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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

Total Angular Momentum Dichroism of the Terahertz Vortex Beams at the Antiferromagnetic Resonances

Sirenko, Andrei A. ; Marsik, Premysl ; Bugnon, Laurent ; Soulier, Mathias ; Bernhard, Christian ; Stanislavchuk, T. N. ; Xu, Xianghan ; Cheong, S.-W.

In: Physical Review Letters, 2021, vol. 126, no. 15, p. 157401

Terahertz vortex beams with different superposition of the orbital angular momentum $l={\pm}1$, ${\pm}2$, ${\pm}3$, and ${\pm}4$ and spin angular momentum ${\sigma}={\pm}1$ were used to study antiferromagnetic (AFM) resonances in TbFe$_3$(BO$_3$)$_4$ and Ni$_3$TeO$_6$ single crystals. In both materials we observed a strong vortex beam dichroism for the AFM resonances that are split in ...

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)....

Université de Fribourg

Infrared study of the multiband low-energy excitations of the topological antiferromagnet MnBi2Te4

Xu, Bing ; Zhang, Y. ; Alizade, E. H. ; Jahangirli, Z. A. ; Lyzwa, Fryderyk ; Sheveleva, Evgeniia ; Marsik, Premysl ; Li, Y. K. ; Yao, Y. G. ; Wang, Z. W. ; Shen, B. ; Dai, Y. M. ; Kataev, V. ; Otrokov, M. M. ; Chulkov, E. V. ; Mamedov, N. T. ; Bernhard, Christian

In: Physical Review B, 2021, vol. 103, no. 12, p. L121103

With infrared spectroscopy, we studied the bulk electronic properties of the topological antiferromagnet MnBi2Te4 with TN ≃ 25 K. With the support of band-structure calculations, we assign the intra- and interband excitations and determine the band gap of Eg ≈ 0.17 eV. We also obtain evidence for two types of conduction bands with light and very heavy carriers. The multiband free-carrier...

Université de Fribourg

Muon spin rotation and infrared spectroscopy study of Ba$_{1-x}$Na$_{x}$Fe$_{2}$As$_{2}$

Sheveleva, Evgeniia ; Xu, Bing ; Marsik, Premysl ; Lyzwa, Fryderyk ; Mallett, Benjamin P. P. ; Willa, K. ; Meingast, C. ; Wolf, Th. ; Shevtsova, T. ; Pashkevich, Yu. G. ; Bernhard, Christian

In: Physical Review B, 2020, vol. 101, no. 22, p. 224515

The magnetic and superconducting properties of a series of underdoped Ba 1 − x Na x Fe 2 As 2 (BNFA) single crystals with 0.19 ≤ x ≤ 0.34 have been investigated with the complementary muon-spin-rotation ( μ SR ) and infrared spectroscopy techniques. The focus has been on the different antiferromagnetic states in the underdoped regime and their competition with superconductivity,...

Université de Fribourg

Seipin accumulates and traps diacylglycerols and triglycerides in its ring-like structure

Zoni, Valeria ; Khaddaj, Rasha ; Lukmantara, Ivan ; Shinoda, Wataru ; Hongyuan, Yang ; Schneiter, Roger ; Vanni, Stefano

In: Proceedings of the National Academy of Sciences, 2021, vol. 118, no. 10, p. e2017205118

Lipid droplets (LDs) are intracellular organelles responsible for lipid storage, and they emerge from the endoplasmic reticulum (ER) upon the accumulation of neutral lipids, mostly triglycerides (TG), between the two leaflets of the ER membrane. LD biogenesis takes place at ER sites that are marked by the protein seipin, which subsequently recruits additional proteins to catalyze LD formation....

Université de Fribourg

New approach for time-resolved and dynamic investigations on nanoparticles agglomeration

Anaraki, Neda Iranpour ; Sadeghpour, Amin ; Iranshahi, Kamran ; Toncelli, Claudio ; Cendrowska, Urszula ; Stellacci, Francesco ; Dommann, Alex ; Wick, Peter ; Neels, Antonia

In: Nano Research, 2020, vol. 13, no. 10, p. 2847–2856

Nanoparticle (NP) colloidal stability plays a crucial role in biomedical application not only for human and environmental safety but also for NP efficiency and functionality. NP agglomeration is considered as a possible process in monodispersed NP colloidal solutions, which drastically affects colloidal stability. This process is triggered by changes in the physicochemical properties of the...

Université de Fribourg

Estimating the accuracy of the MARTINI model towards the investigation of Peripheral Protein-Membrane Interactions

Srinivasan, Sriraksha ; Zoni, Valeria ; Vanni, Stefano

In: Faraday Discussions, 2020, p. -

Peripheral membrane proteins play a major role in numerous biological processes by transiently associating with cellular membranes, often with extreme membrane specificity. Because of the short-lived nature of these interactions, molecular dynamics (MD) simulations have emerged as an appealing tool to characterize at the structural level the molecular details of the protein-membrane...

Université de Fribourg

Rapid detection of carbapenemase-producing Pseudomonas spp. using the NitroSpeed-Carba NP test

Sadek, Mustafa ; Poirel, Laurent ; Nordmann, Patrice

In: Diagnostic Microbiology and Infectious Disease, 2021, vol. 99, no. 3, p. 115280

The NitroSpeed-Carba NP test was used to rapidly detect and discriminate between the different types of carbapenemases (classes A, B, and D) within 30 minutes among a collection of 202 Pseudomonas sp. strains (mostly Pseudomonas aeruginosa). A total of 99 carbapenemase–(including enzymes exhibiting weak carbapenemase activity such as several Guyana Extended-Spectrum (GES)-ß-lactamases) and...