共查询到20条相似文献,搜索用时 31 毫秒
1.
Daniel Lee Magorzata Wolska‐Pietkiewicz Saumya Badoni Agnieszka Grala Janusz Lewiski Gaël De Paëpe 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(48):17323-17328
The unambiguous characterization of the coordination chemistry of nanocrystal surfaces produced by wet‐chemical synthesis presently remains highly challenging. Here, zinc oxide nanocrystals (ZnO NCs) coated by monoanionic diphenyl phosphate (DPP) ligands were derived by a sol‐gel process and a one‐pot self‐supporting organometallic (OSSOM) procedure. Atomic‐scale characterization through dynamic nuclear polarization (DNP‐)enhanced solid‐state NMR (ssNMR) spectroscopy has notably enabled resolving their vastly different surface‐ligand interfaces. For the OSSOM‐derived NCs, DPP moieties form stable and strongly‐anchored μ2‐ and μ3‐bridging‐ligand pairs that are resistant to competitive ligand exchange. The sol‐gel‐derived NCs contain a wide variety of coordination modes of DPP ligands and a ligand exchange process takes place between DPP and glycerol molecules. This highlights the power of DNP‐enhanced ssNMR for detailed NC surface analysis and of the OSSOM approach for the preparation of ZnO NCs. 相似文献
2.
Yi‐Chin Chen Sheng‐Cih Huang Dr. Yu‐Kuo Wang Dr. Yuan‐Ting Liu Prof. Dr. Tung‐Kung Wu Prof. Dr. Teng‐Ming Chen 《化学:亚洲杂志》2013,8(11):2652-2659
In this study, surface‐functionalized, branched polyethylenimine (BPEI)‐modified YVO4:Bi3+,Eu3+ nanocrystals (NCs) were successfully synthesized by a simple, rapid, solvent‐free hydrothermal method. The BPEI‐coated YVO4:Bi3+,Eu3+ NCs with high crystallinity show broad‐band excitation in the λ=250 to 400 nm near‐ultraviolet (NUV) region and exhibit a sharp‐line emission band centered at λ=619 nm under excitation at λ=350 nm. The surface amino groups contributed by the capping agent, BPEI, not only improve the dispersibility and water/buffer stability of the BPEI‐coated YVO4:Bi3+,Eu3+ NCs, but also provide a capability for specifically targeted biomolecule conjugation. Folic acid (FA) and epidermal growth factor (EGF) were further attached to the BPEI‐coated YVO4:Bi3+,Eu3+ NCs and exhibited effective positioning of fluorescent NCs toward the targeted folate receptor overexpressed in HeLa cells or EGFR overexpressed in A431 cells with low cytotoxicity. These results demonstrate that the ligand‐functionalized, BPEI‐coated YVO4:Bi3+, Eu3+ NCs show great potential as a new‐generation biological luminescent bioprobe for bioimaging applications. Moreover, the unique luminescence properties of BPEI‐coated YVO4:Bi3+,Eu3+ NCs show potential to combine with a UVA photosensitizing drug to produce both detective and therapeutic effects for human skin cancer therapy. 相似文献
3.
tert‐Butyl(tert‐butoxy)zinc Hydroxides: Hybrid Models for Single‐Source Precursors of ZnO Nanocrystals 下载免费PDF全文
Kamil Sokołowski Dr. Iwona Justyniak Dr. Wojciech Bury Dr. Justyna Grzonka Prof. Zbigniew Kaszkur Łukasz Mąkolski Michał Dutkiewicz Agnieszka Lewalska Elżbieta Krajewska Dominik Kubicki Dr. Katarzyna Wójcik Prof. Krzysztof J. Kurzydłowski Prof. Janusz Lewiński 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5488-5495
Alkylzinc alkoxides, [RZnOR′]4, have received much attention as efficient precursors of ZnO nanocrystals (NCs), and their “Zn4O4” heterocubane core has been regarded as a “preorganized ZnO”. A comprehensive investigation of the synthesis and characterization of a new family of tert‐butyl(tert‐butoxy)zinc hydroxides, [(tBu)4Zn4(μ3‐OtBu)x(μ3‐OH)4?x], as model single‐source precursors of ZnO NCs is reported. The direct reaction between well‐defined [tBuZnOH]6 ( 16 ) and [tBuZnOtBu]4 ( 24 ) in various molar ratios allows the isolation of new mixed cubane aggregates as crystalline solids in a high yield: [(tBu)4Zn4(μ3‐OtBu)3(μ3‐OH)] ( 3 ), [(tBu)4Zn4(μ3‐OtBu)2(μ3‐OH)2] ( 4 ), [(tBu)4Zn4(μ3‐OtBu)(μ3‐OH)3] ( 5 ). The resulting products were characterized in solution by 1H NMR and IR spectroscopy, and in the solid state by single‐crystal X‐ray diffraction. The thermal transformations of 2 – 5 were monitored by in situ variable‐temperature powder X‐ray diffraction and thermogravimetric measurements. The investigation showed that the Zn?OH groups appeared to be a desirable feature for the solid‐state synthesis of ZnO NCs that significantly decreased the decomposition temperature of crystalline precursors 3 – 5 . 相似文献
4.
Yetria Rilda Reza Safitri Yulia Eka Putri Refinel Refinel Anthoni Agustien Wai Loon Leaw Hadi Nur 《中国化学会会志》2019,66(6):594-599
A superhydrophobic cotton textile with high antibacterial properties has been fabricated. The cotton textile was coated through the in situ growth of ZnO‐SiO2 nanoparticles in presence of chitosan as the template agent via a hydrothermal process at 95 °C. This process was followed by the coating of additional layers of hexadecyltrimethoxysilane (HDTMS). The obtained cotton textile showed antibacterial property against Staphylococcus epidermis and Escherichia coli with inhibition zones up to 18.26 and 8.48 mm, respectively. Scanning electron microscopy (SEM) revealed that the coating had a rough surface, which was attributed to the distribution of ZnO‐SiO2 nanorods of hexagonal shape. This rough surface creates a superhydrophobic layer that repels the bacteria, as proven by the large water contact angle of approximately 150°. Nevertheless, the HDTMS layers prolong the durability of hydrophobicity for up to 3 h. 相似文献
5.
Balancing the Rate of Cluster Growth and Etching for Gram‐Scale Synthesis of Thiolate‐Protected Au25 Nanoclusters with Atomic Precision 下载免费PDF全文
Xun Yuan Bin Zhang Zhentao Luo Qiaofeng Yao Prof. David Tai Leong Prof. Ning Yan Prof. Jianping Xie 《Angewandte Chemie (International ed. in English)》2014,53(18):4623-4627
We report a NaOH‐mediated NaBH4 reduction method for the synthesis of mono‐, bi‐, and tri‐thiolate‐protected Au25 nanoclusters (NCs) with precise control of both the Au core and thiolate ligand surface. The key strategy is to use NaOH to tune the formation kinetics of Au NCs, i.e., reduce the reduction ability of NaBH4 and accelerate the etching ability of free thiolate ligands, leading to a well‐balanced reversible reaction for rapid formation of thermodynamically favorable Au25 NCs. This protocol is facile, rapid (≤3 h), versatile (applicable for various thiolate ligands), and highly scalable (>1 g Au NCs). In addition, bi‐ and tri‐thiolate‐protected Au25 NCs with adjustable ratios of hetero‐thiolate ligands were easily obtained. Such ligand precision in molecular ratios, spatial distribution and uniformity resulted in richly diverse surface landscapes on the Au NCs consisting of multiple functional groups such as carboxyl, amine, and hydroxy. Analysis based on NMR spectroscopy revealed that the hetero‐ligands on the NCs are well distributed with no ligand segregation. The unprecedented synthesis of multi‐thiolate‐protected Au25 NCs may further promote the practical applications of functional metal NCs. 相似文献
6.
Dr. Min‐Rui Gao Zhao‐Yang Lin Dr. Jun Jiang Dr. Chun‐Hua Cui Ya‐Rong Zheng Prof. Dr. Shu‐Hong Yu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(27):8423-8429
We report a first solution strategy for controlled synthesis of Adams’ catalyst (i.e., α‐PtO2) by a facile and totally green approach using H2PtCl6 and water as reactants. The prepared α‐PtO2 nanocrystals (NCs) are ultrasmall in size and have very “clean” surfaces, which can be reduced to Pt NCs easily in ethanol under ambient conditions. Such Adams’ catalysts have been applied as electrocatalysts beyond the field of heterogeneous catalysis. Noticeably, the water‐only synthesized α‐PtO2 NCs and their derivative Pt NCs all exhibit much higher oxygen reduction reaction (ORR) activities and stabilities than that of the state‐of‐art Pt/C electrocatalysts. This study provides an example on the organics‐free synthesis of α‐PtO2 and Pt NCs as promising cathode catalysts for fuel cell applications and, particularly, this simple, straightforward method may open a new way for the synthesis of other “clean” functional nanomaterials. 相似文献
7.
The catalytic effects of two forms of nano‐TiO2, which are prepared via an ordinary or a magnetized process, are investigated in the synthesis of pyridine dicarbonitriles by one‐pot multicomponent reaction of 4‐methyl thiophenol, malononitrile, and aryl aldehydes. The results have shown that both prepared nano‐TiO2 exhibited high catalytic activities toward the synthesis of pyridine dicarbonitrile derivatives but the nano‐TiO2, which is prepared via a magnetized process, has shown better catalytic activity. Furthermore, this new catalytic method for the synthesis of pyridine dicarbonitriles provides rapid access to the desired compounds in high yields and so a simple work‐up procedure in the presence of water at room temperature. Therefore, this method represents a significant improvement incompatible of the other methods that are available for the synthesis of pyridine dicarbonitriles. 相似文献
8.
Nagaraju Kerru Sandeep V.H.S. Bhaskaruni Lalitha Gummidi Surya Narayana Maddila Surjyakanta Rana Parvesh Singh Sreekantha B. Jonnalagadda 《应用有机金属化学》2019,33(5)
An efficient approach for the synthesis of 10 novel pyrazole‐based 1,2,4‐triazolidin‐3‐one derivatives catalyzed by ZnO‐loaded ZrO2 as heterogeneous catalyst with ethanol as solvent is described. The structure of the mixed metal oxide catalyst was characterized by various instrumental techniques (scanning electron microscopy, transmission electron microscopy, X‐ray diffraction and Brunauer–Emmett–Teller). In smooth reactions, products were accomplished in excellent yields (90–94%) with short reaction times (≈ 45 min). ZnO/ZrO2 catalyst exhibited good recyclability. The catalyst is reused six times without any noticeable loss of activity. The major advantages of this method are operational simplicity, mild conditions, simple work‐up procedure and broad functional group tolerance. 相似文献
9.
Synthesis of Lead‐free CsGeI3 Perovskite Colloidal Nanocrystals and Electron Beam‐induced Transformations 下载免费PDF全文
Xiaotong Wu Weidong Song Dr. Qian Li Xixia Zhao Dr. Dongsheng He Prof. Dr. Zewei Quan 《化学:亚洲杂志》2018,13(13):1654-1659
Colloidal nanocrystals (NCs) of metal halide perovskite have recently aroused great research interest, due to their remarkable optical and electronic properties. We report a solution synthesis of a new member in this category, that is, all‐inorganic lead‐free cesium germanium iodine (CsGeI3) perovskite NCs. These CsGeI3 colloidal NCs are confirmed to adopt a rhombohedral structure. Moreover, the electron beam‐induced transformations of these lead‐free perovskite NCs have been investigated for the first time. The fracture of single‐crystalline CsGeI3 nanocubes occurs first, followed by the emergence and growth of cesium iodine (CsI) single crystals and the final fragmentation into small debris with random orientations. Notably, the electron‐reduced Ge species in CsGeI3 nanocubes exhibit a distinctive transformation path, compared to heavier Pb atoms in lead halide perovskite NCs. 相似文献
10.
《Angewandte Chemie (International ed. in English)》2017,56(41):12471-12475
Lead‐based perovskite nanocrystals (NCs) have outstanding optical properties and cheap synthesis conferring them a tremendous potential in the field of optoelectronic devices. However, two critical problems are still unresolved and hindering their commercial applications: one is the fact of being lead‐based and the other is the poor stability. Lead‐free all‐inorganic perovskite Cs3Bi2X9 (X=Cl, Br, I) NCs are synthesized with emission wavelength ranging from 400 to 560 nm synthesized by a facile room temperature reaction. The ligand‐free Cs3Bi2Br9 NCs exhibit blue emission with photoluminescence quantum efficiency (PLQE) about 0.2 %. The PLQE can be increased to 4.5 % when extra surfactant (oleic acid) is added during the synthesis processes. This improvement stems from passivation of the fast trapping process (2–20 ps). Notably, the trap states can also be passivated under humid conditions, and the NCs exhibited high stability towards air exposure exceeding 30 days. 相似文献
11.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(41):12645-12649
Lead‐based perovskite nanocrystals (NCs) have outstanding optical properties and cheap synthesis conferring them a tremendous potential in the field of optoelectronic devices. However, two critical problems are still unresolved and hindering their commercial applications: one is the fact of being lead‐based and the other is the poor stability. Lead‐free all‐inorganic perovskite Cs3Bi2X9 (X=Cl, Br, I) NCs are synthesized with emission wavelength ranging from 400 to 560 nm synthesized by a facile room temperature reaction. The ligand‐free Cs3Bi2Br9 NCs exhibit blue emission with photoluminescence quantum efficiency (PLQE) about 0.2 %. The PLQE can be increased to 4.5 % when extra surfactant (oleic acid) is added during the synthesis processes. This improvement stems from passivation of the fast trapping process (2–20 ps). Notably, the trap states can also be passivated under humid conditions, and the NCs exhibited high stability towards air exposure exceeding 30 days. 相似文献
12.
A carbon tetrabromide (CBr4) catalyzed one-pot synthesis of 4-substituted-1,4,5,6,7,8-hexahydroquinolin-5-one derivatives via a Hantzsch reaction under mild conditions was described. 相似文献
13.
Copper‐supported β‐cyclodextrin‐functionalized magnetic nanoparticles: Efficient multifunctional catalyst for one‐pot ‘green’ synthesis of 1,2,3‐triazolylquinazolinone derivatives 下载免费PDF全文
Saeed Bahadorikhalili Arsalan Ashtari Leila Ma’mani Parviz Rashidi Ranjbar Mohammad Mahdavi 《应用有机金属化学》2018,32(4)
The green synthesis of 2‐(4‐((1‐phenyl‐1H‐1,2,3‐triazol‐4‐yl)oxy)phenyl)quinazolin‐4(3H)‐one derivatives is reported. The catalyst for this synthesis is copper‐supported β‐cyclodextrin‐functionalized magnetic silica–iron oxide nanoparticles ([Cu@BCD@SiO2@SPION]). [Cu@BCD@SiO2@SPION] simultaneously catalyses ‘click’ reaction, oxidation of C? N bond and multicomponent reaction. The desired 1,2,3‐triazolylquinazolinone product is easily obtained in water at room temperature under mild reaction conditions. Another advantage of the catalyst is its reusability. It can simply be isolated using an external magnet and reused in reactions with no significant decrease in catalyst efficiency. Transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometry and Fourier transform infrared spectroscopy are used for exact characterization of the [Cu@BCD@SiO2@SPION] catalyst. 相似文献
14.
Monodisperse AgSbS2 Nanocrystals: Size‐Control Strategy,Large‐Scale Synthesis,and Photoelectrochemistry 下载免费PDF全文
Bin Zhou Mingrun Li Yihui Wu Chi Yang Prof. Wen‐Hua Zhang Prof. Can Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(31):11143-11151
We report an efficient approach to the synthesis of AgSbS2 nanocrystals (NCs) by colloidal chemistry. The size of the AgSbS2 NCs can be tuned from 5.3 to 58.3 nm with narrow size distributions by selection of appropriate precursors and fine control of the experimental conditions. Over 15 g of high‐quality AgSbS2 NCs can be obtained from one single reaction, indicative of the up‐scalability of the present synthesis. The resulting NCs display strong absorptions in the visible‐to‐NIR range and exceptional air stability. The photoelectrochemical measurements indicate that, although the pristine AgSbS2 NC electrodes generate a cathodic photocurrent with a relatively small photocurrent density and poor stability, both of them can be significantly improved subject to CdS surface modification, showing promise in solar energy conversion applications. 相似文献
15.
Semicarbazide functionalized with chlorosulfonic acid on the surface of silica‐coated magnetic nanoparticles, {Fe3O4@SiO2@(CH2)3Semicarbazide‐SO3H/HCl}, as a novel magnetic Brønsted acid catalyst according to the aims of green chemistry was synthesized and fully characterized using Fourier transform infrared, UV–visible and energy‐dispersive X‐ray spectroscopies, X‐ray diffraction, scanning electron, transmission electron and atomic force microscopies and thermogravimetric analysis. The capability and excellent activity of this nanoparticle catalyst were exhibited in the synthesis of two series of compounds with important biological activities, namely 3,3′‐(arylmethylene)bis(4‐hydroxycoumarin) and 1‐carbamato‐alkyl‐2‐naphthol derivatives, under mild, green and solvent‐free conditions. To the best of our knowledge, this is the first study of the synthesis and application of {Fe3O4@SiO2@(CH2)3Semicarbazide‐SO3H/HCl} as Brønsted acid solid magnetic nanoparticles. Consequently the present study can open up a novel and promising intuition in the sequence of logical design, synthesis and applications of task‐specific Brønsted acid magnetic nanoparticle catalyst with favourable properties as a full‐fledged efficient material for sustainable approaches. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
16.
Abraham Bañón‐Caballero Gabriela Guillena Carmen Nájera 《Helvetica chimica acta》2012,95(10):1831-1841
A bottom‐up strategy was used for the synthesis of cross‐linked copolymers containing the organocatalyst N‐{(1R)‐2′‐{[(4‐ethylphenyl)sulfonyl]amino}[1,1′‐binaphthalen]‐2‐yl}‐D ‐prolinamide derived from 2 (Scheme 1). The polymer‐bound catalyst 5b containing 1% of divinylbenzene as cross‐linker showed higher catalyst activity in the aldol reaction between cyclohexanone and 4‐nitrobenzaldehyde than 5a and 5c . Remarkably, the reaction in the presence of 5b was carried out under solvent‐free, mild conditions, achieving up to 93% ee (Table 1). The polymer‐bound catalyst 5b was recovered by filtration and re‐used up to seven times without detrimental effects on the achieved diastereo‐ and enantioselectivities (Table 2). The catalytic procedure with polymer 5b was extended to the aldol reaction under solvent‐free conditions of other ketones, including functionalized ones, and different aromatic aldehydes (Table 3). In some cases, the addition of a small amount of H2O was required to give the best results (up to 95% ee). Under these reaction conditions, the cross‐aldol reaction between aldehydes proceeded in moderate yield and diastereo‐ and enantioselectivity (Scheme 2). 相似文献
17.
Epitaxial Seeded Growth of Rare‐Earth Nanocrystals with Efficient 800 nm Near‐Infrared to 1525 nm Short‐Wavelength Infrared Downconversion Photoluminescence for In Vivo Bioimaging 下载免费PDF全文
Rui Wang Xiaomin Li Lei Zhou Prof. Dr. Fan Zhang 《Angewandte Chemie (International ed. in English)》2014,53(45):12086-12090
Novel β‐NaGdF4/Na(Gd,Yb)F4:Er/NaYF4:Yb/NaNdF4:Yb core/shell 1/shell 2/shell 3 (C/S1/S2/S3) multi‐shell nanocrystals (NCs) have been synthesized and used as probes for in vivo imaging. They can be excited by near‐infrared (800 nm) radiation and emit short‐wavelength infrared (SWIR, 1525 nm) radiation. Excitation at 800 nm falls into the “biological transparency window”, which features low absorption by water and low heat generation and is considered to be the ideal excitation wavelength with the least impact on biological tissues. After coating with phospholipids, the water‐soluble NCs showed good biocompatibility and low toxicity. With efficient SWIR emission at 1525 nm, the probe is detectable in tissues at depths of up to 18 mm with a low detection threshold concentration (5 nM for the stomach of nude mice and 100 nM for the stomach of SD rats). These results highlight the potential of the probe for the in vivo monitoring of areas that are otherwise difficult to analyze. 相似文献
18.
Three reusable and durable superhydrophobic nanofibrous filters were prepared by dip coating the nanofibrous fabric in the three different dispersed solutions of the newly modified nanoparticles (ZnO‐NSPO, AlOO‐NSPO, and titanium dioxide [TiO2]‐NSPO). The contact angle results proved that the TiO2‐NSPO coated nanofibrous polyacrylonitrile (PAN) filter was hydrophobic with the water contact angle (WCA) of 141° while the ZnO‐NSPO and AlOO‐NSPO coated nanofibrous PAN filters were superhydrophobic with the WCA of 168° and 152°, respectively. The as‐prepared filters can be utilized as an effective martial for oil‐water separation with separation efficiency of over 98%. 相似文献
19.
Towards Organized Hybrid Nanomaterials at the Air/Water Interface Based on Liquid‐Crystal/ZnO Nanocrystals 下载免费PDF全文
Dr. Jan Paczesny Małgorzata Wolska‐Pietkiewicz Ilona Binkiewicz Zbigniew Wróbel Monika Wadowska Kinga Matuła Igor Dzięcielewski Dr. Damian Pociecha Dr. Julita Smalc‐Koziorowska Prof. Janusz Lewiński Prof. Robert Hołyst 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(47):16941-16947
The ability to self‐assemble nanosized ligand‐stabilized metal oxide or semiconductor materials offers an intriguing route to engineer nanomaterials with new tailored properties from the disparate components. We describe a novel one‐pot two‐step organometallic approach to prepare ZnO nanocrystals (NCs) coated with deprotonated 4‐(dodecyloxy)benzoic acid (i.e., an X‐type liquid‐crystalline ligand) as a model LC system (termed ZnO‐LC1 NCs ). Langmuir and Langmuir–Blodgett films of the resulting hybrids are investigated. The observed behavior of the ZnO NCs at the air/water interface is rationalized by invoking a ZnO‐interdigitation process mediated by the anchored liquid‐crystalline shell. The ordered superstructures form according to mechanism based on a Z nO‐ i nterdigitation p rocess mediated by l iquid c rystals (termed ZIP‐LC). The external and directed force applied upon compression at the air/water interface and the packing of the ligands that stabilize the ZnO cores drives the formation of nanorods of ordered internal structure. To study the process in detail, we follow a nontraditional protocol of thin‐film investigation. We collect the films from the air/water interface in powder form ( ZnO‐LC1 LB ), resuspend the powder in organic solvents and utilize otherwise unavailable experimental techniques. The structural and physical properties of the resulting superlattices were studied by using electron microscopy, atomic force microscopy, X‐ray studies, dynamic light scattering, thermogravimetric analysis, UV/Vis absorption, and photoluminescence spectroscopy. 相似文献
20.
《Journal of heterocyclic chemistry》2017,54(4):2471-2482
An eco‐friendly method has been developed for the synthesis of 2‐amino‐4‐(9H‐carbazole‐3‐yl)thiophene‐3‐carbonitriles from preliminary carbazole ( 1 ) through an intermediate of 2‐(1‐(9H‐carbazole‐3‐yl)ethylidene)malononitriles using the Knoevenagel condensation followed by the Gewald reaction. On the other hand, the target compounds could also be prepared in a one‐pot three‐component manner by treating equimolar quantities of 1‐(9H‐carbazole‐3‐yl)ethanone ( 3 ), malononitrile, and elemental sulfur. The merits of this preparation are mild reaction conditions. The Gewald reaction is executed with inorganic base NaHCO3 (H2O) in tetrahydrofuran, easy work‐up procedure with good yields. 相似文献