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1.
Carbon dots (C dots) are relatively novel carbon nanomaterials that have attracted significant interest due to their unique photoluminescence, good biocompatibility, and stability. The preparation methods of C dots was usually summarized into "top-down" and "bottom-up", and mixed acid reflux is a top-down strategy that can be used to synthesize C dots, during which neutralization is a necessary step that can significantly influence the properties and potential applications of the final product. Previously, this research area mainly focused on tuning the properties of C dots by changing the starting materials and/or varying the reaction conditions; the influence of the reagents used during neutralization has been largely ignored. As the previously reported C dots prepared by mixed acid reflux were obtained from different starting materials under varied conditions, a meaningful comparison is difficult. Herein, yellow-emitting C dots were prepared by mixed acid-refluxing a carbon-rich material derived from fullerene carbon soot. For the same batch of as-prepared C dots, the influences of four reagents, i.e., NaOH, Na2CO3, K2CO3, and NH3·H2O, during neutralization on the structures and photoluminescence of the resulting C dots were investigated in detail. The results of thermogravimetric analysis, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy clearly showed that the reagent used during neutralization can affect the degree of dissociation of the acidic functional groups on the C dots. This is further supported by examination of the C dot/surfactant mixtures where subtle changes in the phase behavior were observed. Structural changes of the C dots cause variations in their surface states, ultimately altering the optical characteristics, including UV-vis absorption and fluorescence. Among the treated C dots, the sample prepared with Na2CO3 showed the strongest emission under the same excitation wavelength, while that prepared with NH3·H2O exhibited a distinct red shift (~8 nm) in the emission curve. The results presented herein provide clear evidence that neutralization reagent selection is important for optimizing the properties of the resulting C dots obtained by mixed acid reflux. In addition, the photoluminescence of the C dots can be influenced by their counterions, providing a novel method for tuning the properties of C dots while explaining their behavior in saline solutions. In short, the basicity of the neutralizing reagent and the type of counterions affect the structure of the C dots surface, which brings different performances. This work reminds researchers that it is necessary to use the type of neutralizing reagent as an experimental condition when preparing C dots in the future.  相似文献   
2.
A series of nanometer-sized spherical sulfonamide imine ligands HL 1 -HL 5 and their copper and zinc complexes were synthesized and fully characterized based on elemental analyses, spectroscopic (UV/vis, FT-IR, NMR, EPR, SEM) studies, molar conductance and thermal analyses. Furthermore, computational studies of HL 1 -HL 5 were carried out by the DFT/B3LYP method. TD-DFT, HOMO and LUMO energy values, chemical hardness, electronegativity, electrophilic index, softness, and other parameters were calculated. Screening against several pathogenic microorganisms indicated that HL 1 exhibited high activity against the tested Gram-negative bacteria relative to other analogues and the inhibition activity is greater than the standard Gentamicin. Analogously, HL 2 exhibited high potent activity against the tested Gram-positive bacteria. Copper complexes exhibited a higher potent activity than zinc analogues. Noteworthy, inhibition activity of [Cu ( L 3 )(OAc)] complex is higher than that of the standard Ampicillin. [Cu ( L 2 )(OAc)] complex displayed a similar activity of the standard bactericides and fungicides in use. The complexes showed appreciated values of MIC against bacterial strains: B. subtilis (MIC = 0.4 μg / mL), E. coli and S. pneumonia (MIC = 1.95 μg / mL) and P. aeruginosa (MIC = 7.81 μg / mL). in vitro cytotoxic activities study proved that [Cu ( L 3 )(OAc)] complex exhibited appreciable activity versus (HEPG-2); IC50 = 4.8 μg/ml, while [Cu( L 2 )(OAc)] complex showed a high activity against (MCF-7); IC50 = 6.2 μg/ml. These results could be considered as new findings of promising antitumor candidates for experimental chemotherapy.  相似文献   
3.
We report the fabrication and characterization of a magnetically recyclable Fe3O4@Nico@Ag catalyst for reduction reactions in the liquid phase. Fe3O4 is a magnetic core and nicotinic acid was used as the linker for Ag. The characterization was done with X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, vibrating sample magnetometry (VSM), and ultraviolet-visible spectroscopy. VSM measurements proved the super-paramagnetic property of the catalyst.  相似文献   
4.
廖友  王冬梅  谷战军 《化学学报》2021,79(12):1438-1460
放射治疗是利用高能射线抑制癌细胞增殖的治疗方法, 已广泛用于恶性肿瘤的治疗. 但是, 高能射线不可避免地会对机体的正常组织造成损害, 产生放疗相关副作用. 尽管目前有一些小分子放疗防护药物已应用于临床或处于临床前研究, 但其较短的血液循环时间和较快的新陈代谢速度极大地削弱了其防护效果. 近20年来, 随着纳米技术在生物医学领域的飞速发展, 纳米放疗防护剂的出现为提高防护效果提供了新的选择. 通过合理地设计和开发纳米放疗防护剂, 有望解决现有小分子放疗防护药物的缺陷. 鉴于纳米放疗防护剂具有诸多优势, 本Review概述了纳米放疗防护材料的常见设计策略, 同时分析了放射诱导的常见疾病的致病机制和纳米放疗防护材料防治各种放射诱导疾病的研究现状. 最后, 还讨论了纳米材料用于放疗防护所面临的挑战和未来前景.  相似文献   
5.
N‐coordinate Pd2+ complexes [PdL2] (L: N‐N‐quinoline‐8‐yl‐R‐benzenesulfonamides) ( 6–10 ) and [PdL2] complexes assembled on multi‐wall carbon nanotubes (MWCNTs) hybrid nanomaterials were fabricated and characterized by various techniques. The [PdL2] impregnated MWCNTs materials ( 11–15 ) were applied as a counter electrode (CE) catalyst for triiodide to iodide reduction reaction in the dye‐sensitized solar cells (DSSC) and investigated electro‐catalytic activities. The MWCNTs‐supported [PdL2] CEs ( 11–15 ) are exhibits as Pt‐free CE with good power conversion efficiencies (PCEs), and compared to platinum and bare MWCNTs CEs and the PCE of bare MWCNTs was clearly improved by means of [PdL2] complexes ( 6–10 ). The DSSCs based on the hybrid counter electrodes (CEs) ( 11–15 ) and bare MWCNTs are indicated a relative efficiency ( ? rel ) of 64.27%, 54.07%, 53.75%, 51.52% 44.82% and 27.27% concerning a Pt CE control device set at 100%. The report emphasizes that [PdL2] impregnated MWCNTs type counter electrodes (CEs) ( 11–15 ) are promising as effectively catalyst in working device design, particularly taking into account the eco‐friendly approach of the hybrids.  相似文献   
6.
迟景元  李晶  任少康  苏邵  汪联辉 《化学学报》2019,77(12):1230-1238
DNA-二维纳米片层材料传感平台结合DNA分子特异性识别能力与二维纳米片层材料优越的物理、化学特性,已成为化学/生物传感器领域重要的研究方向之一.鉴于二维纳米片层材料领域的快速发展,首先介绍了DNA-二维纳米片层材料传感平台的构筑机理,随后重点综述了该传感平台在化学、生物目标物分析检测中的应用研究,并对该类传感平台的应用前景做了展望.  相似文献   
7.
表面辅助激光解吸附/离子化质谱(Surface-assisted laser desorption/ionization mass spectrometry,SALDI-MS)是一种利用无机纳米粒子或纳米结构表面作为基质,辅助待测分子的解吸附和离子化的质谱技术。由于其具有灵敏度高、耐盐性好、操作简便、重现性好、检测通量高等优势,已经被广泛应用于食品安全、环境监测、生命科学等诸多领域。该文总结了近5年来,SALDI基质材料(金属及金属氧化物材料、碳材料、硅材料、金属有机骨架化合物材料等)的最新研究进展及其在生物检测领域中的应用,并对SALDI-MS基质材料的发展及应用进行了展望。  相似文献   
8.
张佳美  闫瑞  刘小强 《化学研究》2014,(1):41-44,48
采用水热法制备TiO2纳米管(TNTs),然后以12-磷钨杂多酸(PTA)作为交联剂,运用光催化方法在TiO2纳米管表面负载金纳米颗粒(GNPs),从而得到新型复合纳米材料——TNTs-PTA-GNPs;借助傅立叶变换红外光谱仪,X射线衍射仪和透射电子显微镜分析了新型复合纳米材料的结构及形貌,并利用循环伏安法测试了其电化学性能.结果表明,GNPs均匀分布在TNTs表面,从而大幅度改善纳米材料的导电性;但复合纳米材料中无游离的金纳米颗粒.与此同时,TNTs-PTA-GNPs纳米材料具有良好的生物相容性,且可促进酶与电极之间的直接电子转移.  相似文献   
9.
近年来,半导体的纳米材料凭借其奇特的介观物理特性,成为当前研究的热点,特别是纳米金属氧化物。氧化镓纳米材料具备优异的光电、气敏、耐压且低损耗等特性,为材料学、电子学和化学等多个研究领域带来了新的机遇。本文概述了氧化镓纳米结构的制备方法,并展望了其在光电探测方面的应用。  相似文献   
10.
Developing new types of rechargeable batteries with high energy densities and low cost have received increasing attentions, aiming to reduce the dependence on high-priced lithium. Beyond Li-ion batteries, the potential alternatives including Na-ion batteries, Li-S batteries and Li-air batteries have been investigated recently, which are required to be viable for commercial applications. From this point of view, to understand the electrochemical reaction mechanisms and kinetics of these batteries has become the key challenge to make breakthroughs in the field of new energy storage. In this review, we present a critical overview of the two dimensional nanomaterials-based batteries (except Li-ion-based batteries) that could meet such demonds. To develop new energy storage devices with more promising performances, the microstructure evolution and atomic scale storage mechanism of these batteries are comprehensively summarized. In addition, the major challenges and opportunities of advanced characterization techniques are finally discussed. We do hope that this review will give the readers a clear and profound understanding of the electrochemical reaction mechanisms and kinetics of the as-discussed batteries, thus effectively contributing to the smart design of future-generation energy storage devices.  相似文献   
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