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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

Post-protein binding metal-mediated coupling of an acridine orange-based fluorophore

Santoro, Giuseppe ; Blacque, Olivier ; Zobi, Fabio

In: Metallomics, 2012, vol. 4, no. 3, p. 253-259

The HEW lysozyme (Lys) and the fac-[Re(CO)3(H2O)3]+ complex (1) are used as a simple model system for the description of a new approach to the labelling polypeptides with fluorescent tags. The strategy takes advantage of the reaction of an acridine orange-based fluorophore (AO) with the non-native metal fragment 1 hybridized on the enzyme. A synthetic methodology for the quantitative...

Université de Fribourg

Formation and Reactivity of [(tacn)-N-CO-Re(III)Br(CO)(2)](+) in Water : a Theoretical and Experimental Study

Zobi, Fabio ; Blacque, Olivier ; Steyl, Gideon ; Spingler, Bernhard ; Alberto, Roger

In: Inorganic Chemistry, 2009, vol. 48, no. 11, p. 4963-4970

The chemistry of [(tacn)-N-CO-Re(III)(CO)(2)Br]X (X = Cl or Br), obtained in good yield from the reaction of fac-[(tacn)Re(I)(CO)(3)]Br (1, tacn = 1,4,7- triazacyclononane) with X(2) in water, is described. The [(tacn)-N-CO-Re(III)(CO) (2)Br]X complex (2 with X = Br(-); 2a with X = BrCl(2)(-)), which we have previously communicated, is characterized by an unusual three-membered ring acyl amide...

Université de Fribourg

Ligand electronic parameters as a measure of the polarization of the C≡O bond in [M(CO)(x)L(y)]n complexes and of the relative stabilization of [M(CO)(x)L(y)](n/n+1) species

Zobi, Fabio

In: Inorganic Chemistry, 2010, vol. 49, no. 22, p. 10370-10377

The electronic description of octahedral (fac-[M(CO)(3)L(3)](n), with M = Re, Ru, and Mn, and [Cr(CO)(5)L](n)), square-planar (cis-[Pt(CO)(2)L(2)](n)), and tetrahedral ([Ni(CO)(3)L](n)) carbonyl complexes (where L = monodentate ligand) was obtained via density functional theory and natural population analyses in order to understand what effects are probed in these species by vibrational...

Université de Fribourg

Parametrization of the contribution of mono- and bidentate ligands on the symmetric C[triple bond]O stretching frequency of fac-[Re(CO)(3)](+) complexes

Zobi, Fabio

In: Inorganic Chemistry, 2009, vol. 48, no. 22, p. 10845-10855

A ligand parameter, IR(P)(L), is introduced in order to evaluate the effect that different monodentate and bidentate ligands have on the symmetric C[triple bond]O stretching frequency of octahedral d(6) fac-[Re(CO)(3)L(3)] complexes (L = mono- or bidentate ligand). The parameter is empirically derived by assuming that the electronic effect, or contribution, that any given ligand L will add to...

Université de Fribourg

Synthesis and reactivity of the 17 e- complex [Re(II)Br4(CO)2]2 : A convenient entry into rhenium(II) chemistry

Zobi, Fabio ; Kromer, Lukas ; Spingler, Bernhard ; Alberto, Roger

In: Inorganic Chemistry, 2009, vol. 48, no. 18, p. 8965-8970

The reduction of (Et(4)N)[Re(III)Br(4)(CO)(2)] (1) by 0.5 equiv of tetrakis- dimethylaminoethylene in acetonitrile yields directly the air-stable, 17-electron Re(II) synthon (Et(4)N)(2)[Re(II)Br(4)(CO)(2)] (2) in nearly quantitative yield. The versatility of 2 as a synthon for Re(II) chemistry was demonstrated by substitution reactions of [Re(II)Br(4)(CO)(2)](2-) with different mono-, bi-,...

Université de Fribourg

CO and CO-releasing molecules in medicinal chemistry

Zobi, Fabio

In: Future Medicinal Chemistry, 2013, vol. 5, no. 2, p. 175-188

Since the discovery that CO acts as a cytoprotective and homeostatic molecule, increasing research efforts have been devoted to the exploitation of its therapeutic effects. Both endogenous and exogenous CO improves experimental lung, vascular and cardiac injuries and protects against several inflammatory states. The technology is now in place to bring CO to clinical applications, but the use...

Université de Fribourg

Aerobically stable and substitutionally labile α-diimine rhenium dicarbonyl complexes

Schindler, Kevin ; Crochet, Aurélien ; Zobi, Fabio

In: RSC Advances, 2021, vol. 11, p. 7511-7520

New synthetic routes to aerobically stable and substitutionally labile α-diimine rhenium(I) dicarbonyl complexes are described. The molecules are prepared in high yield from the cis–cis–trans-[Re(CO)2(tBu2bpy)Br2]− anion (2, where tBu2bpy is 4,4′- di-tert-butyl-2,2′-bipyridine), which can be isolated from the one electron reduction of the corresponding 17-electron complex (1)....