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Université de Fribourg

Toward large tubular helices based on the polymerization of tri(benzamide)s

Schulze, Maren ; Kilbinger, Andreas F. M.

In: Journal of Polymer Science Part A: Polymer Chemistry, 2016, p. -

Herein we present the synthesis and polycondensation of mono- and di-N-protected, bis-substituted tri(benzamide)s with the aim to create large, tubular helices. We synthesized 2,4-dimethoxy and 2,5-bis-TEGylated aminobenzoic acid derivatives as bent and linear monomers and introduced p-methoxybenzyl (PMB) amide protecting groups to the oligobenzamide backbone. An iterative coupling strategy...

Université de Fribourg

Catalytic living ring-opening metathesis polymerization

Nagarkar, Amit A. ; Kilbinger, Andreas F. M.

In: Nature Chemistry, 2015, vol. 7, no. 9, p. 718–723

In living ring-opening metathesis polymerization (ROMP), a transition-metal–carbene complex polymerizes ring-strained olefins with very good control of the molecular weight of the resulting polymers. Because one molecule of the initiator is required for each polymer chain, however, this type of polymerization is expensive for widespread use. We have now designed a chain-transfer agent (CTA)...

Université de Fribourg

Transient anions of cis- and trans-cyclooctene studied by electron-impact spectroscopy

Regeta, Khrystyna ; Nagarka, Amit ; Kilbinger, Andreas F. M. ; Allan, Michael

In: Physical Chemistry Chemical Physics, 2015, vol. 17, no. 6, p. 4696–4700

The effect which deformation of the double bond in trans-cyclooctene (TCO), compared to cis-cyclooctene (CCO), has on its negative ion – and indirectly on the π* virtual orbital – was studied by electron-impact spectroscopy. Differential elastic and vibrational excitation cross sections were measured at a scattering angle of θ = 135°. The vertical attachment energy (VAE) derived from the...

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,...

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

Synthesis of nanometer-sized rod–coil block copolymers

König, Hannah M. ; Kilbinger, Andreas F. M.

In: CHIMIA International Journal for Chemistry, 2013, vol. 67, no. 11, p. 788–790

We present the solid-supported synthesis of a linear rigid rod-like tetradeca(p-benzamide) nanorod as well as a pentadeca( p -benzamide) nanorod carrying an amide N-hexyl side chain at the center of the rod (on the 8th amino acid of the molecule). These nanorods were conjugated with solubilizing poly(ethylene glycol) chains and their solution aggregation was investigated. Both rod–coil block...

Université de Fribourg

Controlling molecular self-assembly on an insulating surface by rationally designing an efficient anchor functionality that maintains structural flexibility

Hauke, Christopher M. ; Bechstein, Ralf ; Kittelmann, Markus ; Storz, Christof ; Kilbinger, Andreas F. M. ; Rahe, Philipp ; Kühnle, Angelika

In: ACS Nano, 2013, vol. 7, no. 6, p. 5491–5498

Molecular self-assembly on surfaces is dictated by the delicate balance between intermolecular and molecule–surface interactions. For many insulating surfaces, however, the molecule–surface interactions are weak and rather unspecific. Enhancing these interactions, on the other hand, often puts a severe limit on the achievable structural variety. To grasp the full potential of molecular...

Université de Fribourg

ROMP copolymers for orthogonal click functionalizations

Schaefer, Mark ; Hanik, Nils ; Kilbinger, Andreas F. M.

In: Macromolecules, 2012, p. -

The ring-opening metathesis polymerization using ruthenium carbene initiators developed by Grubbs et al. is one of the most functional group tolerant living polymerization methods known. One of the most used postpolymerization functionalization methods used today is the copper-catalyzed 1,3-dipolar cycloaddition between alkynes and organic azides. Organic azides are, however, not tolerated by...

Université de Fribourg

Efficient amine end-functionalization of living ring-Opening metathesis polymers

Nagarkar, Amit A. ; Crochet, Aurelien ; Fromm, Katharina M. ; Kilbinger, Andreas F. M.

In: Macromolecules, 2012, vol. 45, no. 11, p. 4447–4453

An efficient strategy for the synthesis of monoamine end-functionalized living polymers using ring-opening metathesis polymerization with ruthenium initiators is reported. A new end-capping agent for this purpose was synthesized, and its efficiency for end-functionalization was evaluated using two common ruthenium-based initiators. Finally, terminal cross-metathesis was also explored as another...

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...