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981.
Rong Hu Prof. Xiaobing Zhang Dr. Zilong Zhao Dr. Guizhi Zhu Dr. Tao Chen Ting Fu Prof. Weihong Tan 《Angewandte Chemie (International ed. in English)》2014,53(23):5821-5826
We present a facile approach to make aptamer‐conjugated FRET (fluorescent resonance energy transfer) nanoflowers (NFs) through rolling circle replication for multiplexed cellular imaging and traceable targeted drug delivery. The NFs can exhibit multi‐fluorescence emissions by a single‐wavelength excitation as a result of the DNA matrix covalently incorporated with three dye molecules able to perform FRET. Compared with the conventional DNA nanostructure assembly, NF assembly is independent of template sequences, avoiding the otherwise complicated design of DNA building blocks assembled into nanostructures by base‐pairing. The NFs were uniform and exhibited high fluorescence intensity and excellent photostability. Combined with the ability of traceable targeted drug delivery, these colorful DNA NFs provide a novel system for applications in multiplex fluorescent cellular imaging, effective screening of drugs, and therapeutic protocol development. 相似文献
982.
A Protic Ionic Liquid Catalyzes CO2 Conversion at Atmospheric Pressure and Room Temperature: Synthesis of Quinazoline‐2,4(1H,3H)‐diones 下载免费PDF全文
Dr. Yanfei Zhao Bo Yu Dr. Zhenzhen Yang Dr. Hongye Zhang Leiduan Hao Xiang Gao Prof. Zhimin Liu 《Angewandte Chemie (International ed. in English)》2014,53(23):5922-5925
The chemical fixation of CO2 under mild reaction conditions is of significance from a sustainable chemistry viewpoint. Herein a CO2‐reactive protic ionic liquid (PIL), [HDBU+][TFE?], was designed by neutralization of the superbase 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) with a weak proton donor trifluoroethanol (TFE). As a bifunctional catalyst for simultaneously activating CO2 and the substrate, this PIL displayed excellent performance in catalyzing the reactions of CO2 with 2‐aminobenzonitriles at atmospheric pressure and room temperature, thus producing a series of quinazoline‐2,4(1H,3H)‐diones in excellent yields. 相似文献
983.
Significance of Branching for Transfection: Synthesis of Highly Branched Degradable Functional Poly(dimethylaminoethyl methacrylate) by Vinyl Oligomer Combination 下载免费PDF全文
Tianyu Zhao Hong Zhang Dr. Ben Newland Ahmed Aied Dr. Dezhong Zhou Dr. Wenxin Wang 《Angewandte Chemie (International ed. in English)》2014,53(24):6095-6100
A series of degradable branched PDMAEMA copolymers were investigated with the linear PDMAEMA counterpart as gene‐delivery vectors. The branched PDMAEMA copolymers were synthesized by controlled radical cross‐linking copolymerization based on the “vinyl oligomer combination” approach. Efficient degradation properties were observed for all of the copolymers. The degree of branching was found to have a big impact on performance in transfection when tested on different cell types. The product with the highest degree of branching and highest degree of functionality had a superior transfection profile in terms of both transfection capability and the preservation of cell viability. These branched PDMAEMA copolymers show high potential for gene‐delivery applications through a combination of the simplicity of their synthesis, their low toxicity, and their high performance. 相似文献
984.
Enantioselective and Regioselective Pyrone Diels–Alder Reactions of Vinyl Sulfones: Total Synthesis of (+)‐Cavicularin 下载免费PDF全文
Peng Zhao Prof. Dr. Christopher M. Beaudry 《Angewandte Chemie (International ed. in English)》2014,53(39):10500-10503
The total synthesis of (+)‐cavicularin is described. The synthesis features an enantio‐ and regioselective pyrone Diels–Alder reaction of a vinyl sulfone to construct the cyclophane architecture of the natural product. The Diels–Alder substrate was prepared by a regioselective one‐pot three‐component Suzuki reaction of a non‐symmetric dibromoarene. 相似文献
985.
Gold‐Catalyzed 1,2‐Acyloxy Migration/Intramolecular [3+2] 1,3‐Dipolar Cycloaddtion Cascade Reaction: An Efficient Strategy for Syntheses of Medium‐Sized‐Ring Ethers and Amines 下载免费PDF全文
Changgui Zhao Dr. Xingang Xie Shuangshuang Duan Huilin Li Dr. Ran Fang Prof. Dr. Xuegong She 《Angewandte Chemie (International ed. in English)》2014,53(40):10789-10793
A highly efficient strategy for the formation of medium‐sized‐ring ethers and amines based on a gold‐catalyzed cascade reaction, involving enynyl ester isomerization and intramolecular [3+2] cyclization, has been developed. Various multisubstituted medium‐sized‐ring unsaturated ethers and amines were obtained through this transformation. This method represents one of the relatively few transition metal catalyzed intramolecular cycloaddition reactions for medium‐sized ring synthesis. 相似文献
986.
Meilian Zhao Feng Yang Prof. Ying Xue Prof. Dan Xiao Prof. Yong Guo 《Chemphyschem》2014,15(1):157-164
A comprehensive first‐principles theoretical study of the electronic properties and half‐metallic nature of zigzag edge‐oxidized graphene quantum dots (GQDs) is carried out by using density functional theory (DFT) with the screened exchange hybrid functional of Heyd, Scuseria and Ernzerhof (HSE06). The oxidation schemes include ‐OH, ‐COOH and ‐COO groups. We identify oxidized GQDs whose opposite spins are localized at the two zigzag edges in an antiferromagnetic‐type configuration, showing a spin‐polarized ground state. Oxidized GQDs are more stable than the corresponding fully hydrogenated GQDs. The partially hydroxylated and carboxylated GQDs with the same size exhibit half‐metallic state under almost the same electric‐field intensity whereas fully oxidized GQDs behave as spin‐selective semiconductors. The electric‐field intensity inducing the half metal increases with the length of the partially oxidized GQDs, ranging from M=4 to 7. 相似文献
987.
Chong Zhao Dan Lei Prof. Li‐Hua Gan Dr. Zhu‐Xia Zhang Prof. Chun‐Ru Wang 《Chemphyschem》2014,15(13):2780-2784
Sc2S@C84 has recently been detected but not structurally characterized. 1 Density functional theory calculations on C84 and Sc2S@C84 show that the favored isomer of Sc2S@C84 shares the same parent cage as Sc2C2@C84, whereas Sc2S@C84:51383, which violates the isolated‐pentagon rule, is the second lowest energy isomer with the widest HOMO–LUMO gap and shows high kinetic stability. The analysis shows that Sc2S@C84:51575 is favored when the temperature exceeds 2 800 K and it can transform into the most favorable isomer Sc2S@C84:51591. Molecular orbital analysis indicates that both Sc2S and Sc2C2 formally transfer four electrons to the cage, and quantum theory of atoms in molecules analysis demonstrates that there is a covalent interaction between Sc2S and C84:51591. The IR spectra of Sc2S@C84 are provided to aid future structural identification. 相似文献
988.
We present here a facile and practical procedure for the synthesis of tetrasubstituted furans from alkynes catalyzed by palladium acetate together with cupric acetate in acetic acid, using atmospheric oxygen as a terminal oxidant. Various internal aromatic alkynes afforded the target furans in satisfactory yield. 相似文献
989.
The present study reports a sensitive electro-analytical method for the simultaneous determination of dihydroxybenzene isomers by using a thiadiazole film electrode, which was readily prepared by electropolymerization of 2,5-dimercapto-1,3,4-thiadiazole on a glassy carbon electrode with cyclic voltammetry. The functionalized electrode has a distinguishable and sensitive response to dihydroxybenzene isomers. Under the optimized conditions, the linear stripping peak currents showed good linear relationships with hydroquinone, catechol and resorcinol at concentration ranges 0.50-120, 0.50-110 and 1.00-110 μmol/L, and the detection limits are 0.1, 0.1 and 0.3 μmol/L, respectively. The proposed method is applicable to the simultaneous determination of dihydroxybenzene isomers in real samples with the relative standard deviations of less than 5.7% and the recovery rates of 95.6%-106%. The constructed electrode is characterized by simple preparation, good selectivity, and high sensitivity advantages. 相似文献
990.
A simple and selective method for the determination of silver ions was developed by utilizing the red- shift in emission wavelength of the core-shell CdSe/Cd5 quantum dots (QDs) functionalized with rhodanine upon the addition of Ag+. A linear relationship was observed between the shift and the increase in concentration of Ag+ in the range of 0.0125-12.5 μmol/L. The mechanism of the red-shift was investigated and suggested that the coordination between Ag+ and rhodanine on the QDs surface caused an increase of particle size, which resulted in the red-shift of the QDs' emission wavelength. A detection limit of 2 nmol/L was achieved. The developed method showed superior selectivity and was successfully applied to the determination of silver in environmental samples. 相似文献