共查询到20条相似文献,搜索用时 15 毫秒
1.
Dr. Chuanhao Yao Dr. Cong-Qiao Xu Dr. In-Hyeok Park Dr. Meng Zhao Ziyu Zhu Dr. Jing Li Dr. Xiao Hai Hanyan Fang Yong Zhang Gennevieve Macam Dr. Jinghua Teng Dr. Lin Li Dr. Qing-Hua Xu Prof. Feng-Chuan Chuang Dr. Junpeng Lu Dr. Chenliang Su Prof. Jun Li Dr. Jiong Lu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(21):8347-8353
Ligand-induced surface restructuring with heteroatomic doping is used to precisely modify the surface of a prototypical [Au25(SR1)18]− cluster ( 1 ) while maintaining its icosahedral Au13 core for the synthesis of a new bimetallic [Au19Cd3(SR2)18]− cluster ( 2 ). Single-crystal X-ray diffraction studies reveal that six bidentate Au2(SR1)3 motifs (L2) attached to the Au13 core of 1 were replaced by three quadridentate Au2Cd(SR2)6 motifs (L4) to create a bimetallic cluster 2 . Experimental and theoretical results demonstrate a stronger electronic interaction between the surface motifs (Au2Cd(SR2)6) and the Au13 core, attributed to a more compact cluster structure and a larger energy gap of 2 compared to that of 1 . These factors dramatically enhance the photoluminescence quantum efficiency and lifetime of crystal of the cluster 2 . This work provides a new route for the design of a wide range of bimetallic/alloy metal nanoclusters with superior optoelectronic properties and functionality. 相似文献
2.
Ziping Wang Zhiling Zhu Chengkun Zhao Qiaofeng Yao Xiyou Li Heyuan Liu Fanglin Du Xun Yuan Jianping Xie 《化学:亚洲杂志》2019,14(6):765-769
A deep understanding on the luminescence property of aggregation‐induced emission (AIE) featured metal nanoclusters (NCs) is highly desired. This paper reports a systematic study on enhancing the luminescence of AIE‐featured Au NCs, which is achieved by Ag doping to engineer the size/structure and aggregation states of the AuI‐thiolate motifs in the NC shell. Moreover, by prolonging the reaction time, the luminescence of the as‐synthesized AuAg NCs could be further tailored from orange to red, which is also due to the variation of the AuI‐thiolate motifs of NCs. This study can facilitate a better understanding of this AIE‐featured luminescent probe and the design of other synthetic routes for this rising family of functional materials. 相似文献
3.
Zhennan Wu Qiaofeng Yao Osburg Jin Huang Chai Nan Ding Wen Xu Shuangquan Zang Jianping Xie 《Angewandte Chemie (International ed. in English)》2020,59(25):9934-9939
Aggregation‐induced emission (AIE) provides an efficient strategy to synthesize highly luminescent metal nanoclusters (NCs), however, rational control of emission energy and intensity of metal NCs is still challenging. This communication reveals the impact of surface AuI‐thiolate motifs on the AIE properties of Au NCs, by employing a series of water‐soluble glutathione (GSH)‐coordinated Au complexes and NCs as a model ([Au10SR10], [Au15SR13], [Au18SR14], and [Au25SR18]?, SR=thiolate ligand). Spectroscopic investigations show that the emission wavelength of Au NCs is adjustable from visible to the near‐infrared II (NIR‐II) region by controlling the length of the AuI‐SR motifs on the NC surface. Decreasing the length of AuI‐SR motifs also changes the origin of cluster luminescence from AIE‐type phosphorescence to Au0‐core‐dictated fluorescence. This effect becomes more prominent when the degree of aggregation of Au NCs increases in solution. 相似文献
4.
Plasmonic-enhanced luminescence of single molecules enables imaging and detection of low quantities of fluorophores, down to individual molecules. In this work, we present two-photon excited luminescence of single gold nanoclusters, Au18(SG)14, in close proximity to bare gold nanorods (AuNRs). We observed 25-times enhanced emission of gold nanoclusters (AuNCs) in near infrared region, which was mainly attributed to the resonant excitation of localized surface plasmon resonance (LSPR) of AuNRs and spectral overlap of LSPR band with photoluminescence of AuNCs. This work is an initial step in application of combined nanoparticles: gold nanorods and ultrasmall nanoclusters in a wide range of multiphoton imaging and biosensing applications. 相似文献
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Huaping Peng Zhongnan Huang Haohua Deng Weihua Wu Kaiyuan Huang Zhenglian Li Wei Chen Juewen Liu 《Angewandte Chemie (International ed. in English)》2020,59(25):9982-9985
Ligand‐protected gold nanoclusters (AuNCs) have emerged as a new class of electrochemiluminescence (ECL) luminophores for their interesting catalytic and emission properties, although their quantum yield (ΦECL) in aqueous medium is low with a poor mechanistic understanding of the ECL process. Now it is shown that drying AuNCs on electrodes enabled both enhanced electrochemical excitation by an electrocatalytic effect, and enhanced emission by aggregation‐induced ECL (AIECL) for 6‐aza‐2‐thiothymine (ATT) protected AuNCs with triethylamine (TEA) as a coreactant. The dried ATT‐AuNCs/TEA system resulted in highly stable visual ECL with a ΦECL of 78 %, and a similar enhancement was also achieved with methionine‐capped AuNCs. The drying enabled dual‐enhancement mechanism has solved a challenging mechanistic problem for AuNC ECL probes, and can guide further rational design of ECL emitters. 相似文献
7.
Zibao Gan Yuejian Lin Lun Luo Guangmei Han Wei Liu Zhengjie Liu Chuanhao Yao Linhong Weng Lingwen Liao Jishi Chen Xu Liu Yi Luo Chengming Wang Shiqiang Wei Prof. Zhikun Wu 《Angewandte Chemie (International ed. in English)》2016,55(38):11567-11571
The structural features that render gold nanoclusters intrinsically fluorescent are currently not well understood. To address this issue, highly fluorescent gold nanoclusters have to be synthesized, and their structures must be determined. We herein report the synthesis of three fluorescent Au24(SR)20 nanoclusters (R=C2H4Ph, CH2Ph, or CH2C6H4tBu). According to UV/Vis/NIR, differential pulse voltammetry (DPV), and X‐ray absorption fine structure (XAFS) analysis, these three nanoclusters adopt similar structures that feature a bi‐tetrahedral Au8 kernel protected by four tetrameric Au4(SR)5 motifs. At least two structural features are responsible for the unusual fluorescence of the Au24(SR)20 nanoclusters: Two pairs of interlocked Au4(SR)5 staples reduce the vibration loss, and the interactions between the kernel and the thiolate motifs enhance electron transfer from the ligand to the kernel moiety through the Au?S bonds, thereby enhancing the fluorescence. This work provides some clarification of the structure–fluorescence relationship of such clusters. 相似文献
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Lingwen Liao Chengming Wang Shengli Zhuang Nan Yan Yan Zhao Ying Yang Jin Li Haiteng Deng Zhikun Wu 《Angewandte Chemie (International ed. in English)》2020,59(2):731-734
Kernel atoms of Au nanoclusters are packed layer‐by‐layer along the [001] direction with every full (001) monolayer composed of 8 Au atoms (Au8 unit) in nanoclusters with formula of Au8n+4(TBBT)4n+8 (n is the number of Au8 units; TBBTH=4‐tert‐butylbenzenelthiol). It is unclear whether the kernel atoms can be stacked in a defective‐layer way along the [001] direction during growth of the series of nanoclusters and how the kernel layer number affects properties. Now, a nanocluster is synthesized that is precisely characterized by mass spectrometry and single‐crystal X‐ray crystallography, revealing a layer stacking mode in which a half monolayer composed of 4 atoms (Au4 unit) is stacked on the full monolayer along the [001] direction. The size and the odevity of the kernel layer number influence the properties (polarity, photoluminescence) of gold nanoclusters. The obtained nanocluster extends the previous formula from Au8n+4(TBBT)4n+8 to Au4n+4(TBBT)2n+8 (n is the number of Au4 units). 相似文献
10.
Zengchun Xie Panpan Sun Zhi Wang Hongguang Li Longyue Yu Di Sun Mengjun Chen Yuting Bi Xia Xin Jingcheng Hao 《Angewandte Chemie (International ed. in English)》2020,59(25):9922-9927
Luminescent metal nanoclusters (NCs) are emerging as a new class of functional materials that have rich physicochemical properties and wide potential applications. In recent years, it has been found that some metal NCs undergo aggregation‐induced emission (AIE) and an interesting fluorescence‐to‐phosphorescence (F‐P) switching in solutions. However, insights of both the AIE and the F‐P switching remain largely unknown. Now, gelation of water soluble, atomically precise Ag9 NCs is achieved by the addition of antisolvent. Self‐assembly of Ag9 NCs into entangled fibers was confirmed, during which AIE was observed together with an F‐P switching occurring within a narrow time scale. Structural evaluation indicates the fibers are highly ordered. The self‐assembly of Ag9 NCs and their photoluminescent property are thermally reversible, making the metal–organic gels good candidates for luminescent ratiometric thermometers. 相似文献
11.
Yangzhouyun Xie Yong Liu Junchuan Yang Yuan Liu Prof. Fupin Hu Prof. Kui Zhu Prof. Xingyu Jiang 《Angewandte Chemie (International ed. in English)》2018,57(15):3958-3962
Widespread multidrug resistance caused by the abuse of antibiotics calls for novel strategies and materials. Gold nanoclusters (AuNCs) are scarcely explored for combating multidrug‐resistant (MDR) bacteria in vivo. We herein synthesized a novel class of AuNCs, namely quaternary ammonium (QA) capped AuNCs (QA‐AuNCs) as potent antibiotics selectively targeting MDR Gram‐positive bacteria, including methicillin‐resistant Staphylococcus aureus (MRSA) and vancomycin‐resistant Enterococci (VRE), in vivo. QA‐AuNCs kill bacteria through a combined physicochemical mechanism, and show excellent therapeutic effects in both a skin infection model and a bacteremia model induced by MRSA. In addition, owing to their intense fluorescence, QA‐AuNCs can be used for the discrimination of live/dead bacteria and bacteria counting, suggesting their potential for clinical theranostics. 相似文献
12.
Pre‐Incubation of Auric Acid with DNA Is Unnecessary for the Formation of DNA‐Templated Gold Nanoclusters
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Yang Chen Guangyu Tao Ruoyun Lin Xiaojing Pei Prof. Feng Liu Prof. Na Li 《化学:亚洲杂志》2016,11(11):1677-1681
The rationale for the preparation of DNA‐templated gold nanoclusters (DNA‐Au NCs) has not been well understood, thereby slowing down the advancement of the synthesis and applications of DNA‐Au NCs. The interaction between metal ions and the DNA template seems to be the key factor for the successful preparation of DNA‐templated metal nanoclusters. With the help of circular dichroism in this contribution, we put efforts into interrogating the necessity of pre‐incubation of HAuCl4 with poly‐adenine template in the formation of Au NCs by citrate reduction. Our results revealed that the pre‐incubation of HAuCl4 with poly‐adenine is not favorable for the formation of Au NCs, which is distinctly different from the formation process for silver nanoclusters. It is our hope that this study can provide guidance in the preparation of Au NCs with more DNA templates. 相似文献
13.
Soft,Oxidative Stripping of Alkyl Thiolate Ligands from Hydroxyapatite‐Supported Gold Nanoclusters for Oxidation Reactions
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Bin Zhang Prof. Dr. Jun Fang Jingguo Li Jun Jie Lau Prof. Dr. Davide Mattia Dr. Ziyi Zhong Prof. Dr. Jianping Xie Prof. Dr. Ning Yan 《化学:亚洲杂志》2016,11(4):532-539
A strategy for the mild deprotection of alkyl‐thiolated (6‐mercaptohexanoic acid, MHA, and 3‐mercaptopropanoic acid, MPA) gold nanoclusters (Au NCs) supported on hydroxyapatite (HAP) has been developed by employing a peroxide (tert‐butyl hydroperoxide, TBHP, or hydrogen peroxide, H2O2) as an oxidant. The thiol ligands on the supported Au NCs were removed after oxidation, and the size and integrity of the supported clusters were well‐preserved. The bare gold clusters on HAP after removal of the ligands were catalytically effective for the epoxidation of styrene and the aerobic oxidation of benzyl alcohol. These two reactions were also investigated on calcined Au NCs that were supported on HAP for comparison, and the resulting Au NCs that were prepared by using this new strategy showed superior catalytic activity. 相似文献
14.
Carbon Monoxide: A Mild and Efficient Reducing Agent towards Atomically Precise Gold Nanoclusters
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In recent years, thiolate‐protected gold nanoclusters (or thiolated Au NCs) with a core size below 2 nm have emerged as a new class of multifunctional nanoparticles because of their unique molecular‐like properties and the potential to use these properties in many practical applications. A general synthesis of Au NCs may involve the use of a strong reducing agent (e.g., sodium borohydride (NaBH4)), which often leads to the formation of mix‐sized Au NCs if no delicate control is applied. To obtain atomically precise Au NCs, additional physical or chemical selection processes (e.g., high‐resolution separation or size‐focusing) are required, which are difficult to be scaled up or are limited to only thermodynamically stable products. By introducing a milder reducing agent – carbon monoxide (CO) – both stable and metastable thiolated Au NCs, including Au10–12, Au15, Au18, Au25, and Au29, can be synthesized in a one‐pot manner. In addition, CO reduction also enables the synthesis of a highly luminescent Au22(SG)18 NC. Furthermore, the intermediates of Au NC growth can be tracked in the CO‐reduction system due to the mild and readily stoppable nature of CO reduction. Therefore, the use of CO reduction may bring new flexibilities in designing synthetic strategies and understanding the growth mechanism of atomically precise Au NCs, which could contribute to a better design of functional Au NCs, further paving their way towards practical applications in various fields. 相似文献
15.
Dr. Jinhua Liu Dr. Qiang Matthew Zhang Yong Feng Zhengyuan Zhou Prof. Kaimin Shih 《Chemphyschem》2016,17(2):225-231
By tuning the Cu???Cu and hydrogen‐bonding interactions, the small cluster Cu3L can be selectively synthesized to develop a stable and highly fluorescent material, as confirmed by matrix‐assisted laser desorption ionization–time of flight mass spectroscopy. Further characterizations, including absorbance spectroscopy, XPS, and XRD demonstrate the formation of tiny Cu nanoclusters (NCs). In water, the as‐prepared Cu NCs can exhibit high orange fluorescence via solution evaporation to eliminate hydrogen‐bonding, and in dimethylformamide, a strong orange fluorescent gel is obtained by solvent induction to enhance the Cu???Cu and hydrogen‐bonding interactions. More importantly, the Cu NCs in their substantial form exhibit nonlinear optical properties upon two‐photon excitation. These results will shed light on Cu and related cluster applications in two‐photon biological imaging, optical power limiting, and solar energy conversion. 相似文献
16.
Ultrasmall gold nanoclusters consisting of 2-4 Au atoms were synthesized and their performance in electrocatalytic oxygen reduction reactions (ORR) was examined. These clusters were synthesized by exposing AuPPh3Cl to the aqueous ammonia medium for one week. Electrospray ionization mass spectrometry (ESI-MS), X-ray absorption fine structure (XAFS), and X-ray photoelectron spectroscopy (XPS) analyses indicate that the as-synthesized gold clusters (abbreviated as Aux) consist of 2-4 Au atoms coordinated by the triphenylphosphine, hydroxyl, and adsorbed oxygen ligands. A glassy carbon disk electrode loaded with the Aux clusters (Aux/GC) was characterized by the cyclic and linear-sweep voltammetry for ORR. The cyclic voltammogram vs. RHE shows the onset potential of 0.87 V, and the kinetic parameters of JK at 0.47 V and the electron-transfer number per oxygen molecule were calculated to be 14.28 mA/cm2 and 3.96 via the Koutecky-Levich equations, respectively. 相似文献
17.
Sungwoo Kim Prof. Jean Bouffard Prof. Youngmi Kim 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(48):17459-17465
4,4‐Difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY) derivatives bearing varied substituents at the meso position (i.e., CF3, CH3, COOR, CHO, CN, Cl, iPr) were synthesized to elucidate the structure–property relationships that give rise to emissive J‐aggregates. Several new BODIPY derivatives can be added to the previously reported 1,3,5,7‐tetramethyl‐8‐trifluoromethyl derivative to the list of those forming J‐aggregates, in addition to other dyes that are emissive in the solid state without forming J‐aggregates. 相似文献
18.
选用带负电的谷胱甘肽包裹的金纳米簇(GSH-AuNCs)和牛血清白蛋白包裹的金纳米簇(BSA-AuNCs),与带正电荷的聚烯丙胺(PAH)通过静电作用以层层组装的方式制备了发黄色荧光的GSH-AuNCs/PAH薄膜和发红色荧光的BSA-AuNCs/PAH薄膜.在保证荧光强度的前提下,采用具有聚集诱导发光(AIE)效应的GSH-AuNCs能够大幅度降低薄膜厚度,有利于提高传感薄膜的响应速度和灵敏度.据此,以BSA-AuNCs/PAH薄膜作为参比层,GSH-AuNCs/PAH薄膜作为响应层,设计并构建了一种新型的比率荧光复合薄膜传感体系,并以2,4,6-三硝基甲苯(TNT)为例对其传感特性进行了研究. 相似文献
19.
Silica‐Encapsulated Gd3+‐Aggregated Gold Nanoclusters for In Vitro and In Vivo Multimodal Cancer Imaging
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Xiaotong Wu Dr. Chunxia Li Suchan Liao Dr. Lu Li Dr. Tingting Wang Prof. Zhongmin Su Prof. Chungang Wang Jihong Zhao Changping Sui Prof. Jun Lin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(29):8876-8882
Gd3+‐aggregated gold nanoclusters (AuNCs) encapsulated by silica shell (Gd3+‐A‐AuNCs@SiO2 NPs) were strategically designed and prepared. The as‐prepared nanoparticles exhibit aggregation‐enhanced fluorescence (AEF), with an intensity that is up to 3.8 times that of discrete AuNCs. The clusters served as novel nanoprobes for in vitro and in vivo multimodal (fluorescence, magnetic resonance, and computed X‐ray tomography) cancer imaging 相似文献
20.
A series of water soluble gold nanoclusters of variable core size were prepared and characterized. The clusters were synthesized using a ligand substitution reaction between CH3(OCH2CH2)3SH and hexanethiol encapsulated gold nanoclusters, and characterized using NMR, FTIR, and UV/Vis spectroscopy, as well as TGA, DSC, and TEM. Conductivity values were obtained for the clusters and increased as expected along with the gold core size. The substitution reaction used in the synthesis was followed by 1H NMR and found to produce only partial ligand substitution after 24 h, consistent with solubility observations and necessitating use of a two-step preparation scheme. 相似文献