Latest ArticlesBimetallic nanoparticles (AmBn) usually exhibit rich catalytic chemistry and have drawn tremendous attention in heterogeneous catalysis. However, challenged by the huge configuration space, the understanding toward their composition and distribution of A/B element is known little at the atomic level, which hinders the rational synthesis. Herein, we develop an on-the-fly training strategy combing the machine learning model (SchNet) with the genetic algorithm (GA) search technique, which achieve the fast and accurate energy prediction of complex bimetallic clusters at the DFT level. Taking the 38-atom PtmAu38-m nanoparticle as example, the element distribution identification problem and the stability trend as a function of Pt/Au composition is quantitatively resolved. Specifically, results show that on the Pt-rich cluster Au atoms prefer to occupy the low-coordinated surface corner sites and form patch-like surface segregation patterns, while for the Au-rich ones Pt atoms tend to site in the core region and form the core-shell (Pt@Au) configuration. The thermodynamically most stable PtmAu38-m cluster is Pt6Au32, with all the core-region sites occupied by Pt, rationalized by the stronger Pt-Pt bond in comparison with Pt-Au and Au-Au bonds. This work exemplifies the potent application of rapid global search enabled by machine learning in exploring the high-dimensional configuration space of bimetallic nanocatalysts.
Hydroxyphosphoric acids display the unique biological activities, and they have some attractive prospects as clinical drug moleculars. Herein, a new approach for the synthesis of γ-oxo-phosphonates (the precursor of hydroxyphosphoric acid) has been established through the semipinacol rearrangement tactic involved the photo-induced phosphorus radical process. Most important, this transformation is avoid of the external oxidants, and occurs very well under the sunlight irradiation, meanwhile the γ-oxo-phosphonate was easily derivatized to obtain γ-hydroxyphosphoric acid, thus highlights the synthesis value of this method.
Several novel pyridine-oxadiazole iridium complexes were synthesized and characterized through X-ray crystallography. The designed iridium complexes revealed surprisingly high catalytic activity in C-N bondformation of amides and benzyl alcohols with the assistance of non-coordinating anions. In an attempt to achieve borrowing hydrogen reactions of amides with benzyl alcohols, N, N'-(phenylmethylene)dibenzamide products were unexpectedly isolated under non-coordinating anion conditions, whereas N-benzylbenzamide products were achieved in the absence of non-coordinating anions. The mechanism explorations excluded the possibility of "silver effect" (silver-assisted or bimetallic catalysis) and revealed that the reactivity of iridium catalyst was varied by non-coordinating anions. This work provided a convenient and useful methodology that allowed the iridium complex to be a chemoselective catalyst and demonstrated the first example of non-coordinating-anion-tuned selective C-N bond formation.
Nitrogen photofixation using g-C3N4-based photocatalysts have attracted abundant of attentions recently. Herein, in this study, holey g-C3N4 (HGCN) nanosheets possess a good deal of carbon vacancies were prepared by means of thermally treating bulk g-C3N4 (BGCN) under an NH3 atmosphere. Characterization analysis revealed that the as-synthesized sample have identical crystal structure, larger BET specific surface area, stronger reduction capability, and higher photogenerated charge carrier separation rate than that of BGCN. These properties may contribute to enhance the nitrogen photofixation activity. It was also found that the rate of NH4+ production for N2 photofixation of HGCN sample reached~25.54 mg L-1 h-1 gcat-1, which is approximately~5.87 times higher than that of BGCN sample under optimal reactive conditions. Moreover, a plausible mechanism of HGCN for nitrogen photofixation process was illuminated in detail.
In this paper we report the desgin and synthesis of dihydroxyindoles oligomers based reversible fluorescence sensor. We find dihydroxyindoles-2-carboxylic acid derived oligmer (P-DHICA) has the highest selectivity and sensitivity for Cu2+ detection. This work provide a highly efficient, environmentally friendly biosensor for potential use in medical testing.
Carbon dots (CDs) with multi-color emissive properties and a high photoluminescent quantum yield (PLQY) have attracted great attention recently due to their potential applications in chemical, environmental, biological and photo-electronic fields. Solvent-dependent effect in photoluminescence provides a facial and effective approach to tune the emission of CDs. In this study, green emissive nitrogen-doped carbon dots (N-CDs) are synthesized from p-hydroquinone and ethylenediamine through a simple hydrothermal method. The as-prepared N-CDs possess a robust excitation-independent green luminescence and a high PLQYof up to 15.9%. Further spectroscopic characterization indicates that the high PLQY is achieved by the balance of nitrogen doping states and the surface passivation extent in CDs. The N-CDs also exhibit solvent-dependent multi-color emissive property and distinct PLQY in different solvents (the maximum can reach up to 25.3%). Furthermore, the as-prepared N-CDs are applied as fluorescence probes to detect acetone and H2O2 in water. This method has exhibited a low detection limit of acetone (less than 0.1%) and a quick and linear response to the H2O2 with the concentration from 0 to 120 μmol/L. This work broadens the knowledge of applying CDs as probes in the bio and chemical sensing fields.
A simple and feasible potentiometric immunosensing platform based on enzymatic biocatalytic precipitation technique was designed for the sensitive detection of thyroid-stimulating hormone (TSH; a typical kind of biomarkers for thyroid carcinoma), using horseradish peroxidase (HRP)-loaded liposome for the signal amplification. To construct such an assay system, a sandwich-type immunoreaction was readily carried out on monoclonal anti-TSH capture antibody-coated electrode by using polyclonal antiTSH secondary antibody-conjugated HRP-loaded liposome. Accompanying the formation of sandwichtype immunocomplex, the carried liposome was lysed through the added Triton X-100 to release the entrapped HRP molecules, which catalyzed the oxidation of 4-chloro-1-naphthol to produce an insoluble and uncharged organic precipitation on the electrode surface, thereby causing the change of the local electrical potential. Two labeling protocols with and without the liposome were investigated for detection of target TSH, improved analytical features were achieved with HRP-entrapped liposome. Under optimal conditions, the potentiometric immunosensor had good responses for TSH detection within the linear range of 0.01-30 μIU/mL at a detection limit of 0.0067 μIU/mL. Good reproducibility, high specificity and long-time stability were acquired during the assay procedure. Importantly, a wellmatched accuracy between the potentiometric immunosensor and commercial human TSH ELISA kit was gave for the analysis of human serum samples.
Aggregation-induced emission (AIE) active photochromic molecules have attracted growing attention for their versatile applications. Here we designed and synthesized five newly unsymmetrical photochromic diarylethene (DAE) dyads (BTE1-5) by connecting tetraphenylethene (TPE) and aromatic substituent via bithienylethene (BTE) bridge. The chemical structures of those compounds were identified by 1H NMR, 13C NMR and HRMS.The absorption and emission of these dyads were investigated by UV-vis and fluorescence spectroscopy, respectively. The results showed that all those compounds exhibited typically AIE or aggregation-induced emission enhancement (AIEE) characteristic. Particularly, when an aggregation caused quenching (ACQ) fluorophore (triphenylamine) was grafted to the molecule, connecting with TPE via BTE-bridge, the ACQ phenomenon was dissipated and converted to an AIE luminophore, and those compounds exhibited photochromism upon irradiation with alternative UV and visible light. The solution or solid of those compounds showed distinctly fluorescence switching "ON" or "OFF" observation upon irradiation with alternative UV and visible light.It is interesting that BTE1 could be applied in recording and rewritable information storage, and the cyclization quantum yields could be affected by substituent significantly.
The isoindolinone and biaryl scaffolds are prevalent in natural products and drug molecules, which have showed broad and interesting biological activities. The efficient construction of such hybridized molecules and biological evaluation are of great interest to medicinal chemistry community. In this communication, we report an efficient Brønsted acid-promoted C(sp3)-H functionalization approach that enables the rapid construction of biologically important isoindolinone/[1,2,4]triazolo[1, 5-a]pyrimidine hybrids from 5-methyl-7-(2, 4, 6-trimethoxyphenyl)-[1,2,4]triazolo[1, 5-a]pyrimidine, 2-formylbenzoic acid and various anilines. The title compounds were generated in high to excellent yields (up to 96%) regardless of the electronic nature and steric effects of the substituents. In this reaction, an isoindolinone scaffold, one C-C single bond, and two C-N bonds were formed simultaneously with high atom economy. In this work, we have envisioned that the methyl group linked to the electron-deficient Nheterocycles could be used as a new synthetic handle for late-state diversification and may have broad applications in the field of organic and medicinal chemistry. Besides, the title compounds have exhibited promising activity against the SKP2-CKS1 interaction.
Over the past two decades, layer-by-layer (LbL) assembly of micro/nanocapsules has been of interest for the investigation of bio-nano interactions to explore bio-applications, such as drug delivery. The choice of an appropriate template that can be easily dissolved under mild conditions is one of the challenges for the assembly of LbL capsules. Herein, we report the engineering of LbL capsules with tunable morphologies using cuprous oxide (Cu2O) particles as templates. Cu2O particles with cubic, tetradecahedral or spherical morphologies were synthesized via hydrothermal processes, which can be dissolved under mild condition (e.g., sodium thiosulfate solution). The influence of capsule morphologies on cell association was investigated, which indicates that LbL capsules with cubic geometry promoted cell association up to 4 and 9-fold than tetradecahedral and spherical capsules, respectively. The reported method provides a new avenue for the assembly of LbL capsules with different morphologies, which has the potential for better understanding of biological interactions of LbL capsules.
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