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Asymmetric hydrogenation of alkene moieties is important for the synthesis of chiral molecules, but achieving high stereoselectivity remains a challenge. Biocatalysis using ene-reductases (EReds) offers a viable solution. However, the need for NAD(P)H cofactors limits large-scale applications. Here, we explored an electrochemical alternative for recycling flavin-containing EReds using methyl viologen as a mediator. For this, we built a bio-electrocatalytic setup with an H-type glass reactor cell, proton exchange membrane, and carbon cloth electrode. Experimental results confirm the mediator's electrochemical reduction and enzymatic consumption. Optimization showed increased product concentration at longer reaction times with better reproducibility within 4-6 h. We tested two enzymes, Pentaerythritol Tetranitrate Reductase (PETNR) and the Thermostable Old Yellow Enzyme (TOYE), using different alkene substrates. TOYE showed higher productivity for the reduction of 2-cyclohexen-1-one (1.20 mM h-1), 2-methyl-2-cyclohexen-1-one (1.40 mM h-1) and 2-methyl-2-pentanal (0.40 mM h-1), with enantiomeric excesses ranging from 11% to 99%. PETNR outperformed TOYE in terms of enantioselectivity for the reduction of 2-methyl-2-pentanal (ee 59±7% (S)). Notably, TOYE achieved promising results also in reducing ketoisophorone, a challenging substrate, with similar enantiomeric excess compared to published values using NADH., (© 2024 Wiley‐VCH GmbH.)

Background: Diabetic foot ulcers (DFU) are a costly complication of diabetes mellitus (DM), with significant implications for the patient and the healthcare professionals that treat them. The primary objective of this study was to evaluate if there were improved healing rates in patients with a DFU that were taking a statin medication compared to those patients with a DFU who were not taking a statin medication. Secondary outcomes assessed were correlations with wound healing or statin use on data obtained from retrospective chart review., Methods: A case-control series was performed to obtain appropriate demographic information, comorbid conditions, laboratory values, and physical examination findings. From the time of presentation with DFU, these patients were followed for 12 weeks to evaluate for healing. Healing was defined as full epithelialization of the DFU with no further drainage. Wound healing and statin use correlation testing was then done for collected variables and each cohort. Chi square and Pearson correlation were then performed to identify any significant correlations. All p-values were two-sided, and findings were considered statistically significant at p < 0.05., Results: Our study identified 109 patients, 75 patients with a DFU on statin medication and 34 patients with a DFU not on statin medication. The statin cohort was more likely to be older, less than 5-year duration of diabetes, have more comorbidities, decreased low-density lipoprotein (LDL) cholesterol, and decreased total cholesterol (p < 0.05). Among those patients taking a statin medication, 48.0% (36/75) healed their DFU within 12 weeks. Among those patients not taking a statin medication, 44.1% (15/34) healed their DFU within 12 weeks. No correlation was noted between wound healing and statin use (p = 0.7). For wound healing, a negative correlation was noted for prior minor amputations (p < 0.05). For statin use, correlations were noted for age, duration of DM, LDL cholesterol level, total cholesterol level, HTN, CAD, and HLD (p < 0.05)., Conclusions: Statin medication use did not influence DFU healing rates between cohorts. There was a correlation noted between wound healing and prior minor amputations and between statin use and age, duration of DM, LDL cholesterol, total cholesterol, HTN, CAD and HLD. Additionally, we observed no correlation between DFU healing rates and use of a statin medication., (© 2024. The Author(s).)

In the chemical industry, formaldehyde is an important bulk chemical. The traditional synthesis of formaldehyde involves an energy intensive oxidation of methanol over a metal oxide catalyst. The selective electrochemical oxidation of methanol is challenging. Herein, we report a catalytic system with an immobilized TEMPO electrode that selectively oxidizes methanol to formaldehyde with high turnover numbers. Upon the addition of various organic and inorganic bases, the activity of the catalyst could be tuned. The highest Faradaic efficiency that was achieved was 97.5 %, the highest turnover number was 17100. Additionally, we found that the rate determining step changed from the step in which the carbonyl specie is created from the methanol-TEMPO adduct to the oxidative regeneration of the TEMPO + species. Finally, we showed that the system could be applied to the oxidation of other aliphatic alcohols., (© 2024 The Authors. ChemSusChem published by Wiley-VCH GmbH.)

We present here the synthesis and performance of dual-atom catalysts (DACs), analogous to well-known single-atom catalysts (SACs). DACs feature sites containing pairs of metal atoms and can outperform SACs due to their additional binding possibilities. Yet quantifying the improved catalytic activity in terms of proximity effects remains difficult, as it requires both high-resolution kinetic data and an understanding of the reaction pathways. Here, we use an automated bubble counter setup for comparing the catalytic performance of ceria-supported platinum SACs and DACs in ammonia borane hydrolysis. The catalysts were synthesized by wet impregnation and characterized using SEM, HAADF-STEM, XRD, XPS, and CO-DRIFTS. High-precision kinetic studies of ammonia borane hydrolysis in the presence of SACs show two temperature-dependent regions, with a transition point at 43 °C. Conversely, the DACs show only one regime. We show that this is because DACs preorganize both ammonia borane and water at the dual-atom active site. The additional proximal Pt atom improves the reaction rate 3-fold and enables faster reactions at lower temperatures. We suggest that the DACs enable the activation of the water-O-H bond as well as increase the hydrogen spillover effect due to the adjacent Pt site. Interestingly, using ammonia borane hydrolysis as a benchmark reaction gives further insight into hydrogen spillover mechanisms, above what is known from the CO oxidation studies., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)