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Sulfur(VI)‐based functional groups are popular scaffolds in a wide variety of research fields including synthetic and medicinal chemistry, as well as chemical biology. The growing interest in sulfur(VI)‐containing molecules has motivated the scientific community to explore new methods to synthesize and modify them. Here, photocatalysis plays a key role granting access to new types of reactivity under mild reaction conditions. In this Perspective, we present a selection of works reported in the last six years focused on the photocatalytic assembly and reactivity of sulfones, sulfonamides, and sulfoximines. We addressed the key synthetic intermediates for each transformation, while discussing limitations and strength points of the protocols. Future directions of the field are finally presented. [ABSTRACT FROM AUTHOR]

The objective of this work is to evaluate the reprocessing of PLA 3D printing waste from different origins, into filaments and films, and without the addition of any additive. Two types of waste were considered: a blend of different printing wastes (masks, visors, other components) of personal protective equipment coming from an association of Spanish coronamakers, and PLA waste from a single known commercial source. Both types of materials were subjected to repeated extrusion cycles and processed into films by compression molding. Samples were characterized after each cycle and their mechanical and viscosity properties evaluated. Diffusion-ordered NMR spectroscopy (DOSY) experiments were also carried out to estimate molecular weights. The results show a better performance for the PLA waste from the known origin, capable of withstanding up to three re-extrusion cycles per two for the waste blending, without significant degradation. Additionally, a model to address collection and mechanical recycling cycles under two different scenarios (full traceability and not full traceability) was proposed. [ABSTRACT FROM AUTHOR]

The synthesis of small molecules able to mimic the active site of hydrolytic enzymes has been largely pursued in recent decades. The high reaction rates and specificity shown by natural hydrolases present an attractive target, and yet the preparation of suitable small‐molecule mimics remains challenging, requiring activated substrates to achieve productive outcomes. Here we present small synthetic artificial enzymes which mimic the catalytic site and the oxyanion hole of chymotrypsin and N‐terminal hydrolases and are able to perform, for the first time, the transesterification of a non‐activated ester such as ethyl acetate with methanol under mild and neutral reaction conditions. [ABSTRACT FROM AUTHOR]

Cleft type receptors showing the oxyanion hole motif have been prepared in a straightforward synthesis starting from the commercial 3,7‐dihidroxy‐2‐naphthoic acid. The double H‐bond donor pattern is achieved by the introduction of a sulfonamide group in the C‐8 position of naphthalene and a carboxamide at the C‐2 position. This cleft, for which the geometry resembles that of an oxyanion hole, is able to adjust to different guests, as shown by the analysis of the X‐ray crystal structures of associates with methanol or acetic acid. Combination of hydrogen bonds and charge‐transfer interactions led to further stabilization of the complexes, in which the electron‐rich aromatic ring of the receptor was close in space to the electron‐deficient dinitroaromatic guests. Modelling studies and bidimensional NMR experiments have been carried out to provide additional information. [ABSTRACT FROM AUTHOR]

The generation of secondary colors in digital devices by means of the additive red, green, and blue color model (RGB) can be a valuable way to introduce students to the basics of spectroscopy. This work has been focused on the spectral separation of secondary colors of light emitted by a computer screen into red, green, and blue bands, and how the intensity of these bands can be modulated if the portions of each primary color are modified in the RGB coordinates. The option found in the PowerPoint program for defining RGB values in the background of slides has been used in order to tune the color of the analyzed light. On the other hand, a CD-ROM based spectroscope has been found to provide enough resolution for this kind of analysis and an accessible way to perform it. These studies can be carried out qualitatively, comparing the different spectra observed through the spectroscope, as well as quantitatively, if these spectra are photographed using a digital camera and they are plotted after the analysis of the images using ImageJ, an open source program. [ABSTRACT FROM AUTHOR]

Keywords: Artificial Hydrolase; Enzyme Mimic; Organocatalysis; Oxyanion Hole; Transesterification EN Artificial Hydrolase Enzyme Mimic Organocatalysis Oxyanion Hole Transesterification 1 1 1 08/23/22 20220826 NES 220826 B Ein kleines synthetisches Enzym b ist erstmals in der Lage, die Umesterung von unaktivierten Estern unter neutralen und milden Bedingungen durchzuführen. Rücktitelbild: Transesterification of Non-Activated Esters Promoted by Small Molecules Mimicking the Active Site of Hydrolases (Angew. Inspiriert von der katalytischen Maschinerie von Chymotrypsin und N-terminalen Hydrolasen, zeigen José J. Garrido-González, Ángel L. Fuentes de Arriba et al. in ihrem Forschungsartikel (e202206072), dass ein kleines Molekül, das die katalytische Triade und das Oxyanionloch von Hydrolasen nachahmt, im Reagenzglas die katalytischen Eigenschaften hydrolytischer Enzyme nachbilden kann. [Extracted from the article]

Back Cover: Transesterification of Non-Activated Esters Promoted by Small Molecules Mimicking the Active Site of Hydrolases (Angew. Keywords: Artificial Hydrolase; Enzyme Mimic; Organocatalysis; Oxyanion Hole; Transesterification EN Artificial Hydrolase Enzyme Mimic Organocatalysis Oxyanion Hole Transesterification 1 1 1 08/23/22 20220826 NES 220826 B A small synthetic artificial enzyme b is able to accomplish, for the first time, the transesterification of non-activated esters under neutral and mild conditions. Artificial Hydrolase, Enzyme Mimic, Organocatalysis, Oxyanion Hole, Transesterification. [Extracted from the article]

Using supramolecular interactions, a novel macrocyclic receptor is able to selectively extract zwitterionic phenylglycine from neutral aqueous solutions into chloroform with up to 91.8% ee . Modeling studies, nuclear magnetic resonance experiments, and X-ray diffraction analysis were carried out to explain the high enantioselectivity observed.