scholarly journals Frequency dependence of microwave-assisted electron-transfer chemical reactions

2019 ◽  
Vol 118 (13) ◽  
pp. e1685691
Author(s):  
Guennadi A. Kouzaev
2021 ◽  
Author(s):  
Anjali Jha

In the Conventional laboratory or industry heating technique involve Bunsen burner, heating mental/hot plates and electric heating ovens. To produce a variety of useful compounds for betterment of mankind, the Microwave Chemistry was introduced in year 1955 and finds a place in one of the Green chemistry method. In Microwave chemistry is the science of applying microwave radiation to chemical reactions. Microwaves act as high frequency electric fields and will generally heat any material containing mobile electric charges, such as polar molecules in a solvent or conducting ions in a solid. Polar solvents are heated as their component molecules are forced to rotate with the field and lose energy in collisions i.e. the dipole moments of molecules are important in order to proceed with the chemical reactions in this method. It can be termed as microwave-assisted organic synthesis (MAOS), Microwave-Enhanced Chemistry (MEC) or Microwave-organic Reaction Enhancement synthesis (MORE). Microwave-Assisted Syntheses is a promising area of modern Green Chemistry could be adopted to save the earth.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Jorge A. Campos-Gonzalez-Angulo ◽  
Raphael F. Ribeiro ◽  
Joel Yuen-Zhou

Abstract Interaction between light and matter results in new quantum states whose energetics can modify chemical kinetics. In the regime of ensemble vibrational strong coupling (VSC), a macroscopic number $$N$$ N of molecular transitions couple to each resonant cavity mode, yielding two hybrid light–matter (polariton) modes and a reservoir of $$N-1$$ N − 1 dark states whose chemical dynamics are essentially those of the bare molecules. This fact is seemingly in opposition to the recently reported modification of thermally activated ground electronic state reactions under VSC. Here we provide a VSC Marcus–Levich–Jortner electron transfer model that potentially addresses this paradox: although entropy favors the transit through dark-state channels, the chemical kinetics can be dictated by a few polaritonic channels with smaller activation energies. The effects of catalytic VSC are maximal at light–matter resonance, in agreement with experimental observations.


1982 ◽  
Vol 37 (3) ◽  
pp. 324-331 ◽  
Author(s):  
Heindirk torn Dieck ◽  
Ewald Kühl

Abstract Carbonyl complexes of chromium, molybdenum and tungsten of the type DAD M(CO)4 with DAD - diazadiene (R-N=CR′-CR′=NR) are shown by cyclic voltammetry to undergo electron transfer reactions to [DAD M(CO)4]+ and [DAD M(CO)4]-. The rate of subsequent chemical reactions with nucleophiles or by loss of ligands depend on the sol-vent, the metal and the ligands' electronic and steric properties. Chromium(+I) is more readily stabilized than Mo(+I) or W(-I) while the opposite is true for the stability of the anions formed. The dimerisation of a low-coordinate species DAD Mo(CO)3 from the reduction of DAD Mo(CO)3(CH3CN) is detected electrochemically. The stabilization of oxidation states +1 and -I is briefly discussed in view of the DAD ligand properties.


PEDIATRICS ◽  
1958 ◽  
Vol 21 (4) ◽  
pp. 699-699
Author(s):  
SAMUEL J. FOMON

Because most chemical reactions occurring in living organisms are catalyzed by enzymes and because recent developments in methodology have given great impetus to studies of these substances, it is perhaps not surprising that enzyme chemistry is prominently featured in a collection of essays recounting important advances in biochemical research during the past 10 years. The mechanism of synthesis of enzymes and of interaction between enzyme and substrate, the importance of certain of the prosthetic groups, co-enzymes and co-factors, electron transfer and kinetics of enzyme activity are all considered.


2003 ◽  
Vol 26 (12) ◽  
pp. 1207-1216 ◽  
Author(s):  
M. Nüchter ◽  
U. Müller ◽  
B. Ondruschka ◽  
A. Tied ◽  
W. Lautenschläger

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