The hexaprotonated form of the hexaazamacrocycle, 7,22-dimethyl-3,7,11,18,22,26-hexaazatricyclo[26.2.2.2.13.16]tetratriaconta-1(30),13,15,28,31,33-hexaene, (H6Me2[30]pbz2N6)6+, was used as a receptor for the molecular recognition of aliphatic and aromatic carboxylate substrates. The receptor–substrate binding behaviour of (H6Me2[30]pbz2N6)6+ with aliphatic [−O2C(CH2)nCO2−, n = 0 to 4] and aromatic (benzoate, phthalate, isophthalate, and terephthalate) substrates was evaluated by potentiometry and 1H NMR spectroscopy. The association constants of the entities formed were determined in H2O at 298.0 K and 0.1 M KNO3 (by potentiometry) and in D2O (by 1H NMR). The constants for the aliphatic substrates are much lower than for the aromatic ones. NMR spectroscopy allowed the conclusion that the recognition process might involve H-bonding, electrostatic and π–π stacking interactions, the strength and the type of them depending on the substrate. The cooperative conjugation of the three types of interactions only occurs when terephthalate is the substrate. Molecular dynamics simulations (MD) in a periodic box of water solvent molecules were also used to investigate the nature of the binding association between the receptor and the three aromatic dicarboxylate anions (phthalate, isophthalate, and terephthalate). These studies confirmed that the (H6Me2[30]pbz2N6)6+ receptor encapsulates the terephthalate anion with the formation of an inclusion supermolecule stabilized by multiple N–H⋯O hydrogen bonding and π–π interactions. The molecular recognition between the receptor and the other two aromatic anions, phthalate and isophthalate, also occurs via N–H⋯O hydrogen bonds, but outside of the macrocyclic cavity. The results are discussed in terms of energetic and entropic contributions and showed that the binding association between the receptor and these anions is favourable.

Hydrogen sulfide (H₂S) and nitric oxide (NO) are especially known as toxic and polluting gases, yet they are also endogenously produced and play key roles in numerous biological processes. These two opposing aspects of the gases highlight the need for new types of materials to be developed in addition to the most common materials such as activated carbons and zeolites. Herein, a new imine-linked polymer organic framework was obtained using the inexpensive and easy-to-access reagents isophthalaldehyde and 2,4,6-triaminopyrimidine in good yield (64%) through the simple and catalyst-free Schiff-base reaction. The polymeric material has microporosity, an A_BET surface area of 51 m²/g, and temperature stability up to 300 °C. The obtained 2,4,6-triaminopyrimidine imine-linked polymer organic material has a higher capacity to adsorb NO (1.6 mmol/g) than H₂S (0.97 mmol/g). Release studies in aqueous solution showed that H₂S has a faster release (3 h) from the material than NO, for which a steady release was observed for at least 5 h. This result is the first evaluation of the possibility of an imine-linked polymer organic framework being used in the therapeutic release of NO or H₂S.

Biodiesel is produced by the transesterification of animal fats and vegetable oils, producing a large amount of glycerol as a by-product. The crude glycerol cannot be used in the food or pharmaceutical industries. It is crucial to transform glycerol into value-added products with applications in different areas to biodiesel be economically viable. One of the possible applications is its use as a precursor for the synthesis of carbon materials. The glycerol-based carbon materials have distinct properties due to the presence of sulfonic acid groups on the material surface, making them efficient catalysts. Additionally, the glycerol-based activated carbon materials show promising results concerning the adsorption of gases and liquid pollutants and recently as capacitors. Despite their potential, currently, little research has been carried out on the synthesis and application of those materials. This review summarized the preparation and application of carbon materials from glycerol, intending to show the potential of these materials.

The binding affinity of a dichlorocalix[2]arene[2]triazine based bis-urea azamacrocycle was investigated towards a wide range of bio-relevant dicarboxylate anions by a combination of ¹H NMR titrations in CDCl₃ and molecular dynamics simulations.

The search for H₂S donors has been increasing due to the multiple therapeutic effects of the gas. However, the use of nanoporous materials has not been investigated despite their potential. Zeolites and activated carbons are known as good gas adsorbents and their modification with chitosan may increase the material biocompatibility and simultaneously its release time in aqueous solution, thus making them good H₂S donors. Herein, we modified with chitosan a series of A zeolites (3A, 4A and 5A) with different pore sizes and an activated carbon obtained from glycerin. The amount of H₂S adsorbed was evaluated by a volumetric method and their release capacity in aqueous solution was measured. These studies aimed to verify which of the materials had appropriate H₂S adsorption/release properties to be considered a potential H₂S donor. Additionally, cytotoxicity assays using HeLa cells were performed. Considering the obtained results, the chitosan composite with the A zeolite with the larger pore opening was the most promising material to be used as a H₂S donor so a further cytotoxicity assay using H₂S loaded was conducted and no toxicity was observed.