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Nowadays the use of hydrogels for biomedical purposes is increasing because of their interesting features that allow the development of targeted drug delivery systems. Herein, hydrogel based on Laponite® (Lap) clay mineral as gelator and cucurbit[6]uril (CB[6]) molecules were synthetized for the delivery of flufenamic acid (FFA) for potential topical application. Firstly, the interaction between CB[6] and FFA was assessed by UV‐vis spectroscopic measurements and molecular modeling calculations. Then, the obtained complex was used as filler for Lap hydrogel (Lap/CB[6]/FFA). The properties of the hydrogel in terms of viscosity and, self‐repair abilities were investigated; its morphology was imaged by scanning electron and polarized optical microscopies. Furthermore, the changes in the hydrodynamic radii and in the colloidal stability of CB[6]/Lap mixture were investigated in terms of translational diffusion from dynamic light scattering and ζ‐potential measurements. Finally, the kinetic in vitro release of FFA, from Lap/CB[6]/FFA hydrogel, was studied in a medium mimicking the pH of skin and the obtained results were discussed both by an experimental point of view and by molecular modeling calculations. [ABSTRACT FROM AUTHOR]

The article titled "Front Cover: Thixotropic Hydrogels Based on Laponite® and Cucurbituril for Delivery of Lipophilic Drug Molecules" in the journal ChemPlusChem discusses the potential use of laponite hydrogels filled with a supramolecular complex of cucurbit[6]uril and flufenamic acid for topical drug delivery. The cover picture showcases this application. The research article, authored by Viseras‐Iborra, Riela, and their colleagues, provides more detailed information on this topic. The authors of the article are Marina Massaro, Giuseppe Cinà, Ana Borrego‐Sánchez, C. Ignacio Sainz‐Díaz, César Viseras‐Iborra, Rita Sánchez‐Espejo, Raquel de Melo Barbosa, Federica Leone, Ivana Pibiri, Renato Noto, and Serena Riela. [Extracted from the article]

Diimidazolium-based organic salts, bearing peptides or amino acids as anions have been synthesised and tested for their gelling ability in biocompatible solvents. These low molecular weight salts were successfully used as gelators in phosphate buffered saline (PBS) solution and ionic liquids. Then, the properties of the obtained soft materials were analysed in terms of melting temperature and gel strength as accounted for by rheological investigations. The gel-phase formation was studied by using UV/Vis and resonance light scattering measurements, whereas the morphology of the soft materials was analysed by using polarised optical microscopy and scanning electron microscopy. To get information about the organisation of the gelator in the gelatinous matrix, X-ray diffraction measurements were performed both on the neat gelators and their gels. The results collected show that the properties of the gel phases, like the thermal stability, the self-repairing ability, the resistance to flow as well as the morphology, are dependent on the nature of the anion. Furthermore, bioassays revealed that the obtained diimidazolium organic salts possessed antimicrobial activity, against gram-negative and gram-positive tester strains. In particular and noteworthy, the diimidazolium organic salts exert a bactericidal capability, which was retained even if they are included in the gel phase. Thus, a novel kind of bioactive soft material was obtained that could be fruitfully employed as a non-covalent coating exerting antibacterial capability. [ABSTRACT FROM AUTHOR]

Insights are provided into the properties of molecular gels formed by diimidazolium salts both in 'normal' solvents and ionic liquids. These materials can be interesting for applications in green and sustainable chemistry in which ionic liquids play a significant role, like catalysis and energy. In particular, two positional isomers of a diimidazolium cation have been examined with a wide range of anions for their ability to form gel phases. In particular, di-, tri-, and tetravalent anions bearing aliphatic or aromatic spacers were paired with the divalent cations. The properties of the organo- and ionogels formed have been analyzed by means of several different techniques, including calorimetry, rheology, resonance light scattering, UV/Vis absorption, polarizing optical microscopy, and powder X-ray diffraction measurements. The investigations performed enabled us to obtain a wide range of conductive materials characterized by a high thermal stability and a low corrosiveness of the gelator (organogels) or of both gelator and solvent (ionogels). The information gained should be useful in the broader quest to identify and promote their applications. [ABSTRACT FROM AUTHOR]

N-Heterocyclic carbenes (NHCs) are widely used as organocatalysts. Their reactivity (and instability) is related to their basicity and nucleophilicity, which, in turn, are linked to their scaffold. NHCs can be generated by chemical deprotonation or electrochemical reduction of the parent azolium cations, NHCH+s. Cyclic voltammetry enabled the reduction potential of the NHCH+s to be determined; the reduction potential is related to the acidity of the NHCH+s and the oxidation potential of the NHCs, which is related to the nucleophilicity of the NHCs. It was thus possible to order different NHCH+s and NHCs by their acidity and nucleophilicity, respectively. A study on the stability of NHCs was also performed in the absence and in the presence of acetic acid to assess the possibility of the coexistence of NHC and an acid in the same solution, opening the possibility of co-catalysis. Finally, ab initio calculations confirmed the presence, in DMF, of hydrogen-bonded NHCH+-NHC adducts, which could influence catalyst activity. [ABSTRACT FROM AUTHOR]

The supramolecular aggregation of three diimidazolium-functionalized perylene bisimides, differing in the alkyl chain length was investigated. These salts form aggregates in solvents like chloroform, dichloromethane, and glycerol. Solvent-, concentration-, and temperature-dependent spectroscopic studies were carried out, evidencing the occurrence of an isodesmic, enthalpy-driven aggregation process, underpinned by π-π stacking and hydrogen bonding. Moreover, dynamic light scattering (DLS) measurements and SEM images revealed that these salts aggregate in chloroform into elongated structures. [ABSTRACT FROM AUTHOR]

Diimidazolium functionalized perylene bisimide salts conjugate two well ‐ known aggregation motifs, perylene bisimides and imidazolium salts. This conjunction brings about H ‐ aggregates underpinned by π – π stacking and hydrogen ‐ bonding interactions, formed by an enthalpy ‐ driven, isodesmic aggregation process. The solvent plays a significant role in determining the aggregation of the salts studied. Morphological analysis points out that these salts self ‐ assemble into elongated structures. The complete story can be found in the Full Paper by F. D′Anna, S. Marullo and co ‐ workers on page 14780 ff. [ABSTRACT FROM AUTHOR]

Invited for this month's cover are the collaborating groups of Prof. Serena Riela at University of Catania, Prof. César Viseras at University of Granada and Dr. Ignacio Sainz‐Diaz at Instituto Andaluz de Ciencias de la Tierra. The cover picture shows the possible application of the developed system. In particular, flufenamic acid, anti‐inflammatory and anti‐pyretic drug, was complexed into cucurbituril cavity and the supramolecular system obtained was used as filler for laponite® hydrogel for its topical delivery. More information can be found in the Research Article by Viseras‐Iborra, Riela, and co‐workers. [ABSTRACT FROM AUTHOR]