Publications by authors named "J Perez-Ramirez"

In situ monitoring is essential for catalytic process design, offering real-time insights into active structures and reactive intermediates. Electron paramagnetic resonance (EPR) spectroscopy excels at probing geometric and electronic properties of paramagnetic species during reactions. Yet, state-of-the-art liquid-phase EPR methods, like flat cells, require custom resonators, consume large amounts of reagents, and are unsuited for tracking initial kinetics or use with solid catalysts.

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Buchwald-Hartwig (BH) aminations are crucial for synthesizing arylamine motifs in numerous bioactive molecules and fine chemicals. While homogeneous palladium complexes can be effective catalysts, their high costs and environmental impact motivate the search for alternative approaches. Heterogeneous palladium single-atom catalysts (SAC) offer promising recoverable alternatives in C-C cross-couplings.

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Unlabelled: Transmesenteric hernia is an internal hernia without a sac caused by a congenital defect of the mesentery. It is a rare cause of intestinal atresia, usually diagnosed intraoperatively, therefore, its prognosis is variable and may be associated with high morbidity and mortality.

Objective: To report a case of transmesenteric hernia with multiple intestinal atresia of late diagnosis.

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Article Synopsis
  • Diatomic catalysts (DACs) leverage the interactions between adjacent metal atoms to enhance the properties of single-atom catalysts (SACs), but their preparation and characterization pose challenges.
  • A new carbon nitride-supported Pd-DAC was developed, achieving a remarkable 92% yield in photocatalytic water-donating transfer hydrogenation of 4-vinylphenol, outperforming both Pd single atoms (47%) and nanoparticles (1%).
  • This study combines advanced imaging and machine learning to confirm the presence of dimeric Pd species and uses DFT simulations to explain the superior performance of Pd-DAC through improved substrate activation, offering a more sustainable alternative to traditional hydrogenation methods.
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Single-atom heterogeneous catalysts (SACs) are potential, recoverable alternatives to soluble organometallic complexes for cross-coupling reactions in fine-chemical synthesis. When developing SACs for these applications, it is often expected that the need for ligands, which are essential for organometallic catalysts, can be bypassed. Contrary to that, ligands remain almost always required for palladium atoms stabilized on commonly used functionalized carbon and carbon nitride supports, as the catalysts otherwise show limited activity.

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