ChemPlusChem最新文献

The front cover shows how redox-responsive side chain structural changes in amino acids enable reversible conformational transitions in peptides. Peptides incorporating cyclic amino acids with a disulfide adopt predominantly a well-defined 3₁₀-helical conformation in solution. In contrast, peptides containing acyclic amino acids with two thiol groups exhibit a diverse structural ensemble, consisting of both helical and non-helical conformations. More information can be found in the Research Article by Makoto Oba, Masakazu Tanaka, and co-workers (DOI: 10.1002/cplu.202400772).

The presence of potentially toxic elements (PTEs) in drinking water and the food chain is a well-known hazard to human health. Among PTEs, mercury is particularly dangerous for humans and other living organisms due to its wider effects on internal organs. Hg contamination is a critical issue for water bodies used for aquaculture, making its elimination mandatory. Among the techniques proposed for Hg removal, adsorption is advantageous because of its versatility, absence of secondary pollution, and relatively low cost, especially when adsorbents can be obtained from waste materials. In this article, adsorbent materials are synthesized by introducing thiols and primary amino groups into cellulose fibers isolated from soybean hulls. After characterization, the ability of the materials to remove mercury from both ultrapure and aquaculture water solutions is tested. The results confirm the affinity of Hg for thiol groups, leading to the adsorption of 44 mg(Hg)/g in a wide pH range. The amino-modified material adsorbs ≈50% Hg less than the thiol-functionalized one. Test in real water shows that organic matter and salts influence the Hg adsorption process, without affecting the overall efficiency. Finally, in real water, a final concentration below the Hg legal limit for human consumption (1 μg L^-1) is found.

The availability of nucleic acid structural biology methods still lags behind that of proteins, as evidenced by the significantly smaller number of structures deposited in the PDB. The highly skewed ratio of nucleic acid structures, relative to their protein counterparts (~1:50), is inverted with respect to the cellular output of RNA and proteins in higher organisms (~50:1). While nuclear magnetic resonance (NMR) spectroscopy is an attractive biophysical tool to bridge this gap, the  conformational flexibility, line-broadening, and low chemical shift dispersion of nucleic acids have made the NMR method challenging, especially for nucleic acids larger than 35 nucleotides. The incorporation of NMR-active isotope labels is an effective strategy to combat these problems. Here, we review strides made to push the limits of nucleic acid structures solved by NMR using chemo-enzymatic DNA 13C-methyl and RNA aromatic 15N- and 19F-13C-labeling and evaluate some of the challenges and opportunities they present. We anticipate that the combination of these novel isotopic labeling patterns with superior NMR spectroscopic properties, with new emerging DNA/RNA synthesis methods (palindrome-nicking-dependent amplification and Segmental labeling and site-specific Modifications by Template-directed eXtension, may well stimulate advances in NMR studies of high-molecular-weight DNA/RNA and their complexes with important biological functions.

A chiral BODIPY dye, denoted as (R)-2, incorporating near-infrared (NIR) emission and chiral optical behavior was synthesized. The dye was engineered by coupling PEG chains with R-stereogenic centers to a donor-acceptor BODIPY core through a Suzuki coupling reaction. This modification significantly enhances the solubility and facilitates efficient chirality transfer resulting in CD activity, which is quite remakable in organic small molecule solutions. Furthermore, acid-triggered protonation of the dye leads to a bathochromic shift in the maximum absorption wavelength (from 633 to 664 nm) and an increase in NIR emission intensity, which is attributed to the enhanced intramolecular charge transfer in solution.

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous, recalcitrant, bioaccumulative, and toxic. Effective concentration technologies are essential for remediating these compounds, a major focus of environmental science and engineering today. This review provides a comprehensive overview of PFAS, from fundamental chemistry to current research, encompassing fluorine chemistry, PFAS synthesis, and their applications. The review specifically thoroughly examines how fluorine chemistry can be utilized to enhance PFAS removal and enrichment, highlighting examples of aromatic/direct fluorination and aliphatic per- and polyfluorination, where the latter induces the fluorous effect. A comprehensive list of reactions used to design or modify PFAS sorbents is summarized, serving as a resource for ongoing research. Finally, insights are offered into how fluorine chemistry can be studied and employed to further improve PFAS characterization and management.

Ruddlesden-Popper (RP) quasi-two-dimensional (2D) perovskites exhibit enhanced stability compared to their three-dimensional counterparts due to the incorporation of bulky organic spacer cations. However, their efficiency is relatively low owing to the large exciton binding energy and quantum confinement effects associated with these organic spacer cations. In this work, we developed a diversified cation regulation strategy by adjusting both the spacer cations and A-site cations, leading to the fabrication of mixed 4-fluoro-phenethylammonium (F-PEA+)/n-butylammonium (BA+) and formamidinium (FA+)/methylammonium (MA+) n=4 quasi-2D RP perovskite solar cells. Primarily, the introduction of F-PEA+ induced an ordered distribution of the film from low-n to high-n phases, resulting in enhanced crystallinity, larger grain size, fewer cracks and voids as well as high-quality perovskite films with preferred orientation. Furthermore, the incorporation of FA+ reduced the bandgap of the perovskite, facilitating exciton dissociation and enhancing carrier transport capabilities. Ultimately, Under the synergistic effect, the obvious elevation in the efficiency of NiOx-based (BA0.9F-PEA0.1)2(MA0.8FA0.2)3Pb4I13 n=4 quasi-2D RP perovskite solar cells from 12.51% to 15.68% is achieved. Additionally, the unencapsulated devices retained 80.4% of initial efficiency after 1100 hours of heating at 60°C in ambient air with 40% relative humidity, demonstrating excellent thermal and moisture stability.

Styrene maleic acid lipid nanoparticles (SMALPs) arise from amphipathic SMA copolymer encapsulation of membranes into polymer-lipid nanodiscs, structures applied in the native extraction of membrane proteins (MPs). Strategies to immobilise SMALPs via their polymer belt onto surfaces allow the biophysical study of MPs without direct protein-surface anchoring. In this work, reversible addition-fragmentation chain transfer (RAFT) polymerisation was used to synthesise a library of diblock SMA copolymers to determine the optimal sequence for SMALP assembly. The further ability of trithiocarbonate (T) attached (Z)-end-groups, generated by RAFT polymerisation, to tether SMALPs to gold surfaces via sulfur-gold bonds was evaluated. Improved DMPC liposome solubilisation was achieved with a hydrophilic (Z)-end-group, shorter polystyrene block and lower molecular weight for diblock R-(Sty)-b-(Sty-alt-MA)-T-Z polymers. Quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM) revealed that diblock SMA polymers bound to gold as a micellular film, irrespective of the presence of the trithiocarbonate group. SMALPs, however, showed an enhanced gold affinity when terminated by a trithiocarbonate and hydrophilic RAFT (Z)-end-group compared to end-group removed SMALPs, the latter exhibiting non-specific gold adhesion. These findings offer a new approach in utilising RAFT end-groups of nanodisc assembling polymers for label-free analysis of MPs.

The contamination of water with heavy metals, particularly lead (Pb²⁺), has become a critical environmental and public health issue due to increasing industrialization and urbanization. Lead pollution has contributed to severe health problems, impacting over 10,000 people in recent years. In response to this growing concern, we developed a composite material, PANI@NF, by integrating polyaniline (PANI) with agro-waste fibers from date palm leaves, palm leaves, and korai grass. Among the tested composites, PANI@P20% demonstrated outstanding performance, achieving 96.2% lead removal and a sorption capacity of 24.1 mg/g under optimal conditions (pH 6.0, 0.01 g adsorbent, 50 ppm Pb²⁺, 298 K). The adsorption process for PANI@P20% followed a pseudo-second-order kinetic model and conformed well to the Freundlich isotherm, indicating multilayer adsorption on heterogeneous surfaces. Zeta potential analysis further confirmed favourable surface charge interactions at pH 6.0. Additionally, this composite exhibited excellent reusability, maintaining high efficiency over eight adsorption-desorption cycles. This work underscores the potential of using low-cost, biodegradable natural fibers as sustainable adsorbents for effective lead removal, offering a promising solution for water treatment and environmental preservation.

Biphasic molecular catalysis is a promising strategy for combining catalyst recycling with the synthesis of advanced chemical products. The anchoring of catalysts to surfactants in water allows for both catalyst solubility in aqueous media and a simple separation from the organic product. In biphasic epoxidations, this approach allows the use of environmentally benign hydrogen peroxide as oxidant. However, challenges remain due to mass transport limitations between the aqueous and organic phase, incompatibilities in the multi-component system, and side reactions in the acidic medium. Hence, the development of surface-active catalysts that enable controlled phase separation from all other components is highlighted in this Concept article.

Monitoring trace solvent and metal adulteration in biodiesel is crucial for quality control and commercialization. This study explores a mesoporous Cd(II)-MOF for dual-mode fluorescence sensing: 'turn-on' detection of EtOH and 'turn-off' monitoring of Fe3+ in aqueous and biodiesel samples. Synthesized using N-chelating, π-conjugated 2,2'-bipyridine and μ3-η1:η2 bridging 5-hydroxyisophthalic acid, the MOF exhibits high phase purity, lamellar rod morphology, and high thermal stability, attributed to its robust framework, reinforced by supramolecular H-bonding and interlayer π-π stacking interactions. The MOF's blue luminescence enables rapid detection of EtOH (6.27-fold enhancement, LOD: 6.33 ppm, 40s response time) and Fe3+ (>90% quenching, LOD: ~1.17 µM, KSV: 1.318 × 105 M⁻1, 30s response time). The EtOH sensing ensues via photo-induced electron transfer (PET) restriction in the MOF, aided by hydrogen bonding with MOF hydroxyls and polarity effects, while Fe3+ quenching arises from absorption competition quenching (ACQ) and electrostatic interactions. The sensor detects EtOH and Fe3+ in pre-treated biodiesels derived from jatropha and waste cooking oil (recovery: 78-90% and 73-75%, respectively). Further, a 4.89-fold 'turn-on' for EtOH and ~81% quenching for Fe3+ was evidenced when analytes were directly added into untreated jatropha-biodiesel. A smartphone-based RGB calibration further enhances real-time ethanol analysis, ensuring practical applicability.