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Université de Fribourg

Polyether adducts of d-block metal compounds as starting materials for new cluster compounds

Crochet, Aurélien ; Fromm, Katharina M.

In: Zeitschrift für anorganische und allgemeine Chemie, 2010, vol. 636, no. 8, p. 1484–1496

New crystalline cobalt, nickel, zinc, and mercury halide adducts with polyethers as ligands have been isolated, characterized, and identified as [Co(μ-Cl)₂CoCl₂(glyme)₂] (glyme = 1,2-dimethoxyethane), cis-[CoI₂(H₂O)₂(glyme)₂]²⁺[CoI₄]²⁻, [NiI₂(glyme)₂], [ZnI₂(glyme)], [HgCl₂(glyme)], [CoI₂(diglyme)] (diglyme = bis(2-methoxyethyl)ether), [ZnI₂(diglyme)],...

Université de Fribourg

From alkaline earth ion aggregates via transition metal coordination polymer networks towards heterometallic single source precursors for oxidic materials

Gschwind, Fabienne ; Crochet, Aurélien ; Maudez, William ; Fromm, Katharina M.

In: CHIMIA International Journal for Chemistry, 2010, vol. 64, no. 5, p. 299-320

Heterometallic oxides are used as materials in many applications, e.g. from ferroelectrics to superconductors. Making these compounds usually requires high temperatures and long reaction times. Molecular precursors may contribute to render their processing shorter and accessible at lower temperatures, thus cheaper in energy and time. In this review article, different approaches toward oxide...

Université de Fribourg

Of chains and rings: synthetic strategies and theoretical investigations for tuning the structure of silver coordination compounds and their applications

Slenters, Tünde Vig ; Sagué, Jorge L. ; Brunetto, Priscilla S. ; Zuber, Stefanie ; Fleury, Antoine ; Mirolo, Laurent ; Robin, Adeline Y. ; Meuwly, Markus ; Gordon, Oliver ; Landmann, Regine ; Daniels, Alma U. ; Fromm, Katharina M.

In: Materials, 2010, vol. 3, no. 5, p. 3407-3429

Varying the polyethyleneglycol spacer between two (iso)-nicotinic groups of the ligand systems, a large structural variety of silver coordination compounds was obtained, starting with zero-dimensional ring systems, via one-dimensional chains, helices and double-helices to two-dimensional polycatenanes. Theoretical calculations help to understand their formation and allow predictions in some...

Université de Fribourg

Coordination polymer networks: an alternative to classical polymers ?

Fromm, Katharina M. ; Sagué, Jorge L. ; Mirolo, Laurent

In: Macromolecular Symposia, 2010, vol. 291-292, no. 1, p. 75-83

This chapter of "Polymer Networks: Synthesis, Properties, Theory and Applications" provides a brief overview on metal ion containing coordination polymer networks, how and why they are made, as an alternative to classical polymers. Our focus will be polymorphism, supramolecular isomerism and pseudo-polymorphism. Examples from our group of metal ion containing coordination polymer networks with...

Université de Fribourg

Tautocrowns: a concept for a sensing molecule with an active side-arm

Antonov, Liudmil ; Kurteva, Vanya B. ; Simeonov, Svilen P. ; Deneva, Vera V. ; Crochet, Aurélien ; Fromm, Katharina M.

In: Tetrahedron, 2010, vol. 66, no. 24, p. 4292-4297

A new sensing molecule containing aza-15-crown-5 as a receptor and 4- (phenyldiazenyl)naphthalen-1-ol as a signal converter has been synthesized. In the free ligand, the hydrogen bonding between the tautomeric OH group and the nitrogen atom from the macrocycle fully shifts the tautomeric equilibrium towards the enol form. The complexation reverses the equilibrium as a result of the strong...

Université de Fribourg

The Heterometallic Clusters of Trivalent Rare Earth Metals of [Ln(OPh)₆{Li(dme)}₃], with Ln=Eu and Sm

Maudez, William ; Fromm, Katharina M.

In: Helvetica Chimica Acta, 2009, vol. 92, no. 11, p. 2349-2356

Two new heterobimetallic phenoxide LnIII-Li complexes of formula [Ln(μ₂-OPh)₆{Li(dme)}₃] (Ln=Sm, Eu) have been synthesized and characterized using single-crystal X-ray diffraction. These two compounds are isostructural.

Université de Fribourg

Solid state tautomerism in 2-((phenylimino)methyl)naphthalene-1-ol

Nedeltcheva, Daniela ; Kamounah, Fadhil S. ; Mirolo, Laurent ; Fromm, Katharina M. ; Antonov, Liudmil

In: Dyes and Pigments, 2009, vol. 83, no. 1, p. 121-126

The solid state tautomerism of 2-((phenylimino)methyl)naphthalene-1-ol was studied using X-ray measurements and absorption spectroscopy. In the solid state, the keto tautomer predominates. The observed shift in the equilibrium from the enol (dilute solution) to the keto (solid state) forms is explained by the formation of dye aggregates using ab initio quantum chemical calculations.

Université de Fribourg

Multitopic ligand design: a concept for single-source precursors

Gschwind, Fabienne ; Sereda, Olha ; Fromm, Katharina M.

In: Inorganic Chemistry, 2009, vol. 48, no. 22, p. 10535–10547

The multitopic ligand O,O′-bisnicotinic acid tetraethylene glycol, L, was designed for the coordination of two distinct types of metal ions. In this work, we describe how the O-donor part of L is used to coordinate to alkaline earth metal ions and that the N-donor atoms of L bind to group 11 elements. This makes L a suitable ligand for the combination of both metal...

Université de Fribourg

Combating implant infections. Remarks by a women’s team

Arciola, C. R. ; Balaban, N. ; Baldassarri, L. ; Fromm, Katharina M. ; Hänsch, G. M. ; Obst, U. ; Presterl, E. ; Stefani, S. ; Verran, J. ; Visai, L.

In: The International Journal of Artificial Organs, 2008, vol. 31, p. 858 - 864

Research on implant infections requires cooperative efforts and integration between basic and clinical expertises. An international group of women scientists is acting together in this field. The main research topics of the participants of this group are described. Formation of bacterial biofilms, antibiotic resistance and production of virulence factors like adhesins and toxins are investigated....

Université de Fribourg

Silver nanoparticle formation in different sizes induced by peptides identified within split-and-mix libraries

Belser, Kirsten ; Slenters, Tünde Vig ; Pfumbidzai, Conelious ; Upert, Grégory ; Mirolo, Laurent ; Fromm, Katharina M. ; Wennemers, Helma

In: Angewandte Chemie International Edition, 2009, vol. 48, no. 20, p. 3661-3664

Split-and-mix libraries are an excellent tool for the identification of peptides that induce the formation of Ag nanoparticles in the presence of either light or sodium ascorbate to reduce Ag+ ions. Structurally diverse peptides were detected in colorimetric on-bead screenings that generate Ag nanoparticles of different sizes, as confirmed by SEM and X-ray powder diffraction studies