Activation of Aryl Chlorides in the Suzuki-Miyaura Reaction by “Ligand-Free” Pd Species through a Homogeneous Catalytic Mechanism: Distinguishing between Homogeneous and Heterogeneous Catalytic Mechanisms

2021 ◽  
Vol 25 (4) ◽  
pp. 916-925
Author(s):  
Nadezhda A. Lagoda ◽  
Elizaveta V. Larina ◽  
Elena V. Vidyaeva ◽  
Anna A. Kurokhtina ◽  
Alexander F. Schmidt
Keyword(s):  
Catalytic Mechanism ◽  
Aryl Chlorides ◽  
Heterogeneous Catalytic ◽  
Ligand Free ◽  
Catalytic Mechanisms

scholarly journals Functional dissection of the catalytic mechanism of mammalian RNA polymerase II

2005 ◽  
Vol 83 (4) ◽  
pp. 497-504 ◽  
Author(s):  
Benoit Coulombe ◽  
Marie-France Langelier
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Catalytic Mechanism ◽  
Mutational Analysis ◽  
Structural Elements ◽  
Catalytic Mechanisms ◽  
Rnap Ii ◽  
Affinity Peptide

High resolution X-ray crystal structures of multisubunit RNA polymerases (RNAP) have contributed to our understanding of transcriptional mechanisms. They also provided a powerful guide for the design of experiments aimed at further characterizing the molecular stages of the transcription reaction. Our laboratory used tandem-affinity peptide purification in native conditions to isolate human RNAP II variants that had site-specific mutations in structural elements located strategically within the enzyme's catalytic center. Both in vitro and in vivo analyses of these mutants revealed novel features of the catalytic mechanisms involving this enzyme.Key words: RNA polymerase II, transcriptional mechanisms, mutational analysis, mRNA synthesis.

scholarly journals A QM/MM Study of Acylphosphatase Reveals the Nucleophilic-Attack and Ensuing Carbonyl-Assisted Catalytic Mechanisms

2020 ◽  
Author(s):  
zheng zhao ◽  
Phil bourne ◽  
Hao Hu ◽  
Huanyu Chu
Keyword(s):  
Energy Barrier ◽  
Potential Energy Surfaces ◽  
Catalytic Mechanism ◽  
Interaction Networks ◽  
Nucleophilic Attack ◽  
Reaction Coordinates ◽  
Transition State Stabilization ◽  
Catalytic Mechanisms ◽  
Energy Surfaces

Acylphosphatase is one of the vital enzymes in many organs/tissues to catalyze an acylphosphate molecule into carboxylate and phosphate. Here we use a combined <i>ab initio</i> QM/MM approach to reveal the catalytic mechanism of the benzoylphosphate-bound acylphosphatase system. Using a multi-dimensional reaction-coordinates-driving scheme, we obtained a detailed catalytic process including one nucleophilic-attack and then an ensuing carbonyl-shuttle catalytic mechanism by calculating two-dimensional potential energy surfaces. We also obtained an experiment-agreeable energy barrier and validated the role of the key amino acid Asn38. Additionally, we qualified the transition state stabilization strategy based on the amino acids-contributed interaction networks revealed in the enzymatic environment. This study provided usefule insights into the underlying catalytic mechanism to contribute to disease-involved research.

A Study of the Step of Alkene Activation under Ligand-Free Conditions in the Mizoroki–Heck Reaction with Unreactive Aryl Chlorides

2021 ◽  
Vol 62 (2) ◽  
pp. 307-314
Author(s):  
A. A. Kurokhtina ◽  
E. V. Larina ◽  
E. V. Vidyaeva ◽  
N. A. Lagoda ◽  
A. F. Schmidt
Keyword(s):  
Heck Reaction ◽  
Aryl Chlorides ◽  
Ligand Free

scholarly journals Development of Titanium Dioxide-Supported Pd Catalysts for Ligand-Free Suzuki–Miyaura Coupling of Aryl Chlorides

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 461 ◽  
Author(s):  
Yamada ◽  
Masuda ◽  
Park ◽  
Tachikawa ◽  
Ito ◽  
...  
Keyword(s):  
Titanium Oxide ◽  
Palladium Catalysts ◽  
Catalyst Activity ◽  
Acetonitrile Solution ◽  
Palladium Acetate ◽  
Tio2 Anatase ◽  
Aryl Chlorides ◽  
Donation Process ◽  
Ligand Free ◽  
Supported Pd

The catalyst activities of various heterogeneous palladium catalysts supported by anatase-, rutile- and brookite-type titanium oxide for ligand-free Suzuki–Miyaura cross-coupling reactions of aryl chlorides were evaluated. Palladium acetate [Pd(OAc)2], supported on anatase-type titanium oxide (TiO2) via acetonitrile solution impregnation process without reduction [Pd/TiO2 (anatase-type)], demonstrated the highest catalyst activity in comparison to those of other titanium oxide (rutile- or brookite-type) supported Pd(OAc)2 without reduction and reduced Pd/TiO2 (anatase-type) [Pd(red)/TiO2 (anatase-type)]. Various aryl chloride and bromide derivatives were smoothly coupled with arylboronic acids including heteroarylboronic acids in the presence of 5–10 mol% Pd/TiO2 (anatase-type) without the addition of any ligands. Although the fresh Pd/TiO2 (anatase-type) catalyst was surprisingly comprised of ca. 1:2 mixture of palladium(II) and palladium(0) species according to X-ray photoelectron spectroscopy (XPS), in spite of no reduction process, significant further increment of palladium(0) species was observed during the Suzuki–Miyaura coupling reaction, and Pd/TiO2 (anatase-type) was converted into a catalyst, which contained palladium(0) species as the main component [ca. 1:5 mixture of palladium(II) and palladium(0) species]. Therefore, the reduction via the electron donation process to the palladium(II) species may have occurred during the reaction on anatase-type titanium oxide.

In Situ Real-Time Studies of Heterogeneous Catalytic Mechanisms at Ambient Pressures As Probed by Surface-Enhanced Raman and Mass Spectroscopies

1998 ◽  
Vol 37 (6) ◽  
pp. 2307-2315 ◽  
Author(s):  
Christopher T. Williams ◽  
Ho Yeung H. Chan ◽  
Anish A. Tolia ◽  
Michael J. Weaver ◽  
Christos G. Takoudis
Keyword(s):  
Real Time ◽  
Heterogeneous Catalytic ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Catalytic Mechanisms

Is oxidative addition indeed the rate-determining step of the Suzuki–Miyaura reaction with less-reactive aryl chlorides under “ligand-free” conditions?

2020 ◽  
Vol 929 ◽  
pp. 121571
Author(s):  
Alexander F. Schmidt ◽  
Anna A. Kurokhtina ◽  
Elizaveta V. Larina ◽  
Elena V. Vidyaeva ◽  
Nadezhda A. Lagoda
Keyword(s):  
Oxidative Addition ◽  
Aryl Chlorides ◽  
Rate Determining Step ◽  
Ligand Free

Insights into the catalytic mechanism of synthetic glutathione peroxidase mimetics

2015 ◽  
Vol 13 (41) ◽  
pp. 10262-10272 ◽  
Author(s):  
Debasish Bhowmick ◽  
Govindasamy Mugesh
Keyword(s):  
Glutathione Peroxidase ◽  
Catalytic Mechanism ◽  
Catalytic Mechanisms

This review focuses on the variation of the catalytic mechanisms of synthetic glutathione peroxidase (GPx) mimics depending on their structures and reactivities towards thiols and peroxides. Compounds of different categories follow a characteristic mechanism for the reduction of peroxides.

Vapor conversion of methane on serpentinite: An example of a heterogeneous-catalytic mechanism of fluid transformation in the Earth’s crust

2013 ◽  
Vol 453 (2) ◽  
pp. 1213-1217 ◽  
Author(s):  
V. V. Barelko ◽  
O. G. Safonov ◽  
N. V. Bykova ◽  
V. G. Dorokhov ◽  
L. A. Bykov ◽  
...  
Keyword(s):  
Catalytic Mechanism ◽  
Earth’S Crust ◽  
Heterogeneous Catalytic ◽  
Conversion Of Methane ◽  
Earth's Crust
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