Elucidation of the Structure of a Highly Active Catalytic System for CO2/Epoxide Copolymerization: A salen-Cobaltate Complex of an Unusual Binding Mode

2009 ◽  
Vol 48 (21) ◽  
pp. 10455-10465 ◽  
Author(s):  
Sung Jae Na ◽  
Sujith S ◽  
Anish Cyriac ◽  
Bo Eun Kim ◽  
Jina Yoo ◽  
...  
Keyword(s):  
Catalytic System ◽  
Binding Mode ◽  
Highly Active

Deactivation of arenetitanium(II) bromoalane complexes in the cyclotrimerization of butadiene

1986 ◽  
Vol 51 (12) ◽  
pp. 2751-2759 ◽  
Author(s):  
Jindřich Poláček ◽  
Helena Antropiusová ◽  
Lidmila Petrusová ◽  
Karel Mach
Keyword(s):  
Catalytic Activity ◽  
Catalytic System ◽  
Model System ◽  
Highly Active ◽  
Catalytic Stability

The C6H6.Ti(II)(AlBr4)2 (Ib) catalyst deactivates during the butadiene cyclotrimerization to give a solid containing all titanium (mostly as TiBr3) and a mixture of AlBr3 and RAlBr2 compounds dissolved in benzene. The residual cationic catalytic activity of the deactivated Ib system is due to presence of AlBr3. In contrast to TiCl3, the deactivated Ib system and the model system TiBr3 + AlBr3 are not activated by the addition of EtAlCl2 in the presence of butadiene: the highly active benzenetitanium(II) system is re-constituted only after reduction of TiBr3 with Et3Al followed by the addition of EtAlCl2. The addition of Et2AlBr to Ib accelerates the deactivation of the system. Deactivation products of this system contain mainly Ti(II) species which forms benzenetitanium(II) catalytic system after addition of EtAlCl2. All the EtAlCl2 reactivated systems produce (Z, E, E)-1,5,9-cyclododecatriene with high catalytic stability and considerable selectivity (>90%). This behaviour points to the catalysis by benzenetitanium(II) chloroalane complexes containing only low amount of bromine atoms and ethyl groups.

Sodium complexes bearing cavity-like conformations: a highly active and well-controlled catalytic system for macrolactone homo- and copolymerization

2021 ◽  
Vol 12 (13) ◽  
pp. 1957-1966
Author(s):  
Xinya Wang ◽  
Xiaohua Wang ◽  
Nuo Zhen ◽  
Jin Gu ◽  
Hao Zhang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Highly Active ◽  
Sodium Complexes

Sodium complexes displaying cavity-like conformations and, therefore, suppressed transesterification during the ring-opening polymerization of pentadecalactone are disclosed herein.

Water Mapping and Scoring approaches to predict the role of Hydration sites in Binding Affinity of PAK1 inhibitors

2021 ◽  
Vol 24 ◽  
Author(s):  
Jayashree Biswal ◽  
Prajisha Jayaprakash ◽  
Suresh Kumar Rayala ◽  
Ganesh Venkatraman ◽  
Raghu Rangasamy ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Computational Model ◽  
Active Compound ◽  
Scoring Function ◽  
Binding Mode ◽  
Interaction Pattern ◽  
Dynamics Simulation ◽  
Interaction Patterns ◽  
Highly Active ◽  
Group I

Aim: This study aims to develop and establish a computational model that can identify potent molecules for p21-activating kinase 1 (PAK1). Background: PAK1 is a well-established drug target that has been explored for various therapeutic interventions. Control of this protein requires an indispensable inhibitor to curb the structural changes and subsequent activation of signalling effectors responsible for the progression of diseases, such as cancer, inflammatory, viral, and neurological disorders. Objective: To establish a computational model that could identify active molecules which will further provide a platform for developing potential PAK1 inhibitors. Method: A congeneric series of 27 compounds was considered for this study with Ki (nm) covering a minimum of 3 log range. The compounds were developed based on a previously reported Group-I PAK inhibitor, namely G-5555. The 27 compounds were subjected to the SP and XP mode of docking, to understand the binding mode, its conformation and interaction patterns. To understand the relevance of biological activity from computational approaches, the compounds were scored against generated water maps to obtain WM/MM ΔG binding energy. Moreover, molecular dynamics analysis was performed for the highly active compound, to understand the conformational variability and complex’s stability. We then evaluate the predictable binding pose obtained from the docking studies. Result: From the SP and XP modes of docking, the common interaction pattern with the amino acid residues Arg299 (cation-π), Glu345 (Aromatic hydrogen bond), hinge region Leu347, salt bridges Asp393 and Asp407 was observed, among the congeneric compounds. The interaction pattern was compared with the co-crystal inhibitor FRAX597 of the PAK1 crystal structure (PDB id: 4EQC). The correlation with different docking parameters in the SP and XP modes was insignificant and thereby revealed that the SP and XP’s scoring functions could not predict the active compounds. This was due to the limitations in the docking methodology that neglected the receptor flexibility and desolvation parameters. Hence, to recognise the desolvation and explicit solvent effects, as well as to study the Structure-Activity Relationships (SARs) extensively, WaterMap (WM) calculations were performed on the congeneric compounds. Based on displaceable unfavourable hydration sites (HS) and their associated thermodynamic properties, the WM calculations facilitated to understand the significance of correlation in the folds of activity of highly (19 and 17), moderate (16 and 21) and less active (26 and 25) compounds. Furthermore, the scoring function from WaterMap, namely WM/MM, led to a significant R2 value of 0.72, due to a coupled conjunction with MM treatment and displaced unfavourable waters at the binding site. To check the “optimal binding conformation”, molecular dynamics simulation was carried out with the highly active compound 19 to explain the binding mode, stability, interactions, solvent accessible area, etc., which could support the predicted conformation with bioactive conformation. Conclusion: This study determined the best scoring function, established SARs and predicted active molecules through a computational model. This will contribute towards development of the most potent PAK1 inhibitors.

scholarly journals Ruthenium-Based Catalytic Systems Incorporating a Labile Cyclooctadiene Ligand with N-Heterocyclic Carbene Precursors for the Atom-Economic Alcohol Amidation Using Amines

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2413 ◽  
Author(s):  
Cheng Chen ◽  
Yang Miao ◽  
Kimmy De Winter ◽  
Hua-Jing Wang ◽  
Patrick Demeyere ◽  
...  
Keyword(s):  
Catalytic System ◽  
High Resolution Mass Spectrometry ◽  
Amide Bond ◽  
Catalyst Loading ◽  
Catalytic Systems ◽  
Amide Bond Formation ◽  
Highly Active ◽  
Metal Catalyzed ◽  
Ru Species

Transition-metal-catalyzed amide-bond formation from alcohols and amines is an atom-economic and eco-friendly route. Herein, we identified a highly active in situ N-heterocyclic carbene (NHC)/ruthenium (Ru) catalytic system for this amide synthesis. Various substrates, including sterically hindered ones, could be directly transformed into the corresponding amides with the catalyst loading as low as 0.25 mol.%. In this system, we replaced the p-cymene ligand of the Ru source with a relatively labile cyclooctadiene (cod) ligand so as to more efficiently obtain the corresponding poly-carbene Ru species. Expectedly, the weaker cod ligand could be more easily substituted with multiple mono-NHC ligands. Further high-resolution mass spectrometry (HRMS) analyses revealed that two tetra-carbene complexes were probably generated from the in situ catalytic system.

scholarly journals The effect of the components of the PdCl2/Fe/I2/Py catalytic system on nitrobenzene carbonylation to ethyl N-phenylcarbamate

2005 ◽  
Vol 3 (1) ◽  
pp. 28-39 ◽  
Author(s):  
Jadwiga Skupińska ◽  
Monika Karpińska ◽  
Maria Ołówek ◽  
Teresa Kasprzycka-Guttman
Keyword(s):  
Catalytic System ◽  
Considerable Increase ◽  
Constant Level ◽  
The Other ◽  
Reaction Products ◽  
Highly Active

AbstractThe PdCl2/Fe/I2/Py catalytic system (Py-pyridine), reported to be highly active in the reaction of nitrobenzene carbonylation to ethyl phenylcarbamate was studied. The present paper describes the role of catalyst components and its effect on the activity and selectivity of the catalyst. The increase in the amount of PdCl2 in the system while retaining a constant level of the other catalyst components, results in the increase of both carbamate and aniline yields. The increase in the amount of iron while retaining the other components constant, initially causes an increase in the carbamate yield; however, at Fe: Pd ratios higher than 36, the carbamate yield remains constant. The change in the amount of iron has no effect on the amount of aniline formed in the system. An increase in the amount of iodine in the system while retaining the other components constant, results in a decrease in carbamate yield and a considerable increase in the aniline yield of the reaction products.

A Highly Active and Recyclable Catalytic System for CO2/Propylene Oxide Copolymerization

2008 ◽  
Vol 120 (38) ◽  
pp. 7416-7419 ◽  
Author(s):  
Sujith S ◽  
Jae Ki Min ◽  
Jong Eon Seong ◽  
Sung Jea Na ◽  
Bun Yeoul Lee
Keyword(s):  
Catalytic System ◽  
Propylene Oxide ◽  
Highly Active

scholarly journals Ruthenium-Based Catalytic Systems Incorporating a Labile Cyclooctadiene Ligand with N-Heterocyclic Carbene Precursors for the Atom-Economic Alcohol Amidation Using Amines.

2018 ◽  
Author(s):  
Cheng Chen ◽  
Yang Miao ◽  
Kimmy De Winter ◽  
Hua-Jing Wang ◽  
Patrick Demeyere ◽  
...  
Keyword(s):  
Catalytic System ◽  
Amide Bond ◽  
Catalyst Loading ◽  
Catalytic Systems ◽  
Carbene Complexes ◽  
Amide Bond Formation ◽  
Highly Active ◽  
Metal Catalyzed ◽  
Ru Species

Transition-metal-catalyzed amide bond formation from alcohols and amines is an atom-economic and eco-friendly route. Herein, we identified a highly active in situ N-heterocyclic carbene (NHC)/ruthenium (Ru) catalytic system for this amide synthesis. Various substrates, including sterically hindered ones, could be directly transformed into the corresponding amides with the catalyst loading as low as 0.25 mol%. In this system, we replaced the p-cymene ligand of the Ru source with a relatively labile cyclooctadiene (cod) ligand so as to more efficiently obtain the corresponding poly-carbene Ru species. Expectedly, the weaker cod ligand could be more easily substituted with multiple mono-NHC ligands. Further HR-MS analyses revealed that two tetra-carbene complexes were probably generated from the in situ catalytic system.

ChemInform Abstract: A Highly Active Catalytic System for Suzuki-Miyaura Cross-Coupling Reactions of Aryl and Heteroaryl Chlorides in Water.

ChemInform ◽  
2013 ◽  
Vol 44 (19) ◽  
pp. no-no
Author(s):  
Shu-Lan Mao ◽  
Yue Sun ◽  
Guang-Ao Yu ◽  
Cui Zhao ◽  
Zhi-Jun Han ◽  
...  
Keyword(s):  
Catalytic System ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Highly Active

Accessing stable zirconium carboxy-aminophosphonate nanosheets as support for highly active Pd nanoparticles

2015 ◽  
Vol 51 (88) ◽  
pp. 15990-15993 ◽  
Author(s):  
Ferdinando Costantino ◽  
Riccardo Vivani ◽  
Maria Bastianini ◽  
Luca Ortolani ◽  
Oriana Piermatti ◽  
...  
Keyword(s):  
Catalytic System ◽  
Zirconium Phosphate ◽  
Suzuki Coupling ◽  
Pd Nanoparticles ◽  
Highly Active

PdNPs stabilized on exfoliated layered zirconium phosphate–carboxyphosphonate nanosheets as an efficient catalytic system for the Suzuki coupling.

Sign in / Sign up

Export Citation Format

Share Document