Latest Articlesn-Alkanes have been widely used as phase change materials (PCMs) for thermal energy storage applications because of their exceptional phase transition performance, high chemical stability, long term cyclic stability and non-toxicity. However, the thermodynamic properties, especially heat capacity, of n-alkanes have rarely been comprehensively investigated in a wide temperature range, which would be insufficient for design and utilization of n-alkanes-based thermal energy storage techniques. In this study, the thermal properties of n-alkanes (C18H38-C22H46), such as thermal stability, thermal conductivity, phase transition temperature and enthalpy were systematically studied by different thermal analysis and calorimetry methods, and compared with previous results. Thermodynamic property of these n-alkanes was studied in a wide temperature range from 1.9 K to 370 K using a combined relaxation (Physical Property Measurement System, PPMS), differential scanning and adiabatic calorimetry method, and the corresponding thermodynamic functions, such as entropy and enthalpy, were calculated based on the heat capacity curve fitting. Most importantly, the heat capacities and related thermodynamic functions of n-heneicosane and n-docosane were reported for the first time in this work, as far as we know. This research work would provide accurate and reliable thermodynamic properties for further study of n-alkanes-based PCMs for thermal energy storage applications.
Spontaneously blinking probe, which switches between dark and bright state without UV or external additives, is extremely attractive in super resolution imaging of live cells. Herein, a clickable rhodamine spirolactam probe, Atto565-Tet, is rationally constructed for spontaneously blinking after biorthogonal labelling and successfully applied to super resolution imaging of mitochondria and lysosomes.
The scandocene alkyl complex (C5Me5)2ScCH2SiMe3 was found to be an efficient catalyst for the dehydrocoupling of the non-cyclic boranes, dicyclohexylborane and thexylborane, with amines under mild conditions. The reactions afforded the corresponding aminoboranes in high yields with good functional group tolerance. The stoichiometric reaction of scandium alkyl with amine led to the isolation of a scandium amide complex, which was shown to be an active species during the catalysis. Although a borane-coordinated scandium hydride was also obtained from the stoichiometric experiment, it was not involved in the catalytic cycle. In addition, kinetic studies provided insight into this intermolecular dehydrogenation reaction.
Three carbazole derivatives, AcPTC, PxPTC and PtPTC, consisting of two 9,9-dimethyl-9,10-dihydroacridine, phenoxazine or phenothiazine donor groups and one diphenyltriazine acceptor group fixed at 1,8,9-positions of a single carbazole ring via phenylene, are designed and synthesized. X-ray diffraction analysis of AcPTC reveals that there exist multiple π-π interactions between the donor and acceptor groups to form a sandwich-like structural unit with edge-to-face interaction model. The compounds thus show obvious thermally activated delayed fluorescence with through-space charge transfer character and possess considerable photoluminescence quantum yields of up to 73% in doped films with sky-blue to yellow emissions. The solution-processed electroluminescent devices achieve the highest maximum external quantum efficiencies of 10.0%, 11% and 5.6% for AcPTC, PxPTC and PtPTC, respectively, with small efficiency roll-offs.
The development of robust photocatalytic systems is key to harvest the solar power for hydrogen production. In the current study, a series of aluminum-based porphyrinic metal organic frameworks (Al-TCPP) with various morphologies of bulk, carambola-like and nanosheets are synthesized with modulated layer thickness. Morphology-dependent photocatalytic activities in hydrogen production are witnessed and inversely correlate to the thickness of the Al-TCPP micro-platelets or nanosheets. Particularly, the exfoliated metal organic layers (MOLs) of Al-TCPP demonstrated a high hydrogen yield rate of 1.32 × 104 µmol h−1 g−1 that is 21-fold of that from the bulk catalyst, as well as an exceptional TON of 6704 that seldom seen in literature. Through comprehensive photochemical characterizations, the remarkable photocatalytic performance of Al-TCPP-MOL is attributed to the great charge separation efficiency and transfer kinetics endowed by the ultrathin 2D morphology with extended active surface area.
Chemiluminescence (CL) has been widely used for bioanalysis owing to its high sensitivity, low background and simplicity. However, most of the CL systems need acidic/alkaline conditions or organic solvent to enhance their luminescent efficiency, and the non-physiological conditions can usually lead to the misfunction of biomolecules during biosensing. Herein, we report a highly luminous CL system under physiological conditions based on carbon dots-bis(2-carbopentyloxy-3, 5, 6-trichlorophenyl) oxalate (CDs-CPPO) micelles, and further used it in biosensing application. In the CL system, the amphiphilic surfactant packed CPPO and hydrophobic CDs together to form CDs-CPPO micelles. Such micelles solution not only isolated the CPPO from water to prevent its hydrolysis but also made the close proximity between CPPO and CDs, thus significantly enhancing the CDs quantum yield. The CL quantum yield was calculated to be 5.26 × 10−4 einsteins/mol, about 200-fold higher than that of the most commonly used luminol CL system. The oxidases (e.g., glucose oxidase) were tested to be susceptible to the organic solvent and non-physiological pH. Hence, the CL system was used for the detection of oxidase substrates (exemplified by glucose) in serum samples, and the limit of detection was as low as 8.4 nmol/L. The highly luminous CL system that can work under physiological conditions is promising for biosensing applications
Oncolytic virus is an emerging anti-cancer strategy. However, extracellular matrix (ECM), as a physical barrier, limits virus spread within the tumor. To overcome the obstacle, we constructed a recombinant Newcastle disease virus (NDV) expressing matrix metalloproteinase (MMP8) (NDV-MMP8) using with reverse genetic technology. In vitro, NDV-MMP8 was identified and verified by WB and ELISA. Cell viability was detected by CCK-8 assay. In vivo, we established two liver cancer xenograft models. NDV-MMP8 was injected into the tumor to observe the tumor volume and survival of mice. The changes in extracellular matrix were observed by Masson's trichrome staining. Virus expression in tumor tissues was detected by immunofluorescence assay. The virus titer in tumor tissues was detected by TCID50. Histopathological changes were detected by hematoxylin and eosin (HE) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Intratumoral administration of NDV-MMP8 can effectively degrade ECM, promote the spread of the virus within the tumor, and reduce tumor growth rate. Therefore, the method of increasing intratumoral virus accumulation by degradation of the ECM to enhance the oncolytic effect has great potential for clinical application.
The application of Si as the anode materials for lithium-ion batteries (LIBs) is still severely hindered by the rapid capacity decay due to the structural damage caused by large volume change (> 300%) during cycling. Herein, a three-dimensional (3D) aerogel anode of Si@carbon@graphene (SCG) is rationally constructed via a polydopamine-assisted strategy. Polydopamine is coated on Si nanoparticles to serve as an interface linker to initiate the assembly of Si and graphene oxide, which plays a crucial role in the successful fabrication of SCG aerogels. After annealing the polydopamine is converted into N-doped carbon (N-carbon) coatings to protect Si materials. The dual protection from N-carbon and graphene aerogels synergistically improves the structural stability and electronic conductivity of Si, thereby leading to the significantly improved lithium storage properties. Electrochemical tests show that the SCG with optimized graphene content delivers a high capacity (712 mAh/g at 100 mA/g) and robust cycling stability (402 mAh/g at 1 A/g after 1500 cycles). Furthermore, the full cell using SCG aerogels as anode exhibits a reversible capacity of 187.6 mAh/g after 80 cycles at 0.1 A/g. This work provides a plausible strategy for developing Si anode in LIBs.
The bio-nanotechnological fabrication of high-surface-area carbons has attracted widespread interest in supercapacitor applications by using readily-available natural products as raw materials or bio-templates, and is expected to refine on pore accessibility for compact energy storage. Here, a renovated design strategy of semi-biomass interpenetrating polymer network (IPN) derived carbon is demonstrated through physically knitting the biomacromolecule (sodium alginate, SA) polymeric chains into the highly crosslinked resorcinol-formaldehyde (RF) network and subsequent thermochemical conversion. Molecule-level interlacing forces in such IPN efficiently relieve the RF skeleton shrinkage when producing carbon, while the other SA network addresses the macrophase separation issue to sacrifice as an in-knitted porogen and a morphology-directing agent. As a result, porous carbon globules are equipped with moss-like surfaces and interconnected pore architecture for high accessible electrode surface (1013 m2/g), and efficient electrochemical responses are reached with the specific capacitance of 312 F/g at 1 A/g. Taking the advantage of 9 mol/kg NaClO4 complex-solvent electrolyte, the voltage window is extended to 2.4 V, endowing the two-electrode device with the high energy delivery of 32.3 Wh/kg at 240 W/kg.
Introduction of iodosylarnes into biomimetic nonheme chemistry has made great achievement on identification of the subtle metal-oxygen reaction intermediates. However, after more than three decades of experimental and theoretical efforts the nature of the metal-iodosylarene adducts and the related dichotomous one-oxidant/multiple-oxident controversy have remained a matter of speculation. Herein, we report a theoretical study of the structure-activity relationship of the noted iron(Ⅲ)-iodsylarene complex, FeⅢ(PhIO)(OTf)3 (1), in oxygenation of cyclohexene. The calculated results revealed that 1 behaves like a chameleon by adapting its roles as a 2e-oxidant or an oxygen donor, as a response to the regioselective attack of the C–H bond and the C=C bond. The oxidative C–H bond activation by 1 was found, for the first time, to proceed via a novel hydride transfer process to form a cyclohexene carbonium intermediate, such non-rebound step triggers the Ritter reaction to uptake an acetonitrile molecule to form the amide product, or proceeds with the rebound of the hydroxyl group return to the solvent cage to form the hydroxylated product. While in the C=C bond activation, 1 is a normal oxygen donor and shows two-state reactivity to present the epoxide product via a direct oxygen atom transfer mechanism. These mechanistic findings fit and explain the famous Valentine's experiments and enrich the non-rebound scenario in bioinorganic chemistry.
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