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121.
Preparation of novel magnetic fluorescent microspheres from copperas and fluorescence enhancement with zinc ions 总被引:1,自引:0,他引:1
The aim of this study is to develop a new method for the preparation of Fe3O4@SiO2–An NPs from copperas. The core–shell structures of the nanoparticles and chemical composition have been confirmed by TEM, XRD and FTIR techniques. Fluorescence Enhancement of Fe3O4@SiO2–An NPs with zinc ions was investigated by fluorescence emission spectra. The results indicated that the Fe3O4 NPs with a high purity (Total Fe 72.16 %) were obtained from copperas by chemical co-precipitation method and have a uniform spherical morphology with an average diameter of about 10 nm. The Fe3O4 NPs coated with silica nanoparticles were prepared, and an attempt had been made that the Fe3O4@SiO2 NPs were modified by 3-aminopropyltriethoxysilane and 9-anthranone successively. The recommended mole ratio of ethanol to water and the content of ammonia water added were 4:1 and 25 wt% respectively, which have an obviously effect on the combination of the final well-ordered MNPs with the amino functionalities and reactant components. The functionalized Fe3O4@SiO2–An NPs have a fluorescence property and this fluorescence effect can be enhanced with the Zn2+ ions attachment. Meanwhile, the saturated magnetization of Fe3O4@SiO2–An NPs was 37.8 emug?1 at 25 °C and this fluorescent material exhibited excellent magnetic properties. A new way was therefore provided for the comprehensive utilization of the unmarketable copperas. Moreover, the functionalized Fe3O4@SiO2–An NPs have a big potential in environmental decontamination, medical technology and biological science. 相似文献
122.
Houfu Lv Dr. Tianfu Liu Dr. Xiaomin Zhang Dr. Yuefeng Song Hiroaki Matsumoto Prof. Dr. Na Ta Chaobin Zeng Prof. Dr. Guoxiong Wang Prof. Dr. Xinhe Bao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(37):16102-16107
In situ exsolution of metal nanoparticles in perovskite under reducing atmosphere is employed to generate a highly active metal–oxide interface for CO2 electrolysis in a solid oxide electrolysis cell. Atomic-scale insight is provided into the exsolution of CoFe alloy nanoparticles in La0.4Sr0.6Co0.2Fe0.7Mo0.1O3−δ (LSCFM) by in situ scanning transmission electron microscopy (STEM) with energy-dispersive X-ray spectroscopy and DFT calculations. The doped Mo atoms occupy B sites of LSCFM, which increases the segregation energy of Co and Fe ions at B sites and improves the structural stability of LSCFM under a reducing atmosphere. In situ STEM measurements visualized sequential exsolution of Co and Fe ions, formation of CoFe alloy nanoparticles, and reversible exsolution and dissolution of CoFe alloy nanoparticles in LSCFM. The metal–oxide interface improves CO2 adsorption and activation, showing a higher CO2 electrolysis performance than the LSCFM counterparts. 相似文献
123.
Xiangyu Ma Yuyuan Bai Yongbo Song Qinzhen Li Ying Lv Hui Zhang Prof. Haizhu Yu Prof. Manzhou Zhu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(39):17387-17391
Precise atomic structure of metal nanoclusters (NCs) is fundamental for elucidating the structure–property relationships and the inherent size-evolution principles. Reported here is the largest known FCC-based (FCC=face centered cubic) silver nanocluster, [Ag100(SC6H33,4F2)48(PPh3)8]−: the first all-octahedral symmetric nesting Ag nanocluster with a four-layered Ag6@Ag38@Ag48S24@Ag8S24P8 structure, consistent symmetry elements, and a unique rhombicuboctahedral morphology distinct from theoretical predictions and previously reported FCC-based Ag clusters. DFT studies revealed extensive interlayer interactions and degenerate frontier orbitals. The FCC-based Russian nesting doll model constitutes a new platform for the study of the size-evolution principles of Ag NCs. 相似文献
124.
Meng Lv Yang Yu María E. Sandoval-Salinas Prof. Jianhua Xu Dr. Zuhai Lei Prof. David Casanova Prof. Youjun Yang Prof. Jinquan Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22363-22368
Spiro conjugation has been proposed to dictate the efficiency of charge transfer, which could directly affect the spin–orbit charge transfer intersystem crossing (SOCT-ISC) process. However, this process has yet to be exemplified. Herein, we prepared three spirobis[anthracene]diones, in which two benzophenone moieties are locked in close proximity and differentially functionalized to fine-tune the charge transfer state. Its feasibility for SOCT-ISC was theoretically predicted, then experimentally evaluated. Through fine-tuning the spiro conjugation coupling and varying the solvent dielectric constants, ISC rate constants were engineered to vary in a dynamic range of three orders of magnitude, from 7.8×108 s−1 to 1.0×1011 s−1, which is the highest ISC rate reported for SOCT-ISC system to our knowledge. Our findings substantiate the key factors for effective SOCT-ISC and offer a new avenue for the rational design of heavy atom free triplet sensitizers. 相似文献
125.
Yang Lv Dr. Miaomiao Han Dr. Wanbing Gong Dongdong Wang Dr. Chun Chen Prof. Guozhong Wang Prof. Haimin Zhang Prof. Huijun Zhao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(52):23727-23732
Selective hydrogenation of C=O against the conjugated C=C in cinnamaldehyde (CAL) is indispensable to produce cinnamyl alcohol (COL). Nonetheless, it is challenged by the low selectivity and the need to use organic solvents. Herein, for the first time, we report the use of Fe-Co alloy nanoparticles (NPs) on N-doped carbon support as a selective hydrogenation catalyst to efficiently convert CAL to COL. The resultant catalyst with the optimized Fe/Co ratio of 0.5 can achieve an exceptional COL selectivity of 91.7 % at a CAL conversion of 95.1 % in pure water medium under mild reaction conditions, ranking it the best performed catalyst reported to date. The experimental results confirm that the COL selectivity and CAL conversion efficiency are, respectively promoted by the presence of Fe and Co, while the synergism of the alloyed Fe-Co is the key to concurrently achieve high COL selectivity and CAL conversion efficiency. 相似文献
126.
Hypochlorous acid (HOCl), one of the reactive oxygen species (ROS), is a key microbicidal agent which is used for natural defense. However, it is also linked to varieties of human diseases owing to the overproduction of HOCl. Much effort has been made to exploit selective fluorescent sensors for the detection of HOCl, but most of them have some disadvantages such as short excitation wavelength, low selectivity, and slow response and so on. These restrict the biological application of the probes. In this work, BR-O was designed and synthesized on the base of phenoxazine for the detection of HOCl. BR-O exhibited a violent fluorescence enhancement in the presence of HOCl, showing excellent selectivity and high sensitivity. More importantly, the probe BR-O was capable of detecting exogenous and endogenous HOCl in living cells. 相似文献
127.
Fluorescence switch plays a vital role in bioelectronics and bioimaging.Herein,we presented a new kind of facile electrostatic complex nanoparticles(ECNs)for fluorescence switching in cells and marking of individual cell.The ECNs were prepared by mixing positively charged poly(6-(2-(thiophen-3-yl)ethoxy)hexyl trimethylammonium bromide)(PT)and negatively charged diarylethene sodium salt(DAECOONa).DAE-COONa is a photoswitchable molecule which can be transformed between the ring-closed fo rm and ring-open form under the irradiation of UV or visible light.The closed-form of DAE-COONa can efficie ntly quench the fluorescence of PT through intermolecular energy transfer,while the open form of DAE-COONa does not influence the emission of PT.Thus,the fluorescence of ECNs can be modulated by light irradiation,and the ECNs with good fluorescence switching performance have been employed for fluorescence imaging and individual cell lighting up process successfully.We demonstrate that the electrostatic complex strategy provides a facile method to construct fluorescence switch fo r selective cell marking and imaging applications. 相似文献
128.
Structural Chemistry - A first-principle study of dehydrogenation mechanism from Sr(NH2BH3)2 was performed. Three different pathways were explored for Sr(NH2BH3)2 monomer, and the most favorable... 相似文献
129.
Fei Lv Jianfeng Fan Jiarong Huang Liming Cao Xuesong Yan Ling Ge Saifudin Abubakar Yukun Chen 《先进技术聚合物》2020,31(10):2161-2171
As the most successful commercialized thermoplastic vulcanizates (TPVs), polypropylene (PP)/ethylene propylene rubber (EPDM) TPVs exhibit poor oil resistance. In this work, we prepared PP/EPDM/butadiene acrylonitrile rubber (NBR) ternary TPVs with good oil resistance using core‐shell dynamic vulcanization. According to the theoretical analysis of the spreading coefficient and the transmission electron microscopy results, the rubber phases exhibited a special core‐shell structure, in which the cross‐linkedNBR‐core was encapsulated by the EPDM‐shell. The core‐shell structure effectively improved the interfacial compatibility between PP and NBR phase as the EPDM‐shell could avoid the direct contact of them, thus improving the mechanical properties of the TPVs. For example, the PP/EPDM/NBR (40/30/30) ternary TPV showed enhanced tensile strength of 12.57 MPa, compared with 10.71 MPa of PP/EPDM (40/60) TPV and 11.11 MPa of PP/NBR (40/60) TPV, respectively. Moreover, the oil resistance of the TPVs was also improved. Compared with PP/EPDM TPV, the change rates in mass, volume, tensile strength and elongation at break of PP/EPDM/NBR TPV after oil immersion decreased by 42.18%, 48.69%, 52.68% and 28.77%, respectively. 相似文献
130.