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Nanoparticles, Nanochemistry

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https://www.readbyqxmd.com/read/30488554/identification-of-individual-reaction-steps-in-complex-radical-reactions-involving-gold-nanoparticles
#1
Jennifer Lien, Mengqi Su, Ting Guo
A triple-jump model is invoked to help identify individual reaction steps in complex chemical reactions involving radical reactants in the presence of gold nanoparticles. The model consists of three sequential reaction phases: production of radicals, stabilization of radicals, and conversion from radical intermediates to final products. Isolated reaction phases were studied with electron paramagnetic resonance spectroscopy. As examples of the model, we investigated the spin trapping reaction with BMPO and the hydroxylation of 3-CCA, and the results supported the model...
November 28, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/30387990/customizing-the-structure-composition-and-properties-of-alloy-nanoclusters-by-metal-exchange
#2
Shuxin Wang, Qi Li, Xi Kang, Manzhou Zhu
The properties of metal materials can be greatly enriched by including various elements to generate alloys. The galvanic replacement represents a classical method for the preparation of both bulk- and nanoalloy materials. The difference of the electrochemical potential between the two metals acts as the driving force for the galvanic replacement reaction. However, this classical rule partially fails at the ultrasmall size scale, for that novel chemistry emerges by the decrease of the size of materials down to less than 3 nm due to the strong quantum effect...
November 2, 2018: Accounts of Chemical Research
https://www.readbyqxmd.com/read/30276256/a-size-threshold-for-enhanced-magnetoresistance-in-colloidally-prepared-cofe-2-o-4-nanoparticle-solids
#3
Benjamin H Zhou, Jeffrey D Rinehart
The phenomenon of granular magnetoresistance offers the promise of rapid functional materials discovery and high-sensitivity, low-cost sensing technology. Since its discovery over 25 years ago, a major challenge has been the preparation of solids composed of well-characterized, uniform, nanoscale magnetic domains. Rapid advances in colloidal nanochemistry now facilitate the study of more complex and finely controlled materials, enabling the rigorous exploration of the fundamental nature and maximal capabilities of this intriguing class of spintronic materials...
September 26, 2018: ACS Central Science
https://www.readbyqxmd.com/read/29792422/toward-total-synthesis-of-thiolate-protected-metal-nanoclusters
#4
Qiaofeng Yao, Tiankai Chen, Xun Yuan, Jianping Xie
Total synthesis, where desired organic- and/or biomolecules could be produced from simple precursors at atomic precision and with known step-by-step reactions, has prompted centuries-lasting bloom of organic chemistry since its conceptualization in 1828 (Wöhler synthesis of urea). Such expressive science is also highly desirable in nanoscience, since it represents a decisive step toward atom-by-atom customization of nanomaterials for basic and applied research. Although total synthesis chemistry is less established in nanoscience, recent years have witnessed seminal advances and increasing research efforts devoted into this field...
June 19, 2018: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29773785/revealing-isoelectronic-size-conversion-dynamics-of-metal-nanoclusters-by-a-noncrystallization-approach
#5
Qiaofeng Yao, Victor Fung, Cheng Sun, Sida Huang, Tiankai Chen, De-En Jiang, Jim Yang Lee, Jianping Xie
Atom-by-atom engineering of nanomaterials requires atomic-level knowledge of the size evolution mechanism of nanoparticles, which remains one of the greatest mysteries in nanochemistry. Here we reveal atomic-level dynamics of size evolution reaction of molecular-like nanoparticles, i.e., nanoclusters (NCs) by delicate mass spectrometry (MS) analyses. The model size-conversion reaction is [Au23 (SR)16 ]- → [Au25 (SR)18 ]- (SR = thiolate ligand). We demonstrate that such isoelectronic (valence electron count is 8 in both NCs) size-conversion occurs by a surface-motif-exchange-induced symmetry-breaking core structure transformation mechanism, surfacing as a definitive reaction of [Au23 (SR)16 ]-  + 2 [Au2 (SR)3 ]- → [Au25 (SR)18 ]-  + 2 [Au(SR)2 ]- ...
May 17, 2018: Nature Communications
https://www.readbyqxmd.com/read/29460941/water-soluble-platinum-nanoparticles-stabilized-by-sulfonated-n-heterocyclic-carbenes-influence-of-the-synthetic-approach
#6
Edwin A Baquero, Simon Tricard, Yannick Coppel, Juan C Flores, Bruno Chaudret, Ernesto de Jesús
The synthesis of metal nanoparticles (NPs) under controlled conditions in water remains a challenge in nanochemistry. Two different approaches to obtain platinum NPs, which involve the treatment of aqueous solutions of preformed sulfonated (NHC)Pt(ii) dimethyl complexes with carbon monoxide, and of (NHC)Pt(0) diolefin complexes with dihydrogen (NHC = N-heterocyclic carbene), are disclosed here. The resulting NPs were found to be highly stable in water under air for an indefinite time period. Coordination of the NHC ligands to the platinum surface via the carbenic carbon was monitored by solid-state NMR spectroscopy, and the presence of a platinum-carbon bond was unambiguously evidenced by the determination of a 13 C-195 Pt coupling constant (1106 and 1050 Hz for NPs containing 13 C labeled-NHC ligands and prepared under CO and H2 , respectively)...
March 28, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29251371/stimulus-responsive-assembly-of-nanoparticles-using-host-guest-interactions-of-cyclodextrins
#7
Sabrina Engel, Nadja Möller, Bart Jan Ravoo
The design of multifunctional nanomaterials that respond to external stimuli and mimic the capacity of biological materials to respond and adapt to their environment has become a focus of interest in nanotechnology. In this Concept, we describe the development of supramolecular nanoparticle assemblies constructed by use of host-guest interactions between cyclodextrins and suitable guest molecules. The nanoparticle assembly is reversible and can be directed by applying different stimuli that act either on the guest molecules or the nanoparticles...
April 3, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29070592/enamel-crystallite-strength-and-wear-nanoscale-responses-of-teeth-to-chewing-loads
#8
Jing Xia, Z Ryan Tian, Licheng Hua, Lei Chen, Zhongrong Zhou, Linmao Qian, Peter S Ungar
The nanoscale responses of teeth to chewing loads are poorly understood. This has contributed to debate concerning the aetiology of enamel wear and resistance to fracture. Here we develop a new model for reactions of individual hydroxyapatite nanofibres to varying loads and directions of force. Hydroxyapatite nanofibres, or crystallites, composed of chains of bonded nanospheres, are the fundamental building blocks of enamel. This study indicates that these nanofibres respond to contact pressure in three distinct ways depending on force magnitude and direction: (i) plucking (nanosphere loss when the strength of the bonding protein 'glue' is exceeded), (ii) plastic deformation (compression to gradually bend nanofibres and squeeze the protein layer), and (iii) fragmentation (nanofibres fracture when the strength of H-bonds that bind smaller nanoparticles into nanospheres is exceeded)...
October 2017: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/29049882/plasmonic-nanochemistry-based-on-nanohole-array
#9
Bin Ai, Zengyao Wang, Helmuth Möhwald, Gang Zhang
We show that the growth of Ag nanoparticles (NPs) follows the areas of maximum plasmonic field in nanohole arrays (NAs). We thus obtain Ag NP rings not connected to the metallic rim of the nanoholes. The photocatalytic effect resulting from the enhanced E-field of NAs boosts the reaction and is responsible for the site selectivity. The strategy, using plasmonics to control a chemical reaction, can be expanded to organic reactions, for example, synthesis of polypyrrole. After the NA film is removed, ordered ring-shaped Ag NPs are easily obtained, inspiring a facile micropatterning method...
December 26, 2017: ACS Nano
https://www.readbyqxmd.com/read/29030559/understanding-seed-mediated-growth-of-gold-nanoclusters-at-molecular-level
#10
Qiaofeng Yao, Xun Yuan, Victor Fung, Yong Yu, David Tai Leong, De-En Jiang, Jianping Xie
The continuous development of total synthesis chemistry has allowed many organic and biomolecules to be produced with known synthetic history-that is, a complete set of step reactions in their synthetic routes. Here, we extend such molecular-level precise reaction routes to nanochemistry, particularly to a seed-mediated synthesis of inorganic nanoparticles. By systematically investigating the time-dependent abundance of 35 intermediate species in total, we map out relevant step reactions in a model size growth reaction from molecularly pure Au25 to Au44 nanoparticles...
October 13, 2017: Nature Communications
https://www.readbyqxmd.com/read/28560348/molecular-surgery-on-a-23-gold-atom-nanoparticle
#11
Qi Li, Tian-Yi Luo, Michael G Taylor, Shuxin Wang, Xiaofan Zhu, Yongbo Song, Giannis Mpourmpakis, Nathaniel L Rosi, Rongchao Jin
Compared to molecular chemistry, nanochemistry is still far from being capable of tailoring particle structure and functionality at an atomic level. Numerous effective methodologies that can precisely tailor specific groups in organic molecules without altering the major carbon bones have been developed, but for nanoparticles, it is still extremely difficult to realize the atomic-level tailoring of specific sites in a particle without changing the structure of other parts (for example, replacing specific surface motifs and deleting one or two metal atoms)...
May 2017: Science Advances
https://www.readbyqxmd.com/read/28497789/underwater-leidenfrost-nanochemistry-for-creation-of-size-tailored-zinc-peroxide-cancer-nanotherapeutics
#12
Mady Elbahri, Ramzy Abdelaziz, Duygu Disci-Zayed, Shahin Homaeigohar, Justyna Sosna, Dieter Adam, Lorenz Kienle, Torben Dankwort, Moheb Abdelaziz
The dynamic underwater chemistry seen in nature is inspiring for the next generation of eco-friendly nanochemistry. In this context, green synthesis of size-tailored nanoparticles in a facile and scalable manner via a dynamic process is an interesting challenge. Simulating the volcano-induced dynamic chemistry of the deep ocean, here we demonstrate the Leidenfrost dynamic chemistry occurring in an underwater overheated confined zone as a new tool for customized creation of nanoclusters of zinc peroxide. The hydrodynamic nature of the phenomenon ensures eruption of the nanoclusters towards a much colder region, giving rise to growth of monodisperse, size-tailored nanoclusters...
May 12, 2017: Nature Communications
https://www.readbyqxmd.com/read/27812592/designed-synthesis-and-surface-engineering-strategies-of-magnetic-iron-oxide-nanoparticles-for-biomedical-applications
#13
REVIEW
Wei Wu, Chang Zhong Jiang, Vellaisamy A L Roy
Iron oxide nanoparticles (NPs) hold great promise for future biomedical applications because of their magnetic properties as well as other intrinsic properties such as low toxicity, colloidal stability, and surface engineering capability. Numerous related studies on iron oxide NPs have been conducted. Recent progress in nanochemistry has enabled fine control over the size, crystallinity, uniformity, and surface properties of iron oxide NPs. This review examines various synthetic approaches and surface engineering strategies for preparing naked and functional iron oxide NPs with different physicochemical properties...
December 1, 2016: Nanoscale
https://www.readbyqxmd.com/read/27740664/electron-microscopy-reveals-a-soluble-hybrid-network-of-individual-nanocrystals-self-anchored-by-bifunctional-thiol-fluorescent-bridges
#14
Roberto Matassa, Giuseppe Familiari, Ezio Battaglione, Concita Sibilia, Grigore Leahu, Alessandro Belardini, Iole Venditti, Laura Fontana, Ilaria Fratoddi
Today, nanochemistry research of hybrid materials growth in liquid media represents a new challenge for tailoring specific nano-sized materials directly related to the hybrid electron-optical properties. Distinctive assumptions about the origin, the growth, and the functionalization of hybrid nanoparticles have recently been proposed by scientific research to attend the different aspects of observable behaviors. Therefore, appropriate morpho-structural observation of the hybrid nanoparticles is the most important factor for controlling the chemical and physical properties...
October 27, 2016: Nanoscale
https://www.readbyqxmd.com/read/27460290/press-printed-conductive-carbon-black-nanoparticle-films-for-molecular-detection-at-the-microscale
#15
Flavio Della Pelle, Luis Vázquez, Michele Del Carlo, Manuel Sergi, Dario Compagnone, Alberto Escarpa
Carbon black nanoparticle (CBNP) press-transferred film-based transducers for the molecular detection at the microscale level were proposed for the first time. Current-sensing atomic force microscopy (CS-AFM) revealed that the CBNP films were effectively press-transferred, retaining their good conductivity. A significant correlation between the morphology and the resistance was observed. The highest resistance was localized at the top of the press-transferred film protrusions, whereas low values are usually obtained at the deep crevices or grooves...
August 26, 2016: Chemistry: a European Journal
https://www.readbyqxmd.com/read/27278267/prussian-blue-type-nanoparticles-for-biomedical-applications
#16
REVIEW
J Long, Y Guari, C Guérin, J Larionova
Prussian blue type nanoparticles are exciting nano-objects that combine the advantages of molecule-based materials and nanochemistry. Here we provide a short overview focalizing on the recent advances of these nano-objects designed for biomedical applications and give an outlook on the future research orientations in this domain.
November 28, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/26799741/nanochemistry-and-nanomedicine-for-nanoparticle-based-diagnostics-and-therapy
#17
REVIEW
Guanying Chen, Indrajit Roy, Chunhui Yang, Paras N Prasad
No abstract text is available yet for this article.
March 9, 2016: Chemical Reviews
https://www.readbyqxmd.com/read/26728625/localized-plasmon-stimulated-nanochemistry-of-graphene-oxide-on-a-sers-substrate
#18
Lina Ramanauskaite, Huizhong Xu, Valentinas Snitka
In recent years, there has been remarkable progress in the reduction and functionalization of graphene oxide (GO) using nanoparticles and high-energy optical photons. Most of these reactions are carried out in solutions, whereas the local modification of GO on solid substrates still remains a challenge. In this work, we demonstrate the local reduction of GO and its further destruction, leading to the synthesis of polyaromatic hydrocarbons (PAHs) stimulated by localized surface plasmons (LSPs). The reduction of GO and the synthesis of PAHs have been carried out on a substrate designed for surface-enhanced Raman spectroscopy (SERS)...
March 16, 2016: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/26625184/quantifying-the-nucleation-and-growth-kinetics-of-microwave-nanochemistry-enabled-by-in-situ-high-energy-x-ray-scattering
#19
Qi Liu, Min-Rui Gao, Yuzi Liu, John S Okasinski, Yang Ren, Yugang Sun
The fast reaction kinetics presented in the microwave synthesis of colloidal silver nanoparticles was quantitatively studied, for the first time, by integrating a microwave reactor with in situ X-ray diffraction at a high-energy synchrotron beamline. Comprehensive data analysis reveals two different types of reaction kinetics corresponding to the nucleation and growth of the Ag nanoparticles. The formation of seeds (nucleation) follows typical first-order reaction kinetics with activation energy of 20.34 kJ/mol, while the growth of seeds (growth) follows typical self-catalytic reaction kinetics...
January 13, 2016: Nano Letters
https://www.readbyqxmd.com/read/26355960/shaping-and-patterning-gold-nanoparticles-via-micelle-templated-photochemistry
#20
F Kundrat, G Baffou, J Polleux
Shaping and positioning noble metal nanostructures are essential processes that still require laborious and sophisticated techniques to fabricate functional plasmonic interfaces. The present study reports a simple photochemical approach compatible with micellar nanolithography and photolithography that enables the growth, arrangement and shaping of gold nanoparticles with tuneable plasmonic resonances on glass substrates. Ultraviolet illumination of surfaces coated with gold-loaded micelles leads to the formation of gold nanoparticles with micro/nanometric spatial resolution without requiring any photosensitizers or photoresists...
October 14, 2015: Nanoscale
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