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排序方式: 共有762条查询结果,搜索用时 15 毫秒
161.
162.
Duo Xi Yanzi Xu Ruohan Xu Zhi Wang Daomeng Liu Qifei Shen Ling Yue Prof. Dongfeng Dang Prof. Lingjie Meng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(12):2741-2748
To achieve a highly efficient, dual-state emission platform for picric acid (PA) detection and latent fingerprint (LFP) visualization, flexible alkyl chains have been facilely attached to the commercial organic dye 3,4,9,10-perylenetetracarboxylic dianhydride to provide the target perylenetetracarboxylate molecules PTCA-C4, PTCA-C6, and PTCA-C12. Interestingly, all these molecules exhibited impressive fluorescence characteristics with high photoluminescence quantum yields (PLQYs) of around 93.0 % in dilute solution. Also, emissive features were observed in the solid state because close molecular packing is prevented by the alkyl chains, especially for PTCA-C6, which has a high PLQY value of 49.0 %. Benefiting from its impressive fluorescence performance in both solution and as aggregates, PTCA-C6 was used as a dual-state emission platform for PA detection and also LFP visualization. For example, double-responsive fluorescence quenching in solution was observed in PA detection studies, resulting in high quenching constants (KSV) and also low limit-of-detection values. Furthermore, the fingerprint powder based on PTCA-C6 also presented an impressive performance on various substrates in terms of fluorescence intensity and resolution, clearly providing the specific fine details of latent fingerprints. These results demonstrate that the facilely synthesized PTCA-C6 with efficient dual-state emission exhibits great potential in the real-world applications of PA detection and LFP visualization. 相似文献
163.
Gaowei Qian Xiangbing Wang Dr. Shengyue Wang Dr. Yanqiong Zheng Song Wang Prof. Weiguo Zhu Prof. Yafei Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(67):15401-15410
Polymorphism, the intrinsic character of one chemical compound with at least two distinct phase arrangements, plays a very key role in the photophysical properties. In this contribution, four ′T′-shaped molecules bearing the 2,1,3-benzothiadiazole (BTD) skeleton, named 5 a – 5 d , were prepared and characterized. All compounds exhibited excellent thermal stability and polymorphism in the solid state, evident from thermogravimetric analysis, differential scanning calorimetry, and polarized optical microscopy results. Intense emissions with high photoluminescent quantum yields were achieved both in solution (56–97 %) and neat films (33–98 %). All compounds possessed clearly pH-dependent luminescence properties in solution. Additionally, compound 5 d showed useful mechanochromic luminescence owing to the transformation between the crystal and amorphous state. Employing compounds 5 a – 5 d as the dopant, solution-processable organic light-emitting diodes (OLEDs) were fabricated and presented a highest external quantum efficiency of 6.15 %, which is higher than the theoretical value of fluorescence-based OLEDs (∼5 %). This research provided a novel strategy for designing high-efficiency BTD-based polymorphic luminescent materials. 相似文献
164.
Construction of three types of lanthanide complexes based on 3,4‐dimethylbenzoic acid and 5,5′‐dimethyl‐2,2′‐bipyridine: Syntheses,Structures, Thermodynamic properties,Luminescence, and Bacteriostatic activities 下载免费PDF全文
Three novel lanthanide complexes [Er (3,4‐DMBA)3(5,5′‐DM‐2,2′‐bipy)(H2O)] ( 1 ); [Tb2 (3,4‐DMBA)6(5,5′‐DM‐2,2′‐bipy)2(H2O)] ( 2 ); [Eu (3,4‐DMBA)3(3,4‐DMHBA)(5,5′‐DM‐2,2′‐bipy)]2 ( 3 ) (3,4‐DMHBA = 3,4‐dimethylbenzoic acid, 5,5′‐DM‐2,2′‐bipy =5,5′‐dimethyl‐2,2′‐bipyridine) were successfully synthesized via conventional solution method at room temperature and structurally characterized by single crystal diffraction. The structures of the complexes 1 – 3 were confirmed on the basis of elemental analysis, coordination titration analysis, IR and XRD. The molecular structures of complexes 2 and 3 are very particular: complex 2 has two same central metal ions but each metal ion has different coordination environment; in structure of the complex 3 , there are eight carboxylic acid ligands coordinated to the central metal ions, which have rarely been reported previously. The thermal decomposition mechanism of complexes 1 – 3 were investigated by the technology of simultaneous TG/DSC‐FTIR. The heat capacities of the complexes were recorded by means of DSC over the range of from 253.15 K to 345.15 K. The thermodynamic parameters, the smoothed values of heat capacities, enthalpy (HT‐H298.15K) and entropy (ST‐S298.15K) were also calculated. The bacteriostatic activities of the complexes were evaluated against Staphylococcus aureus, Escherichia coli and Candida albicans. What's more, the luminescence properties of complexes 2 and 3 were discussed, and their fluorescence lifetimes as well as the quantum yield of the Eu (III) were measured. To elucidate the energy transfer process of complexes 2 and 3, the energy levels of the relevant electronic states have been estimated. 相似文献
165.
Dr. Xiao-Lu Wang Dr. Jia-Yue Tian Xuan-Chen Guo Prof. Dr. Fu-Qiang Zhang Dr. Linfeng Liang Prof. Dr. Xian-Ming Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(11):3753-3760
Dimethyl sulfoxide (DMSO) is a universally used solvent in various synthetic reactions, and trace amounts of DMSO residual are often seen on the surface of chemical product. It is difficult to quickly determine whether the residual DMSO is washed completely. This work reports a CdII metal–organic framework (MOF) SXU-4 which can detect trace amounts of DMSO in various solvents. Fluorescence experiments reveal its turn-on fluorescence effect toward DMSO with high selectivity and sensitivity, indicating that it can be used as an effective luminescent probe for rapid chemical product purity detection by testing the washing solution. Crystallographically characterized DMSO loaded SXU-4 (DMSO@ SXU-4 ), in combination with computational results uncover that the enhanced DMSO–MOF conjugation through multiple DMSO–MOF supramolecule interactions and charge rearrangement are the main causes of fluorescence intensification. 相似文献
166.
Z. L. Wang C. J. Niu J. F. Ma J. Z. Ni 《Journal of Thermal Analysis and Calorimetry》1994,41(4):899-907
Rare earth complexes ofm-nitrobenzoic acid (LnL3·2H2O,Ln=La-Lu and Y, except Pm, HL=m-nitrobenzoic acid) were synthesized and characterized by elemental analysis, chemical analysis, IR spectroscopy and X-ray diffraction analysis. The dehydration behaviour of these complexes was studied in detail by means of TG-DTA and DSC. Dehydration occurs over the temperature range 76–215°C, and the temperature of formation of the anhydrous complexes decreases with increasing atomic number of the rare earth. The activation energies and enthalpy changes for te dehydration were obtained. 相似文献
167.
Wei‐Yu Bi Xing‐Qiang Lü Wen‐Li Chai Ji‐Rong Song Wai‐Kwok Wong Xiao‐Ping Yang Richard A. Jones 《无机化学与普通化学杂志》2008,634(10):1795-1800
Two heterobimetallic Zn‐Nd phenylene‐bridged Schiff‐base ligands complexes [ZnNd L1 (Py)(NO3)3] ( 1 ) and [Zn L2 Nd(Py)(NO3)3]·MeCN ( 2 ) (Py = pyridine, H2L1 = N,N′‐bis‐ (3‐methoxy‐salicylidene)phenylene‐1,2‐diamine, H2L2 = N,N′‐bis‐5‐bromo‐3‐methoxy‐salicylidene)phenylene‐1,2‐diamine) were obtained. Both 1 and 2 were structurally characterized by X‐ray crystallography, and their near‐infrared (NIR) luminescent properties were determined. For the two complexes, the occupation of pyridine at the axial position of 3d Zn2+ ions could effectively prevent luminescent quenching arising from OH‐, NH‐ or CH oscillators of the solvates around the 4f Nd3+ ions, and the heavy‐atom (Br) effect of the Schiff‐base ligands on their NIR luminescent properties is also discussed. 相似文献
168.
Four novel organometallic compounds containing tin(IV), titanium(IV) and zirconium (IV) ions were synthesized and strong fluorescent emission was observed from two tin(IV) complexes. 相似文献
169.
Henryk Malak Ignacy Gryczynski Joseph R. Lakowicz Gerald J. Meyers Felix N. Castellano 《Journal of fluorescence》1997,7(2):107-112
We examined the intensity and anisotropy decays of DNA labeled with two ruthenium metalligand complexes, [Ru(bpy)2(dppz)]2+ and [Ru(phe)2(dppz)]2+. Both complexes display high emission anisotropies in the absence of rotational diffusion, making them suitable probes for
rotational motions. When bound to DNA, these complexes display decay times as long as 294 ns, providing long-lived probes
of DNA dynamics. The decay times of both complexes were rather insensitive to dissolved oxygen. We examined anisotropy decays
of these complexes bound to B-form DNA. The anisotropy decays revealed correlation times near 10, 50, and several hundred
nanoseconds, suggesting that these probes are sensitive to a wide range of DNA motions. The use of metalligand complexes should
allow resolution of both the torsional and bending motions of DNA, the latter of which has been mostly inaccessible using
shorter-lived fluorescent probes bound to DNA.
Dedicated to Professor Robert F. Steiner upon his retirement 相似文献
170.
采用直接沉淀法制备了WO_3/YF_3∶Eu~(3+)复合纳米材料,并对其结构、组成、形貌和发光性能进行了研究。XRD分析表明:复合纳米材料由纳米粒子WO3和结晶良好的正交晶系的YF3∶Eu~(3+)组成。SEM照片表明:片状WO3颗粒表面沉积了分散性较好、粒径均匀(尺寸为10~50 nm)的YF3∶Eu3纳米颗粒。荧光光谱分析表明:该复合纳米材料具有良好的发光性,以593 nm附近的5D0→7F1磁偶极跃迁为最强发射峰,与纯的YF3∶Eu~(3+)相比WO_3/YF_3∶Eu~(3+)发光强度明显增强,表明具有表面等离子共振效应的WO3纳米粒子对壳层的YF3∶Eu~(3+)起到发光增强作用。 相似文献