Spectroscopy of the transition state: Elementary reactions of the hydroxyl radical studied by photoelectron spectroscopy of O−(H2O) and H3O−2

1995 ◽  
Vol 102 (15) ◽  
pp. 6088-6099 ◽  
Author(s):  
Don W. Arnold ◽  
Cangshan Xu ◽  
Daniel M. Neumark
Keyword(s):  
Transition State ◽  
Hydroxyl Radical ◽  
Photoelectron Spectroscopy ◽  
Elementary Reactions

Study of the transition state region in the Cl+HCl reaction by photoelectron spectroscopy of ClHCl−

1988 ◽  
Vol 88 (2) ◽  
pp. 1463-1465 ◽  
Author(s):  
R. B. Metz ◽  
T. Kitsopoulos ◽  
A. Weaver ◽  
D. M. Neumark
Keyword(s):  
Transition State ◽  
Photoelectron Spectroscopy ◽  
State Region

Direct Ortho-Metallation of Aryl Substituted Heteroaromatic Ligands with TiCl 4 and ZrCl 4 - An Experimental and DFT Study with 2-Phenyl Indole as the Ligand.

2019 ◽  
Author(s):  
Gregory Arzoumanidis ◽  
Ernest Chamot
Keyword(s):  
Dft Calculations ◽  
Transition State ◽  
Photoelectron Spectroscopy ◽  
Analytical Data ◽  
Phenyl Group ◽  
Building Blocks ◽  
One Pot ◽  
Polymerization Catalysis ◽  
Cyclometallated Complexes ◽  
C Nmr

TiCl 4 and ZrCl 4 each react with aryl substituted heteroaromatic ligands such as 2-Phenyl-1H-indole, to thermally undergo one-pot direct orthometallations, and yield new types of cyclometallated complexes. TiCl 4 coordinates at ambient temperature to form the indole complex ( 1 ), which undergoes isomerization to the indolenine ( 2 ). DFT calculations indicate that complex ( 2 ) is more stable than ( 1 ) by 6.4 kcal/mol. Upon warming to about 105°C, extrusion of HCl takes place with simultaneous orthometallation ( 3 ), yielding a metallacyclic complex ( 4 ). The mechanism of the orthometallation has been investigated by DFT, and the transition state c onfir med by IRC. At the elevated temperature the transition state ( 3 ) involves the synchronous transformation of four atoms, Ti, ortho C, H, and the apical Cl. The ortho C of the phenyl group acquires a partial positive charge through conjugation, forming a (C-H)δ + ...Clδ - interaction, with a simultaneous elongation and breaking of the Ti-Cl bond, resulting in the formation of a Ti-C bond. The latter bond is created at the same time a Ti-Cl bond is breaking, and an HCl is being formed, as illustrated in transition state ( 3 ). This HCl is retained in the crystal structure of the final product ( 4 ), by electrostatic interaction with one of the chloride ligands. The reaction sequence may be repeated with ZrCl 4 in place of TiCl 4 . Complex ( 4 ) has been isolated and characterized by solid state 13 C NMR CPMAS/DDMAS spectra, X-ray photoelectron spectroscopy (XPS), infrared and analytical data. The intermediate structures ( 1 through 4 ), as well as the sequence of ligand transformations to produce the ortho-metallated complex are supported by DFT calculations. The new cyclometallated complexes are thermally stable, unlike several other complexes featuring a Ti-C bond. They may have important applications, such as in α-olefin polymerization catalysis, and as building blocks in metalodrugs for cancer therapy.<br>

scholarly journals A Water-Dispersible Carboxylated Carbon Nitride Nanoparticles-Based Electrochemical Platform for Direct Reporting of Hydroxyl Radical in Meat

Foods ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 40
Author(s):  
Tingting Han ◽  
Yang Huang ◽  
Chong Sun ◽  
Daoying Wang ◽  
Weimin Xu
Keyword(s):  
Hydroxyl Radical ◽  
Photoelectron Spectroscopy ◽  
Carbon Nitride ◽  
Great Promise ◽  
Signal Molecule ◽  
Water Dispersible ◽  
Transmission Electron ◽  
One Step ◽  
Meat Samples

In this paper, carboxylated carbon nitride nanoparticles (carboxylated-g-C3N4 NPs) were prepared through a one-step molten salts method. The synthesized material was characterized by transmission electron microscope (TEM), Fourier transform-infrared spectra (FTIR), and X-ray photoelectron spectroscopy (XPS), etc. An electrochemical sensor based on single-stranded oligonucleotide/carboxylated-g-C3N4/chitosan/glassy carbon electrode (ssDNA/carboxylated-g-C3N4/chitosan/GCE) was constructed for determination of the hydroxyl radical (•OH), and methylene blue (MB) was used as a signal molecule. The sensor showed a suitable electrochemical response toward •OH from 4.06 to 122.79 fM with a detection limit of 1.35 fM. The selectivity, reproducibility, and stability were also presented. Application of the sensor to real meat samples (i.e., pork, chicken, shrimp, and sausage) was performed, and the results indicated the proposed method could be used to detect •OH in practical samples. The proposed sensor holds a great promise to be applied in the fields of food safety.

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