Experimental and theoretical investigation of molecular structure, vibrational analysis, chemical reactivity, electrostatic potential of benzyl methacrylate monomer and homopolymer

2016 ◽  
Vol 94 (9) ◽  
pp. 853-864 ◽  
Author(s):  
Feride Akman
Keyword(s):  
Electrostatic Potential ◽  
Density Functional ◽  
Chemical Shifts ◽  
Chemical Reactivity ◽  
Atomic Orbital ◽  
Vibrational Analysis ◽  
Calculated Data ◽  
Basis Set ◽  
Geometrical Parameters ◽  
Molecular Approaches

Until now, a number of new polymers have been discovered with the aid of experimental and computational molecular approaches and indicated to have potential applications. All the computational molecular approaches provide information helpful to further study. So, monomer and homopolymer of benzyl methacrylate (BzMA), which is a popular methacrylate ester monomer, were synthesized and investigated based on density functional theory (DFT) and Hartree–Fock (HF) methods. The monomer and homopolymer were characterized by FTIR, 1H, and 13C NMR techniques. The molecular geometry, geometrical parameters, Mulliken atomic charges, and vibrational frequencies of BzMA monomer and homopolymer (in dimer form) were calculated by using the DFT and HF methods with 6-31G (d, p) as basis set. The molecular electrostatic potential maps and molecular orbitals properties of monomer and homopolymer were calculated using the 6-31G (d, p) basis set of theories. Besides, 1H and 13C chemical shifts were calculated by the gauge–including atomic orbital approach. The results demonstrated that the theoretical values were in good agreement with the experimental values. The calculated data are important to providing insight into molecular analysis and may be used in technological applications.

scholarly journals Molecular Structure, NMR, HOMO, LUMO, and Vibrational Analysis of O-Anisic Acid and Anisic Acid Based on DFT Calculations

2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
R. Mathammal ◽  
N. Jayamani ◽  
N. Geetha
Keyword(s):  
Density Functional ◽  
Chemical Shifts ◽  
Atomic Orbital ◽  
Vibrational Analysis ◽  
Vibrational Frequencies ◽  
Computational Method ◽  
Basis Set ◽  
H Nmr ◽  
Anisic Acid ◽  
Vibrational Bands

This work deals with the vibrational spectroscopy of O-Anisic acid (OAA) and Anisic acid (AA). The fundamental vibrational frequencies and intensity of vibrational bands were evaluated using density functional theory (DFT) with standard B3LYP/6-31G** method and basis set combinations. The vibrational spectra were interpreted, with the aid of normal coordinate analysis based on a scaled quantum mechanical force field. The infrared and Raman spectra were also predicted from the calculated intensities. The effects of carbonyl and methyl substitutions on the structure and vibrational frequencies have been investigated. Comparison of simulated spectra with the experimental spectra provides important information about the ability of the computational method to describe the vibrational modes. The13C and1H NMR chemical shifts of the DFA and CA molecules were calculated using the gauge-invariant-atomic orbital (GIAO) method in DMSO solution using IEF-PCM model and compared with experimental data.

scholarly journals Structural and spectroscopic characterization and DFT studies of 2-amino-1,10-phenanthrolin-1-ium chloride

2019 ◽  
Vol 10 (2) ◽  
pp. 95-101
Author(s):  
Sebile Işık Büyükekşi ◽  
Namık Özdemir ◽  
Abdurrahman Şengül
Keyword(s):  
Density Functional Theory ◽  
Electronic Absorption ◽  
13C Nmr ◽  
Density Functional ◽  
Electronic Absorption Spectra ◽  
Chemical Shifts ◽  
Atomic Orbital ◽  
Basis Set ◽  
Functional Theory ◽  
1H And 13C Nmr

A versatile synthetic building block, 2-amino-1,10-phenanthrolin-1-ium chloride (L∙HCl) was synthesized and characterized by IR, 1H and 13C NMR DEPT analysis, UV/Vis and single-crystal X-ray diffraction technique. The molecular geometry, vibrational wavenumbers and gauge including atomic orbital (GIAO), 1H and 13C NMR chemical shifts values of the title compound in the ground state were obtained by using density functional theory (DFT/B3LYP) method with 6-311++G(d,p) basis set and compared with the experimental data. Electronic absorption spectrum of the salt was determined using the time-dependent density functional theory (TD-DFT) method at the same level. In the NMR and electronic absorption spectra calculations, the effect of solvent on the theoretical parameters was included using the default model with DMSO as solvent. The obtained theoretical parameters agree well with the experimental findings.

scholarly journals Structural and Theoretical Studies of 2-amino-3-nitropyridine

2012 ◽  
Vol 9 (4) ◽  
pp. 2191-2204 ◽  
Author(s):  
N. S. Al-Hokbany ◽  
A. A. Dahya ◽  
I. Kh. Warad ◽  
N. M. Abd El-Salam ◽  
S. T. Akriche ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Single Crystal ◽  
Chemical Shifts ◽  
Vibrational Analysis ◽  
Basis Set ◽  
Geometrical Parameters ◽  
X Ray ◽  
Bond Lengths ◽  
Nuclear Magnetic

Geometrical optimization, spectroscopic analysis, electronic structure and nuclear magnetic resonance of 2-amino-3-nitropyridine (ANP) were investigated by utilizingab-initio(MP2) and DFT(B3LYP) using 6-311++G(d,p) basis set. Geometrical parameters (bond lengths, bond angles and torsion angles) were computed and compared with the experimental values obtained using X-ray single crystal measurements of the title compound. IR spectra were obtained and assigned by vibrational analysis. Comparing the theoretically calculated values (bond lengths, bond and dihedral angles) using both B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) methods of calculations with the experimentally determined data by X-ray single crystal measurements, all the data obtained in this investigation were considered to be reliable. The theoretical infrared spectra have been successfully simulated by means of DFT and MP2 levels of calculations. The1H and13C nuclear magnetic resonance (NMR) chemical shifts of 2-amino-3-nitropyridine were calculated using the GIAO method in DMSO solution using IEF-PCM model and compared with the experimental data. Intramolecular hydrogen bonding interaction in this compound was investigated by means of the NBO analysis. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule.

scholarly journals Microwave synthesis of some N-phenylhydrazine-1-carbothioamide Schiff bases

2018 ◽  
Vol 9 (2) ◽  
pp. 74-78 ◽  
Author(s):  
Bushra Kamil Al-Salami
Keyword(s):  
1H Nmr ◽  
Density Functional ◽  
Atomic Orbital ◽  
Calculated Data ◽  
Density Functional Theory Method ◽  
13C Nmr Spectroscopy ◽  
Basis Set ◽  
Functional Theory ◽  
B3lyp Method ◽  
Ft Ir

We have synthesized and characterized a series of carbothioamide derivatived molecules, obtained by reaction of aromatic aldehyde (Anisaldehyde, 9-anthraldehyde, cinnamaldehyde, indole-3-carboxaldehyde, 1-naphthaldehyde and o-vanillin) with an equimolar amount of 4-phenylthiosemicarbazide with microwave irradiation. The synthesized compounds have been characterized by FT-IR, 1H NMR and 13C NMR spectroscopy. Quantum calculations of the physical properties, based on density functional theory method at B3LYP/6-31+G(d,p) level of theory, were performed, by means of the Gaussian 09W set of programs. The theoretical 1H NMR chemical shift results of the studied compounds have been calculated at B3LYP method and standard 6-31+G(d,p) basis set using the standard Gauge-Independent Atomic Orbital approach. The calculated values are also compared with the experimental data available for these molecules. A good linear relationship between the experimental and calculated data has been obtained.

Systematic Gauge-Including Atomic Orbital-Hybrid Density Functional Theory Linear Regressions for 13C NMR Chemical Shifts Calculation

2020 ◽  
Vol 12 (3) ◽  
pp. 364-370
Author(s):  
Sara Sâmitha Souza ◽  
Mariana Aparecida de Souza Martins ◽  
Antonio Maia de Jesus Chaves Neto ◽  
Gunar Vingre Da Silva Mota ◽  
Fabio Luiz Paranhos Costa
Keyword(s):  
Density Functional Theory ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Density Functional ◽  
Chemical Shifts ◽  
Atomic Orbital ◽  
Basis Set ◽  
Functional Theory ◽  
Linear Regressions ◽  
Nuclear Magnetic

Density-functional theory calculations of the magnetic shielding for nuclear magnetic resonance provide an important contribution to understand the experimental values obtained in laboratory for chemical shifts present in the samples. From of a comparative of the performance of ten hybrid functional within of the framework of the density-functional theory using 10 different hybrid functionals with 3-21G (B1), 6-31G(d) (B2) and 6-31+ G(d, p) (B3) basis set, with intuit of evaluating of performance of the 13 C nuclear magnetic resonance from a representative of the terpene class and a heterocyclic compound, (–)-loliolide ((7aR)-6-hydroxy-4,4,7a-trimethyl-6,7-dihydro-5H1-benzofuran-2-one). This molecule, satisfactorily, represents the main structure of this class, with conformational freedom, optical activity and a benzofuran nucleus. The ωB97X-D, MPW1K and HSEH1PBE functionals presented the best calculation performance. It is interesting to note that after the use of linear regressions all root mean square error values for ωB97X-D were lower than 3 ppm. These are 2.91 ppm (B1), 2.46 (B2) ppm and 2.62 ppm (B3). The information contained in this work can be used for the assignment of experimental nuclear magnetic resonance spectra and will motivate further studies involving the theoretical calculation of the chemical shift of 13C.

scholarly journals Molecular Structure and Vibrational Analysis of 1-Bromo-2-Chlorobenzene Using ab initio HF and Density Functional Theory (B3LYP) Calculations

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
G. Shakila ◽  
S. Periandy ◽  
S. Ramalingam
Keyword(s):  
Density Functional ◽  
Vibrational Analysis ◽  
Vibrational Frequencies ◽  
Basis Set ◽  
Geometrical Parameters ◽  
B3lyp Method ◽  
B3lyp Calculations ◽  
Ft Ir ◽  
Experimental Values ◽  
Ft Raman

The FT-Raman and FT-IR spectra for 1-bromo-2-chlorobenzene (1B2CB) have been recorded in the region 4000–100 cm−1 and compared with the harmonic vibrational frequencies calculated using HF/DFT (B3LYP) method by employing 6-31+G (d, p) and 6-311++G (d, p) basis set with appropriate scale factors. IR intensities and Raman activities are also calculated by HF and DFT (B3LYP) methods. Optimized geometries of the molecule have been interpreted and compared with the reported experimental values of some substituted benzene. The experimental geometrical parameters show satisfactory agreement with the theoretical prediction from HF and DFT. The scaled vibrational frequencies at B3LYP/6-311++G (d, p) seem to coincide with the experimentally observed values with acceptable deviations. The theoretical spectrograms (IR and Raman) have been constructed and compared with the experimental FT-IR and FT-Raman spectra. Some of the vibrational frequencies of the benzene are affected upon profusely with the halogen substitutions in comparison to benzene, and these differences are interpreted.

Calculation of global and local reactivity descriptors of carbodiimides, a DFT study

2017 ◽  
Vol 16 (03) ◽  
pp. 1750019 ◽  
Author(s):  
Kathy Ramirez-Balderrama ◽  
Erasmo Orrantia-Borunda ◽  
Norma Flores-Holguin
Keyword(s):  
Electron Affinity ◽  
Density Functional ◽  
Chemical Reactivity ◽  
Basis Set ◽  
Chemical Hardness ◽  
Geometrical Parameters ◽  
Reactivity Descriptors ◽  
Local Reactivity ◽  
Global And Local ◽  
Local Reactivity Descriptors

Carbodiimides have been widely used for different purposes, such as an intermediary to form peptides bonds and esters, which have generated industrial, organic and biological applications. Diisoproylcarbodiimide (DIC), (3-(dimethylamino) propyl)ethylcarbodiimide (EDC) and N,N′-dicyclohexylcarbodiimide (DCC) are the most common carbodiimides, however, there exist other carbodiimides that are not normally used. Twelve carbodiimides including the above mentioned were chosen to study their chemical reactivity as well as their nucleophilic and electrophilic attack sites. Geometry optimization in gas and solution phases was obtained using Density Functional Theory (DFT) through B3LYP with 6-31G(d) and 6-311[Formula: see text]G(d,p) level. Global and local reactivity descriptors were calculated and analyzed such as chemical hardness, ionization potential, electron affinity, Fukui functions, dual descriptor and hypersoftness. The results obtained for geometrical parameters do not have significant differences for gas and solution phase. The introduction of diffuse functions has great impact in electron affinity, modifying notably the values of reactivity descriptors, but didn’t show qualitative differences, since the results found for both basis set calculations show that Cyanamide or CD1 is the most stable and CD11 present greater reactivity of all studied molecules. Also, the hypersoftness results obtained with 6-31G(d) are in agreement with the general affirmation that carbodiimides are easily attacked by nucleophiles and electrophiles in the central carbon–nitrogen double bond.

scholarly journals EXPERIMENTAL CUM THEORETICAL EVALUATION OF MOLECULAR STRUCTURE, VIBRATIONAL SPECTRA, NBO, UV, NMR, OF A BIOACTIVE COMPOUND – PHENOXYACETOHYDRAZIDE

2015 ◽  
Vol 3 (7) ◽  
pp. 103-115
Author(s):  
M. Sangeetha ◽  
R. Mathammal
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Chemical Shifts ◽  
Atomic Orbital ◽  
Bioactive Compound ◽  
Nbo Analysis ◽  
Basis Set ◽  
Theoretical Evaluation ◽  
Vibrational Assignments ◽  
Key Species

Hydrazide-Hydrazone compounds are key species for a range of bioactivities. The first complete density functional theoretical study of Phenoxyacetohydrazide(PAH) is reported. The normal mode frequencies, intensities and the corresponding vibrational assignments were calculated using the GAUSSIAN 09W set of quantum chemistry codes at the DFT/B3LYP levels of theory using the 6-311++G** basis set. Stability of the molecule arising from hyperconjugative interactions has been probed using NBO analysis. 1H and 13C NMR spectra have been analysed and the chemical shifts were calculated using the gauge independent atomic orbital(GIAO) method. The theoretical UV-Vis spectrum and the electronic properties, such as HOMO(Highest occupied molecular orbital) and LUMO (Lowest unoccupied molecular orbital) were performed by time dependent density functional theory(TD-DFT) approach.

Structural, spectroscopic (FT-IR, FT-Raman, NMR) and computational analysis (DOS, NBO, Fukui) of 3,5-dimethylisoxazole and 4-(chloromethyl)-3,5-dimethylisoxazole: A DFT study

2016 ◽  
Vol 15 (05) ◽  
pp. 1650039 ◽  
Author(s):  
T. Kavitha ◽  
G. Velraj
Keyword(s):  
Density Functional ◽  
Computational Analysis ◽  
Chemical Shifts ◽  
Vibrational Analysis ◽  
Density Functional Theory Calculations ◽  
Basis Set ◽  
Reactivity Descriptors ◽  
The Density Functional Theory ◽  
Ft Ir ◽  
The Difference

The theoretical and computational analysis of two isoxazole derivatives 3,5-dimethylisoxazole and 4-chloromethyl-3,5-dimethylisoxazole were carried out along with some of the experimental evidences. The density functional theory calculations of these compounds were done with DFT/B3LYP/6-31+G(d,p) basis set using Gaussian 09 software. From the DFT calculations, the optimization geometry, vibrational analysis, electronic properties, local reactivity descriptors, natural bond orbitals, and other structural properties of the title compounds were elucidated. The chemical shifts of every C and H atom of the title compounds were calculated using Gauge Independent Atomic orbitals (GIAO) method for both proton and carbon NMR spectra. The molecular electrostatic potential of DMI has been found out and the difference in MEP on addition of chloromethyl group is also discussed. The hyperpolarizability calculations of the investigated molecules shows that the nonlinear optical activity of CDMI is greater when compared to DMI.

scholarly journals Chemical Reactivity, Dipole Moment and First Hyperpolarizability of Aristolochic Acid I

2016 ◽  
Vol 21 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Bhawani Datta Joshi
Keyword(s):  
Dipole Moment ◽  
Electrostatic Potential ◽  
Density Functional ◽  
Molecular Electrostatic Potential ◽  
Aristolochic Acid ◽  
Chemical Reactivity ◽  
Basis Set ◽  
Non Linear ◽  
Linear Optical ◽  
Aristolochic Acid I

Aristolochic acids (AAs) have been used in the treatment of oedema in  Chinese herb medicine  since  long  ago. In this paper, molecular electrostatic potential, chemical reactivity  and non linear optical properties  of  aristolochic  acid  I  (AA  I)  have  been  analyzed  using  density  functional  theory  employing  6-311++G(d,p)  basis set.  The chemical reactivity of the molecule has been explained with the help of chemical reactivity descriptors, molar refractivity and the molecular electrostatic potential surface (ESP).  The calculated dipole moment and first order hyperpolarizability show that the molecule possesses non-linear optical property.Journal of Institute of Science and TechnologyVolume 21, Issue 1, August 2016, page: 1-9

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