The development of CO2 electroreduction (CO2RR) catalysts based on covalent organic frameworks (COFs) is an emerging strategy to produce synthetic fuels. However, our understanding on catalytic mechanisms and structure–activity relationships for COFs is still limited but essential to the rational design of these catalysts. Herein, we report a newly devised CO2 reduction catalyst by loading single-atom centers, {fac-Mn­(CO)3S}, (S = Br, CH3CN, H2O), within a bipyridyl-based COF (COFbpyMn ). COFbpyMn shows a low CO2RR onset potential (η = 190 mV) and high current densities (>12 mA·cm–2, at 550 mV overpotential) in water. TOFCO and TONCO values are as high as 1100 h–1 and 5800 (after 16 h), respectively, which are more than 10-fold higher than those obtained for the equivalent manganese-based molecular catalyst. Furthermore, we accessed key catalytic intermediates within a COF matrix by combining experimental and computational (DFT) techniques. The COF imposes mechanical constraints on the {fac-Mn­(CO)3S} centers, offering a strategy to avoid forming the detrimental dimeric Mn0–Mn0, which is a resting state typically observed for the homologous molecular complex. The absence of dimeric species correlates to the catalytic enhancement. These findings can guide the rational development of isolated single-atom sites and the improvement of the catalytic performance of reticular materials.

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Titanium oxide nanotubes (TNTs) were anodically grown in ethylene glycol electrolyte. The influence of the anodization time on their physicochemical and photoelectrochemical properties was evaluated. Concomitant with the anodization time, the NT length, fluorine content, and capacitance of the space charge region increased, affecting the opto-electronic properties (bandgap, bathochromic shift, band-edge position) and surface hydrophilicity of TiO2 NTs. These properties are at the origin of the photocatalytic activity (PCA), as proved with the photooxidation of methylene blue.

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Background: Alzheimer’s disease (AD) is the most common form of dementia. Neuroimaging methods have widened the horizons for AD diagnosis and therapy. The goals of this work are the synthesis of 2-(3-fluoropropyl)-6-methoxynaphthalene (5) and its [18F]-radiolabeled counterpart ([18F]Amylovis), the in silico and in vitro comparative evaluations of [18F]Amylovis and [11C]Pittsburg compound B (PIB) and the in vivo preclinical evaluation of [18F]Amylovis in transgenic and wild mice. </p><p> Methods: Iron-catalysis cross coupling reaction, followed by fluorination and radiofluorination steps were carried out to obtain 5 and 18F-Amylovis. Protein/A&#223; plaques binding, biodistribution, PET/CT Imaging and immunohistochemical studies were conducted in healthy/transgenic mice. </p><p> Results: The synthesis of 5 was successful obtained. Comparative in silico studies predicting that 5 should have affinity to the A&#946;-peptide, mainly through &#960;-&#960; interactions. According to a dynamic simulation study the ligand-A&#946; peptide complexes are stable in simulation-time (&#916;G = -5.31 kcal/mol). [18F]Amylovis was obtained with satisfactory yield, high radiochemical purity and specific activity. The [18F]Amylovis log Poct/PBS value suggests its potential ability for crossing the blood brain barrier (BBB). According to in vitro assays, [18F]Amylovis has an adequate stability in time. Higher affinity to A&#946; plaques were found for [18F]Amylovis (Kd 0.16 nmol/L) than PIB (Kd 8.86 nmol/L) in brain serial sections of 3xTg-AD mice. Biodistribution in healthy mice showed that [18F]Amylovis crosses the BBB with rapid uptake (7 %ID/g at 5 min) and good washout (0.11&#177;0.03 %ID/g at 60 min). Comparative PET dynamic studies of [18F]Amylovis in healthy and transgenic APPSwe/PS1dE9 mice, revealed a significant high uptake in the mice model. </p><p> Conclusion: The in silico, in vitro and in vivo results justify that [18F]Amylovis should be studied as a promissory PET imaging agent to detect the presence of A&#946; senile plaques.

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Harnessing the excited state of reduced species has long posed a challenge in the field of photocatalysis. This study presents the isolation and characterization of 1-electron reduced iridium complexes commonly employed in photoredox catalysis. Stochiometric reactions unveiled an unprecedented super-reductant ability for the isolated complexes under light irradiation, reaching potentials below 3 V vs SCE. Notably, the reduced iridium complex can also be electrochemically generated in situ with analogous super-reductant ability, enabling electro(photo)catalysis. Experimental and computational studies reveal that photoreactivity rises from intrinsic excitation of the reduced (bpy●‒)* ligand within the iridium complex, while the metal center acts as a spectator. Corroborating this finding, the organic salt Li+bpy●‒ exhibited equivalent super-reducing reactivity under photochemical conditions. Our findings shed light on the access to the super-reductant states of iridium photoredox catalysts and other metalated bipyridines, opening new opportunities for electro(photo) synthetic methodologies.