نتایج جستجو برای: photochemical forming

تعداد نتایج: 124842  

Journal: :Applied Organometallic Chemistry 2022

This Minireview presents and discusses recent developments in photoactive/photoluminescent N-heterocyclic carbene (NHC) transition metal complexes their viability as catalysts bond-forming photocatalysis. Specifically, we summarise key structural motifs adopted by photoactive NHC highlight some of photophysical properties. Representative examples applications photochemical reactions are also sh...

2016
Ana Bahamonde Paolo Melchiorre

Herein we describe our efforts to elucidate the key mechanistic aspects of the previously reported enantioselective photochemical α-alkylation of aldehydes with electron-poor organic halides. The chemistry exploits the potential of chiral enamines, key organocatalytic intermediates in thermal asymmetric processes, to directly participate in the photoexcitation of substrates either by forming a ...

2011
L. Ran C. S. Zhao W. Y. Xu X. Q. Lu M. Han W. L. Lin P. Yan X. B. Xu Z. Z. Deng N. Ma P. F. Liu L. L. Chen

Measurements of ozone and its precursors conducted within the HaChi (Haze in China) project in summer 2009 were analyzed to characterize volatile organic compounds (VOCs) and their effects on ozone photochemical production at a suburban site in the North China Plain (NCP). Ozone episodes, during which running 8-h average ozone concentrations exceeding 80 ppbv lasted for more than 4 h, occurred ...

2004
K. Toyota Y. Kanaya M. Takahashi H. Akimoto

A new chemical scheme is developed for the multiphase photochemical box model SEAMAC (sizeSEgregated Aerosol model for Marine Air Chemistry) to investigate photochemical interactions between volatile organic compounds (VOCs) and reactive halogen species in the marine boundary layer (MBL). Based primarily on critically evaluated kinetic and photochemical rate parameters as well as a protocol for...

2016
Bo Y. Chang Ignacio R. Sola Seokmin Shin Andre Bandrauk

A new perspective on how to manipulate molecules by means of very strong laser pulses is emerging with insights from the so-called light-induced potentials, which are the adiabatic potential energy surfaces of molecules severely distorted by the effect of the strong field. Different effects appear depending on how the laser frequency is tuned, to a certain electronic transition, creating light-...

Journal: :Chemistry 2013
Gábor London Kuang-Yen Chen Gregory T Carroll Ben L Feringa

We report the synthesis of altitudinal molecular motors that contain functional groups in their rotor part. In an approach to achieve dynamic control over the properties of solid surfaces, a hydrophobic perfluorobutyl chain and a relatively hydrophilic cyano group were introduced to the rotor part of the motors. Molecular motors were attached to quartz surfaces by using interfacial 1,3-dipolar ...

Journal: :Molecules 2018
Victoria Kathryn Meader Mallory G John Laysa M Frias Batista Syeda Ahsan Katharine Moore Tibbetts

Plasmas with dense concentrations of reactive species such as hydrated electrons and hydroxyl radicals are generated from focusing intense femtosecond laser pulses into aqueous media. These radical species can reduce metal ions such as Au3+ to form metal nanoparticles (NPs). However, the formation of H₂O₂ by the recombination of hydroxyl radicals inhibits the reduction of Ag⁺ through back-oxida...

Journal: :Icarus 1988
Y L Yung R R Friedl J P Pinto K D Bayes Wen J-S

It is argued that photochemical processes, driven by ultraviolet starlight, could lead to large deuterium fractionation for H2O and CH4 relative to H2 in the primitive solar nebula. Implications for deuterium enrichment observed in planetary atmospheres are briefly discussed.

2017
Luca Buzzetti Alexis Prieto Sudipta Raha Roy Paolo Melchiorre

We report herein that 4-alkyl-1,4-dihydropyridines (alkyl-DHPs) can directly reach an electronically excited state upon light absorption and trigger the generation of C(sp3 )-centered radicals without the need for an external photocatalyst. Selective excitation with a violet-light-emitting diode turns alkyl-DHPs into strong reducing agents that can activate reagents through single-electron tran...

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