Surface acoustic wave sensing of linear alcohols using para-acylcalix[n]arenes

<i>para</i>-Hexanoylcalix[4, 6 or 8]arenes have been used as surface acoustic wave sensor capture layers showing a high efficiency for the detection of linear alcohols, with high reproducibility and rapid response times.<br

Mechanistic insights into Smiles rearrangement. Focus on π–π stacking interactions along the radical cascade

International audienceThe synthesis of new arene and heteroarene scaffolds of therapeutic interest has generated a renewed interest in the domino radical cyclisation–Smiles. In this work we present a detailed mechanistic investigation of the radical version of a cascade involving a desulfonative Smiles rearrangement on an aromatic ring bearing a sulfonamide linker. Competing routes have been explored to characterize the molecular mechanism of the studied reaction. The knowledge gained from previous experimental observations is explained through the energy profile obtained by means of quantum mechanical calculations. This study answers questions about the rate determining step and the type of mechanism involved (two-step or concerted). Supplementary rate constant calculations as well as quantum molecular dynamics support experimental observations. An IGM-δg analysis performed along the reaction path unveils and quantifies an intramolecular π–π stacking interaction accelerating the reaction. This novel post processing IGM-δg tool based on the electron density, turns out to be useful to monitor and quantify specific intramolecular weak interactions along a reaction path from wave functions. From this mechanistic investigation it turns out that Smiles rearrangement here takes place in two steps rather than in a direct intramolecular radical substitution. Furthermore, we show that chain length effects must be taken into account in the functionalization of new sulfonylated derivatives subjected to this radical cascade, given their influence in the reaction rate

Synergy between Indoloquinolines and Ciprofloxacin: An Antibiofilm Strategy against <i>Pseudomonas aeruginosa</i>

Antibiotic treatments can participate in the formation of bacterial biofilm in case of under dosage. The interest of indoloquinoline scaffold for drug discovery incited us to study the preparation of new indolo [2,3-b]quinoline derivatives by a domino radical process. We tested the effect of two different “indoloquinoline” molecules (Indol-1 and Indol-2) without antimicrobial activity, in addition to ciprofloxacin, on biofilm formation thanks to crystal violet staining and enumeration of adhered bacteria. This association of ciprofloxacin and Indol-1 or Indol-2 attenuated the formation of biofilm up to almost 80% compared to ciprofloxacin alone, or even prevented the presence of adhered bacteria. In conclusion, these data prove that the association of non-antimicrobial molecules with an antibiotic can be a solution to fight against biofilm and antibiotic resistance emergence

L’art de la prédication au XVe siècle : efficacité rhétorique et figurative

Si l’efficacité de la prédication n’est pas un thème nouveau, l’analyse des interactions entre instruments rhétoriques et représentations visuelles ou mentales l’est bien davantage. Les contributions rassemblées ici dans une approche résolument interdisciplinaire étudient la manière dont l’art du verbe et la culture visuelle s’interpénètrent dans les sermons, afin d’en mesurer les effets performatifs sur l’auditoire et de discerner les éventuelles mutations qu’engendre une telle interaction sur les formes de dévotion. Autour de Bernardin de Sienne et de Savonarole qui occupent une large place, on trouvera des études notamment consacrées à Catherine de Sienne, Jean de Capistran et Luis de Maluenda

Synthesis and applications of copillar[5]arene dithiols

<p>A novel copillar[4+1]arene incorporating alkylthiol substituents was synthesised in three steps and structurally characterised as the first example of a pillar[n]arene to incorporate two terminal thiols on the same aromatic ring. The macrocycle was attached to gold electrodes through a standard dipping technique. Cyclic voltammetry demonstrated selectivity for Li⁺ over other alkali metal cations. The copillar[4+1]arene was also used as a capping agent in the preparation of 3 nm gold nanoparticles.</p