Positive Charge States and Possible Polymorphism of Gold Nanoclusters on Reduced Ceria

2010 ◽  
Vol 132 (7) ◽  
pp. 2175-2182 ◽  
Author(s):  
Changjun Zhang ◽  
Angelos Michaelides ◽  
David A. King ◽  
Stephen J. Jenkins
Keyword(s):  
Positive Charge ◽  
Gold Nanoclusters ◽  
Charge States

scholarly journals Aromatic character of [Au13]5+ and [MAu12]4+/6+ (M = Pd, Pt) cores in ligand protected gold nanoclusters – interplay between spherical and planar σ-aromatics

2019 ◽  
Vol 21 (45) ◽  
pp. 25215-25219 ◽  
Author(s):  
Nikita Fedik ◽  
Alexander I. Boldyrev ◽  
Alvaro Muñoz-Castro
Keyword(s):  
Gold Nanoclusters ◽  
Strong Link ◽  
Aromatic Character ◽  
Aromatic Species ◽  
Charge States ◽  
Redox Charge

Ligand-protected superatoms are able to behave as both spherical and planar aromatic species, providing a strong link between spherical and planar σ-aromatics, which can be controlled selectively by tuning their redox charge states.

scholarly journals An Easily Synthesized Covalent Nanocage that Hosts Fullerenes in Multiple Charge States and Selectively Binds C70

2021 ◽  
Author(s):  
Daniel A. Rothschild ◽  
Aaron Tran ◽  
William P. Kopcha ◽  
Jianyuan Zhang ◽  
Mark C. Lipke
Keyword(s):  
Positive Charge ◽  
Association Constants ◽  
Redox Properties ◽  
Nmr Studies ◽  
Polar Solvents ◽  
Fullerene Derivatives ◽  
Practical Utility ◽  
Charge States ◽  
Multiple Charge

Discrete nanocages provide a way to solubilize, separate, and tune the properties of molecular guests, including fullerenes and other aromatics. However, few such nanocages can be synthesized efficiently from inexpensive starting materials, limiting their practical utility. To address this limitation, we developed a new pyridinium-linked cofacial porphyrin nanocage (Cage4+) that can be prepared efficiently on a gram scale. NMR studies in CD3CN reveal that Cage4+ binds C60 and C70 with association constants >108 M-1 and complete selectivity for extracting C70 from mixtures of both fullerenes. The solubility of Cage4+ in polar solvents enabled electrochemical characterization of the host-guest complexes C60@Cage4+ and C70@Cage4+, finding that the redox properties of the encapsulated fullerenes are minimally affected despite the positive charge of the host. Complexes of the −1 and −2 charge states of the fullerenes bound in Cage4+ were subsequently characterized by UV-vis-NIR and NMR spectroscopies. The relatively easy preparation of Cage4+ and its ability to bind fullerenes without substantially affecting their redox properties suggests that C60@Cage4+ and C70@Cage4+ may be directly useful as solubilized fullerene derivatives.

Assembly of Magnetic Nano-Fe3O4@GSH-Au NCs Core–Shell Microspheres for the Visualization of Latent Fingerprints

NANO ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. 1850128 ◽  
Author(s):  
Rui Huang ◽  
Tingting Tang
Keyword(s):  
Negative Charge ◽  
Positive Charge ◽  
Gold Nanoclusters ◽  
Core Shell ◽  
Protective Agent ◽  
Latent Fingerprints ◽  
Uniform Size ◽  
Electrostatic Adsorption ◽  
The Core ◽  
Nano Fe3o4

Glutathione (GSH), the protective agent and reducing agent, has been widely used to prepare gold nanoclusters (GSH-Au NCs) with stable fluorescence properties and negative charge of the surface. Meanwhile, polyethyleneimine (PEI) was used as the modification agent to synthesize magnetic ferroferric oxide nanoparticles (Fe3O4) with fantastic dispersibility and positive charge of the surface. Based on the electrostatic adsorption force, magnetic nano-Fe3O4@GSH-Au NCs core–shell microspheres composed of magnetic Fe3O4 nanoparticles modified by PEI as the core and GSH-Au NCs as the shell were assembled. The prepared Fe3O4@GSH-Au NCs microspheres harbored a uniform size (88.6[Formula: see text]nm), high magnetization (29.2[Formula: see text]emu/g) and excellent fluorescence. Due to the coordination bond action between Au atom and sulfhydryl (–SH), amino (–NH2), carboxyl (–COOH) in sweat, Fe3O4@GSH-Au NCs could combine with latent fingerprints. In addition, Fe3O4@GSH-Au NCs with good fluorescence and magnetism could detect fingerprints on various objects. Significantly, the powders were not easy to suspend in the air, which avoided the damage to the health of forensic experts and the fingerprints by only powder contacting. Above all, Fe3O4@GSH-Au NCs was successfully applied to the latent fingerprint visualization, which has great potential in forensic science.

scholarly journals Spectroscopy of Single Semiconductor Quantum Dots at Negative, Neutral, and Positive Charge States

2002 ◽  
Vol 190 (2) ◽  
pp. 491-497 ◽  
Author(s):  
D.V. Regelman ◽  
D. Gershoni ◽  
E. Ehrenfreund ◽  
W.V. Schoenfeld ◽  
P.M. Petroff
Keyword(s):  
Quantum Dots ◽  
Positive Charge ◽  
Semiconductor Quantum Dots ◽  
Charge States

Ultraviolet photoabsorption spectra of silver and gold nanoclusters

1998 ◽  
Vol 78 (4) ◽  
pp. 385-396 ◽  
Author(s):  
V. Kasperovich, V. V. Kresin
Keyword(s):  
Gold Nanoclusters

Utilization of electrical charges in the pores of tofu waste for hydrogen production in water

2020 ◽  
pp. 124-135
Author(s):  
I. N. G. Wardana ◽  
N. Willy Satrio
Keyword(s):  
Magnetic Field ◽  
Hydrogen Production ◽  
Sodium Bicarbonate ◽  
Positive Charge ◽  
Electrical Energy ◽  
Hydrogen Sensor ◽  
Water Molecules ◽  
Partial Charge ◽  
Delocalized Electron ◽  
Water Hydrogen

Tofu is main food in Indonesia and its waste generally pollutes the waters. This study aims to change the waste into energy by utilizing the electric charge in the pores of tofu waste to produce hydrogen in water. The tofu pore is negatively charged and the surface surrounding the pore has a positive charge. The positive and negative electric charges stretch water molecules that have a partial charge. With the addition of a 12V electrical energy during electrolysis, water breaks down into hydrogen. The test was conducted on pre-treated tofu waste suspension using oxalic acid. The hydrogen concentration was measured by a MQ-8 hydrogen sensor. The result shows that the addition of turmeric together with sodium bicarbonate to tofu waste in water, hydrogen production increased more than four times. This is due to the fact that magnetic field generated by delocalized electron in aromatic ring in turmeric energizes all electrons in the pores of tofu waste, in the sodium bicarbonate, and in water that boosts hydrogen production. At the same time the stronger partial charge in natrium bicarbonate shields the hydrogen proton from strong attraction of tofu pores. These two combined effect are very powerful for larger hydrogen production in water by tofu waste.

Sensing of dynamic charge states using single-electron tunneling transistors

1998 ◽  
Vol 168 (2) ◽  
pp. 219
Author(s):  
V.A. Krupenin ◽  
S.V. Lotkhov ◽  
H. Scherer ◽  
A.B. Zorin ◽  
F.-J. Ahlers ◽  
...  
Keyword(s):  
Electron Tunneling ◽  
Single Electron ◽  
Single Electron Tunneling ◽  
Dynamic Charge ◽  
Charge States

A Hydrogen Bond Between Linear Tetrapyrrole and Conserved Aspartate Causes the Far-Red Shifted Absorption of Phytochrome Photoreceptors

2020 ◽  
Author(s):  
Egle Maximowitsch ◽  
Tatiana Domratcheva
Keyword(s):  
Hydrogen Bond ◽  
Light Adaptation ◽  
Positive Charge ◽  
Pyrrole Ring ◽  
Md Simulations ◽  
Spectral Shift ◽  
Specific Domain ◽  
Study Guides ◽  
Rational Engineering ◽  
Tuning Mechanism

Photoswitching of phytochrome photoreceptors between red-absorbing (Pr) and far-red absorbing (Pfr) states triggers light adaptation of plants, bacteria and other organisms. Using quantum chemistry, we elucidate the color-tuning mechanism of phytochromes and identify the origin of the Pfr-state red-shifted spectrum. Spectral variations are explained by resonance interactions of the protonated linear tetrapyrrole chromophore. In particular, hydrogen bonding of pyrrole ring D with the strictly conserved aspartate shifts the positive charge towards ring D thereby inducing the red spectral shift. Our MD simulations demonstrate that formation of the ring D–aspartate hydrogen bond depends on interactions between the chromophore binding domain (CBD) and phytochrome specific domain (PHY). Our study guides rational engineering of fluorescent phytochromes with a far-red shifted spectrum.

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