New Journal of Chemistry最新文献

With the increasing environmental pollution, especially water pollution, it is urgent to develop environmentally friendly, low-consumption, and efficient water treatment technology. Compared with other oxidants (H₂O₂, peroxydisulfate (PDS), etc.), peroxymonosulfate (PMS) can degrade organic pollutants efficiently and at high speed. It is important to design a catalyst suitable for advanced oxidation processes (AOPs). By a simple solvothermal method, metal catalyst NiFe₂O₄ was combined with non-metal materials polyaniline and graphene to activate PMS for rhodamine B degradation. The surface morphology and chemical composition of the catalysts were studied using SEM, EDS, XRD, Raman spectroscopy, and FR-IR. The NiFe₂O₄/PANI/rGO composite catalysts exhibited excellent catalytic activity such that 98.05% rhodamine B could be degraded in the presence of 0.20 g L⁻¹ catalyst and 1.2 mM PMS within 30 min. Combined with the results of X-ray photoelectron spectroscopy characterization of catalysts before and after the catalytic reaction, it is proposed that the possible degradation mechanism is mainly that electrons provided by carbon materials are captured by dissolved oxygen in the system to generate superoxide free radicals, and metal ions react with PMS to generate sulfate free radicals. Some of the generated sulfate radicals will also be converted into hydroxyl radicals, and the organic pollutant molecules will react with the active radicals in the system to achieve the degradation of pollutants.

Silver nanoparticles (AgNPs) are one of the most studied nanomaterials for their multifaceted nature. Among the different synthesis routes for AgNPs, green synthesis is preferred owing to its efficacy and eco-friendly nature. In most cases, biological agents and phytochemicals are used as reducing and capping agents, making the synthesis method cheaper. In this work, a one-pot synthesis of AgNPs was designed using verbascoside, a naturally occurring phenylethanoid glycoside, as the reducing agent. This synthesis procedure was successfully optimized with response surface methodology. Verbascoside-AgNPs (VbAgNPs) were found to be spherical upon characterization using FESEM. Surface plasmon resonance peaks were formed within the range of 415–462 nm. Dynamic light scattering studies showed that the average particle size was 48.8 nm; this was further confirmed using HR-TEM. The presence of elemental silver was proved using XRD, and the participating functional groups in the formation of the VbAgNPs were analyzed using FTIR. Nanoparticles were found to be stable over a period of one year. Biological studies confirmed that VbAgNPs were hemocompatible and exhibited potent antioxidant, antibacterial, and biofilm inhibitory activity. Further these nanoparticles showed promising wound healing potentials in scratch wound assay with no significant cytotoxic effects in RAW 264.7 cells. It also demonstrated angiogenic properties in a fertilized chicken egg 72 hours after administration. Therefore, this nanoparticle holds multifaceted promise as an antioxidant and antibacterial biomaterial with potential for wound healing.

Correction for ‘Activation of the catalytic function of formaldehyde dehydrogenase for formate reduction by single-electron reduced methylviologen’ by T. Ishibashi et al., New J. Chem., 2018, 42, 18508–18512, https://doi.org/10.1039/C8NJ02211A.

The investigation of suitable organic host materials is crucial for the development of high-efficiency triplet exciton-based organic light emitting diodes (OLEDs). In this study, two isomeric carbazole/1,3,5-triazine hybrid bipolar-transport host materials o-3CN-TRZ and o-4CN-TRZ are developed. The alteration of cyano substitution from the 3- to the 4-position of carbazole resulted in a slight reduction in the HOMO levels from −5.80 to −5.87 eV, accompanied by a gentle decline in the singlet/triplet energy levels. This was evidenced by a shift in the fluorescence emission peak from 450 to 474 nm and the observation of relatively high triplet energies of 2.79 and 2.77 eV for o-3CN-TRZ and o-4CN-TRZ, respectively. Notably, compared to the bare carbazole-based model compound o-Cz-TRZ, the introduction of a cyano group at either the 3- or the 4-position led to a notable enhancement in the electron-transport properties. However, the hole-transport behavior of o-3CN-TRZ was evidently inferior to that of o-4CN-TRZ. Therefore, when employed as host materials for both phosphorescence and thermally activated delayed fluorescence OLEDs, o-4CN-TRZ hosted devices all exhibited higher efficiencies than o-3CN-TRZ. Maximum external quantum efficiencies of 20.5, 16.8 and 16.9% versus 19.6, 12.5 and 13.8% were achieved for green phosphorescent (ppy)₂Ir(acac), greenish-yellow TADF 4tCzDOXD and 4tCzCNPy-based devices, respectively.

Metallacycles are structurally diverse molecular entities that have attracted significant research interest due to their potential applications in sensing, catalysis, and biomedicine. In this study, we report the synthesis of two discrete neutral Schiff base-derived dinuclear Cu(II) metallacycles [Cu₂L₂] (1) and [Cu₂L′₂] (2) achieved through coordination driven self-assembly using ligands N,N′-bis(3,5-di-tert-butylsalicylidene)-2,2′-diaminodiphenyl ether (H₂L) and (N,N′-bis(3,5-di-tert-butylsalicylidene)-hydrazine) (H₂L′), respectively. 1 and 2 are characterized by infrared, UV-vis, fluorescence, and electron paramagnetic resonance spectroscopy. The X-ray diffraction analysis confirms that 1 adopts a double helical structure while 2 exhibits a butterfly shape. The magnetic and electrochemical properties of metallacycles are investigated using superconducting quantum interference device (SQUID) magnetometry and cyclic voltammetry. The results revealed that the macrostructure of the metallacycles significantly influences their photophysical, magnetic and electronic properties. In addition, the catalytic efficiency of metallacycles towards ring-opening polymerization of ε-caprolactone is evaluated.

Selectivity control of aniline oxidation and low reactant conversion in traditional synthesis methods are great challenges, and it is desirable to develop a green, low-cost and highly efficient catalytic route toward value-added products. Herein, an Rb-promoted Fe/CeO₂ nanocatalyst was prepared to understand the effects of Rb-promoter on the catalytic performance for the selective oxidation of aniline to azoxybenzene using H₂O₂ as an oxidant. The 0.1 M Rb-4% Fe/CeO₂ (Rb–Fe/CeO₂) catalyst showed a high aniline conversion of 100% with 91% selectivity of azoxybenzene. This is because the existence of Rb contributes to the electron transportation property, decreases activation energy and leads to lattice distortion of Fe/CeO₂ and further formation of oxygen vacancies and Ce³⁺, which contributes to improving the activity of Fe/CeO₂ nanocatalysts for aniline conversion reaction. The Rb used to modify Fe/CeO₂ nanocatalysts can not only passivate the strong Brønsted acid sites and stability of Fe/CeO₂ but also enhance the Fe dispersion and induce an electron-rich chemical environment for the supported Fe species and promote the activation of the substrate. All these effects lead to the desirable catalytic performance. The increased basic strength of the cation-promoted catalyst improves the electron density of the active Fe species, resulting in a higher yield of the desired aromatic azo compounds. This compensates for electronic deficiencies in the Fe, enhancing its catalytic activity without interference. Experiments were conducted as a function of catalyst loading (20–100 mg), time (2–24 h), temperature (25–100 °C), types of solvent and solvent amount (0.5–2 ml) in 50 ml round bottom flask with reflux condenser. Our work proposes a facile approach to develop and promote non-noble metal catalysts for the effective conversion of aniline into azoxybenzene under mild reaction conditions.

Here, we synthesized three covalent organic polymers (COPs) with varying π–π conjugation and coordination numbers. COP-H3, as a luminesent probe, exhibited a highly selective sensing of OH-containing nitro-explosives, while COP-H2 exhibited high selectivity for trinitrophenol and 2,6-DNP. Their sensing behavior could be well explained by the absorption competition quenching mechanism.

Diffusion dialysis (DD) with anion exchange membranes (AEMs) as the core component is an ideal technology for acid recovery from acidic wastewater. Herein, a series of TEA–BPPO AEMs were prepared from triethanolamine (TEA) and brominated polyphenylene ether (BPPO) using the solution casting method. The structures of the prepared membranes were characterized and analyzed through nuclear magnetic resonance hydrogen spectroscopy (¹H NMR), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). In addition, the properties of the membranes, such as ion exchange capacity (IEC), linear swelling rate (LSR), water uptake (W_U), chemical stability, thermal stability and mechanical stability, were explored. In DD experiments, the optimal AEM (i.e., TEA–BPPO–M80) applied to simulate acid recovery from a mixed HCl (1 mol L⁻¹)/FeCl₂ (0.2 mol L⁻¹) solution exhibited an acid dialysis coefficient (U_H⁺) of 0.0629 m h⁻¹ and separation factor (S) of 97.78, which were significantly better than those of the commercial membrane DF-120. In addition, the TEA–BPPO–M80 AEM exhibited excellent thermal stability and acid resistance. In summary, the prepared membranes possess great potential for application in DD acid recovery.

Multifunctional piezoelectric composites are gaining momentum in the industry as a sustainable source of energy. 0.3BaTiO₃–0.7BiFeO₃ (BT–BF) was prepared using a hydrothermal process and utilized to prepare a BT–BF/PVDF–HFP flexible composite with enhanced sensing and dielectric properties as compared to pristine PVDF–HFP. The synergistic combination of a multiferroic ceramic filler and a ferroelectric polymer matrix demonstrated the improved properties of the composites. X-ray diffraction and scanning electron microscopic characterization of the prepared BT–BF sample revealed the perovskite crystal structure and nano-size spherical morphology, respectively. Dielectric characterization of the BT–BF/PVDF–HFP composites showed enhanced dielectric permittivity with a substantial decline in the loss tangent in a higher frequency regime. Also, the stability of the ceramic fillers was confirmed with the help of NMR-based solvent relaxation experiments. It is observed that the stable interfacial interactions between the matrix and the filler played a dominant role in enhancing the dielectric properties. Again, the temperature-dependent dielectric properties were investigated for the 10BP (10 mg BT–BF/PVDF–HFP) composite to explore the temperature-dependent dielectric response of the fabricated system. Finally, a capacitive pressure sensor with enhanced performance was demonstrated with for the 10BP composite, as compared to pristine PVDF–HFP .

A [4+2] annulation reaction of o-acylamino-aryl MBH carbonates with 3-substituted coumarins has been developed. This method exhibits excellent substrate tolerance and constructs a series of tetrahydrochromeno[4,3-b]quinolin-6-ones with yields up to 95%. The application value of this method has also been demonstrated through a 50-fold scale-up.