Reaction Mechanism of Homoprotocatechuate 2,3-Dioxygenase with 4-Nitrocatechol: Implications for the Role of Substrate

2014 ◽  
Vol 118 (7) ◽  
pp. 1791-1798 ◽  
Author(s):  
Geng Dong ◽  
Wenzhen Lai
Keyword(s):  
2001 ◽  
Vol 14 (2) ◽  
pp. 202-210 ◽  
Author(s):  
Catherine Moali ◽  
Jean-Luc Boucher ◽  
Axelle Renodon-Corniere ◽  
Dennis J. Stuehr ◽  
Daniel Mansuy

1996 ◽  
Vol 159 (2) ◽  
pp. 418-426 ◽  
Author(s):  
Dezheng Wang ◽  
Olivier Dewaele ◽  
Ann M.De Groote ◽  
Gilbert F. Froment

1989 ◽  
Vol 149 ◽  
Author(s):  
S. Veprek ◽  
M. Heintze ◽  
R. Bayer ◽  
N. Jurčik-Rajman

ABSTRACTWe present new results of kinetic studies of the deposition of high quality a-Si:H which strongly support the reaction mechanism suggested in our earlier papers: 1. SiH4 → SiH2; 2. SiH2 + SiS4 → Si2H6 (SiH2 + Si2H6 → Si3H6); 3. Si2H6 → 2a-Si:H (Si3H8 → 3a-Si:H). The “SiH3 mechanism”, as promoted by several workers, is in contradiction with these experimental facts.The di- and trisilane, which have a much higher reactive sticking coefficient than monosilane, play the role of reactive intermediates which facilitate the heterogeneous decomposition of silicon carrying species at the surface of the growing film. The values of the reactive sticking coefficient of Si2H6 and Si3H8 depend on the surface coverage by chemisorbed hydrogen; they increase with decreasing surface coverage. Under the conditions of the growth of high quality a-Si:H films the reactive sticking coefficient of disilane amounts to 10−4 to 10−2 which is in a good agreement with recent data of other authors.The rate determining step of the growth of high quality a-Si:H films is the desorption of hydrogen from the surface of the growing film. This can be strongly enhanced by ion bombardment at impact energy of <100 eV. In this way, homogeneous, good quality films were deposited at rates up to 1800 Angströms/min, and there is a well justified hope that this rate can be further increased.


RSC Advances ◽  
2019 ◽  
Vol 9 (46) ◽  
pp. 27125-27135 ◽  
Author(s):  
Elon F. Freitas ◽  
Roberto Y. Souza ◽  
Saulo T. A. Passos ◽  
José A. Dias ◽  
Silvia C. L. Dias ◽  
...  

Heteropolyacids and ionic liquid effect allowed tuning of the Biginelli reaction mechanism and synthesis of 3,4-dihydropyrimidin-2(1H)-one/thione derivatives in an efficient, recyclable fashion. The role of acidic strength and supported heteropolyacid is disclosed.


2020 ◽  
Vol 11 (1) ◽  
pp. 257-263 ◽  
Author(s):  
Gianluca Casotti ◽  
Gianluca Ciancaleoni ◽  
Filippo Lipparini ◽  
Chiara Nieri ◽  
Anna Iuliano

The reaction mechanism of a new conjugate addition reaction of organozinc halides to enones is disclosed by a combined experimental/computational study.


Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3565 ◽  
Author(s):  
Ilya Nifant’ev ◽  
Alexander Vinogradov ◽  
Alexey Vinogradov ◽  
Stanislav Karchevsky ◽  
Pavel Ivchenko

Zirconocene-mediated selective dimerization of α-olefins usually occurs when precatalyst (η5-C5H5)2ZrCl2 is activated by minimal excess of methylalumoxane (MAO). In this paper, we present the results of density functional theory (DFT) simulation of the initiation, propagation, and termination stages of dimerization and oligomerization of propylene within the framework of Zr-Al binuclear mechanism at M-06x/DGDZVP level of theory. The results of the analysis of the reaction profiles allow to explain experimental facts such as oligomerization of α-olefins at high MAO/(η5-C5H5)2ZrCl2 ratios and increase of the selectivity of dimerization in the presence of R2AlCl. The results of DFT simulations confirm the crucial role of the presence of chloride in the selectivity of dimerization. The molecular hydrogen was found in silico and proven experimentally as an effective agent that increases the rate and selectivity of dimerization.


2019 ◽  
Vol 21 (36) ◽  
pp. 20296-20307 ◽  
Author(s):  
Narcisse T. Tsona ◽  
Shanshan Tang ◽  
Lin Du

The role of water in preventing the barrierless hydrogen abstraction in the BrO + HO2 reaction is highlighted.


2019 ◽  
Vol 60 (2) ◽  
pp. 915-922 ◽  
Author(s):  
Fernanda Mendoza ◽  
Fabiola E. Medina ◽  
Verónica A. Jiménez ◽  
Gonzalo A. Jaña

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