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proton-affinity
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Excellent response of the DFT study to the calculations of accurate relative pKa value of different benzo-substituted quinuclidines
, Article Computational and Theoretical Chemistry ; Vol. 1027 , 1 January , 2014 , pp. 191-196 ; Abedin, A ; Fattahi, A ; Hashemi, M. M ; Sharif University of Technology
Abstract
The pKa value for protonated forms of different benzo-substituted quinuclidines in aqueous solution has been calculated using DFT methods (MP2//B3LYP, B3LYP and M06-2X) and 6-311++G(d,p) basis set and are compared with corresponding experimental values. The results were obtained from different theoretical methods so close to the corresponding experimental values but the best agreement were achieved with B3LYP/6-311+G(d,p) level of theory. The average error was found to be less than 1.6pKa unit. Relative pKa values were computed for each protonated benzo-substituted quinuclidine using quinuclidine as a reference. Solvation was included in the calculations in all used different methods using...
Theoretical studies of the influence of protic and aprotic ionic liquids on the basicity of CaO as a solid base catalyst
, Article Chemical Physics ; Volume 504 , 2018 , Pages 31-37 ; 03010104 (ISSN) ; Rahman Setayesh, S ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Proton affinity (PAs) and molecular basicities (GBs) of the CaO cluster and CaO modified with protic and aprotic ionic liquids in the gas phase have been calculated at the DFT/B3LYP level with a 6-311++G (d, p) basis set. The investigations of PAs and GBs in the solution phase have been studied by means of SCRF solvent effect computations using PCM solvation model for water solvent. The influence of the ILs cations and anions on the PA and GB in the gas phase and solution at the same level of theory has been investigated. We also studied the effect of [bmTr][NO3] ionic liquid on the basicity of CaO. The calculations display that this energetic ionic liquid has a high ability to improve the...
Theoretical study of the thermodynamic parameters of (CaO)n nanoclusters with n = 2–16 in the gas and solution phases: proton affinity, molecular basicity, and pKb values
, Article Structural Chemistry ; Volume 30, Issue 5 , 2019 , Pages 1805-1818 ; 10400400 (ISSN) ; Nazari, P ; Rahman Setayesh, S ; Sharif University of Technology
Springer New York LLC
2019
Abstract
Thermodynamic quantities such as proton affinity (PA) and molecular basicity (GB) for (CaO)n nanoclusters with n = 2–16 have been calculated using three computational models of the density functional theory (DFT) (Becke, 3-parameter, Lee-Yang-Parr (B3LYP), Minnesota 2006, Perdew-Wang 1991 (PW91), Coulomb attenuated method-B3LYP, and ωB97XD functionals); Møller-Plesset perturbation theory; and Hartree-Fock with the cc-PVNZ (n = D and T) basis set in the gas phase. Absolute deviation error (AAD%) indicates that obtained PA and GB values using DFT model and the B3LYP method with mean percentage errors of 0.77 and 0.90%, respectively, have the higher accuracy than the other methods and models....
Heteroatom Influence on the Basicity of Amines
, M.Sc. Thesis Sharif University of Technology ; Fattahi, Alireza (Supervisor)
Abstract
Present work focuses on the influence of Heteroatom(s) on the bacisity of specific group of amines through the intramolecular hydrogen bonding. This group includes Aza-Crown Ethers specifically. We used Spartan and Gaussian packages to gain optimized structures for all compounds in order to explore the influence of the intramolecular hydrogen bonding on the bacisity of amines. All the gas phase optimizations and energy calculations were performed at the DFT/B3LYP/6-311++G(d,p) level of theory. The Hf/6-31+G(d,p) level was used for all single point calculations in the solution phase. As commonly used solvents in organic and biological reactions, the solution phase calculations were carried...
Theoretical Investigation of Basicity and Proton Transfer Energy of Protic Energetic Ionic Liquids in the Gas Phase and in Solution
, M.Sc. Thesis Sharif University of Technology ; Rahman Setayesh, Shahrbanoo (Supervisor)
Abstract
The use of energetic ionic liquids as hypergolic fuels, has low toxicity and environmental risk relative the hypergolic fuels such as the hydrazine. In this research by using Gauss view and Gaussian softwares and density functional theory and MP2 methods at the level of B3LYP/6-311G(d,p), the proton transfer from the cations to anions for a set of hypergolic ionic liquids in the gas and solution phases were studied. The most stable configuration of cations and anions are determined. The interaction energies of the selected cations and anions, proton affinities and basicity properties of these hypergolic anions are calculated. The result represents that the lower proton affinity and basicity...
DFT/B3LYP study of thermochemistry of D-glucosamine, a representative polyfunctional bioorganic compound
, Article Scientia Iranica ; Volume 15, Issue 4 , 2008 , Pages 422-429 ; 10263098 (ISSN) ; Ghorat, M ; Pourjavadi, A ; Kurdtabar, M ; Torabi, A. A ; Sharif University of Technology
Sharif University of Technology
2008
Abstract
D-glucosamine, as a representative polyfunctional compound, is a bioactive amino sugar. In this study, the gas phase thermochemical properties of D-glucosamine, including its Metal Ion Affinity (MIA), metal binding sites, Anion Affinity (AA), acidity and proton affinity, have been explored, using the Density Functional Theory (DFT) and a 6-311++G**basis set. The summary of the MIA and AA results (in kcal/mol-1) are: Li+ = 67.6, Na+ = 51.1, K+ = 37.3, Mg2+ = 207.9, Ca2+ = 150.4, Zn2+ = 251.2, Cl- = 27.4, CN- = 28.0. The acidity values calculated at different sites, including four -OH groups and one -NH2 group, range from 344.0 to 373.0 kcal/mol-1. These results, surprisingly, indicate how...
Influence of the hydrogen bonding on the basicity of selected macrocyclic amines
, Article Journal of Physical Organic Chemistry ; Volume 25, Issue 9 , 2012 , Pages 803-810 ; 08943230 (ISSN) ; Shakourian Fard, M ; Fattahi, A ; Sharif University of Technology
2012
Abstract
The optimized minimum-energy geometries of different macrocyclic amines and their protonated structures were determined by using ab initio and density functional theory (DFT) calculations. All the gas phase optimizations and energy calculations were performed at the DFT/B3LYP/6-311++G(d,p) level of theory. The HF/6-31 + G(d,p) level was used for all single point calculations in the solution phase. Geometry optimizations indicate that the most stable structures are stabilized by intramolecular hydrogen bonds. The proton affinity (PA) of macrocyclic amines is controlled by the strength of intramolecular hydrogen bonds of macrocyclic amines. These hydrogen bonds strongly influence the basicity...