Selective hydrogenation of nitrocyclohexane to cyclohexanone oxime over a Cu12Ag17(SR)12(PPh3)4 cluster catalyst

Atomically precise metal cluster catalysts with crystallographically solved structures have been documented to be promising alternatives to tackle the challenge of selective hydrogenation of organics into high value products. Here we report that a Cu12Ag17(SR)12(PPh3)4 (SR = 1,3-benzenedithiol) cluster as a heterogeneous catalyst can achieve a highly catalytic selectivity of cyclohexanone oxime in catalytic hydrogenation of nitrocyclohexane, due to the unique synergy in the bimetallic cluster.

Hydride Formation and Decomposition on Cu(111) in HClO4

Cu electrodeposition and the electrocatalysis of hydrogenation reactions thereupon involve significant interactions with adsorbed hydrogen. Electrochemical mass spectrometry (EC-MS) is used to explore the formation and decomposition of surface hydride on Cu(111) in 0.1 mol L-1 HClO4. Hydride formation is associated with two reduction waves that reflect the potential-dependent Hads coverage and its reconstruction. Voltammetric cycling reveals an additional oxidative and reductive feature at ≈ -0.05 V versus the reversible hydrogen electrode (RHE) that reflects the state of the 2D surface hydride. Extending the voltammetric window to more negative potentials results in an increase in Hads coverage and surface reconstruction that subsequently leads to accelerated hydride decomposition at positive potentials. Voltammetric and chronoamperometric analysis of hydride formation indicates a Hads coverage of ≈0.75 monolayers (ML) between -0.225 V vs RHE and -0.275 V vs RHE with further increases in Hads observed with the onset and acceleration of the HER at more negative potentials. Returning to more positive potentials, hydride decomposition begins above -0.05 V vs RHE. Recombination of Hads to form H2 accounts for desorption of ≈0.5 ML of Hads while its oxidation to H3O+ consumes between ≈0.15 and ≈0.4 ML of Hads, depending on the specific electrochemical conditions. The potential-dependent Hads coverage and surface reconstruction are congruent with trends identified in recent computational and electrochemical scanning tunneling microscopy studies. In contrast to perchloric acid, the presence of strongly adsorbing anions, such as sulfate or halides, favors hydride decomposition via the recombination pathway.

Microfluidic Synthesis of CuH Nanoparticles for Antitumor Therapy through Hydrogen-Enhanced Apoptosis and Cuproptosis

Cuproptosis has drawn enormous attention in antitumor material fields; however, the responsive activation of cuproptosis against tumors using nanomaterials with high atom utilization is still challenging. Herein, a copper-based nanoplatform consisting of acid-degradable copper hydride (CuH) nanoparticles was developed via a microfluidic synthesis. After coating with tumor-targeting hyaluronic acid (HA), the nanoplatform denoted as HA-CuH-PVP (HCP) shows conspicuous damage toward tumor cells by generating Cu+ and hydrogen (H2) simultaneously. Cu+ can induce apoptosis by relying on Fenton-like reactions and lead to cuproptosis by causing mitochondrial protein aggregation. Besides, the existence of H2 can enhance both cell death types by causing mitochondrial dysfunction and intracellular redox homeostatic disorders. In vivo experimental results further exhibit the desirable potential of HCP for killing tumor cells and inhibiting lung metastases, which will broaden the horizons of designing copper-based materials triggering apoptosis and cuproptosis for better antitumor efficacy.

Construction of New Active Sites: Cu Substitution Enabled Surface Frustrated Lewis Pairs over Calcium Hydroxyapatite for CO2 Hydrogenation

Calcium hydroxyphosphate, Ca₁₀ (PO₄ )₆ (OH)₂ , is commonly known as hydroxyapatite (HAP). The acidic calcium and basic phosphate/hydroxide sites in HAP can be modified via isomorphous substitution of calcium and/or hydroxide ions to enable a cornucopia of catalyzed reactions. Herein, isomorphic substitution of Ca²⁺ ions by Cu²⁺ ions especially at very low levels of exchange created new analogs of molecular surface frustrated Lewis pairs (SFLPs) in Cu_x Ca_10-x (PO₄ )₆ (OH)₂ , thereby boosting its performance metrics in heterogeneous CO₂ photocatalytic hydrogenation. In situ Fourier transform infrared spectroscopy characterization and density functional theory calculations provided fundamental insights into the catalytically active SFLPs defined as proximal Lewis acidic Cu²⁺ and Lewis basic OH^- . The photocatalytic pathway proceeds through a formate reaction intermediate, which is generated by the reaction of CO₂ with heterolytically dissociated H₂ on the SFLPs. Given the wealth of information thus uncovered, it is highly likely that this work will spur the further development of similar classes of materials, leading to the advancement and, ultimately, large-scale application of photocatalytic CO₂ reduction technologies.