New Journal of Chemistry最新文献

Highly selective fluorescence “turn on” probes (PTSC and TSC) based on a conjugate of pyrazolone and thiosemicarbazide were devised and synthesized. The structure was verified by ¹H NMR, ¹³C NMR and HR-MS. The probe demonstrated effectiveness, high selectivity, and specificity to capture indium ions. The fluorescence intensity of the probe solution was significantly enhanced by the addition of In³⁺. The 1 : 1 complexation between In³⁺ and probe PTSC was confirmed by Job's plot, and the limit of detection (LOD) of PTSC for In³⁺ was calculated to be 2.01 × 10⁻⁷ M. Furthermore, PTSC was produced as test strips, which have enormous potential to detect In³⁺ ions in the environment.

Non-contact optical temperature measurement has attracted intense attention in recent years due to its advantages of high speed and high safety. In this work, a Lu₂WO₆:Er³⁺ phosphor was successfully prepared by a solid state reaction. The effective energy transfer from the [WO₆]⁶⁻ group to Er³⁺ was proved using the emission spectra and fluorescence lifetime measurements, with an estimated transfer efficiency of 51%. Benefiting from the self-luminescence of the [WO₆]⁶⁻ group, optical thermometry was established based on the fluorescence intensity ratio of [WO₆]⁶⁻ emission to Er³⁺ emission. Remarkably, strong emission color variability from blue to green was observed under 320 nm UV excitation as the temperature increases from 298 K to 548 K, while an opposite trend from green to cyan is observed under 378 nm UV excitation. The maximum relative sensitivity (S_R Max) is 3.37% K⁻¹ (298 K), which is highly superior to most of the previously reported values.

MXenes, advanced 2D layered nanocomposite materials, have exhibited significant potential for enhancing the efficiency and effectiveness of thin film nanocomposite (TFN) membranes in desalination applications. This study aims to develop an efficient TFN membrane for groundwater desalination by integrating a sulfonated polydopamine-functionalized MXene (SPMX) onto a polyethyleneimine (PEI) interlayer. Morphological and functional group analyses of SPMX indicated the alterations in the interlayer spacing of the MXene sheets. Analysis of membrane surface morphology and energy-dispersive X-ray (EDX) spectroscopy confirmed the dispersion of SPMX nanosheets on the TFN surface. The PEI interlayer serves as a pivotal component in interfacial polymerization, facilitating the formation of a thin poly(piperazine-amide) layer and enhancing the anchoring of SPMX. The 0.1 wt% SPMX TFN (iSPMXTFN-2) membrane exhibited a lower contact angle value of 38°, indicating an improvement in hydrophilicity due to SPMX incorporation. The membrane performance analysis revealed that SPMX displayed a superior water permeability of 5.59 L m⁻² h⁻¹ bar⁻¹ and Na₂SO₄ rejection of 97.8%. Additionally, both MXene (iMXTFN) and SPMX TFN (iSPMXTFN) membranes exhibit exceptional antifouling properties against humic acid, calcium sulfate, sodium alginate and bovine serum albumin (BSA) solutions. Incorporation of SPMX into the polyamide layer improved resistance to chlorine attack on poly(piperazine-amide) chains. 0.1 wt% SPMX TFN membranes exhibited superior groundwater desalination performance, with higher flux and a reduced flux reduction ratio of 12%, while achieving removal efficiencies of 90% for SO₄, 66% for Na, and 40% for B. Engineered TFN membranes with PEI-interlayered SPMX demonstrated effective performance as membrane materials in pretreatment for superior groundwater desalination.

This work contributes to an overview of the structure of tautomers and rotamers of 2- and 8-hydroxy azaazulene and their mercapto analogues. This can be accomplished by optimizing the structures at the B3LYP functional with the 6-311+G(d,p) basis sets. Single-point energy calculations were performed at the M06-2X/6-311++G(2d,2p) level. The G3MP2 composite method was employed to obtain more accurate energies. The variations in the local aromaticity of aromatic rings were discussed by using the nucleus-independent chemical shift (NICS), the harmonic oscillator model of aromaticity index (HOMA), the multicenter index (MCI), and the aromatic fluctuation index (FLU and FLU-π) as probes of aromaticity. Additionally, the intramolecular proton transfer and rotation barriers of tautomerization and rotamerization have been extensively discussed. The discussion also encompassed natural bond orbital (NBO) charges and analysis, as well as atoms in molecules (AIM) analysis. The results reveal the presence of intramolecular hydrogen bonds in the 8OH-AZ, 8S-AZ, and 8SH-AZ structures.

Here, we report the synthesis and characterization of a bipincer nickel complex containing bipyridine-based bisphosphine and its catalytic application in quinoline synthesis and α-alkylation of ketones. The reaction of [2,2′-{C₅H₃N-3-N(H)C(O)C₆H₄PPh₂-o}₂] (1) with [NiCl₂(DME)] afforded bipincer complex [{NiCl)(2,2′-C₅H₃N-3-N(H)C(O)C₆H₄PPh₂-o)}-κ³-P,N,N]₂ (2). Complex 2 catalysed efficiently the synthesis of quinoline derivatives via acceptor-less dehydrogenative coupling of 2-aminobenzyl alcohol and ketones or secondary alcohols, and also α-alkylation of ketones with alcohols with a very low catalyst loading (0.5 mol%) at 110 °C.

A detailed investigation on the coordination environment of the Co²⁺ ion has been carried out with the intent of quantifying the contact ion-pair formation in dilute (0.1 mol L⁻¹) CoCl₂ aqueous, methanol (MeOH), and ethanol (EtOH) solutions. An effective approach has been employed combining UV-vis measurements, X-ray absorption spectroscopy, and density functional theory (DFT). The CoCl₂ metal salt is fully dissociated in aqueous solution with the Co²⁺ cation first hydration shell formed by six water molecules arranged in an octahedral fashion. On the other hand, the chloride anion enters the Co²⁺ coordination sphere giving rise to ionic pairs in MeOH and EtOH solution due to the weaker solvation ability of these solvents. The Co–Cl distances are 2.34(2) and 2.26(3) Å in MeOH and EtOH solutions, respectively, as determined by extended X-ray absorption fine structure data analysis. In MeOH solution the dominant species is the octahedral [CoCl(MeOH)₅]⁺ complex, while for EtOH the spectral evidence can be interpreted with an equilibrium between different four-fold metal-chloro species. Structural distortions in the coordination clusters have been evidenced by the X-ray absorption near-edge structure analysis aided by DFT optimizations and allowed us to rationalize the spectroscopic outcome of the UV-vis measurements. The adopted combined approach provided an all-around structural picture of the coordination complexes formed when the CoCl₂ salt is dissolved in solvents with different coordinating properties.

Endowing conductive composites with thermoreversible properties is important for improving the stability and extending the service life of the material and are in line with today's concept of green chemistry. In this study, thermoreversible conductive XNBR-based composites with excellent mechanical, reprocessable and conductive properties were prepared via a simple and feasible emulsion blending technique. Carbon black was used as a conductive filler, and epoxy resin and zinc chloride (ZnCl₂) were added as a crosslinking agent into carboxylated nitrile butadiene rubber (XNBR) through latex mixing. In particular, the –COOH group on the XNBR molecular chain forms β-hydroxy ester and ionic bonds with epoxy groups and Zn²⁺, respectively, constituting a dual dynamic network structure. The prepared rubber has a tensile strength of 10.81 MPa, an elongation at break of more than 300%, and a conductivity of up to 0.0102 S m⁻¹. Moreover, the composite has a high gauge factor (18.4) under fairly large strain (100%) and can accurately detect human activities, thus showing great potential as strain sensors. In addition, the tensile strength and electrical conductivity of the repeatedly processed material can reach 101% and 60%, respectively, of the original sample. Furthermore, based on its stretchability and conductivity, the composite is sensitively capable of capturing variation in strain, which shows great potential for application in strain sensors.

Acrylonitrile hyperbranched polymer/chitosan composite (AC–Hyp/CS) material was synthesized for the removal of diclofenac. In this method, a hyperbranched polymer was prepared by crosslinking an acrylonitrile monomer to obtain a host with a large surface area (AC/Hyp). To improve the functional sites of AC/Hyp, it was functionalized with chitosan (AC–Hyp/CS), which led to excellent removal efficiency. The physiochemical characterization of AC–Hyp/CS was carried out using FTIR, XPS, PXRD, DLS, TGA-DTA and SEM coupled with EDS. The uptake of diclofenac by AC–Hyp/CS was optimized through RSM in combination with BBD. Four factors, namely, AC–Hyp/CS dose (0.002–0.0180 g), concentration of diclofenac (10–30 mg L⁻¹), solution pH (2–6) and contact time (20–100 min), were considered to examine influencing parameters that resulted in the excellent removal efficiency. A high value of R² (0.9969) confirmed the excellent agreement of equilibrium data to the quadratic model. The obtained results suggested that 0.01 g AC–Hyp/CS was sufficient to eliminate 99.6% diclofenac from 20.0 mL (20.0 mg L⁻¹) solution at pH 4. Isothermal investigation suggested that the Langmuir isotherm model was administrated well with equilibrated data as it showed appropriate R² values (0.9814–0.9908) and low values of error functions (SSE: 0.002–11.742, χ²: 1 × 10⁻⁵–0.048 and RMSD: 0.0447–3.426). The adsorption capacity (maximum) obtained from the Langmuir model was 200 mg g⁻¹. The high values of R² (0.9878–0.9982) and low values of error functions (SSE: 0.160–1.343, χ²: 0.004–0.0534, RMSD: 0.40–1.158) of the pseudo-second-order kinetic model confirmed that the absorption was chemisorption. Diffusion-based kinetic studies revealed that both diffusion processes (film and intraparticle) participated in this sorption. Adsorption/desorption cycling test suggested that the composite exhibited excellent reusability characteristics up to 7 cycles, which confirmed that AC–Hyp/CS could be an effective sorbent for elimination of diclofenac from aqueous environments.

Interfacial intermolecular interactions between phosphorescent, square-planar, cyclometallated platinum(II) complexes may lead to the formation of bimolecular excited states that emit at lower energy than the isolated complexes in dilute solution. We study compounds in which two Pt(NCN)Cl units are appended onto a rigid xanthene scaffold to favour the intramolecular formation of such states and thus promote low-energy emission even at high dilution {where NCN represents a cyclometallated tridentate ligand based on 2,6-di(2-pyridyl)benzene}. Here, we show how the metathesis of the monodentate Cl⁻ ligand to thiocyanate SCN⁻ has a profound effect on the emissive properties of such compounds in solution and in polymer-doped and neat films. Intramolecular Pt⋯Pt interactions are promoted by the change to SCN⁻ (as evident by a short Pt⋯Pt distance of 3.253(4) Å in the crystal, determined by X-ray diffraction). This increased propensity for the Pt(NCN) units to interact, induced by the thiocyanate, is also manifest in the emission spectra: the spectra show only the low-energy, excimer-like bands in solution, even at very low concentrations. That contrasts with the appearance of emission bands typical both of isolated Pt(NCN) units and of excimers for the chloro parent compound. Nevertheless, data at low temperature and in dilute polymer-doped films suggest that some degree of conformational change is still required to form the low-energy emitting states. Meanwhile, the change of the monodentate ligand from chloride to iodide suppresses the formation of the low-energy-emitting states and lowers the emission efficiency. Taken together, the results offer new insight into strategies for obtaining efficient NIR-emitting phosphors based on dinuclear Pt^II₂ excited states.

Wide-bandgap 2D materials for UV photodetectors have many advantages, such as flexibility and efficiency. For this reason, the quest for novel 2D semiconductor materials is the primary focus of ongoing research endeavors. In this study, the electronic and optical characteristics of Janus Al₂M₂ClBr (M = O, S) monolayers have been meticulously examined by density functional theory (DFT). It was confirmed that these monolayers exhibit structural robustness for indirect bandgap Al₂O₂ClBr or direct bandgap Al₂S₂ClBr. Moreover, they demonstrate a low effective mass for the photogenerated electrons and holes. The bandgap is notably modulated by strain engineering, whereas the impact of the electric field is minimal. Notably, strong light absorption within the 8 to 12 eV range has been confirmed, with absorption coefficients surpassing 10⁵ cm⁻¹ for Janus Al₂M₂ClBr (M = O, S) monolayers. The optical properties can be finely tuned by strain engineering, although the influence of an electric field on these properties is insignificant. Considering the combination of optical and electrical characteristics, Janus Al₂M₂ClBr (M = O, S) monolayers are promising for UV photodetector applications. As a result, this study provides invaluable theoretical insights into the development of UV photodetectors utilizing Janus monolayers and is poised to significantly enrich the expansion of Janus monolayer materials in the foreseeable future.