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Université de Fribourg

Versatile synthesis of chiral 6-oxoverdazyl radical ligands – new building blocks for multifunctional molecule-based magnets

Solea, Atena B. ; Wohlhauser, Tobie ; Abbasi, Parisa ; Mongbanziama, Yvan ; Crochet, Aurelien ; Fromm, Katharina M. ; Novitchi, Ghenadie ; Train, Cyrille ; Pilkington, Melanie ; Mamula, Olimpia

In: Dalton Transactions, 2018, vol. 47, no. 14, p. 4785–4789

A versatile synthetic methodology to access the first family of chiral verdazyl N,N′- chelate ligands is described and exemplified by N,N′-dimethyl-, N,N′-di-isopropyl- and N,N′-diphenyl oxoverdazyls bearing two isomers of the pinene-pyridine functional group. Their physical properties were probed by X-band EPR spectroscopy, cyclic voltammetry and DFT calculations. Preliminary...

Université de Fribourg

Amide neighbouring-group effects in peptides: phenylalanine as relay amino acid in long-distance electron transfer

Nathanael, Joses G. ; Gamon, Luke F. ; Cordes, Meike ; Rablen, Paul R. ; Bally, Thomas ; Fromm, Katharina M. ; Giese, Bernd ; Wille, Uta

In: ChemBioChem, 2018, vol. 19, no. 9, p. 922–926

In nature, proteins serve as media for long‐distance electron transfer (ET) to carry out redox reactions in distant compartments. This ET occurs either by a single‐step superexchange or through a multi‐step charge hopping process, which uses side chains of amino acids as stepping stones. In this study we demonstrate that Phe can act as a relay amino acid for long‐distance electron...

Université de Fribourg

Puckering behavior in six new phosphoric triamides containing aliphatic six- and seven-membered ring groups and a database survey of analogous ring-containing structures

Alviri, Banafsheh Vahdani ; Pourayoubi, Mehrdad ; Saneei, Anahid ; Keikha, Mojtaba ; Lee, Arie van der ; Crochet, Aurélien ; Ajees, A. Abdul ; Nečas, Marek ; Fromm, Katharina M. ; Damodaran, Krishnan ; Jenny, Titus A.

In: Tetrahedron, 2018, vol. 74, no. 1, p. 28–41

The influence of a N heteroatom on the ring conformations of six- and seven- membered aliphatic rings in six new C(O)NHP(O)-based phosphoric triamide structures (analysed by X-ray crystallography) is investigated. Additionally the influence of steric and crystal packing effects is also studied by the analysis of Hirshfeld surfaces. The results are compared to analogous structures with three-...

Université de Fribourg

Cis- and trans-9,10-di(1H-imidazol-1-yl)-anthracene based coordination polymers of ZnII and CdII: synthesis, crystal structures and luminescence properties

Vasylevskyi, Serhii I. ; Regeta, Khrystyna ; Ruggi, Albert ; Petoud, Stéphane ; Piguet, Claude ; Fromm, Katharina M.

In: Dalton Transactions, 2018, vol. 47, no. 2, p. 596–607

New functional coordination polymers based on the semi-flexible 9,10-di(1H-imidazol- 1-yl)-anthracene ligand (L) with ZnII and CdII, namely {[Zn(μ2-L)2] (ClO4)2·m(MeOH)·n(DCM)}n (1), {[Zn(μ2-L)2](BF4)2·m(MeOH)·n(DCM)}n (2), {[Zn(μ2-L)2(p-Tos)2]·m(DCM)·n(MeOH)}n (3), {[Cd(μ2-L)2(p-Tos)2]·m(DCM)}n (4) {[Cd(μ2-L)2(p-Tos)2]·m(MeOH)·n(Dioxane)}n (5) and {[Zn(μ2-...

Université de Fribourg

WRINKLED1 and ACYL‐COA:DIACYLGLYCEROL ACYLTRANSFERASE1 regulate tocochromanol metabolism in Arabidopsis

Pellaud, Sébastien ; Bory, Alexandre ; Chabert, Valentin ; Romanens, Joëlle ; Chaisse-Leal, Laurie ; Doan, Anh Vu ; Frey, Lucas ; Gust, Andrea ; Fromm, Katharina M. ; M?ne-Saffrané, Laurent

In: New Phytologist, 2018, vol. 217, no. 1, p. 245–260

Photosynthetic organisms such as plants, algae and some cyanobacteria synthesize tocochromanols, a group of compounds that encompasses tocopherols and tocotrienols and that exhibits vitamin E activity in animals. While most vitamin E biosynthetic genes have been identified in plant genomes, regulatory genes controlling tocopherol accumulation are currently unknown.We isolated by forward ...

Université de Fribourg

Influence of anions and solvent molecules on the packing and emission spectra of coordination polymers based on silver ions and an anthracene derivative

Chen, Jing ; Voutier, Noémie ; Rajabi, Jamshid ; Crochet, Aurélien ; Bassani, Dario M. ; Fromm, Katharina M.

In: CrystEngComm, 2017, vol. 19, no. 34, p. 5106–5113

Luminescence between green and blue was observed in the solid state for the free ligand L (anthracene-9,10-diylbis(methylene) dinicotinate) and five different Ag-L coordination polymers upon excitation at 344 nm. Depending on the packing of the anthracene moieties due to coordinating anions and the presence or absence of solvent molecules, the emission maximum is shifted.

Université de Fribourg

Characteristics and properties of nano-LiCoO2 synthesized by pre-organized single source precursors: Li-ion diffusivity, electrochemistry and biological assessment

Brog, Jean?Pierre ; Crochet, Aurélien ; Seydoux, Joël ; Clift, Martin J. D. ; Baichette, Benoît ; Maharajan, Sivarajakumar ; Barosova, Hana ; Brodard, Pierre ; Spodaryk, Mariana ; Züttel, Andreas ; Rothen?Rutishauser, Barbara ; Kwon, Nam Hee ; Fromm, Katharina M.

In: Journal of Nanobiotechnology, 2017, vol. 15, p. 58

LiCoO₂ is one of the most used cathode materials in Li-ion batteries. Its conventional synthesis requires high temperature (>800 °C) and long heating time (>24 h) to obtain the micronscale rhombohedral layered high-temperature phase of LiCoO₂ (HT-LCO). Nanoscale HT-LCO is of interest to improve the battery performance as the lithium (Li⁺) ion pathway is expected to be shorter in...

Université de Fribourg

Influence of the sacrificial polystyrene removal pathway on the TiO₂ nanocapsule structure

Hérault, Nelly ; Fromm, Katharina M.

In: Helvetica Chimica Acta, 2017, vol. 100, no. 6, p. -

This study demonstrates the significant influence of the polystyrene removal pathway on the TiO₂ nanocapsules obtained from PS@TiO₂ core-shell particles. In a first step, the polystyrene spheres were coated with titanium oxide via hydrolysis and condensation of the titanium precursor to form PS@TiO₂ core-shell particles. Then, the creation of the empty cavity to form TiO₂ nanocapsules was...