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Université de Fribourg

Functional metathesis catalyst through ring closing enyne metathesis: one pot protocol for living heterotelechelic polymers

Pal, Subhajit ; Lucarini, Fiorella ; Ruggi, Albert ; Kilbinger, Andreas F. M.

In: Journal of the American Chemical Society, 2018, vol. 140, no. 9, p. 3181–3185

Enyne ring closing metathesis has been used to synthesize functional group carrying metathesis catalysts from a commercial (Ru-benzylidene) Grubbs’ catalysts. The new Grubbs-type ruthenium carbene was used to synthesize living heterotelechelic ROMP polymers without any intermediate purification. Olefin metathesis with a mono substituted alkyne followed by ring closing metathesis with an...

Université de Fribourg

Heterotelechelic polymers by ring‐opening metathesis and regioselective chain transfer

Yasir, Peng Liu, Mohammad ; Ruggi, Albert ; Kilbinger, Andreas F. M.

In: Angewandte Chemie International Edition, 2018, vol. 57, no. 4, p. 914–917

Heterotelechelic polymers were synthesized by a kinetic telechelic ring-opening metathesis polymerization method relying on the regioselective cross-metathesis of the propagating Grubbs’ first-generation catalyst with cinnamyl alcohol derivatives. This procedure allowed the synthesis of hetero-bis-end-functional polymers in a one- pot setup. The molecular weight of the polymers could be...

Université de Fribourg

The influence of substituents on gelation and stacking order of oligoaramid – based supramolecular networks

Drechsler, Susanne ; Balog, Sandor ; Kilbinger, Andreas F. M. ; Casalini, Tommaso

In: Soft Matter, 2019, vol. 15, no. 36, p. 7250–7261

Self-assembly has proven to be a powerful tool for functional, smart materials such as hydrogels derived from low molecular weight compounds. However, the targeted design of functional gelators remains difficult. Here, we present a set of four Y-shaped aromatic amide tetramers with varying functionalities able to undergo different non- covalent interactions. These compounds were explored...

Université de Fribourg

Mechanically induced cis-to-trans isomerization of carbon–carbon double bonds using atomic force microscopy

Radiom, Milad ; Kong, Phally ; Maroni, Plinio ; Schäfer, Mark ; Kilbinger, Andreas F. M. ; Borkovec, Michal

In: Physical Chemistry Chemical Physics, 2016, vol. 18, no. 45, p. 31202–31210

Cis-to-trans isomerization of carbon–carbon double bonds can be induced by the application of mechanical force. Using single molecule force spectroscopy by means of atomic force microscopy (AFM) we pulled polymer molecules which contained cis double bonds in the backbone. In the force versus extension profiles of these polymers, a sudden extension increase is observed which is due to the...

Université de Fribourg

Mono-telechelic polymers by catalytic living ring-opening metathesis polymerization with second-generation Hoveyda–Grubbs catalyst

Liu, Peng ; Dong, Zhenghao ; Kilbinger, Andreas F. M.

In: Materials Chemistry Frontiers, 2020, vol. 4, no. 9, p. 2791–2796

The second-generation Hoveyda–Grubbs (HG2) catalyst, which has a small initiation to propagation rate ratio (ki/kp) in ring-opening metathesis polymerization (ROMP), was successfully used in a recently developed catalytic living ROMP. This proved that slow-initiating catalysts can enable ROMP in a living fashion to produce polymers with narrow dispersity and controlled molecular weight. The...

Université de Fribourg

One-pot synthesis and AFM imaging of a triangular aramide macrocycle

Storz, Christof ; Badoux, Michael ; Hauke, Christopher M. ; Šolomek, Tomáš ; Kühnle, Angelika ; Bally, Thomas ; Kilbinger, Andreas F. M.

In: Journal of the American Chemical Society, 2014, vol. 136, no. 37, p. 12832–12835

Macrocyclizations in exceptionally good yields were observed during the self-condensation of N-benzylated phenyl p-aminobenzoates in the presence of LiHMDS to yield three-membered cyclic aramides that adopt a triangular shape. An ortho-alkyloxy side chain on the N-benzyl protecting group is necessary for the macrocyclization to occur. Linear polymers are formed exclusively in the absence of this...

Université de Fribourg

One-step ring opening metathesis block-like copolymers and their compositional analysis by a novel retardation technique

Yasir, Mohammad ; Liu, Peng ; Markwart, Jens C. ; Suraeva, Oksana ; Wurm, Frederik R. ; Smart, Jansie ; Lattuada, Marco ; Kilbinger, Andreas F. M.

In: Angewandte Chemie International Edition, 2020, vol. 59, no. 32, p. 13597-13601

Using a one-step synthetic route for block copolymers avoids the repeated addition of monomers to the polymerization mixture, which can easily lead to contamination and, therefore, to the unwanted termination of chain growth. For this purpose, monomers (M1–M5) with different steric hindrances and different propagation rates are explored. Copolymerization of M1 (propagating rapidly) with M2...

Université de Fribourg

Polyethylenimine is a strong inhibitor of human papillomavirus and cytomegalovirus infection

Spoden, Gilles A. ; Besold, Katrin ; Krauter, Steffi ; Plachter, Bodo ; Hanik, Nils ; Kilbinger, Andreas F. M. ; Lambert, Carsten ; Florin, Luise

In: Antimicrobial Agents and Chemotherapy, 2012, vol. 56, no. 15, p. 75-82

Polyethylenimines are cationic polymers with potential as delivery vectors in gene therapy and with proven antimicrobial activity. However, the antiviral activity of polyethylenimines has not been addressed in detail thus far. We have studied the inhibitory effects of a linear 25-kDa polyethylenimine on infections with human papillomaviruses and human cytomegaloviruses. Preincubation of cells...

Université de Fribourg

Polyvinyl alcohol as a biocompatible alternative for the passivation of gold nanorods

Kinnear, Calum ; Burnand, David ; Clift, Martin J. D. ; Kilbinger, Andreas F. M. ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke

In: Angewandte Chemie International Edition, 2014, vol. 53, no. 46, p. 12613–12617

The functionalization of gold nanorods (GNRs) with polymers is essential for both their colloidal stability and biocompatibility. However, a bilayer of the toxic cationic surfactant cetyl trimethylammonium bromide (CTAB) adsorbed on the nanorods complicates this process. Herein, we report on a strategy for the biocompatible functionalization of GNRs with a hydrophobic polymeric precursor,...