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Theoretical Studies of Hydrogen Bond Interactions in Fluoroacetic Acid Dimer
Chermahini, Alireza Najafi,Mahdavian, Mohsen,Teimouri, Abbas Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.4
Ab initio and density functional theory methods have been employed to study all theoretically possible conformers of fluoroacetic acid. Molecular geometries and energetic of cis and trans monomers and cis dimers in gaseous phase have been obtained using HF, B3LYP and MP2 levels of theory, implementing 6-311++G(d,p) basis set. It was found that cis rotamers are more stable. In addition, it was found that in comparison with acetic acid the strength of hydrogen bonding in fluoroacetic acid decreased. The infrared spectrum frequencies and the vibrational frequency shifts are reported. Natural population and atom in molecule analysis performed to predict electrostatic interactions in the cyclic H-bonded complexes and charges. The proton transfer reaction is studied and activation energy is compared with acetic acid proton transfer reaction.
Theoretical Studies of Hydrogen Bond Interactions in Fluoroacetic Acid Dimer
Alireza Najafi Chermahini,Mohsen Mahdavian,Abbas Teimouri 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.4
Ab initio and density functional theory methods have been employed to study all theoretically possible conformers of fluoroacetic acid. Molecular geometries and energetic of cis and trans monomers and cis dimers in gaseous phase have been obtained using HF, B3LYP and MP2 levels of theory, implementing 6-311++G(d,p) basis set. It was found that cis rotamers are more stable. In addition, it was found that in comparison with acetic acid the strength of hydrogen bonding in fluoroacetic acid decreased. The infrared spectrum frequencies and the vibrational frequency shifts are reported. Natural population and atom in molecule analysis performed to predict electrostatic interactions in the cyclic H-bonded complexes and charges. The proton transfer reaction is studied and activation energy is compared with acetic acid proton transfer reaction.
Application of modified clays in diazotization and azo coupling reactions in water
Alireza Najafi Chermahini,Maryam Doukheh,Hassan Zadeh Hassan,Mehdi Bostanian 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.2
Diazotization and diazo coupling reaction of a series of aromatic amines and activated aromatic compounds over eco-friendly modified clay catalysts are described. The reaction was catalyzed by modified montmorillonite K-10 including Cu2+, Fe3+, and Zn2+ metal ions. The versatility of this method was checked by using various amines and phenols, which showed reasonable yields of products. These inexpensive, noncorrosive and reusable catalysts were found to exhibit bifunctional catalytic properties for diazotization and diazo coupling reactions. The catalysts could be reused several times without significant loss of their catalytic reactivity.
Teimouri, Abbas,Chermahini, Alireza Najafi,Narimani, M. Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.5
A simple highly versatile and efficient method has been developed for the three-component coupling of aldehydes, amines and alkynes to prepare propargylamines, in the presence of a catalytic amount of $BiCl_3$. The advantages of methods are high yield, mild reaction conditions, no environmental pollution and easy work up procedure.
Dabbagh, Hossein A.,Najafi Chermahini, Ali Reza,Modarresi-Alam, Ali Reza Korean Chemical Society 2005 Bulletin of the Korean Chemical Society Vol.26 No.8
The conformational, configurtational behavior and the structure of N-2-(1,4-Dioxane)-N'-(4-methylbenzenesulfonyl)-O-(4-methylphenoxy) isourea 1 has been studied using DFT method. Calculations predict the imidoyl amino group of the dioxane ring prefers axial conformation and that the tosyl and tolyl groups about the C=N bond retain E configuration. The anomeric effect controls the population of dioxane ring conformers, and anomers. Intramolecular hydrogen bonds contribute to the stability of E isomers. The computational analysis of 1 complements the X-ray findings.
Zahra Mohammadbagheri,Alirza Najafi Chermahini 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.62 No.-
In this study, production of n-butyl levulinate from furfuryl alcohol was investigated using KCC-1/Pr-SO3H as an efficient heterogeneous catalyst. The catalyst was prepared and characterized using FT-IR, N2 adsorption/desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), pyridine-adsorbed FT-IR spectroscopy and TGA techniques. The effects of different parameters on the reaction conditions including temperature, reaction time, catalyst amount, and furfuryl alcohol volume were evaluated. The highest yield of n-butyl levulinate was 81.9% at 120 °C after 3 h. The catalyst was recovered and reused at least four times with insignificant change in yield of n-butyl levulinate.
Theoretical Studies of Hydrogen Bond Interactions in 4-Substituted Benzoic Acids Dimers
Beni, Alireza Salimi,Chermahini, Alireza Najafi,Sharghi, Hashem Korean Chemical Society 2011 대한화학회지 Vol.55 No.3
벤조산 유도체($NH_2$, OH, H, F, Cl, CN, NO, $NO_2$) 의 두 형태를 6-311++G(d,p) 바탕 집합을 이용하여 MP2, DFT 및 HF 수준으로 연구하였으며, cis이성 질체가 더 안정하였다. 벤조산의 수소 결합 형성은 안정화 에너지를 이용하여 추산하였으며, 이합체에 대한 수소결합 에너지 계산치는 고리에서 협동 상호작용이 일어남을 보여주었다. 페닐 고리로 전자를 밀어내는 그룹(ERG)은 더 안정한 수소 결합이 형성하였다. 이합체에서 O-H 결합의 적색이동은 -565.3에서 $-589.3\;cm^{-1}$ 범위였으며, 상호 작용의 특성은 NBO 분석을 이용하여 연구하였다. Two conformations of benzoic acid derivatives ($NH_2$, OH, H, F, Cl, CN, NO, $NO_2$) have been investigated at MP2, DFT and HF level using the 6-311++G(d,p) basis set. It was found that the cis isomers are more stable. Hydrogen bonding formation of benzoic acids has been estimated from stabilization energies. The calculated hydrogen-bonding energies of dimers showed a cooperative interaction in the cyclic ones. It was found that an electron-releasing group (ERG) into the phenyl rings resulted in the formation of more stable hydrogen bonding. Red shift of O-H bond was found from -565.3 to -589.3 for dimers. The natural bond orbital (NBO) analysis was applied to characterize nature of the interaction.
Alireza Nezamzadeh-Ejhieh,Fatemeh Khodabakhshi-Chermahini 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.2
ZnO was incorporated into nano particles of clinoptiloite by ion exchanging the zeolite in a zinc nitrateaqueous solution followed by calcinations process. All raw and modified samples were characterized byXRD, FT-IR, DRS, TG-DTG, SEM, BET and TEM. The prepared catalyst was used in the photocatalyticdegradation of phenylhydrazine (PHZ) and the best experimental parameters were obtained as:0.25 g L-1 of the catalyst, 20 ppm pollutant concentration and pH = 8. The degradation extent wasmonitored by UV–vis spectroscopy and the results were confirmed by HPLC and the chemical oxygendemand (COD).
Hossein A. Dabbagh,Ali Reza Najafi Chermahini,Ali Reza Modarresi-Alam 대한화학회 2005 Bulletin of the Korean Chemical Society Vol.26 No.8
The conformational, configurtational behavior and the structure of N-2-(1,4-Dioxane)-N'-(4-methylbenzenesulfonyl)-O-(4-methylphenoxy) isourea 1 has been studied using DFT method. Calculations predict the imidoyl amino group of the dioxane ring prefers axial conformation and that the tosyl and tolyl groups about the C=N bond retain E configuration. The anomeric effect controls the population of dioxane ring conformers, and anomers. Intramolecular hydrogen bonds contribute to the stability of E isomers. The computational analysis of 1 complements the X-ray findings.