Growing detergentome. Recent synthesis concepts and detergent building blocks, i. e., head, linker, tail, are reviewed regarding their availability and role in the expansion of the detergentome (entirety of all detergents). The development of detergents for membrane protein studies turns out to be a key driver for detergent diversity. Metric-assisted optimization strategies will facilitate the development of tailor-made and safe-to-use detergents.

Abstract

Detergents are amphiphilic molecules that serve as enabling steps for today's world applications. The increasing diversity of the detergentome is key to applications enabled by detergent science. Regardless of the application, the optimal design of detergents is determined empirically, which leads to failed preparations, and raising costs. To facilitate project planning, here we review synthesis strategies that drive the diversification of the detergentome. Synthesis strategies relevant for industrial and academic applications include linear, modular, combinatorial, bio-based, and metric-assisted detergent synthesis. Scopes and limitations of individual synthesis strategies in context with industrial product development and academic research are discussed. Furthermore, when designing detergents, the selection of molecular building blocks, i. e., head, linker, tail, is as important as the employed synthesis strategy. To facilitate the design of safe-to-use and tailor-made detergents, we provide an overview of established head, linker, and tail groups and highlight selected scopes and limitations for applications. It becomes apparent that most recent contributions to the increasing chemical diversity of detergent building blocks originate from the development of detergents for membrane protein studies. The overview of synthesis strategies and molecular blocks will bring us closer to the ability to predictably design and synthesize optimal detergents for challenging future applications.

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 computational 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; their 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 z-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 computational calculations.

Alzheimer’s disease (AD) is the most common form of dementia worldwide, affecting millions of people around the globe. AD is characterized by different pathologies being beta-amyloid (Aβ) plaque formation, metal ion dysregulation, and oxidative stress central topics under investigation. Copper-Aβ complexes have been shown to induce catalytic hydrogen peroxide formation and increase OS in the brain leading to neuronal death. Pincer-type compounds are tridentate ligands that coordinate metals in a planar fashion whose properties can be tuned via group substitutions, giving rise to many possibilities in catalysis and drug discovery. In this work we evaluated the potential pharmaceutical activity of 26 pincer compounds in AD’s copper ion-related oxidative stress framework. In this sense, four key aspects were considered: 1) Lipinski’s rule of five, 2) blood-brain barrier permeation, 3) standard reduction potential (SRP) of the formed copper complexes, and 4) the ligand’s affinity towards copper cations. The evaluation of these criteria was performed by means of bioinformatic tools and electronic structure calculations at the DFT level of theory. Our results suggest that two compounds from this set are potential antioxidant agents, whereas five of them are promissory distributor-like compounds in the context of AD.

This review analyzes critically the production of valeric biofuels from γ-valerolactone, a relevant biomass-derived platform molecule. Initially, the main properties of valeric esters as fuels for spark- and compression-ignition engines are summarized. Then, catalytic routes to valeric esters from γ-valerolactone are meticulously analyzed, describing the acid- and metal-catalyzed reactions taking part in the tandem catalysis. Only works focused on the production of the valeric biofuels were considered, excluding the cases where these esters were observed in minor amounts or as byproducts. The role of the appropriate selection of the support, catalytic species, catalyst preparation and experimental conditions on the valeric ester productivity are thoroughly commented. Finally, some concluding remarks and perspectives are given, mentioning the areas where additional efforts must be done in order to turn the dream of a massive and renewable valeric biofuel production into a reality.

Pyrazole-containing iodonium triflates and silver(I) triflate bind to each other, and such an interplay significantly affects the total catalytic activity of the mixture of these Lewis acids. The obtained results indicate that such a cooperation additionally results in prevention of decomposition of the organocatalysts during the reaction progress.

Abstract

Kinetic data based on ¹H NMR monitoring and computational studies indicate that in solution, pyrazole-containing iodonium triflates and silver(I) triflate bind to each other, and such an interplay results in the decrease of the total catalytic activity of the mixture of these Lewis acids compared to the separate catalysis of the Schiff condensation, the imine–isocyanide coupling, or the nucleophilic attack on a triple carbon−carbon bond. Moreover, the kinetic data indicate that such a cooperation with the silver(I) triflate results in prevention of decomposition of the iodonium salts during the reaction progress. XRD study confirms that the pyrazole-containing iodonium triflate coordinates to the silver(I) center via the pyrazole N atom to produce a rare example of a pentacoordinated trigonal bipyramidal dinuclear silver(I) complex featuring cationic ligands.

The [M4–Hal]– (M = the title compound; Hal = Cl, Br, and I) complexes were isolated in the form of salts of [Et4N]+ cation and characterized by XRD, NMR, UV-Vis, DFT, QTAIM, EDD, and EDA. Their stoichiometry is caused by a cooperative interplay of σ-hole-driven chalcogen (ChB) and hydrogen (HB) bondings. In the crystal, [M4–Hal]– are connected by the π-hole-driven ChB; overall, each [Hal]– is six-coordinated. In the ChB, the electrostatic interaction dominates over orbital and dispersion interactions. In UV-Vis spectra of the M + [Hal]– solutions, ChB-typical and [Hal]–-dependent charge-transfer bands are present; they reflect orbital interactions and allow identification of the individual [Hal]–. However, the structural situation in the solutions is not entirely clear. Particularly, the UV-Vis spectra of the solutions are different from the solid-state spectra of the [Et4N]+[M4–Hal]–; very tentatively, species in the solutions are assigned [M–Hal]–. It is supposed that the formation of the [M4–Hal]– proceeds during the crystallization of the [Et4N]+[M4–Hal]–. Overall, M can be considered as a chromogenic receptor and prototype sensor of [Hal]–. The findings are also useful for crystal engineering and supramolecular chemistry.

Light manipulation of supramolecular assemblies is a promising method for developing complex, programmable, or multifunctional systems and nanoscopic machine-like entities. In this minireview, we discuss self-assembled and covalently bound cages and macrocycles containing photoswitches, allowing for a geometry change, breaking apart, or the disassembly and reassembly of the structures.

Abstract

The utilisation of light to achieve precise manipulation and control over the structure and function of supramolecular assemblies has emerged as a highly promising approach in the development of complex, configurable, or multifunctional systems and nanoscopic machine-like entities. In this minireview, we highlight recent examples of self-assembled and covalently bound cages and macrocycles with a focus on the external and internal functionalisation of a structure with a photoswitchable unit or the embedment of a photoswitch into the framework of a structure. Functionalising the interior or exterior of a supramolecular cage or macrocycle with a photoresponsive group enables control over different properties, such as guest binding or assembly in the solid-state, while the overall shape of the assembly often undergoes no significant change. By directly integrating a photoswitchable unit into the framework of a supramolecular structure, the isomerisation can either induce a geometry change, the disassembly, or the disassembly and reassembly of the structure. Historical and recent examples covered in this review are based on azobenzene, diarylethene, stilbene photoswitches, or alkene motors that were incorporated into macrocycles and cages constructed by metal-organic, dynamic covalent, or covalent bonds.

The cover feature image shows measurement of Raman optical activity spectra, which provide extended information about molecular behavior in solutions. If coupled with multi-scale density functional theory and molecular dynamics computations, whole potential energy maps can be deduced from the spectra. The maps can serve, for example, to verify or improve common force fields. For glutathione, a limited effect of pH on the backbone conformation was found. More information can be found in the Research Article by Petr Bouř and co-workers.

The extensive π system in the naphthalene structure and the carboxylic acid group of 1,4-naphthalene dicarboxylic acid (NA) render it an exceptional organic semiconductor for doping TiO₂ using a calcination-free sol-gel method. The resulting catalyst exhibited a significantly improved hydrogen production rate by photolyzing water molecules under visible light, outperforming the efficiency of the calcined material. Read more about the story behind the cover in the Cover Profile and about the research itself (DOI: 10.1002/cplu.202300172).

Abstract

Invited for this month's cover are the collaborating groups of Dr. Jianwei Li at the University of Turku and Prof. Chunman Jia, Kang Yang and Dan Wei at Hainan University. The cover image compares the structure of calcined (left) and non-calcined (right) rutile TiO₂ doped with a molecule NA. The calcination process enlarges the pores in TiO₂, reducing its surface area and hydrogen production efficiency under visible light. The “sad face” symbolizes the damaged pore structure. Conversely, doping TiO₂ with NA without high-temperature calcination forms a covalent bond, resulting in smaller pores, larger surface area, and improved hydrogen production efficiency. The “smiley face” represents the structurally intact TiO₂ hybrid material. More information can be found in the Research Article by Jianwei Li, Chunman Jia, and co-workers.

The synthesis of four gold(I) [AuClL] compounds containing chloro and biologically active protonated thiosemicarbazones based on 5-nitrofuryl (L=HSTC) is reported. The cytotoxicity of the gold compounds and thiosemicarbazone ligands was evaluated against selected cancer cell lines and compared to that of Auranofin. Read more about the story behind the cover in the Cover Profile and about the research itself (DOI: 10.1002/cplu.202300115).

Abstract

Invited for this month's cover are the collaborating groups of Esteban Rodríguez-Arce from the University of Chile and María Contel from The City University of New York Brooklyn College. The cover picture shows “Supergold“ a very powerful gender neutral warrior with superpowers who fights against cancer! The warrior's golden armor and sword represent the pharmacological power of the gold atom. Engraved on the shield, the gold-thiosemicarbazone molecules are the warrior's coat of arms. Supergold selectively destroys different cancer cells. More information can be found in the Research Article by Esteban Rodríguez-Arce, María Contel, and co-workers.