scholarly journals Computational Study of Geometry, IR Spectrum and Molecular Properties of Acetanilide

2016 ◽  
Vol 19 (2) ◽  
pp. 170-178 ◽  
Author(s):  
Mohammad Firoz Khan ◽  
Rahatullah Razan ◽  
Ridwan Bin Rashid ◽  
Faiza Tahia ◽  
Mohammad A Rashid

In this paper an effort has made to conduct and repot the computational study of geometry, IR spectrum and different molecular properties like Molecular Electrostatic Potential (MESP), Mulliken Charge Distribution, Global Reactivity Descriptors such as chemical hardness, softness, chemical potential, electronegativity, and electrophilicity index of acetanilide. All calculations were performed on Hartee-Fock (HF), Becke and 3-parameter, Lee-Yang-Parr (B3LYP) with 6-31G(d) and 6-31+G(d,p) basis sets. The calculated geometries (bond length, bond angle and dihedral angle) were in a good agreement with the experimental data for both level of theories and basis sets. In case of IR frequencies the scaled calculated frequencies agreed reasonably well with the experimental results.Bangladesh Pharmaceutical Journal 19(2): 170-178, 2016

Author(s):  
Mohammad Firoz Khan ◽  
Ridwan Bin Rashid ◽  
Shahidul M. Islam ◽  
Mohammad A. Rashid

Ab initio calculations were carried out to study the geometry, solvation free energy, dipole moment, molecular electrostatic potential (MESP), Mulliken and Natural charge distribution, polarizability, hyperpolarizability, Natural Bond Orbital (NBO) energetic and different molecular properties like global reactivity descriptors (chemical hardness, softness, chemical potential, electronegativity, electrophilicity index) of 2-methylimidazole. B3LYP/6-31G(d,p) level of theory was used to optimize the structure both in the gas phase and in solution. The solvation free energy, dipole moment and molecular properties were calculated by applying the Solvation Model on Density (SMD) in four solvent systems, namely water, dimethylsulfoxide (DMSO), n-octanol and chloroform. The computed bond distances, bond angles and dihedral angles of 2-methylimidazole agreed reasonably well with the experimental data except for C(2)-N(1), C(4)-C(5) and N(1)-H(7) bond lengths and N(1)-C(5)-C(4) bond angle. The solvation free energy, dipole moment, polarizability, first order hyperpolarizability, chemical potential, electronegativity and electrophilicity index of 2-methylimidazole increased on going from non-polar to polar solvents. Chemical hardness also increased with increasing polarity of the solvent and the opposite relation was found in the case of softness. These results provide better understanding of the stability and reactivity of 2-methylimidazole in different solvent systems.  


2017 ◽  
Vol 16 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Mohammad Firoz Khan ◽  
Ridwan Bin Rashid ◽  
Md Aslam Hossain ◽  
Mohammad A Rashid

Ab initio calculations were carried out to studysolvation free energy, dipole moment, molecular electrostatic potential (MESP), Mulliken charge distribution, polarizability, hyperpolarizability and different molecular properties like global reactivity descriptors (chemical hardness, softness, chemical potential, electronegativity, electrophilicity index) of betulin. B3LYP/6-31G(d,p) level of theory was used to optimize the structure both in gas phase and in solution. The solvation free energy, dipole moment and molecular properties were calculated by applying the Solvation Model on Density (SMD) in six solvent systems namely water, dimethyl sulfoxide (DMSO), acetonitrile, n-octanol, chloroform and carbontetrachloride. The solvation free energy of betulin increases with decreasing polarity of the solvent. No systematic trend of hyperpolarizability with solvent polarity is found. Molecular electrostatic potential (MESP) and Mulliken population analysis (MPA) reveal that the most possible sites for nucleophilic attack are C30, H76 and H77 and electrophilic attack are O1 and O2 among the atoms in betulin. However, the dipole moment, polarizability, chemical potential, electronegativity and electrophilicity index of betulin increase on going from non-polar to polar solvents. Chemical hardness was also increased with decreasing polarity of the solvent and opposite relation was found in the case of softness. These results provide better understanding of the stability and reactivity of betulin in different solvent systems.Dhaka Univ. J. Pharm. Sci. 16(1): 1-9, 2017 (June)


2016 ◽  
Vol 19 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Mohammad Firoz Khan ◽  
Ridwan Bin Rashid ◽  
Md Yeunus Mian ◽  
Mohammad S Rahman ◽  
Mohammad A Rashid

A computational study of medium effect on solvation free energy, dipole moment, polarizability, hyperpolarizability and different molecular properties like chemical hardness & softness, chemical potential, electronegativity and electrophilicity index of metronidazole have been reported in this paper. Becke, 3-parameter, Lee-Yang-Parr (B3LYP) level of theory with 6-31G (d,p) basis set was applied for gas phase and solution. The effect of solvent polarity on solvation free energy, dipole moment, polarizability, hyperpolarizability and molecular properties were calculated by employing Solvation Model on Density (SMD). The solvation free energies and dipole moment of metronidazole were found to be increased in nonpolar to polar solvents. The dipole moment of metronidazole was higher in different solvent than that of the gas phase. Moreover, from non-polar to polar solvents the chemical potential, electronegativity and electrophilicity index were increased. On the other hand, opposite relation was found in the case of chemical hardness and softness. The results obtained in this study may lead to understand the stability and reactivity of metronidazole and the results will be of assistance to use the title molecule as reaction intermediates and pharmaceuticals.Bangladesh Pharmaceutical Journal 19(1): 9-14, 2016


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Fatih Şen ◽  
Ramazan Şahin ◽  
Muharrem Dinçer ◽  
Ömer Andaç ◽  
Murat Taş

The paper presents a combined experimental and computational study of hexa(1-vinylimidazole)Ni(II) perchlorate complex. The complex was prepared in the laboratory and crystallized in the monoclinic space group P21/n with a=8.442(5), b=13.686(8), c=16.041(9) Å, α=γ=90, β=96.638(5), and Z=1. The complex has been characterized structurally (by single-crystal X-Ray diffraction) and its molecular structure in the ground state has been calculated using the density functional theory (DFT) methods with 6-31G(d) and LanL2DZ basis sets. Thermal behaviour and stability of the complex were studied by TGA/DTA analyses. Besides, the nonlinear optical effects (NLO), molecular electrostatic potential (MEP), frontier molecular orbitals (FMO), and the Mulliken charge distribution were investigated theoretically.


2013 ◽  
Vol 15 (39) ◽  
pp. 16566
Author(s):  
T. S. Chwee ◽  
G. S. Lim ◽  
W. Y. Fan ◽  
M. B. Sullivan

2020 ◽  
Vol 76 (3) ◽  
pp. 212-224
Author(s):  
Magdalena Małecka ◽  
Lilianna Chęcińska ◽  
Joachim Kusz ◽  
Marta Biernacka ◽  
Bogumiła Kupcewicz

The present study examines a series of flavanone and chalcone derivatives substituted with electron-withdrawing groups (Cl or Br) and electron-donating groups (OH, CH3 and OCH3), namely, 7-methoxy-2-phenyl-3,4-dihydro-2H-1-benzopyran-4-one, C16H14O3, 2-(4-methoxyphenyl)-3,4-dihydro-2H-1-benzopyran-4-one, C16H14O3, 2-(4-methoxyphenyl)-6-methyl-3,4-dihydro-2H-1-benzopyran-4-one, C17H16O3, 2-(4-chlorophenyl)-3,4-dihydro-2H-1-benzopyran-4-one, C15H11ClO2, 8-bromo-6-methyl-2-phenyl-3,4-dihydro-2H-1-benzopyran-4-one, C16H13BrO2, (2E)-1-(2-hydroxyphenyl)-3-(4-methoxyphenyl)prop-2-en-1-one, C16H14O3, and (2E)-1-(2-hydroxyphenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one, C15H12O3. It compares the two groups of derivatives with regard to their intermolecular interactions in the crystal lattice and lattice energy calculations, together with energy framework visualization and global reactivity descriptors (chemical hardness, chemical potential and electrophilicity index). It also discusses the relationships between different noncovalent interactions derived from Hirshfeld surface analysis, crystal lattice energy and global reactivity descriptors of the compounds.


Quantum chemical calculations of molecular geometry, HOMO-LUMO, Mulliken charge distributions and vibrational assignments of 4-methoxyaniline hydroquinone (4MAHQ) were carried out by DFT (B3LYP) and HF methods. Spectral analysis on 4MAHQ has been studied both by the computational and experimental methods to assign vibrational modes of all the functional groups. The investigation is extensive to calculate the FMOs, population analysis, Molecular Electrostatic Potential and Non Linear Optical efficiency of 4MAHQ. The electron affinity, ionization and chemical potential, electrophilicity index, chemical hardness, electro negativity and global softness of 4-methoxyaniline hydroquinone were calculated by FMO analysis


2021 ◽  
Author(s):  
Mohammad J Abunuwar ◽  
Adnan A Dahadha

Abstract In this study eight selected of the most potent cyclin dependent kinase 2 inhibitors in which targeting adenosine triphosphate -pocket site theoretically investigated to support literature information of frontier molecular orbitals, molecular electrostatic maps, and global chemical reactivity descriptors such as chemical hardness, chemical softness, chemical potential, electronegativity and electrophilicity of cyclin dependent kinase 2 inhibitors. Calculation and three-dimensional plotting were achieved through Gaussian 09W and Gausview 6 software’s utilizing density functional theory quantum modeling applying both hybrids extended and not extended basis set. Crystal structure of CDK2 with inhibitors was obtained from protein data bank and visualized through PyMol Schrödinger software to assign polar and non-polar interactions of inhibitors with enzyme. A promising conclusion trend obtained in this research regarding to molecules that could have an inhibition activity toward the cyclin dependent kinase 2 enzymes. Our theoretical investigation emphasizes that, the anti-cancer activity has directly relationship with value of chemical hardness and chemical softness, where the most potent compounds was the pyrazolopyrimidine and imidazole pyrimidine and they have higher chemical hardness value and at the same time lower value of chemical softness compared with the rest of compounds.


2016 ◽  
Vol 15 (02) ◽  
pp. 1650017
Author(s):  
Priyanka ◽  
Sanjay Kumar Srivastava ◽  
Diksha Katiyar

The FTIR, UV–Vis and NMR spectra of 4-(2-hydroxy-3-morpholin-4-yl-propoxy)-chromen-2-one (4-HMPC) have been recorded and analyzed. The optimized geometry and harmonic vibrational frequencies of 4-HMPC were obtained by the Hartree–Fock (HF) and density functional theory (DFT) using B3LYP functional with 6-311[Formula: see text]G basis set. The 1H and [Formula: see text]C NMR chemical shifts were calculated by the GIAO method in chloroform. The absorption spectra of 4-HMPC were computed in ethanol and water solutions using TD-B3LYP/6-311[Formula: see text]G(d,p) approach. The correlation of theoretical and experimental results provides a detailed description of the structural and physicochemical properties of the molecule. The results obtained from the studies of HOMO and LUMO were used to calculate the conceptual-DFT-based global reactivity descriptors such as electronic chemical potential, electronegativity, chemical hardness, global softness and electrophilicity index of the compound.


Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4221 ◽  
Author(s):  
Rimadani Pratiwi ◽  
Slamet Ibrahim ◽  
Daryono H. Tjahjono

The interaction of three cationic porphyrins—meso-tetrakis (N-methylpyridinium-4-yl) porphyrin (TMPyP), meso-tetrakis (1,3-dimethylimidazolium-2-yl) porphyrin (TDMImP), and meso-tetrakis (1,2-dimethylpyrazolium-4-yl) porphyrin (TDMPzP)—with five heavy metals was studied computationally, and binding constants were calculated based on data obtained by an experimental method and compared. The reactivity and stability of their complexes formed with lead, cadmium, mercury, tin, and arsenic ions were observed in DFT global chemical reactivity descriptors: the electronic chemical potential (µ), chemical hardness (η), and electrophilicity (ω). The results show that M-TDMPzP has higher chemical hardness and lower electrophilicity compared to M-TMPyP and M-TDMImP, indicating the reaction of TDMPzP with metals will form a more stable complex. Specifically, Cd-TDMPzP complexes can stabilize the system, with a lower energy and electronic chemical potential, higher chemical hardness, smaller electrophilicity, and higher binding constant value compared to Pb-TDMPzP and Hg-TDMPzP. This result suggests that the interaction of the Cd2+ ion with TDMPzP will produce a stable complex.


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