Université de Fribourg

Design, synthesis and in vivo evaluation of 3-arylcoumarin derivatives of rhenium(I) tricarbonyl complexes as potent antibacterial agents against methicillin-resistant Staphylococcus aureus (MRSA)

Sovari, Sara Nasiri ; Vojnovic, Sandra ; Bogojevic, Sanja Skaro ; Crochet, Aurelien ; Pavic, Aleksandar ; Nikodinovic-Runic, Jasmina ; Zobi, Fabio

In: European Journal of Medicinal Chemistry, 2020, vol. 205, p. 112533

We have prepared a series of ten 3-arylcoumarin molecules, their respective fac- [Re(CO)3(bpy)L]+ and fac-[Re(CO)3(L⁀L)Br] complexes and tested all compounds for their antimicrobial efficacy. Whereas the 3-arylcoumarin ligands are virtually inactive against the human-associated pathogens with minimum inhibitory concentrations (MICs) > 150 μM, when coordinated to the fac-[Re(CO)3]+ core,...

Université de Fribourg

Resonance raman optical activity shows unusual structural sensitivity for systems in resonance with multiple excited states: vitamin B12 case

Machalska, Ewa ; Zajac, Grzegorz ; Gruca, Anna ; Zobi, Fabio ; Baranska, Malgorzata ; Kaczor, Agnieszka

In: The Journal of Physical Chemistry Letters, 2020, vol. 11, no. 13, p. 5037–5043

In this work, cobalamins with different upper axial substituents and a cobalamin derivative with a ring modification were studied using chiroptical spectroscopies, in particular resonance Raman optical activity (RROA), to shed light on the influence of structural modifications on RROA spectra in these strongly chiral systems in resonance with multiple excited states at 532 nm excitation. We...

Université de Fribourg

Cytotoxicity of Mn-based photoCORMs of ethynyl-α-diimine ligands against different cancer cell lines: The key role of CO-depleted metal fragments

Rossier, Jeremie ; Delasoie, Joachim ; Haeni, Laetitia ; Hauser, Daniel ; Rothen-Rutishauser, Barbara ; Zobi, Fabio

In: Journal of Inorganic Biochemistry, 2020, vol. 209, p. 111122

A series of tricarbonyl manganese complexes bearing 4-ethynyl-2,2′-bipyridine and 5- ethynyl-1,10-phenanthroline α-diimine ligands were synthetized, characterized and conjugated to vitamin B12, previously used as a vector for drug delivery, to take advantage of its water solubility and specificity toward cancer cells. The compounds act as photoactivatable carbon monoxide-releasing molecules...

Université de Fribourg

Correlation of MLCTs of Group 7 fac-[M(CO)3]+ complexes (M = Mn, Re) with bipyridine, pyridinylpyrazine, azopyridine, and pyridin-2-ylmethanimine type ligands for rational photoCORM design

Kottelat, Emmanuel ; Lucarini, Fiorella ; Crochet, Aurelien ; Ruggi, Albert ; Zobi, Fabio

In: European Journal of Inorganic Chemistry, 2019, vol. 2019, no. 33, p. 3758–3768

A mathematical correlation of the MLCT absorption maxima of structurally related fac‐ [M(CO)3L2Br] complexes (M = Mn, Re; L2 = bidentate ligand) is obtained by the comparison of a total of 50 species bearing bipyridine, pyridinylpyrazine, azopyridine and pyridin‐2‐ylmethanimine L2 type ligands. The empirical relationship is first derived by the initial comparison of the MLCT absorption...

Université de Fribourg

Evaluation of the potential of cobalamin derivatives bearing ru(ii) polypyridyl complexes as photosensitizers for photodynamic therapy

Jakubaszek, Marta ; Rossier, Jeremie ; Karges, Johannes ; Delasoie, Joachim ; Goud, Bruno ; Gasser, Gilles ; Zobi, Fabio

In: Helvetica Chimica Acta, 2019, vol. 102, no. 7, p. -

The current photosensitizers (PSs) for photodynamic therapy (PDT) lack selectivity for cancer cells. To tackle this drawback, in view of selective cancer delivery, we envisioned conjugating two ruthenium polypyridyl complexes to vitamin B12 (Cobalamin, Cbl) to take advantage of the solubility and active uptake of the latter. Ultimately, our results showed that the transcobalamin pathway is...

Université de Fribourg

Antiplasmodial activity and in vivo bio-distribution of chloroquine molecules released with a 4-(4-ethynylphenyl)-triazole moiety from organometallo-cobalamins

Rossier, Jeremie ; Sovari, Sara Nasiri ; Pavic, Aleksandar ; Vojnovic, Sandra ; Stringer, Tameryn ; Bättig, Sarah ; Smith, Gregory S. ; Nikodinovic-Runic, Jasmina ; Zobi, Fabio

In: Molecules, 2019, vol. 24, no. 12, p. 2310

We have explored the possibility of using organometallic derivatives of cobalamin as a scaffold for the delivery of the same antimalarial drug to both erythro- and hepatocytes. This hybrid molecule approach, intended as a possible tool for the development of multi-stage antimalarial agents, pivots on the preparation of azide- functionalized drugs which, after coupling to the vitamin, are...

Université de Fribourg

Modified biovectors for the tuneable activation of anti-platelet carbon monoxide release

Prieto, Lucas ; Rossier, Jeremie ; Derszniak, Katarzyna ; Dybas, Jakub ; Oetterli, René M. ; Kottelat, Emmanuel ; Chlopicki, Stefan ; Zelder, Felix ; Zobi, Fabio

In: Chemical Communications, 2017, vol. 53, no. 51, p. 6840–6843

This communication describes the anti-platelet effects of a new class of cis-rhenium(II)- dicarbonyl-vitamin B12 complexes (B12-ReCORMs) with tuneable CO releasing properties.

Université de Fribourg

Correlation of surface pressure and hue of planarizable push-pull chromophores at the air/water interface

Neuhaus, Frederik ; Zobi, Fabio ; Brezesinski, Gerald ; Molin, Marta Dal ; Matile, Stefan ; Zumbuehl, Andreas

In: Beilstein Journal of Organic Chemistry, 2017, vol. 13, no. 1, p. 1099–1105

It is currently not possible to directly measure the lateral pressure of a biomembrane. Mechanoresponsive fluorescent probes are an elegant solution to this problem but it requires first the establishment of a direct correlation between the membrane surface pressure and the induced color change of the probe. Here, we analyze planarizable dithienothiophene push–pull probes in a monolayer at...

Université de Fribourg

Heptacoordinate Coii complex: a new architecture for photochemical hydrogen production

Lucarini, Fiorella ; Pastore, Mariachiara ; Vasylevskyi, Serhii ; Varisco, Massimo ; Solari, Euro ; Crochet, Aurelien ; Fromm, Katharina M. ; Zobi, Fabio ; Ruggi, Albert

In: Chemistry - A European Journal, 2017, p. -

The first heptacoordinate cobalt catalyst for light-driven hydrogen production in water has been synthesized and characterized. Photochemical experiments using [Ru(bpy)₃]²⁺ as photosensitizer gave a turnover number (TON) of 16300 mol H₂ (mol cat.)⁻¹ achieved in 2 hours of irradiation with visible (475 nm) light. This promising result provides a path forward in the...

Université de Fribourg

Organometallic cobalamin anticancer derivatives for targeted prodrug delivery via transcobalamin-mediated uptake

Rossier, Jeremie ; Hauser, Daniel ; Kottelat, Emmanuel ; Rothen-Rutishauser, Barbara ; Zobi, Fabio

In: Dalton Transactions, 2017, vol. 46, no. 7, p. 2159–2164

Herein we report the synthesis of new water-soluble vitamin B12 prodrugs bearing metal complexes at the β-upper side of the cobalt center. A total of three derivatives with the general design {Co–C[triple bond, length as m-dash]C-bpy–M}, where M represents a cytotoxic metal complex, were prepared and tested for their cytotoxicity against MCF-7 breast cancer cells. The choice of the metal...