Enzymes are the most efficient and specific catalysts to date. Although they have been thoroughly studied for years, building a true enzyme mimic remains a challenging and necessary task. Here, we show how a three-dimensional geometry analysis of the key catalytic residues in natural hydrolases has been exploited to design and synthesize small-molecule artificial enzymes which mimic the active centers of chymotrypsin and N-terminal hydrolases. The optimized prototype catalyzes the methanolysis of the acyl enzyme mimic with a half-life of only 3.7 min at 20 °C, and it is also able to perform the transesterification of vinyl acetate at room temperature. DFT studies and X-ray diffraction analysis of the catalyst bound to a transition state analogue proves the similarity with the geometry of natural hydrolases.

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.

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.

Dedicated to François Diederich. We are so grateful to be part of the Diederich chemistry family: his contagious enthusiasm and inspiration will always guide us.

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.