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Université de Fribourg

Li0.5Ni0.5Ti1.5Fe0.5(PO4)3/C electrode material for lithium ion batteries exhibiting faster kinetics and enhanced stability

Srout, Mohammed ; Kwon, Nam Hee ; Ben Youcef, Hicham ; Semlal, Nawal ; Fromm, Katharina M. ; Saadoune, Ismael

In: ACS Applied Materials & Interfaces, 2020, vol. 12, no. 16, p. 18496–18503

Natrium super ionic conductor (NASICON) materials providing attractive properties such as high ionic conductivity and good structural stability are considered as very promising materials for use as electrodes for lithium- and sodium-ion batteries. Herein, a new high-performance electrode material, Li0.5Ni0.5Ti1.5Fe0.5(PO4)3/C, was synthesized via the sol–gel method and was...

Université de Fribourg

Tautomerism and self-association in the solution of new pinene-bipyridine and pinene-phenanthroline derivatives

Solea, Atena B. ; Cornu, Ivan ; Deneva, Vera ; Crochet, Aurelien ; Fromm, Katharina M. ; Antonov, Liudmil ; Allemann, Christophe ; Mamula, Olimpia

In: Molecules, 2020, vol. 25, no. 2, p. 298

Two novel pinene-type ligands have been synthesized and their tautomeric and self-associating behavior studied in solution and in the solid state. The first ligand, an acetylated derivative of 5,6-pinene-bipyridine, displays keto-enol tautomerism in solution. This tautomeric equilibrium was studied by NMR and UV-Vis spectroscopy in various solvents, and the results were compared with the...

Université de Fribourg

Chemistry of alkaline earth metals: It is not all ionic and definitely not boring!

Fromm, Katharina M.

In: Coordination Chemistry Reviews, 2020, vol. 408, p. 213193

Some scientists might consider group 2 chemistry as “boring, closed shell and all ionic, aqueous chemistry, where everything is known! It is not worth investigating”. How wrong they are! Far from forming only purely ionic compounds, this review will shed light on some spectacular molecules, showing that alkaline earth metal ions can behave similar to transition metal ions. After general...

Université de Fribourg

Kinetics and mechanism of mineral respiration: how iron hemes synchronize electron transfer rates

Chabert, Valentin ; Babel, Lucille ; Füeg, Michael P. ; Karamash, Maksym ; Madivoli, Edwin S. ; Herault, Nelly ; Dantas, Joana M. ; Salgueiro, Carlos A. ; Giese, Bernd ; Fromm, Katharina M.

In: Angewandte Chemie International Edition, 2020, p. -

Anaerobic microorganisms of the Geobacter genus are effective electron sources for the synthesis of nanoparticles, for bioremediation of polluted water, and for the production of electricity in fuel cells. In multistep reactions, electrons are transferred via iron/heme cofactors of c‐type cytochromes from the inner cell membrane to extracellular metal ions, which are bound to outer membrane...

Université de Fribourg

Different coordination abilities of 1,7- and 4,7-phenanthroline in the reactions with copper(II) salts: Structural characterization and biological evaluation of the reaction products

Stevanović, Nevena Lj. ; Andrejević, Tina P. ; Crochet, Aurélien ; Ilic-Tomic, Tatjana ; Drašković, Nenad S. ; Nikodinovic-Runic, Jasmina ; Fromm, Katharina M. ; Djuran, Miloš I. ; Glišić, Biljana Đ.

In: Polyhedron, 2019, vol. 173, p. 114112

The reactions between equimolar amounts of CuX2 (X = NO3− and CF3SO3−) and two aromatic nitrogen-containing heterocycles differing in the position of nitrogen atoms, 1,7- and 4,7-phenanthroline (1,7- and 4,7-phen), were performed in ethanol/methanol at room temperature. When CuX2 salts were mixed with 4,7-phen, two copper(II) complexes, [Cu(NO3)2(4,7-Hphen)2](NO3)2 (1) and...

Université de Fribourg

Sequential multiple-target sensor: In3+, Fe2+, and Fe3+ discrimination by an anthracene-based probe

Finelli, Alba ; Chabert, Valentin ; Hérault, Nelly ; Crochet, Aurélien ; Kim, Cheal ; Fromm, Katharina M.

In: Inorganic Chemistry, 2019, vol. 58, no. 20, p. 13796–13806

Indium is a nonphysiological toxic metal widely used in industry. While misunderstood, its toxicity is proposed to be linked to a perturbation of Fe3+ homeostasis through the binding of In3+ ions to essential iron metalloproteins such as transferrins. Therefore, the monitoring of In3+ and Fe3+ in biological environments is of prime interest for both basic research and diagnosis. Here we...

Université de Fribourg

Surface modifications of positive-electrode materials for lithium ion batteries

Kwon, Nam Hee ; Conder, Joanna ; Srout, Mohammed ; Fromm, Katharina M.

In: CHIMIA International Journal for Chemistry, 2019, vol. 73, no. 11, p. 880–893

Lithium ion batteries are typically based on one of three positive-electrode materials, namely layered oxides, olivine- and spinel-type materials. The structure of any of them is 'resistant' to electrochemical cycling, and thus, often requires modification/post- treatment to improve a certain property, for example, structural stability, ionic and/or electronic conductivity. This review...

Université de Fribourg

New Ni0.5Ti2 (PO4)3@C NASICON-type electrode material with high rate capability performance for lithium-ion batteries: Synthesis and electrochemical properties

Srout, Mohammed ; Kwon, Nam Hee ; Luo, Wen ; Züttel, Andreas ; Fromm, Katharina M. ; Saadoune, Ismael

In: ChemSusChem, 2019, vol. 12, no. 21, p. 4846–4853

Ni0.5Ti2(PO4)3/C NASICON‐type phosphate is introduced as a new anode material for lithium‐ion batteries (LIBs). Ni0.5Ti2(PO4)3/C was synthesized through the sol–gel route and delivered some remarkable electrochemical performances. Specifically, the Ni0.5Ti2(PO4)3/C electrode demonstrates a high rate capability performance and delivers high reversible capacities ranging from...

Université de Fribourg

Tautomerism as primary signaling mechanism in metal sensing: the case of amide group

Deneva, Vera ; Dobrikov, Georgi ; Crochet, Aurelien ; Nedeltcheva, Daniela ; Fromm, Katharina M. ; Antonov, Liudmil

In: Beilstein Journal of Organic Chemistry, 2019, vol. 15, no. 1, p. 1898–1906

The concept for sensing systems using the tautomerism as elementary signaling process has been further developed by synthesizing a ligand containing 4- (phenyldiazenyl)naphthalene-1-ol as a tautomeric block and an amide group as metal capturing antenna. Although it has been expected that the intramolecular hydrogen bonding (between the tautomeric hydroxy group and the nitrogen atom from the...

Université de Fribourg

Synthesis and structural analysis of polynuclear silver(I) complexes with 4,7-phenanthroline

Stanojević, Ivana M. ; Savić, Nada D. ; Crochet, Aurélien ; Fromm, Katharina M. ; Đuran, Miloš I. ; Glišić, Biljana Đ.

In: Journal of the Serbian Chemical Society, 2019, vol. 84, no. 7, p. 689–699

New polynuclear silver(I) complexes, [Ag(CF3SO3)(4,7-phen)(CH3CN)]n (1) and [Ag(PO2F2)(4,7-phen)]n (2), were synthesized by the reaction of 4,7-phenanthroline (4,7-phen) and the corresponding AgX salt (X = CF3SO3 - and PF6 -) in 1:2 mole ratio, respectively, in methanol/acetone (1:1 volume ratio) at room temperature. The characterization of the complexes was established on the basis of...