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Université de Fribourg

Kinetik des Ionentransports durch supramolekulare Kanäle in Einkristallen

Assouma, Cyrille D. ; Crochet, Aurélien ; Chérémond, Yvens ; Giese, Bernd ; Fromm, Katharina M.

In: Angewandte Chemie, 2013, vol. 125, no. 17, p. 4780-4783

Einkristall-zu-Einkristall-Umwandlungen sind durch Ionenaustausch- und Transportreaktionen durch supramolekulare Kanäle möglich, die aus Kronenether- Molekülen bestehen und Trihalogenid-Ionen als Gerüst nutzen. In kinetischen Messungen des Ionentransports bei unterschiedlichen Temperaturen wurde die Aktivierungsenergie für solche Systeme bestimmt, und ein schneller Austausch zwischen K+-...

Université de Fribourg

Elektronentransfer in Peptiden : Bildung von Silbernanopartikeln

Kracht, Sonja ; Messerer, Matthias ; Lang, Matthieu ; Eckhardt, Sonja ; Lauz, Miriam ; Grobéty, Bernard ; Fromm, Katharina M. ; Giese, Bernd

In: Angewandte Chemie, 2015, vol. 127, no. 10, p. 2954-2958

Einige Mikroorganismen zeigen anaerobe mineralische Respiration, bei der sie Metallionen zu Metallnanopartikeln reduzieren. Hierbei werden Peptide als Medium für den Elektronentransfer (ET) verwendet. Diese Reaktionsklasse wird anhand eines Modellpeptids und Silber als Metall diskutiert. Erstaunlicherweise können Silberionen, die von Peptiden mit Histidin als silberbindender Aminosäure und...

Université de Fribourg

New Antimicrobial and Biocompatible Implant Coating with Synergic Silver–Vancomycin Conjugate Action

Varisco, Massimo ; Khanna, Nina ; Brunetto, Priscilla S. ; Fromm, Katharina M.

In: ChemMedChem, 2014, vol. 9, no. 6, p. 1221-1230

Materials foreign to the body are used ever more frequently, as increasing numbers of patients require implants. As a consequence, the numbers of implant-related infections have grown as well, and with increasing resistance. Treatments often fail; thus, new antibacterial coating strategies are being developed by scientists to avoid, or at least strongly reduce, bacterial adhesion to implant...

Université de Fribourg

A simple reaction for dna sensing and chemical delivery

Janett, Elia ; Diep, Kim-Long ; Fromm, Katharina M. ; Bochet, Christian G.

In: ACS Sensors, 2020, vol. 5, no. 8, p. 2338–2343

Reactions templated by nucleic acids are currently at the heart of applications in biosensing and drug release. The number of chemical reactions selectively occurring only in the presence of the template, in aqueous solutions, and at room temperature and able to release a chemical moiety is still very limited. Here, we report the use of the p-nitrophenyl carbonate (NPC) as a new reactive...

Université de Fribourg

Handling (nano)silver as antimicrobial agent: therapeutic window, dissolution dynamics, detection methods and molecular interactions

Abram, Sarah‐Luise ; Fromm, Katharina M.

In: Chemistry – A European Journal, 2020, vol. 26, no. 48, p. 10948–10971

Silver is an antimicrobial agent well known since antiquity. With the emergence of multiresistant bacteria, it has come back into the focus of research, and ionic as well as nano‐sized silver have been studied in vitro and in vivo. The results are controversial, silver being discussed as the “silver bullet” or a “wolf in sheep's clothing”. A thorough search of literature from...

Université de Fribourg

Bimetallic salen-based compounds and their potential applications

Finelli, Alba ; Abram, Sarah-Luise ; Hérault, Nelly ; Crochet, Aurélien ; Fromm, Katharina M.

In: Crystal Growth & Design, 2020, vol. 20, no. 8, p. 4945–4958

The new bimetallic coordination compounds [LNiAg(NO3)], [LCuMn(NO3)2], [LCuCu(NO3)2], [LCuZn(NO3)2], and [{LCuBi(NO3)3}(ACN)] have been synthesized from a salen-type ligand L containing two distinct coordination sites to accommodate (different) metal ions M1 and M2. In the solid state, the formation of 1:1 compounds (LCu:M2) is always observed, but interactions between the compounds lead to ...

Université de Fribourg

A nano-rattle SnO2@carbon composite anode material for high-energy Li-ion batteries by melt diffusion impregnation

Maharajan, Sivarajakumar ; Kwon, Nam Hee ; Brodard, Pierre ; Fromm, Katharina M.

In: Nanomaterials, 2020, vol. 10, no. 4, p. 804

The huge volume expansion in Sn-based alloy anode materials (up to 360%) leads to a dramatic mechanical stress and breaking of particles, resulting in the loss of conductivity and thereby capacity fading. To overcome this issue, SnO2@C nano- rattle composites based on < 10 nm SnO2 nanoparticles in and on porous amorphous carbon spheres were synthesized using a silica template and tin melting...

Université de Fribourg

Metal nanoparticle–microbe interactions: synthesis and antimicrobial effects

Khan, Mujeebur R. ; Fromm, Katharina M. ; Rizvi, Tanveer F. ; Giese, Bernd ; Ahamad, Faheem ; Turner, Raymond J. ; Füeg, Michael ; Marsili, Enrico

In: Particle & Particle Systems Characterization, 2020, vol. 37, no. 5, p. 1900419

Metal nanoparticles (NPs), chalcogenides, and carbon quantum dots can be easily synthesized from whole microorganisms (fungi and bacteria) and cell‐free sterile filtered spent medium. The particle size distribution and the biosynthesis time can be somewhat controlled through the biomass/metal solution ratio. The biosynthetic mechanism can be explained through the ion‐reduction theory and...

Université de Fribourg

Metal nanoparticle–microbe interactions: synthesis and antimicrobial effects

Khan, Mujeebur R. ; Fromm, Katharina M. ; Rizvi, Tanveer F. ; Giese, Bernd ; Ahamad, Faheem ; Turner, Raymond J. ; Füeg, Michael ; Marsili, Enrico

In: Particle & Particle Systems Characterization, 2020, vol. 37, no. 5, p. 1900419

Metal nanoparticles (NPs), chalcogenides, and carbon quantum dots can be easily synthesized from whole microorganisms (fungi and bacteria) and cell‐free sterile filtered spent medium. The particle size distribution and the biosynthesis time can be somewhat controlled through the biomass/metal solution ratio. The biosynthetic mechanism can be explained through the ion‐reduction theory and...

Université de Fribourg

Indirect solvent assisted tautomerism in 4-substituted phthalimide 2-hydroxy-Schiff bases

Yordanov, Dancho ; Deneva, Vera ; Georgiev, Anton ; Crochet, Aurélien ; Fromm, Katharina M. ; Antonova, Liudmil

In: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2020, vol. 237, p. 118416

The paper presents the synthesis and characterization of two 4-substituted phthalimide 2-hydroxy-Schiff bases containing salicylic (4) and 2-hydroxy-1-naphthyl (5) moieties. The structural differences of 2-hydroxyaryl substituents, resulting in different enol/keto tautomeric behaviour, depending on the solvent environment were studied by absorption UV–Vis spectroscopy. Compound 5 is...