Long-wavelength fluorescence of carbon dots (CDs) show the great importance in multiple fields, especially for the biochemical sensing. Here we proposed one type of CDs doped with nitrogen and sulfur through the hydrothermal method, which exhibited the obvious yel-low-fluorescence in aqueous. Importantly, their fluorescence intensity of CDs decreased with pH decreasing in the acidic range, thus a linear relationship between pH and fluorescence intensity was established, and exhibiting the potential of pH sensing. Additionally, in-troducing tigecycline into CDs resulted in their decreased fluorescence, thus we further established a strategy of detecting tigecycline with the concentration range of 200 μM to 7 nM. Meanwhile, we elucidated the static quenching as the major mechanism for CDs responding tigecycline, which was induced by the formed new complex between CDs and tigecycline. Furthermore, the practicality of the method was verified by examining the recovery of tigecycline in the actual lake-water samples.
With the increasing demand for homoallylic silanes and allylic silanes, the highly efficient and regioselective hydrosilylations of conjugated dienes are urgently needed. Herein, we developed a Ni-catalyzed regiodivergent hydrosilylation of aromatic conjugated dienes by adjusting the temperature and ligands. Under low temperature (-30 oC), an eternal-ligand-free system (Ni/t-BuOK) can efficiently facili-tate the 3,4-anti-Markovnikov hydrosilylation to provide homoallylic silanes via electrophilic activation process; under room temperature (25 oC), a ligand-controlled system (Ni/t-BuOK/PPh3) can eventuate the 3,4-Markovnikov hydrosilylation to produce allylic silanes via Chalk-Harrod process. Both systems are compatible with various conjugated dienes and primary silanes in excellent yields and regioselec-tivities.
L-Hexoses are key components of many biologically relevant natural products and pharmaceuticals. As rare sugars, L-hexoses are not readily obtained from natural sources. Access to L-hexose building blocks from commercially available and inexpensive D-sugars is highly desirable from the viewpoints of organic synthesis and drug discovery. As demonstrated by the convenient preparation of L-glucosyl, L-galactosyl, and L-mannosyl fluorides from readily available β-D-C-glucosyl, β-D-C-mannosyl, and β-D-C-galactosyl derivatives, we describe a novel and efficient approach to the demanding L-glycosyl fluorides. The transformation features the installation of anomeric hydroxymethyl group under mild conditions and head-to-tail inversion of sugar rings through radical decarboxylative fluorination of uronic acids. The power of this protocol is highlighted by the first assembly of a pentasaccharide repeating unit of Pseudomonas ATCC 31554 extracellular polysaccharide (S-88). This synthesis relies on the efficient extension of sugar chain at the sterically hindered hydroxy group and the facile introduction of L-mannosyl unit using L-mannosyl fluoride as glycosylating agent. The methods developed in this work would provide new tools to the arsenal of synthesis of L-sugar building blocks and of assembly of glycans containing L-sugar moieties.
Dehydration of serine/threonine residues necessitates the activity of a dehydratase enzyme (domain) during the biosynthesis of ribosomally synthesized and post-translationally modified peptide (RiPP). Recently, it was reported that the dehydration process in thioviridamide relies on a distinct dehydratase complex which showcases the activities of a phosphotransferase TvaC for serine/threonine phosphorylation and a lyase TvaD for subsequent phosphate elimination. Herein, we report that the dehydration process of lantibiotic cacaoidin involves a similar dehydratase complex, CaoK/CaoY. Remarkably, this dehydratase complex exhibits flexible enzymatic activity and tolerates significant variations in its substrate peptide sequence. By binding with the leader peptide (LP) sequence of precursor peptide CaoA, the dehydration reactions proceed directionality from the C-terminus of the core peptide (CP) to its N-terminus, and C-terminally truncated variants of CP are acceptable. We show that fusing CaoK to CaoY in a 1:1 molar ratio enables the resulting enzyme CaoYK to exert enhanced dehydration activity. CaoK binds with the LP to improve its own solubility and to ensure the phosphate transfer activity, while CaoY functions independently of the LP. This work advances our understanding of the dehydration process of cacaoidin, and provides valuable enzymes and methods for the studies of the rapidly emerging RiPPs.
Electrocatalytic reduction of CO2 to fuels and chemicals possesses huge potential to alleviate current environmental crisis. Heteroatom doping in metal-nitrogen-carbon (M-N-C) single-atom catalysts (SACs) has been found capable to promote the electrocatalytic CO2 reduc-tion reaction (CO2RR). However, the origin of the enhanced activity is still elusive. Here, we report that sulfur-doped cobalt-nitrogen-carbon single-atom catalyst (Co1-SNC) exhibits superior CO2RR performance compared to sulfur-free counterpart (Co1-NC). On the basis of in situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), kinetic isotope effect (KIE) and theoretical calculation, it is demonstrated that sulfur doping can promote water activation, elevate the d-band center of Co active site, and reduce the free energy of *COOH intermediate formation. This work deepens the understanding of the CO2RR chemistry over heteroatom-doped SACs for designing efficient CO2RR processes.
The alkenylzincation of internal alkynes is an effective method for the synthesis of multi-substituted conjugated dienes; however, the current catalytic systems for this reaction are limited in terms of substrate scope and selectivity control, which restricts its practical applications. Herein, we report the first iron-catalyzed alkenylzincation of internal alkynes, which features mild conditions, simple oper-ation, broad substrate scope (including aryl/alkyl, diaryl, and dialkyl acetylenes), excellent functional group tolerance (tolerating highly active functional groups such as ester, methylthio, amide, sulfonyl, cyano, etc), and high activity (with a turnover number of up to 11500, the highest record for carbometallation reactions). Notably, the catalytic system described in this article also realized the highly selective vinylzincation of unfunctionalized internal alkynes as well as the alkenylzincation of unsymmetrical diarylacetylenes and dial-kyl acetylenes, which have not been achieved with other catalytic systems reported in the literatures. The current study provides a highly selective access to synthetically important multi-substituted conjugated dienes.
Hypochlorite (ClO-) is an important reactive oxygen species produced by the immune system to fight off invading pathogens, but its over-expression can interfere with normal physiological process and induce serious diseases. Although a variety of molecular probes have been reported for detecting ClO-, the development of advanced fluorescent tools with faster response and higher sensitivity to precisely monitor ClO- remains a challenge. In this work, two Hantzsch ester (a derivative of 1,4-dihydropyridine) derived fluorescent probes MeDHP-BCl and MeDHP-PhBCl were constructed based on asymmetric BODIPY-matrix. These probes exhibit significant fluo-rescence turn-on in the ultra-sensitive (detection limit < 1 nM) and ultra-fast response (≤ 5 s) to ClO-, the reaction has determined to be a highly selective N-Chlorination of Hantzsch ester which cannot be activated by various common bioactive species, including nitric ox-ide (NO) that could oxidize Hantzsch ester under aerobic physiological conditions in most reports. MeDHP-PhBCl possess a relatively longer fluorescence emission wavelength and higher quantum yield after activation, while more notably, MeDHP-BCl displayed lower cytotoxicity and more remarkable fluorescence increasement in the response to ClO-, enabling selective and precise visualization of endogenous ClO- over-expression in living RAW264.7 cells.
The issue of energy consumption has garnered significant interest due to its excessive usage. Recently, thermoelectric devices have been getting increased attention, as they can harness waste heat from various sources, such as solar radiation, human body, and industrial processes. Traditionally, the recovery of low-grade heat has been a challenge, resulting in unsustainable energy use and significant losses. While considerable advances have been made in thermoelectric materials in recent decades, the majority of these devices still primarily employ semiconductors. Nevertheless, the emergence of quasi-solid-state thermoelectric materials represents a novel devel-opment with profound promise for the environment and society. These materials offer several advantages, such as improved energy conversion capacities, cost-effectiveness, versatility, and scalability, to support increased usage. Additionally, this review explores the application of thermoelectric materials in self-powered sensors, integrated modules, and heat harvesting management. Lastly, the po-tential of high-performance thermocouples based on thermogalvanic effects is assessed, along with the challenges that must be over-come to realize this goal.
All-Polymer solar cells (all-PSCs) have attracted considerable attention due to their inherent advantages over other types of organic solar cells, including superior optical and thermal stability, as well as exceptional mechanical durability. Recently, all-PSCs have experi-enced remarkable advancements in device performance thanks to the invention of polymerized small-molecule acceptors (PSMAs) since 2017. Among these PSMAs, PY-IT has garnered immense interest from the scientific community due to its exceptional perfor-mance in all-PSCs. In this review, we presented the design principles of PY-IT and discussed the various strategies employed in device engineering for PY-IT-based all-PSCs. These strategies include additive and interface engineering, layer-by-layer processing methods, meniscus-assisted coating methods, and ternary strategy. Furthermore, this review highlighted several novel polymeric donor materials that are paired with PY-IT to achieve efficient all-PSCs. Lastly, we summarized the inspiring strategies for further advancing all-PSCs based on PY-IT. These strategies aim to enhance the overall performance and stability of all-PSCs by exploring new materials, optimizing device architectures, and improving fabrication techniques. By leveraging these approaches, we anticipate significant progress in the development of all-PSCs and their potential as a viable renewable energy source.
It’s urgent to develop benzocyclobutene (BCB)-based polymers with low curing temperatures for temperature-sensitive applications such as liquid crystal display (LCD) and flexible electronics. Herein, the effect of substituents on the ring-opening behavior of BCB derivatives was investigated. The ring-opening activation energy barriers (ΔGA) of BCB derivatives with one or two substituents on the four-membered alkyl ring were systematically calculated using the B3LYP function. Both mono- and di-substituted BCBs adopted the conrotatory ring-opening process, obeying the Woodward-Hoffmann’s Rules upon heating. The mono-/di-substituted BCBs ex-hibited 8.2 – 69% lower ΔGA compared with BCB, attributed to the electronic effects of the substituents. Disubstituted BCBs with both electron-donating and electron-withdrawing groups, e.g., 1-NH2-8-NO2-BCB, demonstrated the lowest ΔGA. In addition, BCB derivatives with amide/ester/acyloxy group modified on C1 position were synthesized as model molecules, and their ring-opening temperature can be decreased by 20 °C compared to the unsubstituted one, also consistent with our calculation results. This work combined the theoretical calculation method with experimental results to provide valuable insights into the design and synthesis of BCB derivatives and next-generation BCB functional packaging materials with low ring-opening temperatures.
Various optically active polymers are known to afford sophisticated chirality-related functionalities, i.e. asymmetric catalysis, chiroptical switching and memory in UV-vis-NIR region, chromatographic separation of enantiomers, and sensors for molecular chirality. Recently, material researchers are received much attention to design chiral supramolecular architectures from achiral polymers upon intermolecular interactions with help of greener biosources. The present article reports an instantaneous generation of ambidextrous supramolecules revealing light-driven chiroptical switching/memory in UV-vis region when achiral azobenzene-containing vinylpolymers are non-covalently interacted with alkyl ester derivatives of natural cellulose and D-/L-glucose. It was recognized that the semi-synthetic biomaterials efficiently work as chirality-inducing scaffoldings to several achiral and optically inactive molecules, oligomers, and polymers. Our successful results shed light on a new approach of how inexpensive poly-/mono-saccharide derivatives can afford supramolecular chiroptical systems with the azobenzene pendant polymer as aggregates in suspension and liquid-crystalline films with minimal energy, time, and cost.
An efficient Pd/Cu-catalyzed oxidative self-carbonylation of arylhydrazine with CO and molecular oxygen as an oxidant to afford symmetrical biaryl ketones via C-N bond activation has been developed. In this approach, arylhydrazine hydrochlorides are used as a green arylating agent which releases nitrogen and water as a byproduct. This developed protocol significantly restricts the for-mation of aryl iodide and homo-coupled azobenzene products even under favorable conditions. A library of symmetrical biaryl ke-tones with wide functionalities was synthesized in good yields under mild conditions.
In recent years, flexible photodetectors (FPDs) have received increasing attention due to their applications in electronic eyes, flexible sensing, terminal devices, and wearable devices. In addition, metallic halide perovskite materials are considered as future materials for FPDs due to their compatibility with flexible substrates, low cost, simple synthesis methods, and superior optoelectronic properties. This review provides a comprehensive overview of the relevant cutting-edge research in the field of flexible perovskite photodetectors (FPPDs) from 2020 to 2022. First, the evaluation criteria for FPPDs are discussed and the development of perovskite stability criteria is emphatically described. Afterwards, the synthesis methods and device construction processes of metal halide perovskite materials commonly used by researchers in the past three years were described. These include single crystals and low-dimensional materials. Moreover, we have elaborated on the research of self-powered FPPD and its contributions in wearability, terminals, and portability. Finally, a summary of developments and possibilities in the field of FPPDs from 2020 to 2022 is provided.
The study of luminescence phenomena in non-conjugated systems, namely clusteroluminescence, has gained significant attention for the development of advanced luminescent materials. While conventional strategies to manipulate the luminescent performances are based on complicated chemical reactions. In contrast, nature employs complexation to modulate luminescence, inspiring researchers to adopt an engineering approach for the construction of efficient clusteroluminogens. In this work, we explore the complexation-induced clusteroluminescence of carbonyl-based polymers with nitrogen-containing organic bases, exemplified by polyamide, polyester, polycarbonate, and poly(monothiocarbonate). The results demonstrate an increase in the intrinsic 440 nm emission of carbonyl groups and the emergence of new emission peaks upon complexation. The study proposes a through-space n‧‧‧π complex mechanism, highlighting the potential of complexation as a strategy for modulating the clusteroluminescent properties of non-conjugated systems. Further research is necessary to unravel underlying mechanisms, optimize cluster structures, and explore new materials for complexation, thereby advancing optoelectronics and photonics fields and enabling practical applications of clusteroluminescent materials.
Phenols are ubiquitous substructures in natural products and bioactive compounds. However, practical methods for the direct construction of phenols under mild conditions remains challenging. Herein, a photocatalytic acceptorless dehydrogenative aro-matization of cyclohexanones or cyclohexenones at room temperature has been developed. The reaction features the visible-light and cobalt co-catalyzed sequential dehydrogenation of in-situ formed enol silyl ethers, which are regarded as a challenging process. This operationally simple method enables the synthesis of a series of phenols with diverse substitution patterns from cyclohexanones or cyclohexenones. Moreover, diverse substituted 1,2-, 1,3-, and 1,4-benzenediols were obtained from cyclo-hexanediones, providing a general and straightforward method for the synthesis of phenols from simple starting materials un-der mild conditions
A novel type of A-type nanogrids (AGs) with axial and central chirality was synthesized via Friedel-Crafts gridization of thiophenes and difluorenyl biaromatic derivatives, yielding 9–30%. Additionally, the effect of stereoisomers of 1,1’-binaphthyl difluorenols (BINDFOH) was investigated to demonstrate that R/S-BINDFOH is more advantageous for the synthesis of AGs than Mix-BINDFOH. Furthermore, Tests on OFET memory devices showed that AGs have a larger storage window, indicating potential for data storage applications.
The colonization of marine microorganisms, animals and plants on underwater surface forms marine biofouling. It has profound ef-fects on marine industries. To solve the problem, we proposed a strategy of Dynamic Surface Antifouling (DSAF), i.e., continuously changing surfaces can effectively inhibit biofouling organisms landing and adhering, and developed degradable polymer based ma-rine antifouling material. The degradation of polymer chain enables the surface dynamic or self-renewing even on static conditions. The final degradation products of these polymers are low molecular weight molecules, and do not produce marine microplastics. Meanwhile, the degradable polymers act as carriers and controlled release systems for antifoulants, further improving the antifoul-ing efficiency. This article reviews the development of dynamic surface antifouling materials.