals3,4,5. In contrast to the precise analysis of individual defects in metals, ceramics and inorganic semiconductors enabled by electron microscopy, substantially greater ambiguity remains in the experimental determination of individual dislocation character and slip systems in molecular materials3. In large part, nanoscale dislocation analysis in molecular crystals has been hindered by the low electron doses required to avoid irreversibly degrading these crystals6. Here we present a low-dose, single-exposure approach enabling nanometre-resolved analysis of individual dislocations in molecular crystals. We demonstrate the approach for a range of crystal types to reveal dislocation character and operative slip systems unambiguously.
A genome-wide atlas of human cell morphology
A key challenge of the modern genomics era is developing empirical data-driven representations of gene function. Here we present the first unbiased morphology-based genome-wide perturbation atlas in human cells, containing three genome-wide genotype–phenotype maps comprising CRISPR–Cas9-based knockouts of >20,000 genes in >30 million cells. Our optical pooled cell profiling platform (PERISCOPE) combines a destainable high-dimensional phenotyping panel (based on Cell Painting) with optical sequencing of molecular barcodes and a scalable open-source analysis pipeline to facilitate massively parallel screening of pooled perturbation libraries. This perturbation atlas comprises high-dimensional phenotypic profiles of individual cells with sufficient resolution to cluster thousands of human genes, reconstruct known pathways and protein–protein interaction networks, interrogate subcellular processes and identify culture media-specific responses. Using this atlas, we identify the poorly characterized disease-associated TMEM251/LYSET as a Golgi-resident transmembrane protein essential for mannose-6-phosphate-dependent trafficking of lysosomal enzymes. In sum, this perturbation atlas and screening platform represents a rich and accessible resource for connecting genes to cellular functions at scale.
C(sp3)–heteroatom bond formation by iron-catalyzed soft couplings
Carbon–heteroatom bonds are of great importance due to their prevalence in pharmaceuticals, agrochemicals, materials, and natural products. Despite the effective use of metal-catalyzed cross-coupling reactions between sp2-hybridized organohalides and soft heteroatomic nucleophiles for carbon–heteroatom bond formation, the use of sp3-hybridized organohalides remain limited and the coupling with thiols remains elusive. Here, we report the coupling of sp3-hybridized benzyl or tertiary halides with soft thiol nucleophiles catalyzed by iron and extend the utility to alcohol and amine nucleophiles. The reaction is broad in substrate scope for both coupling partners and applicable in the construction of congested tri- and tetrasubstituted carbon centers as well as β-quaternary heteroatomic products. The synthetic utility is further emphasized by gram-scale synthesis and rapid herbicide library synthesis. Overall, we provide an efficient method to prepare pharmaceutically and materially relevant carbon–heteroatom bonds by expanding iron-catalyzed cross-coupling reactions to the coupling of sp3-hybridized organohalides with soft nucleophiles.
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