The use of cucurbit[8]uril as a molecular host has emerged in the chemical literature as a reliable strategy for the creation of dynamic chemical systems, owing to its ability to form homo- and heteroternary complexes in aqueous media with appropriate molecular switches as guests. In this manner, CB[8]-based supramolecular switches can be designed in a predictable and modular fashion, through the selection of appropriate guests able to condition the redox, photochemical, or pH-triggered behavior of tailored multicomponent systems. Furthermore, CB[8] allows the implementation of dual/triple and linear/orthogonal stimuli-dependent properties into these molecular devices by a careful selection of the guests. This versatility in their design gives these supramolecular switches great potential for the rational development of new materials, in which their function is not only determined by the custom-made stimuli-responsiveness, but also by the transient aggregation/disaggregation of homo- or heteromeric building blocks.

Cucurbit[8]uril (CB[8])‐Based Supramolecular Switches

Molecularly Imprinted Materials: Science and Technology

Enzymes, as nature’s catalysts, speed up the very reactions that make life possible. Hydrolytic enzymes are a particularly important enzyme class responsible for the catalytic breakdown of lipids, ...

Synthetic Catalysts Inspired by Hydrolytic Enzymes

Molecular imprinting within cross-linked micelles using 4-vinylphenylboronate derivatives of carbohydrates provided water-soluble nanoparticle receptors selective for the carbohydrate templates. Complete differentiation of d-aldohexoses could be achieved by these receptors if a single inversion of hydroxyl occurred at C2 or C4 of the sugar or if two or more inversions took place. Glycosides with a hydrophobic aglycan displayed stronger binding due to increased hydrophobic interactions.

/pdf/selective-recognition-of-d-aldohexoses-in-water-by-boronic-1p836ob49j.pdf

Selective Recognition of d-Aldohexoses in Water by Boronic Acid-Functionalized, Molecularly Imprinted Cross-Linked Micelles

A critical review of different prominent nanotechnologies adapted to catalysis is provided, with focus on how they contribute to the improvement of selectivity in heterogeneous catalysis. Ways to modify catalytic sites range from the use of the reversible or irreversible adsorption of molecular modifiers to the immobilization or tethering of homogeneous catalysts and the development of well-defined catalytic sites on solid surfaces. The latter covers methods for the dispersion of single-atom sites within solid supports as well as the use of complex nanostructures, and it includes the post-modification of materials via processes such as silylation and atomic layer deposition. All these methodologies exhibit both advantages and limitations, but all offer new avenues for the design of catalysts for specific applications. Because of the high cost of most nanotechnologies and the fact that the resulting materials may exhibit limited thermal or chemical stability, they may be best aimed at improving the selective synthesis of high value-added chemicals, to be incorporated in organic synthesis schemes, but other applications are being explored as well to address problems in energy production, for instance, and to design greener chemical processes. The details of each of these approaches are discussed, and representative examples are provided. We conclude with some general remarks on the future of this field.

Designing Sites in Heterogeneous Catalysis: Are We Reaching Selectivities Competitive With Those of Homogeneous Catalysts?

Hydrolysis of phosphodiester bonds is catalyzed efficiently by DNA- and RNA-hydrolyzing enzymes, but their synthetic mimics often fail to display catalytic turnovers because the phosphate products ...

Controlling Product Inhibition through Substrate-Specific Active Sites in Nanoparticle-Based Phosphodiesterase and Esterase

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=2021&context=chem_pubs

Molecularly Responsive Binding through Co-occupation of Binding Space: A Lock–Key Story

Enzymes have substrate-tailored active sites with optimized molecular recognition and catalytic features. Although many different platforms have been used by chemists to construct enzyme mimics, it is challenging to tune the structure of their active sites systematically. By molecularly imprinting template molecules within doubly cross-linked micelles, we created protein-sized nanoparticles with catalytically functionalized binding sites. These enzyme mimics accelerated the hydrolysis of activated esters thousands of times over the background reaction, whereas the analogous catalytic group (a nucleophilic pyridyl derivative) was completely inactive in bulk solution under the same conditions. The template molecules directly controlled the size and shape of the active site and modulated the resulting catalyst's performance at different pHs. The synthetic catalysts displayed Michaelis–Menten enzymatic behavior and, interestingly, reversed the intrinsic reactivity of the activated esters during the hydrolysis.

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https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=2203&context=chem_pubs

Cross‐Linked Micelles with Enzyme‐Like Active Sites for Biomimetic Hydrolysis of Activated Esters

A difficult challenge in synthetic enzymes is the creation of substrate-selective active sites with accurately positioned catalytic groups. Covalent molecular imprinting in cross-linked micelles afforded such active sites in protein-sized, water-soluble nanoparticle catalysts. Our method allowed a systematic tuning of the distance of the catalytic group to the bound substrate. The catalysts displayed enzyme-like kinetics and easily distinguished substrates with subtle structural differences.

Lan Hu

Papers

Controlling Product Inhibition through Substrate-Specific Active Sites in Nanoparticle-Based Phosphodiesterase and Esterase

Molecularly Responsive Binding through Co-occupation of Binding Space: A Lock–Key Story

Cross‐Linked Micelles with Enzyme‐Like Active Sites for Biomimetic Hydrolysis of Activated Esters

Molecularly imprinted artificial esterases with highly specific active sites and precisely installed catalytic groups

Controllably solar-driven C‒C coupling organic synthesis integrated with H2 production over P-doped g-C3N4 with NiS nanoparticles modification