Latest ArticlesDeoximation is an important transformation in synthetic industry. It can be employed in protection, characterization and purification of the carbonyls, and in the synthesis of ketones from non-carbonyl molecules. In the field, oxidative deoximation reaction can utilize the driving force caused by the oxidation process so that the reaction can occur under relatively mild conditions. Recently, we designed and prepared polyaniline-supported molybdenum (Mo@PANI) just by immersing PANI into the EtOH/H2O solution of MoCl5. The material was successfully applied as the efficient catalyst for oxidative deoximation reactions, which were performed in ethanol using H2O2 as the clean oxidant. The substrate scope of the reaction was wide. It could be applied on heterocycle-containing substrates, making this protocol preferable for pharmaceutical intermediate synthesis. Since Mo is a necessary trace element for both animals and plants, this method is environment-friendly and is suitable for large-scale preparation. This work as the first example of Mo-catalyzed oxidative deoximation reaction may inspire novel ideas for both catalyst design and synthetic process development.
Chiroptical switches based on circularly polarized luminescence (CPL) have shown the promising applications in advanced information technologies. Herein, a pair of lanthanide coordination polymer enantiomers [Eu2(LR)3(BTFPO)2]n and [Eu2(LS)3(BTFPO)2]n with light-regulated CPL property are designed, which are assembled by a chiral binuclear triple-stranded Eu3+ helicates [Eu2(LR/S)3] coordinated with two photochromic triphenylphosphine oxides (BTFPO). Upon the alternative UV and 526 nm light irradiation, the complexes show the reversible photochromism, PL and CPL responses. Notably, the luminescence dissymmetry factor, glum of 5D0→7F1 (591 nm) transition shows an obvious increase from 0.19 to 0.29 before and after 275 nm light irradiation. Additionally, the emission from Eu3+ center is not completely quenched in closed-ring state due to the low photocyclization (Фo-c) quantum yield of the polymer. The partial maintenance of emissive intensity is of essential importance for the monitor of CPL signal. More importantly, the CPL photo-switching property of the complexes in solid hybrid film is maintained, and still displays the enhanced CPL emission in photostationary state. Further, the potential applications of the doping film in logic gate and anti-counterfeiting were investigated.
Colorectal cancer causes the third most common type of malignant tumors with high morbidity and mortality. Chemotherapy is currently one of the most effective and common treatments for colorectal cancer. However, the poor water solubility of some chemotherapeutics, untargeted drug delivery, and the undesirable systemic side effects of conventional treatment remain the major issues for colorectal cancer chemotherapy. Fortunately, drug delivery systems (DDS) based on biomaterials have been widely investigated and found to be capable of resolving those issues with good performance. Therefore, the main goal of this review is to summarize and discuss the progress and potential advantages of different DDS for colorectal cancer chemotherapy. We not only reviewed the nanocarriers used to improve the solubility of chemotherapeutics, including liposomes, micelles, and nanoparticles, but also discussed targeted DDS based on specific ligand-receptor recognition and tumor microenvironmental stimulus responses. Furthermore, locally administered systems based on hydrogels and microspheres, which have been shown to increase drug accumulation at the tumor site while decreasing systemic toxicity, were also emphasized. DDS provides a good option for improving the efficacy of chemotherapy in the treatment of colorectal cancer.
Improving the performance of all-small-molecule organic solar cells (ASM-OSCs) largely depends on the design and application of novel donors with appropriate crystallinity. Extending molecular conjugation is an effective method for regulating molecular stacking and crystallinity. In this work, we successfully designed and synthesized two novel acceptor-donor-donor-donor-acceptor (A-D-D-D-A) type oligomeric donors with three dithieno[2,3-d:2’,3’-d’]benzo[1,2-b:4,5-b’]dithiophene (DTBDT) as the central unit, named as 3DTBDT-Cl and 3DTBDT, depending on with and without chlorine substitution on the thiophene side chains. We found that the introduction of chlorine atoms makes the blend films display stronger crystallinity but with large-scale phase separation morphology and more defects, which eventually leads to a power conversion efficiency (PCE) of only 10.83%, whereas the blend films based 3DTBDT with appropriate crystallinity achieved 13.74% PCE. Compared with 3DTBDT-Cl/L8-BO, the 3DTBDT/L8-BO films exhibited a nanoscale bi-continuous interpenetrating network morphology with a smaller domain size and more suitable crystallinity, which guarantees the corresponding devices obtained more efficient exciton dissociation, efficient charge transport, reduced bimolecular recombination, and performed more balanced carrier mobility. These results demonstrated that regulating the crystallinity of oligomeric donors to obtain the desired phase separation morphology in the blend films could facilitate further improving the performance of ASM-OSCs.
Enzyme prodrug therapies (EPTs) have been intensively explored as attractive approaches to selective activation of systemically administered benign prodrugs by the exogenous enzymes or enzymes expressed at the desired target site, thus achieving localized, site-specific therapeutic effect. Many effective strategies (e.g., antibody-, viral-, gene-, as well as polymer-directed EPT) have been developed for enzyme localization to locally activate systemically administered benign prodrugs. Nevertheless, intrinsic limitations (e.g., complex intracellular environment and catalyst instability) make the practical application of EPT strategies a task that presents itself as highly challenging. As a promising alternative to natural enzyme, nanozyme has attracted substantial attention since its discovery in 2007, mainly due to the advantages of robust catalytic activity, high stability, low cost, and facile synthesis. Recently, nanozyme-activated prodrug strategies bring a new opportunity for targeted therapy, referred to as nanozyme-activating prodrug therapies. This review focuses on recently reported nanozyme-activated prodrug strategies, aiming to provide some new insights into the potential applications in site-specific drug synthesis.
Activated hepatic stellate cells (aHSCs), the main source of extracellular matrix deposition, are key targets in liver fibrosis. However, no effective drug specific to aHSCs has been clinically applied due to poor drug delivery efficiency. Herein, we designed a CXC chemokine receptor 4 (CXCR4)-targeted reactive oxygen species (ROS)-responsive platform AMD-Dex-ROS-responsive-sorafenib (ARS) based on natural polysaccharide and thioctic acid frame, which can deliver anti-fibrosis drug represented by sorafenib specifically to aHSCs on account of CXCR4 over-expression on aHSCs, and smartly disassemble via ROS-responsive thioketal rupture relying on high intracellular ROS in HSCs, realized on-demand drug release and effective liver fibrosis reversion. Notably, in this platform, the CXCR4 antagonist AMD3100 not only enhanced aHSCs targeting efficiency of sorafenib but also effectively magnified the aHSCs elimination of sorafenib by blocking stroma cell derived factor-1 (SDF-1)/CXCR4-induced aHSCs protection, resulting in synergistic anti-fibrosis effect. The platform provided a new approach for drug delivery system design and liver fibrosis treatment.
Calcium dibutyryladenosine cyclophosphate is a widely used cardiovascular drug. The traditional batch synthesis process suffers from long reaction times, tedious operations, and unstable yields. Herein, a sequential continuous flow synthesis combined with a multistage in-line purification process of calcium dibutyryladenosine cyclophosphate was developed. The acylation reaction was completed in a continuous coil reactor at 160 ℃ in 20 min. And the high toxic solvent pyridine was replaced by acetonitrile. Furthermore, the multistage in-line purification process was integrated into the homemade 3D circular cyclone-type micromixer chip. Combining with the membrane phase separators, the residence time of the purification step was 30 s. The isolated yield of this sequential continuous process was 92% with 99% purity.
The unique properties of metal oxide surfaces, crystal surfaces and defects play vital roles in biomass upgrading reactions. In this work, hierarchical porous bowl-shaped ZrO2 (HB-ZrO2) with mixed crystal phase was designed and employed as the support for loading AuPd bimetal with different proportions to synthesize AuPd/HB-ZrO2 catalysts. The effects of surface chemistry, oxygen defects, bimetal interaction and metal-support interaction of AuPd/HB-ZrO2 on catalytic performance for the selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) were systematically investigated. The Au2Pd1/HB-ZrO2 catalyst afforded a satisfactory FDCA yield of 99.9% from HMF oxidation using O2 as the oxidant in water, accompanied with an excellent FDCA productivity at 97.6 mmol g−1 h−1. This work offers fresh insights into rationally designing efficient catalysts with oxygen-rich defects for the catalytic upgrading of biomass platform chemicals.
Modulating surface charge redistribution based on interface and defect engineering has been considered as a resultful means to boost electrocatalytic activity. However, the mechanism of synergistic regulation of heterojunction and vacancy defects remains unclear. Herein, a Vs-CoP-CoS2/C n-n heterojunction with sulfur vacancies is successfully constructed, which manifests superior electrocatalytic activity for oxygen evolution, as demonstrated by a low overpotential of 170 mV to reach 10 mA/cm2. The experimental results and density functional theory calculations testify that the outstanding OER performance of Vs-CoP-CoS2/C heterojunction is owed to the synergistic effect of sulfur vacancies and built-in electric field at n-n heterogeneous interface, which accelerates the electron transfer, induces the charge redistribution, and regulates the adsorption energy of active intermediates during the reaction. This study affords a promising means to regulate the electrocatalytic performance by the construction of heterogeneous interfaces and defects, and in-depth explores the synergistic mechanisms of n-n heterojunction and vacancies.
A bottleneck in biomimetic synthesis consists in the full copy of, for example, the hierarchical structure of proteins directed by weak interactions. By contrast with covalent bonds bearing definite orientation and high stability, weak intermolecular forces within a continuous dynamic equilibrium can be hardly tamed for molecular design. In this endeavor, a ligand-dominated strategy that embodies tunable electrostatic repulsion and π…π stacking was first employed to shape polyoxovanadate-based metal-organic polyhedra (VMOPs). Structural evolution involving transformation, interlock, and discovery of an unprecedented prototype of the Star of David was hence achievable. Not only as a handy tool for the primary structural control over VMOPs, these weak forces allow for an advanced management on the spatial distribution of such manmade macromolecules as well as the associated physicochemical behaviors, representing an ideal model for simulating and interpreting the conformation-function relationship of proteins.
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