Spectroscopic Detection of Hydrogen Atom Spillover from Au Nanoparticles Supported on TiO2:  Use of Conduction Band Electrons

2007 ◽  
Vol 111 (7) ◽  
pp. 2959-2964 ◽  
Author(s):  
Dimitar A. Panayotov ◽  
John T. Yates
Keyword(s):  
Hydrogen Atom ◽  
Conduction Band ◽  
Au Nanoparticles

scholarly journals Femtosecond Spectroscopy of Au Hot-Electron Injection into TiO2: Evidence for Au/TiO2 Plasmon Photocatalysis by Bactericidal Au Ions and Related Phenomena

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 217 ◽  
Author(s):  
Marina Radzig ◽  
Olga Koksharova ◽  
Inessa Khmel ◽  
Vladimir Ivanov ◽  
Khursand Yorov ◽  
...  
Keyword(s):  
Visible Light ◽  
Tio2 Nanoparticles ◽  
Conduction Band ◽  
Light Absorption ◽  
Au Nanoparticles ◽  
Visible Region ◽  
Electron Injection ◽  
Femtosecond Spectroscopy ◽  
Hot Electron ◽  
Resonance Band

In the present work, we provide evidence for visible light irradiation of the Au/TiO2 nanoparticles’ surface plasmon resonance band (SPR) leading to electron injection from the Au nanoparticles to the conduction band of TiO2. The Au/TiO2 SPR band is shown to greatly enhance the light absorption of TiO2 in the visible region. Evidence is presented for the light absorption by the Au/TiO2 plasmon bands leading to the dissolution of Au nanoparticles. This dissolution occurs concomitantly with the injection of the hot electrons generated by the Au plasmon into the conduction band of TiO2. The electron injection from the Au nanoparticles into TiO2 was followed by femtosecond spectroscopy. The formation of Au ions was further confirmed by the spectral shift of the transient absorption spectra of Au/TiO2. The spectral changes of the SPR band of Au/TiO2 nanoparticles induced by visible light were detected by spectrophotometer, and the morphological transformation of Au/TiO2 was revealed by electron microscopy techniques as well. Subsequently, the fate of the Au ions was sorted out during the growth and biofilm formation for some selected Gram-negative bacteria. This study compares the bactericidal mechanism of Au ions and Ag ions, which were found to be substantially different depending on the selected cell used as a probe.

On the role of gold nanoparticles in the selective photooxidation of 2-propanol over Au/TiO2

2015 ◽  
Vol 17 (16) ◽  
pp. 10391-10397 ◽  
Author(s):  
Alexander Lüken ◽  
Martin Muhler ◽  
Jennifer Strunk
Keyword(s):  
Gold Nanoparticles ◽  
Electron Transfer ◽  
Reaction Mechanism ◽  
Conduction Band ◽  
Electron Acceptor ◽  
Au Nanoparticles ◽  
Hole Capture ◽  
Insight Into

Partial insight into the reaction mechanism of the photooxidation of 2-propanol over Au/TiO2. 2-Propanol is activated by hole capture and converted to acetone requiring the presence of O2 as an electron acceptor. The deposited Au nanoparticles are assumed to facilitate the electron transfer from the TiO2 conduction band to adsorbed O2.

Site-Independent Hydrogenation Reactions on Oxide-Supported Au Nanoparticles Facilitated by Intraparticle Hydrogen Atom Diffusion

ACS Catalysis ◽  
2021 ◽  
pp. 9875-9884
Author(s):  
Shahar Dery ◽  
Hillel Mehlman ◽  
Lillian Hale ◽  
Mazal Carmiel-Kostan ◽  
Reut Yemini ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Au Nanoparticles ◽  
Atom Diffusion ◽  
Hydrogenation Reactions

Measurement of the Lamb shift in the hydrogen atom

1982 ◽  
Vol 138 (10) ◽  
pp. 347 ◽  
Author(s):  
Yurii L. Sokolov ◽  
V.P. Yakovlev
Keyword(s):  
Hydrogen Atom ◽  
Lamb Shift

Direct Cyclization of Alkenyl Thioester via Transition Metal‐hydrogen Atom Transfer/radical‐polar Crossover Mechanism

2019 ◽  
Author(s):  
Shiori Date ◽  
Kensei Hamasaki ◽  
Karen Sunagawa ◽  
Hiroki Koyama ◽  
Chikayoshi Sebe ◽  
...  
Keyword(s):  
Natural Products ◽  
Hydrogen Atom ◽  
Transition Metal ◽  
Hydrogen Atom Transfer ◽  
Synthetic Method ◽  
Atom Transfer ◽  
Reaction Conditions ◽  
Hydride Hydrogen ◽  
Sulfur Heterocycles ◽  
One Step

<div>We report here a catalytic, Markovnikov selective, and scalable synthetic method for the synthesis of saturated sulfur heterocycles, which are found in the structures of pharmaceuticals and natural products, in one step from an alkenyl thioester. Unlike a potentially labile alkenyl thiol, an alkenyl thioester is stable and easy to prepare. The powerful Co catalysis via a cobalt hydride hydrogen atom transfer and radical-polar crossover mechanism enabled simultaneous cyclization and deprotection. The substrate scope was expanded by the extensive optimization of the reaction conditions and tuning of the thioester unit.</div>

Synthesis of Spongidine A, D and Petrosaspongiolide L Methyl Ester Using Pyridine C-H Functionalization

2019 ◽  
Author(s):  
Florian Bartels ◽  
Manuela Weber ◽  
Mathias Christmann
Keyword(s):  
Natural Products ◽  
Methyl Ester ◽  
Hydrogen Atom ◽  
Phospholipase A2 ◽  
Late Stage ◽  
Hydrogen Atom Transfer ◽  
Ring System ◽  
Tetracyclic Core ◽  
Intramolecular Hydrogen ◽  
Phospholipase A2 Inhibitors

<div>An efficient strategy for the synthesis of the potent phospholipase A2 inhibitors spongidine A and D is presented. The tetracyclic core of the natural products was assembled via an intramolecular hydrogen atom transfer‐initiated Minisci reaction. A divergent late‐stage functionalization of the tetracyclic ring system was also used to achieve a concise synthesis of petrosaspongiolide L methyl ester.</div>

Catalytic Synthesis of Cyclic Guanidines via Hydrogen Atom Transfer and Radical-Polar Crossover

2020 ◽  
Author(s):  
Shunya Ohuchi ◽  
Hiroki Koyama ◽  
Hiroki Shigehisa
Keyword(s):  
Hydrogen Atom ◽  
Functional Group ◽  
Hydrogen Atom Transfer ◽  
Catalytic Synthesis ◽  
Membered Ring ◽  
Biologically Active ◽  
Atom Transfer ◽  
Powerful Method ◽  
Protective Groups ◽  
The Common

A catalytic synthesis of cyclic guanidines, which are found in many biologically active compounds and natu-ral products, was developed, wherein transition-metal hydrogen atom transfer and radical-polar crossover were employed. This mild and functional-group tolerant process enabled the cyclization of alkenyl guanidines bearing common protective groups, such as Cbz and Boc. This powerful method not only provided the common 5- and 6-membered rings but also an unusual 7-membered ring. The derivatization of the products afforded various heterocycles. We also investigated the se-lective cyclization of mono-protected or hetero-protected (TFA and Boc) alkenyl guanidines and their further derivatiza-tions.

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