Latest ArticlesAfter discovering a new class of two-dimensional (2D) material, i.e., MXene, a further new scope, came into existence for researchers. Due to their remarkable physical, chemical, and biological properties, MXenes find their role in almost every research discipline. They have been used in biosensors, bioimaging, tissue engineering, drug delivery systems, and other areas. The MXenes can be functionalized with a wide range of atoms/molecules, making them diverse materials. Therefore, the potential of using MXenes in nanofibers can be much more than expected. In this review, we will understand the structure, synthesis, and general properties of MXenes. We will explain using MXenes while encasing them into nanofibers, providing their specific properties. For instance, MXenes-incorporated nanofibers are used in biomedical applications, including soft and hard-tissue engineering and delivery of antimicrobials. Furthermore, MXenes, when incorporated into nanofibers, are used in promoting cellular differentiation, wound healing, and neural tissue restoration, which are briefly discussed in this communication.
Suzuki coupling reactions between symmetrical monomers were conducted in various mesoporous silica nanoreactors grafted with palladium catalysts, enabling the selective formation of [12]cycloparaphenylene precursor with separate yield up to 25% in one-pot reactions, much higher than that in homogeneous reaction. The spatial nanoconfinement of the nanoreactors promotes the macrocyclization while limits the concomitant linear oligomer formation, offering more possibilities for the synthesis of macrocycles from symmetrical monomers in one-pot reaction.
Single atom catalysts (SACs) with atomically dispersed transition metals on nitrogen-doped carbon supports have recently emerged as highly active non-noble metal electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), showing great application potential in Zn-air batteries. However, because of the complex structure-performance relationships of carbon-based SACs in the oxygen electrocatalytic reactions, the contribution of different metal atoms to the catalytic activity of SACs in Zn-air batteries still remains ambiguous. In this study, SACs with atomically dispersed transition metals on nitrogen-doped graphene sheets (M-N@Gs, M = Co, Fe and Ni), featured with similar physicochemical properties and M-N@C configurations, are obtained. By comparing the on-set potentials and the maximum current, we observed that the ORR activity is in the order of Co-N@G > Fe-N@G > Ni-N@G, while the OER activity is in the order of Co-N@G > Ni-N@G > Fe-N@G. The Zn-air batteries with Co-N@G as the air cathode catalysts outperform those with the Fe-N@G and Ni-N@G. This is due to the accelerated charge transfer between Co-N@C active sites and the oxygen-containing reactants. This study could improve our understanding of the design of more efficient bifunctional electrocatalysts for Zn-air batteries at the atomic level.
Two bis-naphthalimide-based supramolecular gelators (NN-3 and NN-4) with a little difference of position of amino groups were designed and synthesized for the detection of oxaloyl chloride and phosgene. Energy transfer could be occurred between two naphthalimide groups in molecules NN-3 and NN-4. Yellow gels NN-3 and NN-4 were formed in some mixed solvents, and nanofibers with different size were obtained in these gels. The self-assembly processes of NN-3 and NN-4 in different solvents were investigated by UV-vis absorption, fluorescent spectra, SEM, FTIR, XRD and NMR. Gelators NN-3 and NN-4 could selectively detect oxaloyl chloride in solution and film states, but detect phosgene only in solution. NN-3 exhibited the ratiometric detection ability towards oxaloyl chloride and phosgene with the low limit of detection (LOD) of 210 nmol/L and 90 nmol/L, respectively. NN-4 as the corresponding control sample, it owned the higher LOD towards oxaloyl chloride and phosgene of 12.4 µmol/L and 64 µmol/L, respectively. Interestingly, films NN-3 and NN-4 could sensitively detect oxaloyl chloride gases with the low LOD of 2.0 ppm and 8.34 ppm, respectively. The detection mechanisms of NN-3 and NN-4 were well studied by 1H NMR titration, HRMS and theoretical calculation.
Organic-inorganic hybrid perovskites (OIHPs) materials with high phase transition temperature (Tp) have been widely studied in the field of molecular switches, solar energy and electric power. At present, the OIHPs with high Tp are generally constructed through molecular design, which can be applied to a wide temperature range. Here, three one-dimensional (1D) OIHPs [R-ClEQ]PbCl3 (Tp = 442 K), [R-ClEQ]PbBr3 (Tp= 499 K) and [R-ClEQ]PbI3 (Tp above m.p.) (R-ClEQ = (R)-N-chloroethyl-3-quinuclidinol) with different Tp are obtained by regulating the halogen-halogen interaction and hydrogen bonding in the system. Especially in [R-ClEQ]PbX3 (X = Cl, Br and I) crystal system, all the halogen bonds tend to form at approximately 180°angles and the strength of halogen bonding is found to be increased from 1.59 × 10–3 Hartree to 2.35 × 10–3 Hartree with increased atom number from Cl to I. The synergistic effect of halogen bonding and hydrogen bonding provide a useful strategy for the design OIHPs phase transition materials with high Tp.
It is greatly desired to develop novel gadolinium-based contrast agents (GBCAs) as improved platforms for magnetic resonance imaging (MRI). Herein, we report the syntheses of a series of nonionic cyclen-based GBCAs by precisely tuning carboxylate group on DO3A-pyridine scaffold. [Gd-DO3A-4cp] is isolated which adopts an octadentate coordination mode with a free carboxylate group at 4-position of pyridine. It shows the r1 relaxivity of 5.8 (mmol/L)−1 s-1 (3 T, 25 ℃), which is 75% higher than 3.3 (mmol/L)−1 s-1 of the clinic used [Gd-DOTA]. The possible mechanisms behind the enhanced relaxivity are investigated and proposed by structure-property relationship studies. After validation of low cytotoxicity and considerable kinetic inertness, in-vivo studies are further examined, demonstrating its good MRI performance, biodistribution as well as the way of excretion.
Twenty-four novel neonicotinoid analogues with nitromethylene and five-membered aromatic heterocycles were designed and synthesized. All target molecular structures have been confirmed by analytical and spectral data. Some compounds exhibited notable insecticidal activities against aphid (Aphis medicaginis) and brown planthopper (Nilaparvata lugens). The aqueous stability test confirmed that the stabilities of those compounds were superior to the leading compound, and the photostability was even better than that of imidacloprid.
Zinc-ion batteries are under current research focus because of their uniqueness in low cost and high safety. However, the pursuing of high-performance cathode materials of aqueous Zinc ion batteries (AZBs) with low cost, high energy density and long cycle life has become the key problem to be solved. Herein we synthesized a series of amorphous nickel borate (AM-NiBO) nanosheets by varying corrosion time with in-situ electrochemical corrosion method. The AM-NiBO-T13 as electrode material possesses a high areal capacity of 0.65 mAh/cm2 with the capacity retention of 95.1% after 2000 cycles. In addition, the assembled AM-NiBO-T13//Zn provides high energy density (0.77 mWh/cm2 at 1.76 mW/cm2). The high areal capacity and better cycling performance can be owing to the amorphous nanosheets structure and the stable coordination characteristics of boron and oxygen in borate materials. It shows that amorphous nickel borate nanosheets have great prospects in the field of energy storage.
Voriconazole (VZL) is a second-generation and broad-spectrum triazole against fungal infections. Being a BCS (biopharmaceutics classification system) class Ⅱ compound, the poor aqueous solubility has limited its bioavailability and clinical efficacy. Aims to overcome this disadvantage, a cocrystallization strategy based on crystal engineering principles has resulted in five new multi-component crystals of VZL with maleic acid, L-tartaric, protocatechuic, gallic, and 3,5-dinitrobenzoic acids. Structure analysis revealed that the hydroxyl/carboxylic acid···triazole N3 hydrogen bonding interaction appears as a main supramolecular heterosynthon in the VZL multi-component crystals with organic acids. And VZL molecule has a flexible conformation in each of the five multi-component structures. The newly synthesized multi-component crystals showed impressive solubility improvement compared to that of the raw material of VZL. Molecular electrostatic potential surfaces (MEPS) analysis based on density functional (DFT) calculations revealed that hydrogen bond interactions in cocrystals mainly involved pairwise interactions in the global maxima and minima sites, but this rule is not always followed. This study indicates the potential of cocrystals to improve the solubility and dissolution rate of VZL
Nitrogen electro-reduction reaction (NERR) is a promising alternative method for ammonia production to the Haber–Bosch approach due to mild reaction conditions and free harmful by-product emission. A formidable challenge in bringing NERR closer to the practical application is developing an electro-catalyst which can simultaneously improve the Faraday efficiency and reduce the reaction over-potential. Herein, we fabricated a catalyst of nitrogen-doped carbon dots modified copper-phosphate nanoflower petals (CuPo-NCDs NF) via a self-assembly method. The flower structure endowed the CuPo-NCDs NF with large specific surface area, and thus enabled more active sites to be exposed. In particular, we demonstrated that the NCDs modified CuPo petals with flower-like structure can accelerate the interfacial proton-electron transfer, suppressing the competing hydrogen evolution reaction and promoting the desired NERR process. Ultimately, for the CuPo-NCDs NF catalyzed NERR, the FENH3 and the reaction potential both were boosted, the resultant energy efficiency of NERR reached a record-breaking value of 56.5%, and the NH3 yield rate increased by 7 times compared to NCDs. This study provides a novel catalyst with a new pathway to boost the NERR.