The temporal control (ON/OFF/ON) of the fluorescence of a dichloromethane/acetonitrile 1 : 1 solution of calixarene 3 decorated with two pyrenyl moieties at the upper rim is attained by the addition of CCl₃CO₂H used as a convenient chemical fuel.

Nitroaromatic explosives are the most common explosives, and their detection is important to public security, human health, and environmental protection. In particular, the detection of solid explosives through directly revealing the presence of their vapors in air would be desirable for compact and portable devices. In this study, amino-functionalized carbon nanotubes were used to produce resistive sensors to detect nitroaromatic explosives by interaction with their vapors. Devices formed by carbon nanotube networks working at room temperature revealed trinitrotoluene, one of the most common nitroaromatic explosives, and di-nitrotoluene-saturated vapors, with reaction and recovery times of a few and tens of seconds, respectively. This type of resistive device is particularly simple and may be easily combined with low-power electronics for preparing portable devices.

Eleven calix[4]arene ligands, bearing zwitterionic α‐amino acids or charged ammonium or sulfonate/carboxylate groups, are synthesized and screened for the binding to the envelopes of three bacterial strain representatives of Gram‐positive, Gram‐negative, and mycobacteria. The binding is followed by on‐cell Saturation Transfer Difference Nuclear Magnetic Resonance (NMR) experiments directly on alive cells. While the anionic tetrasulfonatocalixarene does not bind to any bacterial strains significantly and the cationic calixarenes strongly bind to both Gram‐positive and Gram‐negative bacteria, the zwitterionic tetraprolino‐ and tetraphenylalaninocalix[4]arene show a remarkable selectivity for Gram‐negatives over Gram‐positives and mycobacteria. The tetraprolinocalixarene binds to the lipopolysaccharides extracted from two Gram‐negative bacteria (Pseudomonas putida or Escherichia coli), suggesting these biomacromolecules as possible targets in the recognition of their cell walls. The ligand binding epitope map demonstrates a deep involvement of the amino acids and calixarene aromatic nuclei in the interaction. In this study, for the first time, the ability of synthetic macrocycles to selectively recognize the envelope of Gram‐negative bacteria is highlighted, and the way to the chemical modifications of the ligand structure is paved to develop devices for the detection or treatment of bacterial infections, thus allowing to add another string to the bow for the fight against antimicrobial resistance.

The design, construction, and operation of devices and machines at the molecular scale using the bottom-up approach captivates a lot of interest in nanoscience. Particularly intriguing are interlocked molecular architectures, which are ideal candidates for these aims. [n]Pseudorotaxanes, [n]rotaxanes, and [n]catenanes serve as versatile prototypes for constructing molecular machines because they can be engineered to execute a diverse range of functions, including mechanical-like movements in response to chemical, photochemical, or electrochemical stimuli. The study explores the synthesis and characterization of a two-station two-gate calix[6]arene-based [2]catenane. Building on prior work with calix[6]arene-based Mechanically Interlocked Molecules (MIMs), this research integrates two functional gates—an azobenzene unit and a stilbene unit —into a two-station “track” ring. The synthesis employed threading and capping strategies to prepare the precursor [2]rotaxane isomers 12(azo-up) and 12(azo-down). Challenges in the deprotection of TBS groups led to the adoption of a supramolecular-assisted approach for the direct synthesis of the desired pseudorotaxane. The final catenation reaction, using a trans-stilbene-based bisacyl chloride as the “clipping unit”, afforded the [2]catenane C3(azo-down) in 25% yield after purification. Mass spectrometry and NMR spectroscopy confirmed the successful synthesis and orientation of C3(azo-down).

Polymeric membrane-based technology offers an energy-efficient solution for post-combustion carbon capture. Owing to their rigid, contorted backbones that endow them with exceptional CO ₂ permeability, Polymers of Intrinsic Microporosity (PIMs) are among the most promising candidates, but their application is constrained by physical aging. Here, the covalent inclusion of calix[4]arenes as monomeric units in PIMs based on Tröger's Base (PIM-TBs) is presented as valuable solution for the mitigation of this progressive free-volume collapse, by taking advantage of their intrinsic cavity. For this purpose, upper rim functionalised diamino-tetrapropoxy calix[4]arenes in defined geometrical arrangements ( cone , partial cone , and 1,3-alternate ) are exploited in the preparation of both homo- ( PIM-CXn-TBs ) and co-polymers ( PIM-Trip-CXn-TBs ) with diaminotriptycene units, which are fully characterised in terms of molecular weight distributions, textural parameters and CO ₂ /N ₂ adsorption properties at room temperature. PIM-Trip-CX3-TB , obtained from the copolymerisation of the 1,3-alternate conformer, and its post-polymerisation dealkylated counterpart ( PIM-Trip-CX3(OH)-TB ) are solution processed in films and tested in permeation and aging experiments. These studies reveal that, whereas the propylated copolymer mirrors the aging behaviour of pristine PIM-Trip-TB , PIM-Trip-CX3(OH)-TB exhibits a reduced early-stage loss of CO ₂ permeability, thus evidencing a concomitant effect of the covalent calix[4]arene incorporation and cavity rigidification promoted by intramolecular hydrogen-bonding interactions.

Triptycene-based PIM-TB with covalently incorporated calix[4]arene units exhibits reduced early-stage CO ₂ permeability loss after macrocycles dealkylation.