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991.
Liangliang Liang Wei Yan Xian Qin Xiao Peng Han Feng Yu Wang Ziyu Zhu Lingmei Liu Yu Han Qinghua Xu Junle Qu Xiaogang Liu 《Angewandte Chemie (International ed. in English)》2020,59(2):746-751
Stimulated emission depletion (STED) microscopy enables ultrastructural imaging of biological samples with high spatiotemporal resolution. STED nanoprobes based on fluorescent organosilica nanohybrids featuring sub‐2 nm size and near‐unity quantum yield are presented. The spin–orbit coupling (SOC) of heavy‐atom‐rich organic fluorophores is mitigated through a silane‐molecule‐mediated condensation/dehalogenation process, resulting in bright fluorescent organosilica nanohybrids with multiple emitters in one hybrid nanodot. When harnessed as STED nanoprobes, these fluorescent nanohybrids show intense photoluminescence, high biocompatibility, and long‐term photostability. Taking advantage of the low‐power excitation (0.5 μW), prolonged singlet‐state lifetime, and negligible depletion‐induced re‐excitation, these STED nanohybrids present high depletion efficiency (>96 %), extremely low saturation intensity (0.54 mW, ca. 0.188 MW cm?2), and ultra‐high lateral resolution (ca. λem/28). 相似文献
992.
Yan Su Yongfeng Zhang Zhonghao Wang Weichen Gao Peng Jia Dan Zhang Chaolong Yang Youbing Li Yanli Zhao 《Angewandte Chemie (International ed. in English)》2020,59(25):9967-9971
Organic room temperature luminescent materials present a unique phosphorescence emission with a long lifetime. However, many of these materials only emit single blue or green color in spite of external stimulation, and their color tunability is limited. Herein, we report a rational design to extend the emission color range from blue to red by controlling the doping of simple pyrene derivatives into a robust polymer matrix. The integration of these pyrene molecules into the polymer films enhances the intersystem crossing pathway, decreases the first triplet level of the system, and ensures the films show a sensitive response to excitation energy, finally yielding excitation‐dependent long‐life luminescent polymeric systems under ambient conditions. These materials were used to construct anti‐counterfeiting patterns with multicolor interconversion, presenting a promising application potential in the field of information security. 相似文献
993.
Huixin Fan Chensheng Lin Kaichuang Chen Guang Peng Bingxuan Li Ge Zhang Xifa Long Ning Ye 《Angewandte Chemie (International ed. in English)》2020,59(13):5268-5272
An ammonium‐containing metal iodate fluoride compound, (NH4)Bi2(IO3)2F5, featuring a two‐dimensional double‐layered framework constructed by [BiO2F5]6? and [BiO4F4]9? polyhedra, as well as [IO3]? groups, was successfully synthesized. The well‐ordered alignment of these SHG‐active units leads to an extraordinary strong SHG response of 9.2 times that of KDP. Moreover, this compound possesses a large birefringence (Δn=0.0690 at 589.3 nm), a wide energy band gap (Eg=3.88 eV), and a high laser damage threshold (LDT; 40.2×AgGaS2). In particular, thermochromic behavior was observed for the first time in this type of compound. Such multifunctional crystals will expand the application of nonlinear optical materials. 相似文献
994.
Wenjuan Ji Xinjian Ji Qi Zhang Dhanaraju Mandalapu Zixin Deng Wei Ding Peng Sun Qi Zhang 《Angewandte Chemie (International ed. in English)》2020,59(23):8880-8884
Sulfur‐based homolytic substitution (SH reaction) plays an important role in synthetic chemistry, yet whether such a reaction could occur on the positively charged sulfonium compounds remains unknown. In the study of the anaerobic coproporphyrinogen III oxidase HemN, a radical S‐adenosyl‐l ‐methionine (SAM) enzyme involved in heme biosynthesis, we observed the production of di‐(5′‐deoxyadenosyl)methylsulfonium, which supports a deoxyadenosyl (dAdo) radical‐mediated SH reaction on the sulfonium center of SAM. The sulfonium‐based SH reactions were then investigated in detail by density functional theory calculations and model reactions, which showed that this type of reactions is thermodynamically favorable and kinetically competent. These findings represent the first report of sulfonium‐based SH reactions, which could be useful in synthetic chemistry. Our study also demonstrates the remarkable catalytic promiscuity of the radical SAM superfamily enzymes. 相似文献
995.
Vladislav V. Klepov Anna A. Berseneva Kristen A. Pace Vancho Kocevski Mengqi Sun Peng Qiu Hui Wang Fanglin Chen Theodore M. Besmann Hans‐Conrad zur Loye 《Angewandte Chemie (International ed. in English)》2020,59(27):10836-10841
Most ternary sulfides belonging to the MGaS2 structure‐type have been known for many years and are well‐characterized. Surprisingly, there have been no reports of the NaGaS2 composition, which contains Na, a monovalent cation slightly larger in size than Li, found in LiGaS2, a compound known for its non‐linear optical properties. Now it is demonstrated for the first time that the unique reversible water absorption in NaGaS2 has resulted in its absence from previous reports owing to difficulties encountered when characterizing this compound by SC XRD. The layered structure of this compound coupled with uniquely easy migration of water molecules between the layers allows for ion exchange with 3d and 5f metal cations. Some cations, for example, Ni2+, facilitate exfoliation of the layers, providing a facile synthetic route to a new class of 2D chalcogenide materials and furthermore demonstrating that NaGaS2 can readily uptake uranyl species from aqueous solutions. 相似文献
996.
Peng Zhang Xue Feng Lu Deyan Luan Xiong Wen Lou 《Angewandte Chemie (International ed. in English)》2020,59(21):8128-8132
Photocatalysts with well‐designed compositions and structures are desirable for achieving highly efficient solar‐to‐chemical energy conversion. Heterostructured semiconductor photocatalysts with advanced hollow structures possess beneficial features for promoting the activity towards photocatalytic reactions. Here we develop a facile synthetic strategy for the fabrication of Fe2TiO5–TiO2 nanocages (NCs) as anode materials in photoelectrochemical (PEC) water splitting cells. A hydrothermal reaction is performed to transform MIL‐125(Ti) nanodisks (NDs) to Ti–Fe–O NCs, which are further converted to Fe2TiO5–TiO2 NCs through a post annealing process. Owing to the compositional and structural advantages, the heterostructured Fe2TiO5–TiO2 NCs show enhanced performance for PEC water oxidation compared with TiO2 NDs, Fe2TiO5 nanoparticles (NPs) and Fe2TiO5–TiO2 NPs. 相似文献
997.
Haidong Li Qichao Yao Feng Xu Yueqing Li Dayeh Kim Jeewon Chung Gain Baek Xiaofeng Wu Prima Fitria Hillman Eun Young Lee Haoying Ge Jiangli Fan Jingyun Wang Sang‐Jip Nam Xiaojun Peng Juyoung Yoon 《Angewandte Chemie (International ed. in English)》2020,59(25):10186-10195
Monitoring fluctuations in enzyme overexpression facilitates early tumor detection and excision. An AIEgen probe (DQM‐ALP) for the imaging of alkaline phosphatase (ALP) activity was synthesized. The probe consists of a quinoline‐malononitrile (QM) core decorated with hydrophilic phosphate groups as ALP‐recognition units. The rapid liberation of DQM‐OH aggregates in the presence of ALP resulted in aggregation‐induced fluorescence. The up‐regulation of ALP expression in tumor cells was imaged using DQM‐ALP. The probe permeated into 3D cervical and liver tumor spheroids for imaging spatially heterogeneous ALP activity with high spatial resolution on a two‐photon microscopy platform, providing the fluorescence‐guided recognition of sub‐millimeter tumorigenesis. DQM‐ALP enabled differentiation between tumor and normal tissue ex vivo and in vivo, suggesting that the probe may serve as a powerful tool to assist surgeons during tumor resection. 相似文献
998.
Peng‐Ju Xia Dan Song Zhi‐Peng Ye Yuan‐Zhuo Hu Jun‐An Xiao Hao‐Yue Xiang Xiao‐Qing Chen Hua Yang 《Angewandte Chemie (International ed. in English)》2020,59(17):6706-6710
A photoinduced SET process enables the direct B?H bond activation of NHC–boranes. In contrast to common hydrogen atom transfer (HAT) strategies, this photoinduced reaction simply takes advantage of the beneficial redox potentials of NHC–boranes, thus obviating the need for extra radical initiators. The resulting NHC–boryl radical was used for the borylation of a wide range of α‐trifluoromethylalkenes and alkenes with diverse electronic and structural features, providing facile access to highly functionalized borylated molecules. Labeling and photoquenching experiments provide insight into the mechanism of this photoinduced SET pathway. 相似文献
999.
Xinsheng Liu Lei Zhao Bin Miao Zhiqi Gu Jin Wang Huoxiang Peng Jiande Li Wei Sun Jiadong Li 《Electroanalysis》2020,32(2):422-428
Biosensors based on field‐effect transistor (FET) structures have attracted considerable attention because they offer rapid, inexpensive parallel sensing and ultrasensitive label‐free detection. However, long‐term repeatable detection cannot be performed, and Ag/AgCl reference electrode design is complicated, which has hindered FET biosensors from becoming truly wearable health‐monitoring platforms. In this paper, we propose a novel wearable detection platform based on AlGaN/GaN high‐electron‐mobility transistors (HEMTs). In this platform, a sweatband was used to continuously collect sweat, and a pH detecting unit and a potassium ion detecting unit were formed by modifying different sensitive films to realize the long‐term stable and repeatable detection of pH and potassium ions. Experimental data show that the wearable detection platform based on AlGaN/GaN HEMTs has good sensitivity (pH 3–7 sensitivity is 45.72 μA/pH; pH 7.4–9 sensitivity is 51.073 μA/pH; and K+ sensitivity is 4.94 μA/lgαK+), stability (28 days) and repeatability (the relative standard deviation (RSD) of pH 3–7 sensitivity is 2.6 %, the RSD of pH 7.4–9 sensitivity is 2.1 %, and the RSD of K+ sensitivity is 7.3 %). Our newly proposed wearable platform has excellent potential for predictive analytics and personalized medical treatment. 相似文献
1000.
The polylactic acid (PLA) nanofiber membranes reinforced with hyperbranched PLA‐modified cellulose nanocrystals (H‐PLA‐CNCs) were prepared by electrospinning. The H‐PLA‐CNCs and the nanofiber membranes were researched by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The outcomes embodied that the cellulose nanocrystals (CNCs) could be successfully improved by the hyperbranched PLA, which would offer powerful CNCs/matrix interfacial adhesion. Thus, the mechanical and shape memory properties of PLA can be improved by adding the H‐PLA‐CNCs. In particular, when the addition of H‐PLA‐CNCs was 7 wt%, the tensile strength and an ultimate strain of PLA composite nanofiber membranes was 15.56 MPa and 25%, which was 228% and 72.4% higher than that of neat PLA, respectively. In addition, the shape recovery rate of the PLA/5 wt% H‐PLA‐CNCs composite nanofiber membrane was 93%, which was 37% higher than that of neat PLA. We expected that this present study would provide unremitting efforts for the development of more effective approaches to prepare biology basic shape memory membranes with high mechanical properties. 相似文献