ATRP Catalyst Removal and Ligand Recycling Using CO2-Switchable Materials

Molecularly Imprinted Microspheres in Active Compound Separation from Natural Product

Molecularly Imprinted Microspheres (MIMs) or Microsphere Molecularly Imprinted Polymers represent an innovative design for the selective extraction of active compounds from natural products, showcasing effectiveness and cost-efficiency. MIMs, crosslinked polymers with specific binding sites for template molecules, overcome irregularities observed in traditional Molecularly Imprinted Polymers (MIPs). Their adaptability to the shape and size of target molecules allows for the capture of compounds from complex mixtures. This review article delves into exploring the potential practical applications of MIMs, particularly in the extraction of active compounds from natural products. Additionally, it provides insights into the broader development of MIM technology for the purification of active compounds. The synthesis of MIMs encompasses various methods, including precipitation polymerization, suspension polymerization, Pickering emulsion polymerization, and Controlled/Living Radical Precipitation Polymerization. These methods enable the formation of MIPs with controlled particle sizes suitable for diverse analytical applications. Control over the template-to-monomer ratio, solvent type, reaction temperature, and polymerization time is crucial to ensure the successful synthesis of MIPs effective in isolating active compounds from natural products. MIMs have been utilized to isolate various active compounds from natural products, such as aristolochic acids from Aristolochia manshuriensis and flavonoids from Rhododendron species, among others. Based on the review, suspension polymerization deposition, which is one of the techniques used in creating MIPs, can be classified under the MIM method. This is due to its ability to produce polymers that are more homogeneous and exhibit better selectivity compared to traditional MIP techniques. Additionally, this method can achieve recovery rates ranging from 94.91% to 113.53% and purities between 86.3% and 122%. The suspension polymerization process is relatively straightforward, allowing for the effective control of viscosity and temperature. Moreover, it is cost-effective as it utilizes water as the solvent.

Progress Toward Sustainable Reversible Deactivation Radical Polymerization

The recent focus of media and governments on renewability, green chemistry, and circular economy has led to a surge in the synthesis of renewable monomers and polymers. In this review, focussing on renewable monomers for reversible deactivation radical polymerizations (RDRP), it is highlighted that for the majority of the monomers and polymers reported, the claim to renewability is not always accurate. By closely examining the sustainability of synthetic routes and the renewability of starting materials, fully renewable monomers are identified and discussed in terms of sustainability, polymerization behavior, and properties obtained after polymerization. The holistic discussion considering the overall preparation process of polymers, that is, monomer syntheses, origin of starting materials, solvents used, the type of RDRP technique utilized, and the purification method, allows to highlight certain topics which need to be addressed in order to progress toward not only (partially) renewable, but sustainable monomers and polymers using RDRPs.

CuBr2/EDTA-mediated ATRP for ultrasensitive fluorescence detection of lung cancer DNA

In this paper, we reported a system for the ultrasensitive fluorescence detection of cytokeratin fragment antigen 21-1 DNA (CYFRA21-1 DNA) for the early diagnosis of lung cancer. The approach used electron transfer atom transfer radical polymerization (ARGET-ATRP) with ethylenediaminetetraacetic acid (EDTA) as the metal ligand. Firstly, thiolated peptide nucleic acid (PNA) was linked to aminated magnetic beads solutions (MBs) by a cross-linking agent and then hybridized with CYFRA21-1 DNA (tDNA). Subsequently, Zr4+ was introduced into the MBs by conjugating with the phosphate group of tDNA, and the initiator of ARGET-ATRP was introduced into via phosphate-Zr4+-carboxylate chemistry. Next, Cu(II)Br/EDTA was reduced to Cu(I)/EDTA by ascorbic acid (AA) to trigger ARGET-ATRP and then a large amount of fluorescein-o-acrylate (FA) molecules were grafted from the surface of the MBs, which amplified significantly the fluorescent signal. Under optimal conditions, a strong linear relationship of tDNA over the range from 0.1 fM to 1 nM (R2 = 0.9988). The limit of detection was as low as 23.8 aM (~143 molecules). The fluorescence detection based on the ARGET-ATRP strategy yielded excellent sensitivity, selectivity, outstanding anti-interference properties, and cost-effectiveness. These results indicated that this strategy has considerable potential for biological detection and early clinical diagnosis.

Designing a robust recyclable tricopolymer poly(ionic liquid) macroligand for copper-mediated atom transfer radical polymerization in non-aqueous biphasic systems

Herein, a robust thermoregulated poly(ionic liquid) macroligand was designed, synthesized and applied in an ICAR-based ATRP-TPSC system with efficient recycling/reuse.

An isocyanide ligand for the rapid quenching and efficient removal of copper residues after Cu/TEMPO-catalyzed aerobic alcohol oxidation and atom transfer radical polymerization

Three for the price of one: 1,4-bis(3-isocyanopropyl)piperazine allows for the removal of Cu impurities, can quench Cu-catalyzed reactions, and can prevent undesirable Glaser coupling.

Nitroxide-Mediated Copolymerization of Itaconate Esters with Styrene

Replacing petro-based materials with renewably sourced ones has clearly been applied to polymers, such as those derived from itaconic acid (IA) and its derivatives. Di-n-butyl itaconate (DBI) was (co)polymerized via nitroxide mediated polymerization (NMP) to impart elastomeric (rubber) properties. Homopolymerization of DBI by NMP was not possible, due to a stable adduct being formed. However, DBI/styrene (S) copolymerization by NMP at various initial molar feed compositions fDBI,0 was polymerizable at different reaction temperatures (70–110 °C) in 1,4 dioxane solution. DBI/S copolymerizations largely obeyed first order kinetics for initial DBI compositions of 10% to 80%. Number-average molecular weight (Mn) versus conversion for various DBI/S copolymerizations however showed significant deviations from the theoretical Mn as a result of chain transfer reactions (that are more likely to occur at high temperatures) and/or the poor reactivity of DBI via an NMP mechanism. In order to suppress possible intramolecular chain transfer reactions, the copolymerization was performed at 70 °C and for a longer time (72 h) with fDBI,0 = 50%–80%, and some slight improvements regarding the dispersity (Ð = 1.3–1.5), chain activity and conversion (~50%) were observed for the less DBI-rich compositions. The statistical copolymers produced showed a depression in Tg relative to poly(styrene) homopolymer, indicating the effect of DBI incorporation.

Synthesis of chitosan-mimicking cationic glycopolymers by Cu(0)-LRP for efficient capture and killing of bacteria

A schematic representation of the preparation of cationic magnetic glyconanoparticles by Cu(0)-LRP to efficiently capture, kill and separate E. coli from water.