Comparative quantum chemical studies in the framework of Gaussian approximations of the acidic characteristics of the simplest zeolite clusters and of the sulfuric acid molecule

1996 ◽  
Vol 45 (7) ◽  
pp. 1551-1557
Author(s):  
I. N. Senchenya ◽  
D. A. Zhurko ◽  
M. V. Frash
Keyword(s):  
Sulfuric Acid ◽  
Quantum Chemical ◽  
Acid Molecule ◽  
Chemical Studies ◽  
Quantum Chemical Studies

scholarly journals Conformational-dependent reaction mechanism: case of acid hydrolysis of N-benzoyl-9-azabicyclo[6.1.0]non-4-ene

2017 ◽  
Vol 95 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Djallila Missaoui ◽  
Ali Rahmouni ◽  
Okkacha Bensaid ◽  
Néji Besbes
Keyword(s):  
Sulfuric Acid ◽  
Reaction Mechanism ◽  
Acid Hydrolysis ◽  
Gas Phase ◽  
Quantum Chemical ◽  
Basis Sets ◽  
Stable Conformer ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Hydrolysis Of

Quantum chemical studies of the acid hydrolysis of cis-cis-N-benzoyl-9-azabicyclo[6.1.0]non-4-ene in gas phase and sulfuric acid solution have been carried out. Conformational analysis of reactant and intermediates were done at DFT level of calculations, using different basis sets. Transition states were identified and IRC calculations were done at the same level. In the first step of the reaction, the protonation occurs preferentially on the nitrogen atom. Three products are obtained. The type of mechanism, stepwise or concerted, depends on the stable conformers and the cleaved N–C bond. The main conclusion is that the products of the reaction depend on the nature of the stable conformer of the reactant.

Quantum chemical studies on peroxodisulfuric acid–sulfuric acid–water clusters

2011 ◽  
Vol 967 (2-3) ◽  
pp. 219-225
Author(s):  
Martta Toivola ◽  
Theo Kurtén ◽  
Ismael K. Ortega ◽  
Markku Sundberg ◽  
Ville Loukonen ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Quantum Chemical ◽  
Water Clusters ◽  
Acid Water ◽  
Chemical Studies ◽  
Quantum Chemical Studies

Quantum Chemical Studies of Hole Transfer in Liquid Hexane

2017 ◽  
Vol 137 (7) ◽  
pp. 435-441
Author(s):  
Masahiro Sato ◽  
Akiko Kumada ◽  
Kunihiko Hidaka ◽  
Toshiyuki Hirano ◽  
Fumitoshi Sato
Keyword(s):  
Quantum Chemical ◽  
Hole Transfer ◽  
Chemical Studies ◽  
Quantum Chemical Studies

ESR, spectroscopic, and quantum-chemical studies on the electronic structures of complexes formed by Cu(I) with radicals

1986 ◽  
Vol 22 (1) ◽  
pp. 27-33
Author(s):  
N. P. Gritsan ◽  
O. M. Usov ◽  
N. V. Shokhirev ◽  
I. V. Khmelinskii ◽  
V. F. Plyusnin ◽  
...  
Keyword(s):  
Electronic Structures ◽  
Quantum Chemical ◽  
Chemical Studies ◽  
Quantum Chemical Studies

scholarly journals Quantum-Chemical Search for Keto Tautomers of Azulenols in Vacuo and Aqueous Solution

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 497
Author(s):  
Ewa D. Raczyńska
Keyword(s):  
Aqueous Solution ◽  
Quantum Chemical ◽  
Biologically Active ◽  
Deprotonation Reaction ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Scanty Information ◽  
Derivatives Of ◽  
Common Anion ◽  
Tautomeric Mixture

Keto-enol prototropic conversions for carbonyl compounds and phenols have been extensively studied, and many interesting review articles and even books appeared in the last 50 years. Quite a different situation takes place for derivatives of biologically active azulene, for which only scanty information on this phenomenon can be found in the literature. In this work, quantum-chemical studies have been undertaken for symmetrically and unsymmetrically substituted azulenols (constitutional isomers of naphthols). Stabilities of two enol (OH) rotamers and all possible keto (CH) tautomers have been analyzed in the gas phase {DFT(B3LYP)/6-311+G(d,p)} and also in aqueous solution {PCM(water)//DFT(B3LYP)/6-311+G(d,p)}. Contrary to naphthols, for which the keto forms can be neglected, at least one keto isomer (C1H, C2H, and/or C3H) contributes significantly to the tautomeric mixture of each azulenol to a higher degree in vacuo (non-polar environment) than in water (polar amphoteric solvent). The highest amounts of the CH forms have been found for 2- and 5-hydroxyazulenes, and the smallest ones for 1- and 6-hydroxy derivatives. The keto tautomer(s), together with the enol rotamers, can also participate in deprotonation reaction leading to a common anion and influence its acid-base properties. The strongest acidity in vacuo exhibits 6-hydroxyazulene, and the weakest one displays 1-hydroxyazulene, but all azulenols are stronger acids than phenol and naphthols. Bond length alternation in all DFT-optimized structures has been measured using the harmonic oscillator model of electron delocalization (HOMED) index. Generally, the HOMED values decrease for the keto tautomers, particularly for the ring containing the labile proton. Even for the keto tautomers possessing energetic parameters close to those of the enol isomers, the HOMED indices are low. However, some kind of parallelism exists for the keto forms between their relative energies and HOMEDs estimated for the entire molecules.

Sign in / Sign up

Export Citation Format

Share Document