New Journal of Chemistry最新文献

We report the synthesis of two spiroborate-linked COFs, BSCOF-1 and BSCOF-2, which were characterized by PXRD, FT-IR, solid-state ¹¹B NMR, XPS, and N₂ sorption measurements. Both BSCOF-1 and BSCOF-2 displayed enhanced hydrolytic stability over that of COF-5. Density functional theory (DFT) calculations were performed to reveal the strong resilience in aqueous and acidic environments for BSCOF-1, indicating high energy barriers for hydrolysis of the 1,3-diol-boronic ester bonds. This study should provide a strategy for constructing stable boronate ester-linked COFs, opening avenues for their application under demanding conditions.

Nanofluids have materialized as promising contenders for boosting the thermal properties of heat transfer fluids, yet their synthesis often involves complex procedures. As the demand for efficient solar energy utilization continues to rise, an innovative nanofluid synthesis method offering a sustainable solution to address critical thermal management challenges is highly needed. Here, we present a one-step chemical reduction synthesis method facilitated by ribose, offering simplicity and environmental friendliness compared to traditional methods. The resulting nanofluid comprises nano-scale cuprous oxide particles, exhibiting Newtonian behavior. Remarkably, the nanofluid demonstrates a high thermal conductivity of 3.45 W m⁻¹ K⁻¹ and maintains stability over a remarkable 6-month period, attributed to the inclusion of polyvinyl pyrrolidone as a stabilizing agent. By leveraging the unique properties of nanofluids, we aim to contribute to the advancement of solar technologies, by enabling increased efficiency and reliability in solar energy systems by customizing the nanofluid properties to specific energy needs.

Microencapsulated curing agents (MCA) offer a novel solution with considerable industrial promise. In this study, we synthesized various polymethyl methacrylate-polybutyl methylacrylate (P(MMA-co-BMA)) random copolymers with a narrow molecular weight distribution via atom transfer radical polymerization (ATRP), adjusting the monomer ratios of methyl methacrylate and butyl methylacrylate. Subsequently, MCAs termed Kar/P(MMA-co-BMA) were prepared utilizing the solvent evaporation method, wherein P(MMA-co-BMA) served as the wall material and the Karstedt catalyst as the core material. The glass transition temperature of the resulting polymers ranged from 83 to 99 °C, easily modifiable by varying the monomer feed ratios. Characterization revealed an average particle diameter of approximately 7 µm and a core content of about 20 wt%. Additionally, we evaluated the curing characteristics of one-component silicone rubber incorporating different MCAs, finding that the formulation achieved complete curing at 100 °C within one hour. Notably, decreased BMA content significantly increased ambient latency time, exhibiting a latency of 10 weeks.

Traditional perovskite solar cells use Pb-based organic–inorganic hybrid perovskites as the absorber layer and organic Spiro-OMeTAD as the hole transport layer. The toxicity of lead and the instability of organic components are significant drawbacks. This study explores a lead-free all-inorganic perovskite solar cell with CsSn_0.5Ge_0.5I₃ as the absorber layer and inorganic materials as charge transport layers. After model validation, the impacts of thickness, doping concentration, and defect density of the absorber and hole transport layer on cell performance were systematically studied. Additionally, the effects of the valence band offset between the absorber and hole transport layers and the back electrode work function were explored. Through systematic optimization, the solar cell achieved a power conversion efficiency of 30.09%, a short-circuit current density of 27.73 mA cm⁻², an open-circuit voltage of 1.23 V, and a fill factor of 88.20%. This study provides insights for the development of efficient, low-cost, and stable lead-free perovskite solar cells.

Two-dimensional (2D) MoS₂ demonstrates significant potential for applications in flexible electronic sensing devices due to its unique physical and chemical properties and ultrathin layered structure. Metallic 1T phase MoS₂ is inherently metastable and tends to transform into the thermodynamically stable semiconducting 2H phase. Atomic doping can regulate the crystal phase of the MoS₂ and carrier concentration, and enhance the material stability. In this study, 2D metallic Sn-doped MoS₂ (Sn_xMo_1−xS₂) nanosheets were successfully synthesized via a hydrothermal method. The film resistance of Sn_xMo_1−xS₂ can be precisely controlled to change by two orders of magnitude through the precise regulation of the Sn doping concentration. The Sn_0.4Mo_0.6S₂-based temperature sensor displayed a negative temperature coefficient of resistance of −0.020 °C⁻¹, exhibiting an 82% improvement compared with 1T MoS₂. Meanwhile, the temperature-sensing performance of Sn_0.4Mo_0.6S₂ nanosheets is superior to that of reported doped and un-doped TMDs and their composites. In addition, the TCR remained stable under different bending conditions owing to the special nanosheet structure. Therefore, the Sn_0.4Mo_0.6S₂ sensor showed promising applicability for flexible and wearable human body temperature monitoring and activity tracking devices.

To address the high consumption and cost of noble metal catalysts during the production of hexanitrohexaazaisowurtzitane (HNIW, CL-20), nitrogen-doped titanium dioxide (TN) was synthesized using ammonium hydroxide as a nitrogen source. PdO/TN catalysts were then fabricated via a deposition–precipitation route and applied to the continuous hydrogenolysis debenzylation of hexabenzylhexaazaisowurtzitane (HBIW). Characterization by XRD, TEM, Raman spectroscopy, XPS, and H₂-TPR revealed that nitrogen incorporation effectively promoted the generation of surface oxygen vacancies and strengthened metal–support interactions, thereby enhancing catalyst stability. Moreover, the oxygen vacancy concentration could be tuned by adjusting calcination conditions. The PdO/TN-400-2 catalyst, prepared at 400 °C for 2 h, exhibited the highest catalytic activity, with an oxygen vacancy fraction of 19.64%. Further decreasing the calcination severity increased defect density but did not yield additional performance gains. These findings demonstrate that nitrogen doping can regulate surface defect chemistry and metal–support coupling, offering a viable strategy for the design of efficient catalysts for hexabenzylhexaazaisowurtzitane (HBIW) debenzylation.

Reaction of ligand N-phenyl-2,2-bis(3,5-dimethylpyrazol-1-yl)thioacetamide (pbptamH) with MCl₂ (M = Pd, Pt) in acetonitrile results in the formation of cationic complexes 1a-b with the general formula [(pbptamH)₂M]Cl₂. If the former reaction is modified by the addition of K₂CO₃, neutral complexes 2a-b with the formula [(pbptam)₂M] are obtained in excellent yields. Both types of complexes, neutral and cationic complexes 1 and 2, display coordination to the metal centers via the thioacetamide sulfur atom and one pyrazole moiety. Additionally, the stoichiometric treatment of ligand N-phenyl-2,2-bis(3,5-dimethylpyrazol-1-yl)acetamide (pbpamH) with MCl₂ (M = Pd, Pt) results in the generation of monoligated complexes 3a-b with the general formula [(pbpamH)MCl₂] in which the metal center is stabilized via coordination of two pyrazolyl fragments in a chelating fashion. If ligand pbpamH is treated with half an equivalent of MCl₂ (M = Pd, Pt) in the presence of excess NaBF₄, cationic complexes 5a-b of the type [(pbpamH)₂M](BF₄)₂ are generated. The reaction conditions, isolation, and characterization of the products are discussed in detail. The palladium and platinum complexes were tested in the hydrosilylation of terminal alkynes, unveiling complex 3b as the best of the series with excellent conversions under low catalyst loadings and good selectivity toward the E isomer.

The production of 2,5-bis(hydroxymethyl)furan (BHMF) is of considerable scientific interest and strategic value for the development of novel biodegradable polyesters. In this study, a non-precious CuO/MgO catalyst was synthesized by a facile coprecipitation method and applied to the transfer hydrogenation of 5-hydroxymethylfurfural (HMF) under mild conditions. Using isopropanol (10 mL) as the hydrogen donor, efficient conversion of HMF was achieved within 4 h at 160 °C and 0.5 MPa N₂ over the 10% CuO/MgO catalyst, yielding BHMF with 90.5% selectivity. Comprehensive characterization by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and N₂ adsorption–desorption analysis suggested a reaction mechanism consistent with the Meerwein–Ponndorf–Verley (MPV) reaction. Single-factor experiments were conducted to evaluate the effects of copper oxide loading, solvent type, catalyst dosage, reaction time, and temperature on the conversion of HMF and the selectivity of BHMF. Additionally, the selectivity of BHMF remained stable after using CuO/MgO for five cycles. These results provide a foundation for developing more efficient selective hydrogenation processes in the biomass industry.

Polymeric micelles have gained significant attention in cancer therapy due to their potential to enhance drug delivery efficiency while minimizing toxic side effects. In this contribution, two biocompatible polyethyleneglycol₂₀₀₀ (PEG) based amphiphiles, mPEG–palmitic acid (mPEG–PALMA) and mPEG–stearic acid (mPEG–STE), have been synthesised by conjugating palmitic acid and stearic acid (featuring hydrophobic alkyl tails C16 and C18 respectively) with PEG through amide linkage and applied for the micellar encapsulation and tumoral release of hydrophobic drug doxorubicin. Both amphiphiles form well defined micelles with CMC in the range of 10–35 µM and within the micellar size of <20 nm. A good degree of doxorubicin encapsulation efficiency (EE) of ∼90% and a drug loading (DL) capacity of ∼9% were determined for both the micelles. From the transmission electron microscopy (TEM), dynamic light scattering (DLS) and differential scanning calorimetry (DSC) analyses, it may be noted that the hydrophobic drug doxorubicin is encapsulated within the micellar core and the stability of the doxorubicin-loaded mPEG–PALMA and mPEG–STE micelles is higher than that of the unloaded micelle, which confirmed a more compact structural arrangement in the presence of the hydrophobic drug. A pH-sensitive release of doxorubicin (faster release with a decrease in pH) is observed for doxorubicin-loaded mPEG–PALMA and mPEG–STE micelles, which is attributed to the diffusion and relaxation/erosion of micellar aggregates. The in vitro drug delivery and anticancer efficacy of both the doxorubicin loaded micelles were studied using SCC9 oral cancer cell lines, which demonstrated that the blank mPEG–PALMA and mPEG–STE micelles were noncytotoxic at lower concentrations (<50 µM), while doxorubicin-loaded micelles exhibited significant cytotoxicity even at very low concentrations of 1–2 nM, attributable to enhanced intracellular delivery of doxorubicin. In conclusion, the mPEG–PALMA and mPEG–STE micellar assembly, with the advantages of good stability, small size, high encapsulation efficiency, simple preparation technique, biocompatibility, and good in vitro performance, may have the potential to be used as a drug carrier for sustained and stimuli-responsive release of the hydrophobic drug doxorubicin.

The synthesis of pyrrolidine derivatives containing an organophosphorus moiety at the 2-position of the ring is based on the reaction of an imine, 3-arylidene-1-pyrrolinium trifluoroacetate, with various H-phosphonates. The proposed method is characterized by a high reaction rate, mild reaction conditions, and the ability to use a variety of solvents, including water. The yield of the isolated product reaches 99%. All these advantages are achieved through the simultaneous activation of the imine and H-phosphonates.