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采用三氯化铁选择性刻蚀法获得了预定长径比的金纳米棒.相比于晶种生长法,三氯化铁选择性刻蚀法可以更加简便快捷地调控金纳米棒形貌.以三氯化铁为刻蚀剂的刻蚀反应优先发生在金纳米棒尖端,这是因为金纳米棒尖端反应活性更高且表面活性剂钝化作用更弱.通过控制刻蚀反应时间及刻蚀剂浓度,可以精确调控金纳米棒的长径比.实验结果表明,增加刻蚀剂浓度、卤素离子浓度以及升高反应温度可以加快刻蚀反应速率.进一步讨论了金属离子的刻蚀作用机理. 相似文献
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利用电化学沉积方法在重离子径迹模板中制备出直径从45 nm到200 nm, 长径比达700的金纳米线阵列, 利用扫描电子显微镜(SEM)和X射线衍射(XRD)对所制备金纳米线的形貌及晶体结构进行分析, 结果表明, 在1.5 V(无参比电极)沉积电压下所制备出的直径为200 nm金纳米线沿[100]晶向具有较好择优取向. 利用紫外-可见光谱(UV-Vis)对镶嵌在透明模板中平行排列的金纳米线阵列光学特性进行研究, 发现金纳米线直径为45 nm时, 其紫外可见光谱在539 nm处有强烈吸收峰, 随着金纳米线直径增加, 吸收峰红移, 当金纳米线直径达到200 nm时, 其吸收峰峰位移至700 nm. 结合金纳米颗粒相关表面等离子体共振吸收效应对实验结果进行了讨论. 相似文献
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Sonia Maniappan Camelia Dutta Diego M. Solís José M. Taboada Dr. Jatish Kumar 《Angewandte Chemie (International ed. in English)》2023,62(21):e202305433
Fabrication and transmission of plasmonic chirality is a rapidly developing area of research. While nanoscale chirality is reasonably well explored, research on intrinsically chiral nanostructures, that has ramifications to origin of homochirality, is still in its infancy. Herein, we report the synthesis of dog-bone shaped chiral gold nanostructures using a chiral cationic surfactant with excess ascorbic acid. Chiral growth is attributed to the specific binding and structure breaking ability of chiral surfactant and ascorbic acid. The controlled assembly of particles facilitated tuning and enhancement of chiral signals. Experimental observations were validated with theoretical simulations modelled in frequency domain with a surface integral-equation parameterization. Work highlighting the generation and tuning of plasmonic chirality provides new insights into the understanding of intrinsic chirality and paves way for their application in enantioselective catalysis and biosensing. 相似文献
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Mayu Fukuda Mai Morikawa Dr. Daisuke Hirose Dr. Tsuyoshi Taniguchi Dr. Tatsuya Nishimura Prof. Eiji Yashima Prof. Katsuhiro Maeda 《Angewandte Chemie (International ed. in English)》2023,62(15):e202217020
We report an ultra-fast helix induction and subsequent static helicity memory in poly(biphenylylacetylene) (PBPA- A ) assisted by a catalytic amount of nonracemic ammonium salts comprised of non-coordinating tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BArF−) as a counter anion. The remarkable acceleration of the helix-induction rate in PBPA- A accompanied by the significant amplification of the asymmetry relies on the two methoxymethoxy groups of the biphenyl pendants, which can gain access to enfold the chiral ammoniums in a crown-ether manner in specific aromatic solvents, leading to ultra-fast helicity induction, which is completed within 30 s. In aromatic solvents, helicity memory is lost rapidly, but is quite stable in long-chain hydrocarbons. The best use of specific solvents for helicity induction and static helicity memory, respectively, provides a highly sensitive chirality sensing system toward a small amount of chiral amines and amino acids when complexed with BArF−. 相似文献
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Zongshang Li Dr. Ke Xiao Dr. Qingyun Wan Rui Tang Dr. Kam-Hung Low Prof. Xiaodong Cui Prof. Chi-Ming Che 《Angewandte Chemie (International ed. in English)》2023,62(10):e202381061
Introduction of multiple kinetic aggregation states (Aggs) into the self-assembly pathway could bring complexity and flexibility to the self-assemblies, which is difficult to realize due to the delicate equilibria established among different Aggs bonded by weak noncovalent interactions. Here, we describe a series of chiral and achiral d10 AuI bis(N-heterocyclic carbene, NHC) complexes, and the achiral complex could undergo self-assembly with multiple kinetic Aggs. Generation of multiple kinetic Aggs was realized by applying chiral or achiral seeds exhibiting large differences in elongation temperatures for their respective cooperative self-assembly processes. We further showed that the chiral AuI self-assemblies having non-centrosymmetric packing forms exhibit nonlinear optical response of second harmonic generation (SHG), while the SHG signal is absent in the achiral analogue. The crystalline achiral AuI self-assemblies could function as optical waveguides with strong emission polarization. 相似文献
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Tobias Wesp Tim Bruckhoff Prof. Hubert Wadepohl Prof. Lutz H. Gade 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(53):e202201706
Octaazaperopyrenedioxides (OAPPDOs) are a new class of fluorescent polycyclic aromatic hydrocarbons based on a tetraazaperylene core that is formally condensed with N-substituted urea units in the two opposite peri positions. Here, we report the synthesis of series of substituted OAPPDO derivatives with different N-substitution patterns (H, alkyl, benzyl) in the peri positions, including bay-chlorinated OAPPDOs. Starting from the latter, a series of bay-arylated OAPPDOs was synthesized by Suzuki cross coupling, which resulted in the formation of helically chiral OAPPDO derivatives. The electrochemical and photophysical properties were investigated by UV/Vis and fluorescence spectroscopy as well as cyclic voltammetry. The P and M enantiomers of a phenylated OAPPDO were separated by semipreparative HPLC and further analyzed by CD spectroscopy. The frontier orbital energies, the mechanism of the isomerization, the electronic excitation and the CD spectrum (TD-DFT) were computed and compared to the experimental data. The reversible 1e− oxidation of the OAPPDOs generates the corresponding radical cations, one of which was characterized by EPR spectroscopy. The reversible oxidation process was also systematically investigated by spectro-electrochemistry. 相似文献
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制备了谷胱甘肽(GSH)功能化的金纳米棒复合材料,根据金纳米棒的等离子体吸收峰对其组装排列敏感的特性,研究了功能化的金纳米棒在不同p H值下的组装行为及与Cu2+离子作用后引起的聚集程度、排列方式和光学吸收等变化.同时,测试了纯金纳米棒和谷胱甘肽修饰的金纳米棒分别与铜离子作用后所得复合材料的光热转换性能.结果表明,相对于纯金纳米棒材料强的光热转换效应,铜离子能明显降低复合材料的光热转换效应,与其它金属离子比较,GSH修饰的金纳米棒的等离子光学特性对铜离子具有选择性的变化. 相似文献
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Teresa Łuczak 《Electroanalysis》2009,21(23):2557-2562
Thiodipropionoc acid (TDPA), cysteamine (CA) and gold nanoparticles (Au‐NPs) modified gold pure electrodes have been applied in voltammetric sensors for simultaneous detection of epinephrine (EP), ascorbic (AA) and uric (UA) acids. Modified electrodes with self assembled layers (SAMs) show high selectivity, sensitivity, reproducibility and stability. A linear relationship between the epinephrine concentration and the current response is obtained in the range of 0.1 μM to 0.65 μM with the detection limit ≤0.065 μM for the electrodes modified at 2D surface and in the range of 0.1 μM to 0.75 μM with the detection limit ≤0.082 μM for the electrodes modified at the 3D surface. 相似文献
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以L-苯丙氨酸(L-Phe)、L-色氨酸(L-Trp)和L-亮氨酸(L-Leu)3种常见的氨基酸为手性源,经过酯化、缩合等步骤制备3种手性功能单体AAc-L-Phe(AAc:丙烯酸)、AAc-L-Trp和AAc-L-Leu,其结构经过IR、1H NMR确证。 并将手性单体AAc-L-Phe与温敏材料N-异丙基丙烯酰胺(NIPAam)共聚,制备了手性共聚物P(NIPAam-co-AAc-L-Phe),结构经IR确证,示差扫描量热分析测试证明其具有温敏性。 这些手性功能单体有可能用于制备环境响应性手性高分子聚合物。 相似文献
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Edit Csapó Dániel Sebők Julia Makrai Babić Filip Šupljika Gabriella Bohus Imre Dékány 《Journal of Dispersion Science and Technology》2014,35(6):815-825
Gold nanoparticles reduced by sodium citrate (d ~ 10 nm) and purchased gold colloid particles (d ~ 500 nm) were examined and compared. The properties of both gold particles and their biofunctionalized derivatives with L-cysteine and L-glutathione were studied in the presence of sodium nitrate. The structural investigations indicated an aggregated inner structure. The isoelectric points of pure gold, citrate reduced gold, and functionalized gold were measured and compared. The low isoelectric point of pure gold/water interface was explained by considering the distribution and accumulation of H+ and OH? ions within the interfacial water layer, being more pronounced for OH? ions. 相似文献
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电化学沉积金纳米线结构及其电学特性 总被引:4,自引:1,他引:4
用电化学沉积方法,在有机介孔模板上制备出直径为90 nm的金纳米线.透射电子显微镜(TEM)分析结果表明,纳米线表面光滑并呈单晶结构.去除有机模板的金纳米线阵列用扫描电子显微镜(SEM)测试,纳米线顶端呈平台状,直径分布均一.我们利用原子力显微镜(AFM)测量了金纳米线阵列的微观结构,得到与SEM相一致的结果.在大气和室温条件下,用导电AFM针尖在接触模式下测量了单根纳米线的轴向I-V特性曲线,其结果为金属性. 相似文献
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金纳米微粒与盐酸氯丙嗪相互作用的共振Rayleigh散射光谱研究及其分析应用 总被引:2,自引:3,他引:2
在pH 1.8~3.3的酸性介质中,金纳米微粒本身有一定的共振瑞利散射(RRS)强度,但盐酸氯丙嗪本身的RRS强度十分微弱,当二者共存时,溶液的RRS强度显著增强并出现新的RRS光谱,在280~368 nm之间产生强烈的散射带,其最大散射波长位于368 nm,并在284、440、498 nm处有明显的散射峰。在一定条件下,盐酸氯丙嗪在0~0.08 mg/L范围内与ΔIRRS强度成正比,方法具有较高的灵敏度,对盐酸氯丙嗪的检出限(3σ)达到1.75μg/L。本文考察了反应体系的RRS光谱特征,研究了适宜的反应条件、影响因素及分析化学性质,研究了共存物质的影响,表明方法具有较好的选择性,据此发展了一种用金纳米微粒作RRS探针测定盐酸氯丙嗪的新方法。 相似文献
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分别从手性构型高度稳定的(R)和(S)-2,2'-二乙炔基-1,1'-联萘模板出发, 通过保护基的控制导入、偶联反应、保护基脱去以及分子间偶合成环4个步骤成功地合成了一种具有螺旋结构特征的新的光学活性分子方(Molecular square)(R,R,R,R)-1和(S,S,S,S)-1. 用MS, IR, UV-Vis, 1H和13C NMR以及元素分析等方法对目标化合物进行了结构表征. 测定并分析比较了2个目标化合物的比旋光度[α]D和圆二色性(CD)等光学性质. 在CH2Cl2溶液中, 异构体(R,R,R,R)-1和(S,S,S,S)-1的[α]25D值分别为+887.3°和-889.7°, 并且其CD谱表现出对称的镜像特征. 相似文献
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R. Kalai Selvan A. Gedanken P. Anilkumar G. Manikandan C. Karunakaran 《Journal of Cluster Science》2009,20(2):291-305
We report herein on an efficient sonochemical method for the synthesis of rare earth orthovanadate nanorods/nanoparticles/nanospindles,
(general formula RVO4; R = La, Ce, Nd, Sm, Eu and Gd). TGA, XRD, FTIR, Raman, UV–Vis, and TEM studies are employed for their characterization and
for understanding their morphologies. In order to vary the textural properties of the rare earth vanadates, two surfactants,
polyethylene glycol (PEG) and amphiphilic triblock copolymer Pluronic P123, are chosen in the preparation. While the sonochemical
synthesis in the presence of PEG results in the formation of nearly spherical nanoparticles of LaVO4, CeVO4, SmVO4 and EuVO4, the same technique yields nanorods and nanospindles of NdVO4 and GdVO4, respectively. When P123 is used as the surfactant, the morphologies of RVO4 are strikingly different, and in most cases nanorods and nanospindles are formed. The photocatalytic activities of the rare
earth orthovanadate have been evaluated by studying the degradation of methylene blue, and CeVO4 seems to be the best catalyst in the heterogeneous photolysis. The electrocatalytic activity of the vanadates has been examined
by studying the hydrogen evolution reaction using a linear sweep voltammogram technique in 1 M of a H2SO4 solution. GdVO4 seems to be the best electrocatalyst.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献