Transitioning from Supramolecular Chemistry to Molecularly Imprinted Polymers in Chemical Sensing

A new surface molecularly imprinted polyacrylamide nanoprobe for trace Cr(VI) with RRS technique

This article was used potassium dichromate as the template molecule, silver nanoclusters as the nano matrix, acrylamide as the monomer, ethylene glycol dimethacrylate (EGDMA) as the crosslinking agent, and azodiisobutyronitrile (AIBN) as the initiator to prepare a new silver nanocluster surface MIP (AgNCs@MIP) nanoprobe for chromate. Upon addition of Cr(VI), it selectively adsorbs on the surface of AgNCs@MIP nanoprobes. The dichromate ion absorption peak at 350 nm overlaps with the AgNCs@MIP RRS peak at 370 nm, resulting in strong RRS energy transfer (RRS-ET) and a decrease in the RRS intensity. The decreased RRS intensity is directly proportional to the concentration of dichromate ions in the range of 0.0025-0.015 µmol/L, with a detection limit of 0.8 nmol/L. Therefore, a simple, fast, sensitive and selective RRS method for the determination of trace Cr(VI) in mineral water has been established, with a relative standard deviation of 9.2-9.8 % and recovery of 95.20 %-103.60 %.

Recent Developments of Fluorescence Sensors Constructed from Pillar[n]arene-Based Supramolecular Architectures Containing Metal Coordination Sites

The field of fluorescence sensing, leveraging various supramolecular self-assembled architectures constructed from macrocyclic pillar[n]arenes, has seen significant advancement in recent decades. This review comprehensively discusses, for the first time, the recent innovations in the synthesis and self-assembly of pillar[n]arene-based supramolecular architectures (PSAs) containing metal coordination sites, along with their practical applications and prospects in fluorescence sensing. Integrating hydrophobic and electron-rich cavities of pillar[n]arenes into these supramolecular structures endows the entire system with self-assembly behavior and stimulus responsiveness. Employing the host-guest interaction strategy and complementary coordination forces, PSAs exhibiting both intelligent and controllable properties are successfully constructed. This provides a broad horizon for advancing fluorescence sensors capable of detecting environmental pollutants. This review aims to establish a solid foundation for the future development of fluorescence sensing applications utilizing PSAs. Additionally, current challenges and future perspectives in this field are discussed.

Applications of Supramolecular Polymers Generated from Pillar[n]arene-Based Molecules

Supramolecular chemistry enables the manipulation of functional components on a molecular scale, facilitating a "bottom-up" approach to govern the sizes and structures of supramolecular materials. Using dynamic non-covalent interactions, supramolecular polymers can create materials with reversible and degradable characteristics and the abilities to self-heal and respond to external stimuli. Pillar[n]arene represents a novel class of macrocyclic hosts, emerging after cyclodextrins, crown ethers, calixarenes, and cucurbiturils. Its significance lies in its distinctive structure, comparing an electron-rich cavity and two finely adjustable rims, which has sparked considerable interest. Furthermore, the straightforward synthesis, uncomplicated functionalization, and remarkable properties of pillar[n]arene based on supramolecular interactions make it an excellent candidate for material construction, particularly in generating interpenetrating supramolecular polymers. Polymers resulting from supramolecular interactions involving pillar[n]arene find potential in various applications, including fluorescence sensors, substance adsorption and separation, catalysis, light-harvesting systems, artificial nanochannels, and drug delivery. In this context, we provide an overview of these recent frontier research fields in the use of pillar[n]arene-based supramolecular polymers, which serves as a source of inspiration for the creation of innovative functional polymer materials derived from pillar[n]arene derivatives.