Reactivity descriptors in acid catalysis: acid strength, proton affinity and host–guest interactions

2020 ◽  
Vol 56 (54) ◽  
pp. 7371-7398
Author(s):  
Prashant Deshlahra ◽  
Enrique Iglesia
Keyword(s):  
Proton Affinity ◽  
Acid Catalysis ◽  
Transition States ◽  
Acid Strength ◽  
Reactivity Descriptors

Acid strength and proton affinity, the independent properties of catalysts and molecules, are incomplete descriptors of because cations and conjugate anions reorganize their charges as they interact as bound intermediates and transition states.

Mechanistic Details and Reactivity Descriptors in Oxidation and Acid Catalysis of Methanol

ACS Catalysis ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. 666-682 ◽  
Author(s):  
Prashant Deshlahra ◽  
Robert T. Carr ◽  
Song-Hai Chai ◽  
Enrique Iglesia
Keyword(s):  
Acid Catalysis ◽  
Reactivity Descriptors

Acid Strength of H3PW x Mo12−x O40 and H6P2W x Mo18−x O62 Heteropolyacid Catalysts as a Probe of Acid Catalysis for 2-Propanol Conversion Reaction

2008 ◽  
Vol 126 (3-4) ◽  
pp. 308-312 ◽  
Author(s):  
Dong Ryul Park ◽  
Sang Hee Lee ◽  
Joohyung Lee ◽  
Sun Ho Song ◽  
Heesoo Kim ◽  
...  
Keyword(s):  
Acid Catalysis ◽  
Acid Strength ◽  
Conversion Reaction

Lewis Acid Catalysis Alters the Shapes and Products of Bis-Pericyclic Diels−Alder Transition States

2007 ◽  
Vol 129 (15) ◽  
pp. 4528-4529 ◽  
Author(s):  
Nihan Çelebi-Ölçüm ◽  
Daniel H. Ess ◽  
Viktorya Aviyente ◽  
K. N. Houk
Keyword(s):  
Lewis Acid ◽  
Acid Catalysis ◽  
Transition States ◽  
Diels Alder ◽  
Lewis Acid Catalysis

Characterization and Acid Catalytic Properties of NiO Supported on ZrO2 and Modified with MoO3

2007 ◽  
Vol 124-126 ◽  
pp. 1797-1800 ◽  
Author(s):  
Jong Rack Sohn ◽  
Dong Cheol Shin
Keyword(s):  
Aqueous Solution ◽  
Catalytic Activity ◽  
Acid Catalysis ◽  
Catalytic Properties ◽  
Orthorhombic Phase ◽  
Acid Strength ◽  
Two Dimensional ◽  
Ammonium Heptamolybdate ◽  
Cumene Dealkylation

Nickel oxide supported on zirconia and modified with MoO3 for acid catalysis was prepared by drying powdered Ni(OH)2-Zr(OH)4 with ammonium heptamolybdate aqueous solution, followed by calcining in air at high temperature. The characterization of prepared catalysts was performed using FTIR, Raman, XRD, and DSC. MoO3 equal to or less than 15 wt% was dispersed on the surface of catalyst as two-dimensional polymolybdate or monomolybdate, while for MoO3 above 15 wt%, crystalline orthorhombic phase of MoO3 was formed. The high acid strength and acidity were responsible for the Mo=O bond nature of the complex formed by the interaction between MoO3 and ZrO2. The catalytic activity for cumene dealkylation was correlated with the acidity of the catalyst measured by the ammonia chemisorption method

Cobalt/Lewis Acid Catalysis for Hydrocarbofunctionalization of Alkynes via Cooperative C–H Activation

2020 ◽  
Author(s):  
Chang-Sheng Wang ◽  
Sabrina Monaco ◽  
Anh Ngoc Thai ◽  
Md. Shafiqur Rahman ◽  
Chen Wang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Lewis Acid ◽  
Hydrogen Transfer ◽  
Acid Catalysis ◽  
Rate Limiting Step ◽  
Site Selectivity ◽  
Set Up ◽  
Site Selective ◽  
First Time ◽  
Rate Limiting

A catalytic system comprised of a cobalt-diphosphine complex and a Lewis acid (LA) such as AlMe3 has been found to promote hydrocarbofunctionalization reactions of alkynes with Lewis basic and electron-deficient substrates such as formamides, pyridones, pyridines, and azole derivatives through site-selective C-H activation. Compared with known Ni/LA catalytic system for analogous transformations, the present catalytic system not only feature convenient set up using inexpensive and bench-stable precatalyst and ligand such as Co(acac)3 and 1,3-bis(diphenylphosphino)propane (dppp), but also display distinct site-selectivity toward C-H activation of pyridone and pyridine derivatives. In particular, a completely C4-selective alkenylation of pyridine has been achieved for the first time. Mechanistic stidies including DFT calculations on the Co/Al-catalyzed addition of formamide to alkyne have suggested that the reaction involves cleavage of the carbamoyl C-H bond as the rate-limiting step, which proceeds through a ligand-to-ligand hydrogen transfer (LLHT) mechanism leading to an alkyl(carbamoyl)cobalt intermediate.

Atom Condensed Fukui Function for Condensed Phases and Biological Systems and Its Application to Enzymatic Fixation of Carbon Dioxide

2019 ◽  
Author(s):  
Javier Oller ◽  
David A. Sáez ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Carbon Dioxide ◽  
Aqueous Solution ◽  
Molecular System ◽  
Chemical Reactivity ◽  
Nucleophilic Attack ◽  
Stable Conformation ◽  
Fukui Functions ◽  
Reactivity Descriptors ◽  
Dynamics Simulations ◽  
Fixation Of Carbon Dioxide

<div><div><div><p>Local reactivity descriptors such as atom condensed Fukui functions are promising computational tools to study chemical reactivity at specific sites within a molecule. Their applications have been mainly focused on isolated molecules in their most stable conformation without considering the effects of the surroundings. Here, we propose to combine QM/MM Born-Oppenheimer molecular dynamics simulations to obtain the microstates (configurations) of a molecular system using different representations of the molecular environment and calculate Boltzmann weighted atom condensed local reac- tivity descriptors based on conceptual DFT. Our approach takes the conformational fluctuations of the molecular system and the polarization of its electron density by the environment into account allowing us to analyze the effect of changes in the molecular environment on reactivity. In this contribution, we apply the method mentioned above to the catalytic fixation of carbon dioxide by crotonyl-CoA carboxylase/reductase and study if the enzyme alters the reactivity of its substrate compared to an aqueous solution. Our main result is that the protein en- vironment activates the substrate by the elimination of solute-solvent hydrogen bonds from aqueous solution in the two elementary steps of the reaction mechanism: the nucleophilic attack of a hydride anion from NADPH on the α, β unsaturated thioester and the electrophilic attack of carbon dioxide on the formed enolate species.</p></div></div></div>

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