Frontal Analysis Continuous Capillary Electrophoresis Study on the Interaction of an Amphiphilic Alternating Copolymer with Triton X-100

The interaction of amphiphilic alternating copolymers of sodium maleate and dodecyl vinyl ether (Mal/C12) with a nonionic surfactant, Triton X-100 (TX), was investigated by frontal analysis continuous capillary electrophoresis (FACCE). The binding isotherms obtained from FACCE data were indicative of weak cooperative interaction for all the polymers examined. The cooperative interaction was also analyzed by the Hill model, and the results were compared with the previous results on the interaction of statistical copolymers of sodium 2-acrylamido-2-methylpropanesulfonate and N-dodecylmethacrylamide with TX

C–H bond activation of benzene and thiophene by photochemically generated rhenocene cation

A cationic rhenocene-acetonitrile adduct [Cp2Re(NCMe)](BF4)(1) reacted with an excess of benzene, thiophene, 2-methylthiophene, and pyrrole under UV irradiation to afford the C–H bond activation products [Cp2Re(H)R]BF4 (R = phenyl, 2-thienyl, 2-(5-methylthienyl), 2-pyrrolyl) in high yields. In cases of thiophene derivatives and pyrrole, α-C–H bonds are selectively activated. A plausible mechanism involves the photodissociation of acetonitrile from 1 to generate a coordinatively unsaturated rhenocene cation [Cp2Re]+. When 2,5-dimethylthiophene and dibenzothiophene, having no α-C–H bonds, were used as substrates, products of the activation of other C–H bonds were formed first, but they isomerized to thermodynamically more stable η11-S-coordinated complexes in refluxing acetone. On the other hand, irradiation of the η1-S-coordinated complexes reproduced the original C–H bond activation products. Because of the cationic character, [Cp2Re(H)R]BF4 were readily deprotonated by triethylamine to give neutral rhenocene derivatives Cp2ReR. When R is thienyl or 2-(5-methylthienyl), treatment of Cp2ReR with HBF4⋅Et2O and MeI resulted in protonation and methylation to give [Cp2Re(H)R]BF4 (R = and [Cp2Re(Me)R]I. Thermolysis of [Cp2Re(Me)R]I in the presence of PPh3 unexpectedly resulted in migration of R to the Cp ring to give [(2 thienyl C5H4)CpRe(PPh3)]I

Synthesis and Metal Ion Adsorption Properties of a Dense Triazole Polymer Carrying Cysteine Residues

Ejima R., Nakahata M., Kamon Y., et al. Synthesis and Metal Ion Adsorption Properties of a Dense Triazole Polymer Carrying Cysteine Residues. Journal of Polymer Science, (2025); https://doi.org/10.1002/pol.20240752.Copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) is promising as a reaction to synthesize functional polymers consisting of 1,2,3-triazole units. Recently, we reported a series of dense 1,2,3-triazole polymers of 4-azido-5-hexynoic acid derivatives. Herein, we designed a new water-soluble dense 1,2,3-triazole polymer carrying amino acid residues in the side chains, that is, poly(N-(4-azido-5-hexynoyl)cysteine) (poly(AC)), bearing L-cysteine as a ligand for metal ions. CuAAC polymerization of a protected monomer followed by deprotection and neutralization yielded the sodium salt of poly(AC) (poly(AC)Na). The adsorption capacity of poly(AC)Na with Cd2+ was investigated with a colorimetric assay. Furthermore, the interactions for poly(AC) with group 12 metal ions (Zn2+, Cd2+, and Hg2+) were investigated using isothermal titration calorimetry (ITC) and transmittance measurements. Utilizing the colorimetric assay data, the Cd2+ adsorption capacity per unit weight of poly(AC)Na was evaluated to be 4–5 mmol g−1, comparable to those of Cd2+ adsorbents reported previously. The ITC data demonstrated that the interactions of poly(AC)Na with Zn2+, Cd2+, and Hg2+ were predominantly exothermic. Based on the ITC data, apparent dissociation constants of interactions were roughly estimated to be in the order of 10−5–10−4 M, which are comparable to those for metal-binding biomolecules. The transmittance data indicated that the poly(AC)Na/CdCl2 system underwent phase separation

Photoswitchable gel assembly based on molecular recognition

The formation of effective and precise linkages in bottom-up or top-down processes is important for the development of self-assembled materials. Self-assembly through molecular recognition events is a powerful tool for producing functionalized materials. Photoresponsive molecular recognition systems can permit the creation of photoregulated self-assembled macroscopic objects. Here we demonstrate that macroscopic gel assembly can be highly regulated through photoisomerization of an azobenzene moiety that interacts differently with two host molecules. A photoregulated gel assembly system is developed using polyacrylamide-based hydrogels functionalized with azobenzene (guest) or cyclodextrin (host) moieties. Reversible adhesion and dissociation of the host gel from the guest gel may be controlled by photoirradiation. The differential affinities of α-cyclodextrin or β-cyclodextrin for the trans-azobenzene and cis-azobenzene are employed in the construction of a photoswitchable gel assembly system

The second wave of formose research

This review article highlights key developments in the second wave of formose research (from approximately 2000), summarizing approximately 100 relevant studies. Section 1 introduces the basics of formose reaction and its historical context. Section 2 provides a brief overview of the pioneering works from the first wave of formose research (from 1970 to 1990). Section 3 then overviews the second wave of formose research, in which formose reactions under various conditions, mechanistic studies of the formose reaction, formose reactions and the origin of life, and applications of formose reactions are described. Finally, Section 4 offers summary and outlook

Density Function Theory Study on the Energy and Circular Dichroism Spectrum for Methylene-Linked Triazole Diads Depending on the Substitution Position and Conformation

Since the discovery of metal-catalyzed azide–alkyne cycloadditions, 1,2,3-triazoles have been widely used as linkers for various residues. 1,2,3-Triazole is an aromatic five-membered cyclic compound consisting of three nitrogen and two carbon atoms with large dipoles that absorb UV light. In the past decade, we have been working on the synthesis of dense triazole polymers possessing many 1,2,3-triazole residues linked through a carbon atom in their backbone as a new type of functional polymer. Recently, we reported that stereoregular dense triazole uniform oligomers exhibit a circular dichroism signal based on the chiral arrangement of two neighboring 1,2,3-triazole residues. In this study, to investigate the chiral conformation of two neighboring 1,2,3-triazole residues in stereoregular dense triazole uniform oligomers, density functional theory (DFT) calculations were performed using 1,2,3-triazole diads with different substitution positions and conformations as model compounds and compared with our previous results