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A series of metal-free imidazole-benzimidazole catalysts (ImBenz-H, ImBenz-NO 2 , ImBenz-OCH 3 ) for oxygen reduction reaction (ORR) were prepared. We demonstrate that the electrocatalytic O 2 reduction by ImBenz-NO 2 with the electron-withdrawing group showed high selectivity toward H 2 O with the number of electrons transferred (n=3.7) in a neutral aqueous solution. The highest ORR selectivity toward H 2 O 2 was achieved using ImBenz-H (n=2.4) in an alkaline solution. Electrochemical studies of reaction kinetics disclosed that the highest turnover frequencies were obtained from ImBenz-H in both neutral and alkaline aqueous solutions. The results prove that the ORR selectivity is tunable by modulating the substituent of the ImBenz catalysts. Furthermore, DFT calculations suggested that the ORR mechanism of ImBenz-H involves the electron transfer from imidazole-benzimidazole to O 2 resulting in the formation of H 2 O 2 which supports the redox active properties of the catalysts ImBenz., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Ensuring continuous and sustainable lithium supply requires the development of highly efficient separation processes such as LLE (liquid-liquid extraction) for both primary sources and certain waste streams. In this work, 4-phosphoryl pyrazolones are used in an efficient pH-controlled stepwise separation of Li + from Ca 2+ , Mg 2+ , Na + and K + . The factors affecting LLE process, such as the substitution pattern of the extractant, diluent/water distribution, co-ligand, pH, and speciation of the metal complexes involved, were systematically investigated. The maximum extraction efficiency of Li + at pH 6.0 was 94 % when Mg 2+ and Ca 2+ were previously separated at pH<5.0, proving that the separation of these ions is possible by simply modulating the pH of the aqueous phase. Our study points a way to separation of lithium from acid brine or from spent lithium ion battery leaching solutions, which supports the future supply of lithium in a more environmentally friendly and sustainable manner., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Herein, we introduced a new chemosensor, bis-BODIPY linked-triazole based on catechol (BODIPY-OO) prepared by bridging two units of BODIPY fluorophore/triazole binding group with a catechol unit. A solution of this compound displayed 4- and 2-fold enhancements in fluorescence intensity after adding a mole equivalent amount of Ag + and Hg 2+ ions in methanol media, respectively. 1 H NMR titrations of BODIPY-OO with Ag + and Hg 2+ suggested that the triazole was involved in the recognition process. BODIPY-OO showed high sensitivity toward Ag + and Hg 2+ over other metal ions with detection limits of 0.45 μM and 1 μM, respectively. It can also distinguish Hg 2+ from Ag + by addition of an EDTA. This compound can therefore be employed as practical fluorescent probe for monitoring the presence of Ag + and Hg 2+ ions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Iron oxide nanoparticles were used as supporters for in situ polymerization to produce polymer nanocomposites with well-dispersed fillers in polymer matrix. Iron oxide could be sustained as colloidal solutions by cassava starch to produce a good dispersion of iron oxide in the matrix. New supports based on iron oxide/cassava starch or cassava starch for Ziegler-Natta catalysts were utilized as heterogeneous supporters for partially hydrolyzed triethylaluminum. Then, TiCl4 was immobilized on the supports as catalysts for polymerization of ethylene. High-density polyethylene (HDPE) composites were obtained by the synthesized catalysts. A good dispersion of iron oxide/cassava starch particles was observed in the synthesized polymer matrix promoting to good mechanical properties of HDPE., (Copyright © 2014 Elsevier Ltd. All rights reserved.)