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991.
Singly versus Doubly Reduced Nickel Porphyrins for Proton Reduction: Experimental and Theoretical Evidence for a Homolytic Hydrogen‐Evolution Reaction 下载免费PDF全文
Yongzhen Han Dr. Huayi Fang Huize Jing Huiling Sun Haitao Lei Prof. Dr. Wenzhen Lai Prof. Dr. Rui Cao 《Angewandte Chemie (International ed. in English)》2016,55(18):5457-5462
A nickel(II) porphyrin Ni‐P (P=porphyrin) bearing four meso‐C6F5 groups to improve solubility and activity was used to explore different hydrogen‐evolution‐reaction (HER) mechanisms. Doubly reduced Ni‐P ([ Ni‐P ]2?) was involved in H2 production from acetic acid, whereas a singly reduced species ([ Ni‐P ]?) initiated HER with stronger trifluoroacetic acid (TFA). High activity and stability of Ni‐P were observed in catalysis, with a remarkable ic/ip value of 77 with TFA at a scan rate of 100 mV s?1 and 20 °C. Electrochemical, stopped‐flow, and theoretical studies indicated that a hydride species [H‐ Ni‐P ] is formed by oxidative protonation of [ Ni‐P ]?. Subsequent rapid bimetallic homolysis to give H2 and Ni‐P is probably involved in the catalytic cycle. HER cycling through this one‐electron‐reduction and homolysis mechanism has been proposed previously but rarely validated. The present results could thus have broad implications for the design of new exquisite cycles for H2 generation. 相似文献
992.
Dual‐Targeting Nanovesicles for In Situ Intracellular Imaging of and Discrimination between Wild‐type and Mutant p53 下载免费PDF全文
Ruocan Qian Yue Cao Prof. Yi‐Tao Long 《Angewandte Chemie (International ed. in English)》2016,55(2):719-723
p53 is a tumor‐suppressor protein related to the cell cycle and programmed cell apoptosis. Herein, dual‐targeting nanovesicles are designed for in situ imaging of intracellular wild‐type p53 (WTp53) and mutant p53 (MUp53). Nanovesicle‐encapsulated plasmonic gold nanoparticles (AuNPs) were functionalized with consensus DNA duplexes, and a fluorescein isothiocyanate (FITC)‐marked anti‐MUp53 antibody was conjugated to the nanovesicle surface. After entering the cytoplasm, the released AuNPs aggregated through recognition of WTp53 and the double‐stranded DNA. The color changes of AuNPs were observed using dark‐field microscopy, which showed the intracellular WTp53 distribution. The MUp53 location was detected though the immunological recognition between FITC‐labeled anti‐MUp53 and MUp53. Thus, a one‐step incubation method for the in situ imaging of intracellular WTp53 and MUp53 was obtained; this was used to monitor the p53 level under a drug treatment. 相似文献
993.
An Alignment Medium for Measuring Residual Dipolar Couplings in Pure DMSO: Liquid Crystals from Graphene Oxide Grafted with Polymer Brushes 下载免费PDF全文
Wen Zong Gao‐Wei Li Jiang‐Ming Cao Prof. Xinxiang Lei Prof. Mao‐Lin Hu Dr. Han Sun Prof. Christian Griesinger Prof. Ren Xiang Tan 《Angewandte Chemie (International ed. in English)》2016,55(11):3690-3693
Residual dipolar couplings (RDCs) have attracted attention in light of their great impact on the structural elucidation of organic molecules. However, the effectiveness of RDC measurements is limited by the shortage of alignment media compatible with widely used organic solvents, such as DMSO. Herein, we present the first liquid crystal (LC) based alignment medium that is compatible with pure DMSO, thus enabling RDC measurements of polar and intermediate polarity molecules. The liquid crystals were obtained by grafting polymer brushes onto graphene oxide (GO) using free radical polymerization. The resulting new medium offers several advantages, such as absence of background signals, narrow line shapes, and tunable alignment. Importantly, this medium is compatible with π‐conjugated molecules. Moreover, sonication‐induced fragmentation can reduce the size of GO sheets. The resulting anisotropic medium has moderate alignment strength, which is a prerequisite for an accurate RDC measurement. 相似文献
994.
Xuemei Liu Limei Cao Wei Sun Zhenhua Zhou Ji Yang 《Research on Chemical Intermediates》2016,42(7):6289-6300
A heterojunction thin film consisting of n-type titanium dioxide (TiO2) and p-type cuprous oxide (Cu2O) was fabricated on an FTO conducting glass. The TiO2 films were grown on the FTO glass by sol–gel and spray pyrolysis methods, and Cu2O was deposited on it via the hydrothermal method. The morphology, crystalline structure, and optical absorption characteristics were studied by scanning electron microscopy, X-ray diffraction, and ultraviolet–visible diffuse reflectance spectrum, respectively. The results show that the surface of the Cu2O/TiO2 film was composed of net and large grains, which contributed to a large specific surface area. The crystal phase of the TiO2 in the Cu2O/TiO2 film remained anatase. The crystal phase of the Cu2O could not be detected as it is found in traces. The Cu2O/TiO2 film had a stronger optical absorption ability than the pure TiO2 film. To investigate catalytic activity, a photocatalytic degradation experiment of the Cu2O/TiO2 film was performed in a homemade thin-layer micro-reactor. The photocatalytic degradation of methylene blue increased with increasing amounts of deposited Cu2O until a maximum limit was reached. The photocatalytic activity might have declined with an increase in Cu2O content. The metallic oxide has the potential to screen other photocatalysts from the UV source. 相似文献
995.
996.
Porous Organic Molecular Frameworks with Extrinsic Porosity: A Platform for Carbon Storage and Separation 下载免费PDF全文
Dr. Jian Lü Prof. Dr. Rong Cao 《Angewandte Chemie (International ed. in English)》2016,55(33):9474-9480
The assembly of porous organic molecular frameworks (POMFs), which typically evidence common feasibility and compatibility, purification, and regeneration at practical conditions, remains a strategic challenge in modern materials science and is crucial for their favorable applications in biological, medical, and environmental realms. However, instructive knowledge of well‐organized POMF assembly by supramolecular interactions is, in general, ambiguous to date. Nevertheless, a significant advance in controlled POMF assembly has been recently achieved. This Minireview highlights these approaches, with a particular focus on the design of molecular constituents and assembly strategies. We also look beyond the field of solid‐state POMF materials into the assembly and recognition in solution, thus covering recent advances in POMFs based on material design and applications in carbon storage and separation. 相似文献
997.
Yan-Hua Zhang Hai-Long Zhang Yi Cao Yi Yang Bao-Qiang Xu Ming Zhao Mao-Chu Gong Hai-Di Xu Yao-Qiang Chen 《Chemical Papers》2016,70(10):1370-1379
A series of Co-modified Ce0.5Zr0.5O2 catalysts with different concentrations of Co (mass %: 0, 2, 4, 6, 8, 10) was investigated for diesel soot combustion. Ce0.5Zr0.5O2 was prepared using the coprecipitation method and Co was loaded onto the oxide using the incipient wetness impregnation method. The activities of the catalysts were evaluated by thermogravimetric (TG) analysis and temperature-programmed oxidation (TPO) experiments. The results showed the soot combustion activities of the catalysts to be effectively improved by the addition of Co, 6 % Co/Ce0.5Zr0.5O2 and that the 8 % Co/Ce0.5Zr0.5O2 catalysts exhibited the best catalytic performance in terms of lower soot ignition temperature (Ti at 349°C) and maximal soot oxidation rate temperature (Tm at 358°C). The reasons for the improved activity were investigated by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), H2 temperature-programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). These results revealed that the presence of Co could lower the reduction temperature due to the synergistic effect between Co and Ce, thereby improving the activity of the catalysts in soot combustion. The 6 % Co catalyst exhibited the best catalytic performance, which could be attributed to the greater amounts of Co3+ and surface oxygen species on the catalyst. 相似文献
998.
Characterization of dissolved organic matter (DOM) at the molecular level will greatly improve our understanding of its bio-geochemical role in controlling the fate of contaminants in the environment, and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) is the most powerful analytical technique for this purpose. Before FT-ICR-MS analysis, isolation, desalination and concentration of DOM are necessary, and solid-phase extraction (SPE) is the most widely applied pretreatment procedure. However, some molecular information is lost using conventional SPE methods. Here, we propose a novel strategy of SPE enrichment using stepwise elution (SPE-SE). Compounds in DOM were divided into three fractions by this SPE-SE procedure according to their polarity and ionization efficiency. The diversity of DOM molecules identified by ESI-FT-ICR-MS using SPE-SE exceeded those using conventional SPE methods by more than 50%. This method is feasible and has the potential to be used as a pretreatment strategy for complex DOM matrixes prior to ESI-FT-ICR-MS analysis, especially for those rich in nitrogenous molecules, carbohydrates, lipids and/or aromatic compounds. 相似文献
999.
Jia Cao Qi Li Zhi Xiang Wang Lou Jun Gao Feng Fu Bo Fan Yao Wang 《Journal of Cluster Science》2016,27(3):993-1004
The geometric structures, relative stabilities, magnetic properties of Mo-doped gold clusters Au n Mo(n = 1–10) have been investigated at the PBE1PBE/def2TZVP level of theory. The results show that molybdenum doping has a significant effect on the geometric structures and electronic properties of Au n Mo(n = 1–10) clusters. For the lowest energy structures of Au n Mo(n = 1–10), the two dimensional to three dimensional transition occurs at cluster size n ≥ 8, and their relative stabilities exhibit odd–even oscillation with the change of Au atom number. It is found that charge in corresponding Au n Mo clusters transfers from Mo atom to Au n host in the size range n = 1–7, whereas the charge in opposition direction in the size range n = 8–10. In addition, the magnetic properties of Au n Mo clusters are enhanced after doping single Mo atom into the corresponding gold clusters. Our results are valuable for the design of magnetic material. 相似文献
1000.
Light‐Harvesting Photosensitizers for Photodynamic Inactivation of Bacteria under Both Visible and Near‐Infrared Excitations 下载免费PDF全文
Dr. Bo Hu Dr. Xian Cao Ms. Tevhide Ozkaya Ahmadov Dr. Rui Ding Dr. Hong Tang Dr. Peng Zhang 《化学:亚洲杂志》2016,11(7):1092-1097
We report a hybrid singlet oxygen production system, where strong resonance coupling between plasmonic nanoparticles and photosensitizing molecules results in exceptionally high singlet oxygen production under both visible light and near‐infrared light excitation, even for the photosensitizing molecules without near‐infrared absorption. The light‐harvesting property of the plasmon‐photosensitizer hybrids leads to an enhanced, broad‐spectrum photodynamic inactivation of bacteria under a wide range of excitations, including that with near‐infrared light. 相似文献