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Sukanya R, Aruldhas D, Hubert Joe I, Balachandran S. Spectroscopic and quantum chemical computation on molecular structure, AIM, ELF, RDG, NCI, and NLO activity of 4-VINYL benzoic acid: A DFT approach. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.132273] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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2
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Hosny NM, Belal A, Motawea R, Hussien MA, Abdel-Rhman MH. Spectral characterization, DFT, docking and cytotoxicity of N-benzyl-4,5-dihydro-3-methyl-5-oxo-1H-pyrazole-4-carbothioamide and its metal complexes. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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3
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Singh I, Al-Wahaibi LH, Srivastava R, Prasad O, Pathak SK, Kumar S, Parveen S, Banerjee M, El-Emam AA, Sinha L. DFT Study on the Electronic Properties, Spectroscopic Profile, and Biological Activity of 2-Amino-5-trifluoromethyl-1,3,4-thiadiazole with Anticancer Properties. ACS OMEGA 2020; 5:30073-30087. [PMID: 33251442 PMCID: PMC7689922 DOI: 10.1021/acsomega.0c04474] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 11/03/2020] [Indexed: 11/29/2022]
Abstract
Extensive investigation on the molecular and electronic structure of 2-amino-5-trifluoromethyl-1,3,4-thiadiazole in the ground state and in the first excited state has been performed. The energy barrier corresponding to the conversion between imino and amino tautomers has been calculated, which indicates the existence of amino tautomer in solid state for the title compound. The FT-Raman and FT-IR spectra were recorded and compared with theoretical vibrational wavenumbers, and a good coherence has been observed. The MESP map, dipole moment, polarizability, and hyperpolarizability have been calculated to comprehend the properties of the title molecule. High polarizability value estimation of the title compound may enhance its bioactivity. Natural bonding orbital analysis has been done on monomer and dimer to investigate the charge delocalization and strength of hydrogen bonding, respectively. Strong hydrogen bonding interaction energies of 17.09/17.49 kcal mol-1 have been calculated at the B3LYP/M06-2X functional. The UV-vis spectrum was recorded and related to the theoretical spectrum. The title compound was biologically examined for anticancer activity by studying the cytotoxic performance against two human cancer cell lines (A549 and HeLa) along with the molecular docking simulation. Both molecular docking and cytotoxic performance against cancer cell lines show positive outcomes, and the title compound appears to be a promising anticancer agent.
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Affiliation(s)
- Isha Singh
- Department of Physics, University of Lucknow, Lucknow 226007, India
| | - Lamya H. Al-Wahaibi
- Department of Chemistry, College of Sciences, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia
| | - Ruchi Srivastava
- Department of Physics, University of Lucknow, Lucknow 226007, India
| | - Onkar Prasad
- Department of Physics, University of Lucknow, Lucknow 226007, India
| | - Shilendra K. Pathak
- Department of Physics, M. M. M. P. G. College, Bhatpar Rani, Deoria 274702, India
| | - Saurabh Kumar
- Molecular & Human Genetics Lab, Department of Zoology, University of Lucknow, Lucknow 226007, India
| | - Shama Parveen
- Molecular & Human Genetics Lab, Department of Zoology, University of Lucknow, Lucknow 226007, India
| | - Monisha Banerjee
- Molecular & Human Genetics Lab, Department of Zoology, University of Lucknow, Lucknow 226007, India
| | - Ali A. El-Emam
- Department of Medicinal Chemistry, Faculty of Pharmacy, University of Mansoura, Mansoura 35516, Egypt
| | - Leena Sinha
- Department of Physics, University of Lucknow, Lucknow 226007, India
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4
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Manikandan D, Swaminathan J, Tagore SS, Gomathi S, Sabarinathan N, Ramalingam M, Balasubramani K, Sethuraman V. Crystallographic, spectral and computational studies on (S)-4-(4-aminobenzyl) oxazolidin-2-one. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 239:118484. [PMID: 32470808 DOI: 10.1016/j.saa.2020.118484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/15/2020] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
The experimental geometry (XRD), vibrational (IR and Raman), electronic (UV-visible) and NMR spectra of (S)-4-(4-Amino-benzyl)-oxazolidin-2-one (ABO) have been corroborated with the corresponding first principle calculated values at DFT using hybrid B3LYP exchange correlation functional invoking 6-311++g(d, p) basis set. The optimized geometrical parameters were found to be in satisfactory agreement with the experimental values obtained from the X-ray diffraction structural features of ABO. The scaled down computed vibrational frequencies with appropriate scaling factors were in good correspondence with the experimental observations. Room-temperature 1H and 13C nuclear magnetic resonance (NMR) studies were supported by advanced density functional theory calculations. The theoretical spectrograms of FT-IR, FT-Raman, 1H NMR, 13C NMR and UV of the title compound have been constructed and compared with experimental spectra and Hirshfeld surface analysis has also been made to study the intermolecular interactions. The electronic structure of the title compound has also been studied in terms of HOMO, LUMO and MESP diagrams.
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Affiliation(s)
- D Manikandan
- Department of Chemistry, Periyar Maniammai Institute of Science & Technology, Vallam, Thanjavur, Tamilnadu, India
| | - J Swaminathan
- Department of Chemistry, A.V.C. College of Engineering, Mayiladuthurai, Tamilnadu, India
| | - S Sharmila Tagore
- Department of Chemistry, M.R. Govt. Arts College, Mannargudi, TamilNadu, India
| | - S Gomathi
- Department of Chemistry, Periyar Maniammai Institute of Science & Technology, Vallam, Thanjavur, Tamilnadu, India
| | - N Sabarinathan
- Department of Chemistry, Presidency College, Chennai, India
| | - M Ramalingam
- Department of Chemistry, Bon Secours College for Women, Thanjavur, Tamilnadu, India
| | - K Balasubramani
- Department of Chemistry, Govt. Arts College, Thanthonimalai, Karur, TamilNadu, India
| | - V Sethuraman
- Department of Chemistry, Periyar Maniammai Institute of Science & Technology, Vallam, Thanjavur, Tamilnadu, India.
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5
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Mechanical and thermal characterization of bagasse fiber/coconut shell particle hybrid biocomposites reinforced with cardanol resin. RESULTS IN CHEMISTRY 2020. [DOI: 10.1016/j.rechem.2020.100056] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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6
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Molecular, vibrational (FT-IR and FT-Raman), NMR and UV spectral analysis of imidazo[1,2-b]pyridazine using experimental and DFT calculations. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2019.136943] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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7
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Zayed EM, Zayed M, Abd El Salam HA, Noamaan MA. Novel Triazole Thiole ligand and some of its metal chelates: Synthesis, structure charactertization, thermal behavior in comparison withcomputational caculations andbiological activities. Comput Biol Chem 2019; 78:260-272. [DOI: 10.1016/j.compbiolchem.2018.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 12/12/2018] [Accepted: 12/20/2018] [Indexed: 01/10/2023]
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8
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Udhayasankar R, Karthikeyan B, Balaji A. Coconut shell particles reinforced cardanol–formaldehyde resole resin biocomposites: Effect of treatment on thermal properties. INTERNATIONAL JOURNAL OF POLYMER ANALYSIS AND CHARACTERIZATION 2018. [DOI: 10.1080/1023666x.2018.1427187] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- R. Udhayasankar
- Department of Mechanical Engineering, Faculty of Engineering and Technology, Annamalai University, Chidambaram, Tamil Nadu, India
| | - B. Karthikeyan
- Department of Mechanical Engineering, Faculty of Engineering and Technology, Annamalai University, Chidambaram, Tamil Nadu, India
| | - A. Balaji
- Department of Mechanical Engineering, A.V.C. College of Engineering, Mayiladuthurai, Tamil Nadu, India
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9
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Balaji A, Karthikeyan B, Swaminathan J, Sundar Raj C. Thermal behavior of cardanol resin reinforced 20 mm long untreated bagasse fiber composites. INTERNATIONAL JOURNAL OF POLYMER ANALYSIS AND CHARACTERIZATION 2017. [DOI: 10.1080/1023666x.2017.1387448] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- A. Balaji
- Department of Mechanical Engineering, A.V.C. College of Engineering, Mayiladuthurai, Tamil Nadu, India
| | - B. Karthikeyan
- Department of Mechanical Engineering, Faculty of Engineering and Technology, Annamalai University, Chidambaram, Tamil Nadu, India
| | - J. Swaminathan
- Department of Chemistry, A.V.C. College of Engineering, Mayiladuthurai, Tamil Nadu, India
| | - C. Sundar Raj
- Department of Mechanical Engineering, A.V.C. College of Engineering, Mayiladuthurai, Tamil Nadu, India
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10
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Karuppasamy A, Udhaya kumar C, Karthikeyan S, Velayutham Pillai MP, Ramalingan C. Synthesis, spectral, structural prediction and computational studies of octylcarbazole ornamented 3-phenothiazinal. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.06.136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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11
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Srivastava A, Karthick T, Joshi BD, Mishra R, Tandon P, Ayala AP, Ellena J. Spectroscopic (far or terahertz, mid-infrared and Raman) investigation, thermal analysis and biological activity of piplartine. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 184:368-381. [PMID: 28538206 DOI: 10.1016/j.saa.2017.05.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 05/03/2017] [Accepted: 05/04/2017] [Indexed: 06/07/2023]
Abstract
Research in the field of medicinal plants including Piper species like long pepper (Piper longum L.- Piperaceae) is increasing all over the world due to its use in traditional and Ayurvedic medicine. Piplartine (piperlongumine, 5,6-dihydro-1-[(2E)-1-oxo-3-(3,4,5-trimethoxyphenyl)-2-propenyl]-2(1H)-pyridinone), a biologically active alkaloid/amide was isolated from the phytochemical investigations of Piper species, as long pepper. This alkaloid has cytotoxic, anti-fungal, anti-diabetic, anti-platelet aggregation, anti-tumoral, anxiolytic, anti-depressant, anti-leishmanial, and genotoxic activities, but, its anticancer property is the most promising and has been widely explored. The main purpose of the work is to present a solid state characterization of PPTN using thermal analysis and vibrational spectroscopy. Quantum mechanical calculations based on the density functional theory was also applied to investigate the molecular conformation and vibrational spectrum, which was compared with experimental results obtained by Raman scattering, far (terahertz) and mid-infrared adsorption spectroscopy. NBO analysis has been performed which predict that most intensive interactions in PPTN are the hyperconjugative interactions between n(1) N6 and π*(O1C7) having delocalization energy of 50.53kcal/mol, Topological parameters have been analyzed using 'AIM' analysis which governs the three bond critical points (BCPs), one di-hydrogen, and four ring critical points (RCPs). MEP surface has been plotted which forecast that the most negative region is associated with the electronegative oxygen atoms (sites for nucleophilic activity). Theoretically, to confirm that the title compound has anti-cancer, anti-diabetic and anti-platelet aggregation activities, it was analyzed by molecular docking interactions with the corresponding target receptors. The obtained values of H-bonding parameters and binding affinity prove that its anti-cancer activity is the more prominent than the other properties.
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Affiliation(s)
- Anubha Srivastava
- Department of Physics, University of Lucknow, University Road, Lucknow 226 007, Uttar Pradesh, India.
| | - T Karthick
- Department of Physics, University of Lucknow, University Road, Lucknow 226 007, Uttar Pradesh, India
| | - B D Joshi
- Department of Physics, Tribhuvan University, Siddhanath Sc. Campus, Nepal 10400, India; Departamento de Física, Universidade Federal do Ceará, C. P. 6030, 60.455-900 Fortaleza, CE, Brazil
| | - Rashmi Mishra
- Department of Physics, University of Lucknow, University Road, Lucknow 226 007, Uttar Pradesh, India; Department of Physics, Seth G.B. Podar College, Nawalgarh, Rajasthan, India
| | - Poonam Tandon
- Department of Physics, University of Lucknow, University Road, Lucknow 226 007, Uttar Pradesh, India.
| | - A P Ayala
- Departamento de Física, Universidade Federal do Ceará, C. P. 6030, 60.455-900 Fortaleza, CE, Brazil
| | - Javier Ellena
- Instituto de Física de São Carlos, Universidade de São Paulo, CP. 369, 13560-970, São Carlos, SP, Brazil
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12
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Priya YS, Rao KR, Chalapathi P, Satyavani M, Veeraiah A. Vibrational and UV spectroscopic studies of 2-coumaranone by experimental and density functional theory calculations. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.05.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Udhaya Kumar C, Velayutham Pillai M, Gokula Krishnan K, Ramalingan C. Synthesis, spectral and structural characterization of isobutyl 4-(2-chlorophenyl)-5-cyano-6-(((dimethylamino)methylene)amino)-2-methyl-4H-pyran-3-carboxylate. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.05.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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14
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Anand S, Sundararajan RS, Ramachandraraja C, Ramalingam S, Durga R. Molecular vibrational investigation [FT-IR, FT-Raman, UV-Visible and NMR] on Bis(thiourea) Nickel chloride using HF and DFT calculations. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 138:203-215. [PMID: 25498815 DOI: 10.1016/j.saa.2014.11.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 10/27/2014] [Accepted: 11/20/2014] [Indexed: 06/04/2023]
Abstract
In the present research work, the FT-IR, FT-Raman spectra of the Bis(thiourea) Nickel chloride (BTNC) were recorded and analyzed. The observed fundamental frequencies in finger print and functional group regions were assigned according to their uniqueness region. The computational calculations were carried out by HF and DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The present organo-metallic compound was made up of covalent and coordination covalent bonds. The modified vibrational pattern of the complex molecule associated with ligand group was analyzed. Furthermore, the (13)C NMR and (1)H NMR spectral data were calculated by using the gauge independent atomic orbital (GIAO) method with B3LYP/6-311++G(d,p) basis set and their spectra were simulated and the chemical shifts linked to TMS were compared. A investigation on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies were carried out. The kubo gap of the present compound was calculated related to HOMO and LUMO energies which confirm the occurring of charge transformation between the base and ligand. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. The NLO properties related to Polarizability and hyperpolarizability based on the finite-field approach were also discussed.
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Affiliation(s)
- S Anand
- Department of Physics, A.V.C. College, Mayiladuthurai, Tamil Nadu, India.
| | - R S Sundararajan
- Department of Physics, Government Arts College, Kumbakonam, Tamil Nadu, India
| | - C Ramachandraraja
- Department of Physics, Government Arts College, Kumbakonam, Tamil Nadu, India
| | - S Ramalingam
- Department of Physics, A.V.C. College, Mayiladuthurai, Tamil Nadu, India
| | - R Durga
- Department of Physics, A.V.C. College, Mayiladuthurai, Tamil Nadu, India
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15
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Bahgat K, Fraihat S. Normal coordinate analysis, molecular structure, vibrational, electronic spectra and NMR investigation of 4-Amino-3-phenyl-1H-1,2,4-triazole-5(4H)-thione by ab initio HF and DFT method. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 135:1145-1155. [PMID: 25195198 DOI: 10.1016/j.saa.2014.05.081] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 05/26/2014] [Accepted: 05/30/2014] [Indexed: 06/03/2023]
Abstract
In the present work, the characterization of 4-Amino-3-phenyl-1H-1,2,4-triazole-5(4H)-thione (APTT) molecule was carried out by quantum chemical method and vibrational spectral techniques. The FT-IR (4000-400 cm(-1)) and FT-Raman (4000-100 cm(-1)) spectra of APTT were recorded in solid phase. The UV-Vis absorption spectrum of the APTT was recorded in the range of 200-400 nm. The molecular geometry, harmonic vibrational frequencies and bonding features of APTT in the ground state have been calculated by HF and DFT methods using 6-311++G(d,p) basis set. The complete vibrational frequency assignments were made by normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMF). The molecular stability and bond strength were investigated by applying the natural bond orbital analysis (NBO) and natural localized molecular orbital (NLMO) analysis. The electronic properties, such as excitation energies, absorption wavelength, HOMO and LUMO energies were performed by time depended DFT (TD-DFT) approach. The (1)H and (13)C nuclear magnetic resonance chemical shift of the molecule were calculated using the gauge-including atomic orbital (GIAO) method and compared with experimental results. Finally, the calculation results were analyzed to simulate infrared, FT-Raman and UV spectra of the title compound which shows better agreement with observed spectra.
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Affiliation(s)
- Khaled Bahgat
- Chemistry Department, Faculty of Petroleum and Mining Engineering, Suez University, Suez, Egypt; Chemistry Department, Collage of Science, Al Jouf University, Sakaka, Saudi Arabia
| | - Safwan Fraihat
- Chemistry Department, Collage of Science, Al Jouf University, Sakaka, Saudi Arabia
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16
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Structural, vibrational, NLO, MEP, NBO analysis and DFT calculation of bis 2,5-dimethylanilinium sulfate. J Mol Struct 2015. [DOI: 10.1016/j.molstruc.2014.09.084] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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17
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Guidara S, Feki H, Abid Y. Molecular structure, NLO, MEP, NBO analysis and spectroscopic characterization of 2,5-dimethylanilinium dihydrogen phosphate with experimental (FT-IR and FT-Raman) techniques and DFT calculations. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 133:856-866. [PMID: 25014546 DOI: 10.1016/j.saa.2014.06.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 05/20/2014] [Accepted: 06/03/2014] [Indexed: 06/03/2023]
Abstract
Single crystals of 2,5-dimethylanilinium dihydrogen phosphate were grown by slow evaporation method at room temperature. The synthesized compound was characterized by powder X-ray diffraction analysis to confirm its crystalline nature. The optimized molecular structure, vibrational spectra and the optical properties were calculated by the density functional theory (DFT) method using the B3LYP function with the 6-31G(d,p) basis set. Theoretical simulation of infrared and Raman spectra led to excellent overall agreement with the observed spectral patterns. The complete assignments of the vibrational spectra were carried out with the aid of potential energy distribution (PED). The stability of the molecule arising from hyperconjugative interaction and charge delocalization has been analyzed using natural bond orbital (NBO) analysis leading to high nonlinear optical (NLO) activity. The lowering in the HOMO and LUMO energy gap explains the eventual charge transfer interactions that take place within the molecules.
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Affiliation(s)
- Sameh Guidara
- Laboratoire de Physique Appliquée (LPA), Université de Sfax, Faculté des Sciences, BP 1171, 3000 Sfax, Tunisia.
| | - Habib Feki
- Laboratoire de Physique Appliquée (LPA), Université de Sfax, Faculté des Sciences, BP 1171, 3000 Sfax, Tunisia
| | - Younes Abid
- Laboratoire de Physique Appliquée (LPA), Université de Sfax, Faculté des Sciences, BP 1171, 3000 Sfax, Tunisia
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Govindasamy P, Gunasekaran S, Srinivasan S. Molecular geometry, conformational, vibrational spectroscopic, molecular orbital and Mulliken charge analysis of 2-acetoxybenzoic acid. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 130:329-36. [PMID: 24793483 DOI: 10.1016/j.saa.2014.03.056] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 03/01/2014] [Accepted: 03/20/2014] [Indexed: 05/24/2023]
Abstract
The Fourier transform infrared (FT-IR) and FT-Raman spectra of 2-acetoxybenzoic acid (2ABA), a painkiller agent were recorded in the region 4000-450 cm(-1) and 5000-50 cm(-1) respectively. Hartree Fock (HF) and Density functional theory (DFT) methods have been used to determine its optimized geometrical parameter, atomic charges, and vibrational wavenumbers and intensity of the vibrational bands of the title molecule. The computed vibrational wave numbers were compared with the FT-IR and FT-Raman experimental data. The computational calculations were done at HF and DFT/B3LYP level with 6-311++G(d,p) basis set. The complete vibrational assignments were performed on the basis of the potential energy distribution (PED) analysis. The Mulliken charges, UV-Visible spectral analysis and HOMO-LUMO energy gap have been calculated and reported. The B3LYP method of calculated parameters is a good complement with the experimental findings. The thermodynamic properties like entropy, heat capacity and zero vibrational energy have been calculated and discussed. The electrostatic potential (ESP) contour surface and molecular electrostatic potential (MESP) of the molecule were constructed.
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Affiliation(s)
- P Govindasamy
- Department of Physics, Karpagam University, Eachanari, Coimbatore 641021, TN, India.
| | - S Gunasekaran
- Research and Development St. Peter's Institute of Higher Education and Research, St. Peter's University, Avadi, Chennai 600054, TN, India
| | - S Srinivasan
- Department of Physics, Presidency College, Chennai 600005, India
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Govindasamy P, Gunasekaran S, Ramkumaar GR. Natural bond orbital analysis, electronic structure and vibrational spectral analysis of N-(4-hydroxyl phenyl) acetamide: a density functional theory. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 130:621-633. [PMID: 24813292 DOI: 10.1016/j.saa.2014.03.065] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/14/2014] [Accepted: 03/21/2014] [Indexed: 06/03/2023]
Abstract
The Fourier transform infrared (FT-IR) and FT-Raman spectra of N-(4-hydroxy phenyl) acetamide (N4HPA) of painkiller agent were recorded in the region 4000-450 cm(-1) and 4000-50 cm(-1) respectively. Density functional theory (DFT) has been used to calculate the optimized geometrical parameter, atomic charges, and vibrational wavenumbers and intensity of the vibrational bands. The computed vibrational wave numbers were compared with the FT-IR and FT-Raman experimental data. The computational calculations at DFT/B3LYP level with 6-31G(d,p), 6-31++G(d,p), 6-311G(d,p) and 6-311++G(d,p) basis sets. The complete vibrational assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes calculated using Vibrational energy distribution analysis (VEDA 4) program. The oscillator's strength calculated by TD-DFT and N4HPA is approach complement with the experimental findings. The NMR chemical shifts 13C and 1H were recorded and calculated using the gauge independent atomic orbital (GIAO) method. The molecular electrostatic potential (MESP) and electron density surfaces of the molecule were constructed. The Natural charges and intermolecular contacts have been interpreted using Natural Bond orbital (NBO) analysis the HOMO-LUMO energy gap has been calculated. The thermodynamic properties like entropy, heat capacity and zero vibrational energy have been calculated.
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Affiliation(s)
- P Govindasamy
- Department of Physics, Karpagam University, Eachanari, Coimbatore 641021, TN, India
| | - S Gunasekaran
- Research and Development St. Peter's Institute of Higher Education and Research, St. Peter's University, Avadi, Chennai 600054, TN, India.
| | - G R Ramkumaar
- PG and Research Department of Physics, Pachaiyappa's College, Chennai 600030, TN, India
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20
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Guidara S, Ahmed AB, Abid Y, Feki H. Molecular structure, vibrational spectra and nonlinear optical properties of 2,5-dimethylanilinium chloride monohydrate: a density functional theory approach. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 127:275-285. [PMID: 24632236 DOI: 10.1016/j.saa.2014.02.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 01/30/2014] [Accepted: 02/09/2014] [Indexed: 06/03/2023]
Abstract
Single crystals of 2,5-dimethylanilinim chloride monohydrate were grown by slow evaporation at room temperature and were characterized by X-ray powder diffraction study to confirm the crystalline nature of the synthesized compound. The optimized molecular structure, vibrational spectra and the optical properties were calculated by the density functional theory (DFT) method using the B3LYP function with the 6-31G(d,p) basis set. Simulation of infrared and Raman spectra led to excellent overall agreement with the observed spectral patterns. The complete assignments of the vibrational spectra were carried out with the aid of potential energy distribution (PED). The stability of the molecule arising from hyperconjugative interaction and charge delocalization has been analyzed using natural bond orbital (NBO) analysis leading to high nonlinear optical (NLO) activity. The lowering in the HOMO and LUMO energy gap explains the eventual charge transfer interactions that take place within the molecules.
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Affiliation(s)
- Sameh Guidara
- Laboratoire de Physique Appliquée (LPA), Université de Sfax, Faculté des Sciences, BP.1171, 3000 Sfax, Tunisia.
| | - Ali Ben Ahmed
- Laboratoire de Physique Appliquée (LPA), Université de Sfax, Faculté des Sciences, BP.1171, 3000 Sfax, Tunisia
| | - Younes Abid
- Laboratoire de Physique Appliquée (LPA), Université de Sfax, Faculté des Sciences, BP.1171, 3000 Sfax, Tunisia
| | - Habib Feki
- Laboratoire de Physique Appliquée (LPA), Université de Sfax, Faculté des Sciences, BP.1171, 3000 Sfax, Tunisia
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Sakthivel S, Alagesan T, Al-Saadi AA, Renuga S, Muthu S. Vibrational spectra of 3,5-diamino-6-chloro-N-(diaminomethylene) pyrazine-2-carboxamide: combined experimental and theoretical studies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 127:157-167. [PMID: 24632230 DOI: 10.1016/j.saa.2014.02.066] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 01/25/2014] [Accepted: 02/11/2014] [Indexed: 06/03/2023]
Abstract
In this work, the vibrational spectral analysis of 3,5-diamino-6-chloro-N-(diaminomethylene)pyrazine-2-carboxamide(3DCNDPC) was carried out using FT-Raman and FT-IR spectroscopy in the range 4000-50cm(-1) and 4000-500cm(-1) respectively. The experimental spectra were recorded in the solid phase. The fundamental vibrational frequencies and intensity of vibrational bands were evaluated using density functional theory (DFT) B3LYP with the standard basis set 6-311++G(d,p). The optimized geometric parameters (bond lengths and bond angles) were compared with experimental values. Normal co-ordinate calculations were performed with the DFT force field corrected by a recommended set of scaling factors yielding fairly good agreement between observed and calculated frequencies. Simulation of infrared and Raman spectra utilizing the results of these calculations led to excellent overall agreement with the observed spectral patterns. The complete assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. The stability of the molecule arising from hyper conjugative interactions and the charge delocalization has been analyzed by using Natural Bond Orbital (NBO) analysis. UV-Vis spectrum of the compound was recorded. The calculated HOMO and LUMO energies show that chemical activity of the molecule.
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Affiliation(s)
- S Sakthivel
- Department of Physics, Panimalar Engineering College, Chennai, Tamil Nadu, India
| | - T Alagesan
- Department of Physics, Presidency College, Chennai, India
| | - Abdulaziz A Al-Saadi
- Department of Chemistry, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia
| | - S Renuga
- Department of Physics, Indira Institute of Engineering and Technology, Thiruvallur, Tamil Nadu, India
| | - S Muthu
- Department of Physics, Sri Venkateswara College of Engineering, Sriperumbudur, India.
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Saravanan S, Balachandran V, Viswanathan K. Spectroscopic investigation of 4-nitro-3-(trifluoromethyl)aniline, NBO analysis with 4-nitro-3-(trichloromethyl)aniline and 4-nitro-3-(tribromomethyl)aniline. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 121:685-697. [PMID: 24374555 DOI: 10.1016/j.saa.2013.12.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Revised: 12/01/2013] [Accepted: 12/04/2013] [Indexed: 06/03/2023]
Abstract
The Fourier transform infrared (FT-IR) and FT-Raman spectra of 4-nitro-3-(trifluoromethyl)aniline (NTFA) were recorded in the regions 4000-400 cm(-1) and 3500-100 cm(-1), respectively. Utilizing the observed FT-IR and FT-Raman data, a complete vibrational assignment and analysis of the fundamental modes of the compounds was carried out. Extensive studies on the vibrational, structural, thermodynamic characteristics as well as the electronic properties of NTFA were carried out using ab initio and DFT methods. In this kind of systems, the position of the substituent group in the benzene ring as well as its electron donor-acceptor capabilities play a very important role on the molecular and electronic properties. The values of the total dipole moment (μ) and the first order hyperpolarizability (β) were computed using B3LYP/6-311++G(d,p) and B3LYP/6-311G(d) calculations. The Mulliken's charges, the natural bonding orbital (NBO) analysis on 4-nitro-3-(trifluoromethyl)aniline, 4-nitro-3-(trichloromethyl)aniline and 4-nitro-3-tribromomethyl)aniline were carried out for various intramolecular interactions that are responsible for the stabilization of the molecule. Thermodynamic functions of the investigated molecule were also computed. The calculated HOMO-LUMO energies show that charge transfer occurs in the molecule. The influence of fluorine, amino and nitro group on the geometry of benzene and its normal modes of vibrations has also been discussed.
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Affiliation(s)
- S Saravanan
- Department of Physics, Karpagam University, Coimbatore 641 021, India; Department of Physics, J.J. College of Arts and Science (Autonomous), Pudukkottai 622 422, India
| | - V Balachandran
- Centre for Research, Department of Physics, AA Government Arts College, Musiri, Tiruchirappalli 621 211, India.
| | - K Viswanathan
- Department of Physics, Karpagam University, Coimbatore 641 021, India
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Arı H, Büyükmumcu Z, Özpozan T, İlhan İÖ, Bahadır Ö. Vibrational and theoretical analysis of pentyl-4-benzoyl-1-[2,4-dinitrophenyl]-5-phenyl-1H-pyrazole-3-carboxylate. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 110:193-204. [PMID: 23563638 DOI: 10.1016/j.saa.2013.03.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 12/14/2012] [Accepted: 03/03/2013] [Indexed: 06/02/2023]
Abstract
Infrared spectrum of the compound, pentyl-4-benzoyl-1-[2,4-dinitrophenyl]-5-phenyl-1H-pyrazole-3-carboxylate (PBDPPC) has been measured. Conformational search through relaxed scan has been carried out to find the most stable conformational isomer. After the full geometry optimization for the most stable conformer using B3LYP and BLYP hybrid functionals of Density Functional Theory (DFT), vibrational normal modes have been calculated at the same theoretical levels. Potential Energy Distribution (PED) of each normal mode has been calculated by means of VEDA4 to obtain contributions of internal coordinates to the normal modes. Natural Bond Orbital (NBO) analysis has been performed to get insights into the possible hydrogen bonding sites for all the conformational isomers.
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Affiliation(s)
- Hatice Arı
- Bozok University, Faculty of Arts and Sciences, Department of Chemistry, Yozgat, Turkey
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Ramalingam S, Periandy S, Karabacak M, Karthikeyan N. Spectroscopic (FT-IR/FT-Raman) and computational (HF/DFT) investigation and HOMO/LUMO/MEP analysis on 2-amino-4-chlorophenol. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 104:337-351. [PMID: 23274261 DOI: 10.1016/j.saa.2012.11.107] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 11/24/2012] [Accepted: 11/30/2012] [Indexed: 06/01/2023]
Abstract
The spectra (FT-IR and FT-Raman) of the present compound; 2-amino-4-chlorophenol (2A4CP) were recorded in the range of 4000-100 cm(-1). All the computational calculations were made in the ground state using the HF and DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets. From potential energy surface calculation, there are two conformers, Rot-1 and Rot-2 for this molecule. The computational results detected that Rot-1 form is the most stable conformer. Making use of the recorded data, the complete vibrational assignments were made and analysis of the observed fundamental bands of molecule is carried out. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQMs) method and PQS program. The shifting of the frequencies in the vibrational pattern of the title molecule due to the substitutions; NH(2) and Cl were deeply investigated by the vibrational analysis. Moreover, (13)C NMR and (1)H NMR chemical shifts were calculated by using the gauge independent atomic orbital (GIAO) method with HF/B3LYP/B3PW91 methods with 6-311++G(d,p). A study on the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. Besides frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP) was performed. NLO properties and Mulliken charges of the 2A4CP were also calculated and interpreted. The thermodynamic properties (heat capacity, entropy, and enthalpy) of the title compound at different temperatures were calculated in gas phase.
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Affiliation(s)
- S Ramalingam
- Department of Physics, AVC College, Mayiladuthurai, Tamilnadu, India.
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Balachandran V, Parimala K. Molecular structures, FT-IR and FT-Raman spectra, NBO analysis, NLO properties, reactive sites and quantum chemical calculations of keto-enol tautomerism (2-amino-4-pyrimidinol and 2-amino-pyrimidine-4(1H)-one). SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 102:30-51. [PMID: 23220518 DOI: 10.1016/j.saa.2012.10.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 10/02/2012] [Accepted: 10/10/2012] [Indexed: 06/01/2023]
Abstract
The keto-enol tautomerism of 2-amino-4-pyrimidinol (APN) and 2-amino-pyrimidine-4(1H)-one (APO) are investigated by vibrational spectroscopy and quantum chemical method. FT-IR and FT-Raman spectra are recorded in the regions of 4000-400 cm(-1) and 3500-100 cm(-1), respectively for APN. Geometrical parameters, vibrational wavenumbers of APN and APO are predicted by density functional theory (DFT) employing B3LYP level with 6-311++G(d,p) and 6-311++G(2d,p) basis sets. The non-linear optical (NLO) properties of the title molecules are computed. The molecular electrostatic potential (MEP) surface maps are plotted and explained in detail. Natural bond orbital (NBO) analyses have been performed on APN molecule. The significant changes in occupancies and the energies of bonding and antibonding orbital have been explained in detail. Thermodynamic properties (heat capacities, entropies, and enthalpy) and their correlations with temperatures are also obtained from the calculated frequencies of the optimized structures. Reactivity descriptors, Fukui functions and electrophilic sites are found and discussed.
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Affiliation(s)
- V Balachandran
- PG and Research Department of Physics, A.A. Government Arts College, Musiri, Tiruchirappalli 620 211, India.
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Prasad MVS, Chaitanya K, Udaya Sri N, Veeraiah V. Vibrational and electronic absorption spectral studies of 5-amino-1-(4-bromophenyl)-3-phenyl-1-H-pyrazole. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 99:379-389. [PMID: 23022613 DOI: 10.1016/j.saa.2012.09.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 08/16/2012] [Accepted: 09/04/2012] [Indexed: 06/01/2023]
Abstract
The FT-IR and FT-Raman spectra of 5-amino-1-(4-bromophenyl)-3-phenyl-1-H-pyrazole have been measured in the regions 4000-400 cm(-1) and 3500-100 cm(-1), respectively. The equilibrium geometry, bonding features and harmonic vibrational frequencies have been carried out with the help of DFT method. The assignments of the vibrational spectra have been carried out with the normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMFF). The first-order hyperpolarizability (β(0)) and related properties (μ, α(0), and Δα) of 5A4BP3PP are calculated by using HF/6-31G(d,p) method on the finite field approach. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bonding orbital (NBO) analysis. The results show that electron density (ED) in the σ(*) and π(*) antibonding orbitals and second order delocalization energies E(2) confirms the occurrence of the intramolecular charge transfer (ICT) within the molecule. UV-vis spectrum of the compound was recorded and the electronic properties, such as HOMO and LUMO energies, were performed by TDDFT using 6-31G(d,p). The HOMO-LUMO calculations indicating the charge transfer takes place within the molecule.
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Affiliation(s)
- M V S Prasad
- Molecular Spectroscopy Laboratories, Department of Physics, Andhra University, Visakhapatnam, India
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Balachandran V, Parimala K. Tautomeric purine forms of 2-amino-6-chloropurine (N9H10 and N7H10): structures, vibrational assignments, NBO analysis, hyperpolarizability, HOMO-LUMO study using B3 based density functional calculations. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 96:340-351. [PMID: 22706099 DOI: 10.1016/j.saa.2012.05.050] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 04/30/2012] [Accepted: 05/17/2012] [Indexed: 06/01/2023]
Abstract
Two purine tautomers of 2-amino-6-chloropurine (ACP), in labeled as N(9)H(10) and N(7)H(10), were investigated by vibrational spectroscopy and quantum chemical method. The FT-IR and FT-Raman spectra of ACP have been recorded in the regions 4000-400 cm(-1) and 3500-100 cm(-1), respectively. The measured spectra were interpreted by aid of a normal coordinate analysis following DFT full geometry optimization and vibrational frequency calculations at B3LYP/6-311++G(d,p) level. First-order hyperpolarizability, HOMO and LUMO energies were calculated at same level of theory. The calculated molecular geometry has been compared with the X-ray data. The observed and calculated frequencies were found in good agreement. The obtained NBO data and second-order perturbation energy values to elucidate the Lewis and non-Lewis types of bonding structures in the purine tautomer N(9)H(10), have indicated the presence of an intramolecular hyperconjucative interaction between lone pair N and N-C bond orbital.
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Affiliation(s)
- V Balachandran
- Research Department of Physics, A.A. Government Arts College, Musiri, Tiruchirappalli 620211, India.
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Udaya Sri N, Chaitanya K, Prasad M, Veeraiah V, Veeraiah A. Experimental (FT-IR, FT-Raman and UV–Vis spectra) and density functional theory calculations of diethyl 1H-pyrazole-3,5-dicarboxylate. J Mol Struct 2012. [DOI: 10.1016/j.molstruc.2012.03.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Arivazhagan M, Thilagavathi G. Vibrational study, first hyperpolarizability and HOMO-LUMO analyses on the structure of 2-hydroxy-6-nitro toluene. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 91:411-418. [PMID: 22402481 DOI: 10.1016/j.saa.2012.02.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 02/05/2012] [Accepted: 02/09/2012] [Indexed: 05/31/2023]
Abstract
Vibrational spectral measurements, namely, FT-infrared (4000-400 cm(-1)) and FT-Raman (3500-50 cm(-1)) spectra have been made for 2-hydroxy-6-nitrotoluene (HNT) and assigned to different normal modes of the molecule. Quantum chemical calculations of energies, geometrical structure, harmonic vibrational frequencies intensities and vibrational wavenumbers of HNT were carried out by ab initio HF and density functional theory (DFT/B3LYP) method with 6-311++G(d,p) basis set. The differences between the observed and scaled wave number values of most of the fundamentals are very small. The values of the total dipole moment (μ) and first hyperpolarizability (β) of the investigated molecule were computed by using ab initio HF and density functional theory (DFT/B3LYP) methods with 6-311++G(d,p) basis set quantum mechanical calculations. The calculated results also show that the HNT molecule might have microscopic nonlinear optical (NLO) behavior with non-zero values. A detailed interpretation of the infrared and Raman spectra of HNT is also reported based on total energy distribution (TED). The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. The results of the calculations were applied to simulated infrared and Raman spectra of the title compound which showed excellent agreement with the observed spectra.
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Affiliation(s)
- M Arivazhagan
- Department of Physics, A.A. Govt. Arts College, Musiri 621 201, India.
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Ramalingam S, Periandy S. Vibrational spectroscopy [FTIR and FTRaman] investigation, computed vibrational frequency analysis and IR intensity and Raman activity peak resemblance analysis on 4-chloro 2-methylaniline using HF and DFT [LSDA, B3LYP and B3PW91] calculations. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 78:1149-1161. [PMID: 21237700 DOI: 10.1016/j.saa.2010.12.068] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 11/21/2010] [Accepted: 12/17/2010] [Indexed: 05/30/2023]
Abstract
In the present study, the FT-IR and FT-Raman spectra of 4-chloro-2-methylaniline (4CH2MA) have been recorded in the range of 4000-100 cm(-1). The fundamental modes of vibrational frequencies of 4CH2MA are assigned. All the geometrical parameters have been calculated by HF and DFT (LSDA, B3LYP and B3PW91) methods with 6-31G (d, p) and 6-311G (d, p) basis sets. Optimized geometries of the molecule have been interpreted and compared with the reported experimental values for aniline and some substituted aniline. The harmonic and anharmonic vibrational wavenumbers, IR intensities and Raman activities are calculated at the same theory levels used in geometry optimization. The calculated frequencies are scaled and compared with experimental values. The scaled vibrational frequencies at LSDA/B3LYP/6-311G (d, p) seem to coincide with the experimentally observed values with acceptable deviations. The impact of substitutions on the benzene structure is investigated. The molecular interactions between the substitutions (Cl, CH(3) and NH(2)) are also analyzed.
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Affiliation(s)
- S Ramalingam
- Department of Physics, AVC College, Mayiladuthurai, Nagai District, Tamilnadu, India.
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Mohamed TA, Hassan AM, Soliman UA, Zoghaib WM, Husband J, Abdelall MM. Infrared, Raman and NMR spectra, conformational stability, normal coordinate analysis and B3LYP calculations of 5-amino-4-cyano-3-(methylthio)-1H-pyrazole-1-carbothioamide. J Mol Struct 2011. [DOI: 10.1016/j.molstruc.2010.11.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Ramalingam S, Periandy S, Mohan S. Vibrational spectroscopy (FTIR and FTRaman) investigation using ab initio (HF) and DFT (B3LYP and B3PW91) analysis on the structure of 2-amino pyridine. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2010; 77:73-81. [PMID: 20627807 DOI: 10.1016/j.saa.2010.04.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 04/21/2010] [Accepted: 04/27/2010] [Indexed: 05/29/2023]
Abstract
The FTIR and FTRaman spectra of 2-amino pyridine (2-AP) molecule have been recorded using Bruker IFS 66 V spectrometer in the range of 4000-100 cm(-1). The molecular geometry and vibrational frequencies in the ground state are calculated by using the ab initio Hartree-Fock (HF) and DFT (B3LYP and B3PW91) methods with 6-31++G (d, p) and 6-311++G (d, p) basis sets. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. Making use of the recorded data, the complete vibrational assignments are made and analysis of the observed fundamental bands of molecule is carried out. The geometries and normal modes of vibrations obtained from ab initio HF and B3LYP/B3PW91 calculations are in good agreement with the experimentally observed data. The differences between the observed and scaled wave number values of most of the fundamentals are very small in B3LYP than HF. The influence of N atom and amine group in the skeletal ring vibrations of the title molecule has also been discussed.
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Affiliation(s)
- S Ramalingam
- Department of Physics, A.V.C. College (Autonomous), 14, Sivasakthi Nagar, Mappadugai, Mayiladuthurai, Nagai District, India.
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Ramalingam S, Periandy S, Narayanan B, Mohan S. FTIR and FTRaman spectroscopic investigation of 2-bromo-4-methylaniline using ab initio HF and DFT calculations. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2010; 76:84-92. [PMID: 20335064 DOI: 10.1016/j.saa.2010.02.050] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 02/17/2010] [Accepted: 02/26/2010] [Indexed: 05/29/2023]
Abstract
The FTIR and FTRaman spectra of 2-bromo-4-methyl aniline (2-B-4-MA) molecule have been recorded using Brucker IFS 66V spectrometer in the range of 4000-100 cm(-1). The molecular geometry and vibrational frequencies in the ground state are calculated using the Hartree-Fock (HF) and B3LYP with 6-31+G*(d, p), 6-311+G*(d, p) and 6-311++G* (d, p) basis sets. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. The isotropic HF and DFT analysis showed good agreement with experimental observations. Comparison of the fundamental vibrational frequencies with calculated results by HF and B3LYP methods indicates that B3LYP/6-311++G* (d, p) is superior to HF/6-31+G* for molecular vibrational problems. The complete data of this title compound provide the information for future development of substituted aniline. The influences of bromine atom, methyl group and amine group on the geometry of benzene and its normal modes of vibrations have also been discussed.
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Affiliation(s)
- S Ramalingam
- Department of Physics, A.V.C. College (Autonomous), 14 Sivasakthi Nagar, Mappadugai, Mayiladuthurai, Nagai District 609305, India.
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Ramalingam S, Periandy S, Govindarajan M, Mohan S. FT-IR and FT-Raman vibrational spectra and molecular structure investigation of nicotinamide: A combined experimental and theoretical study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2010; 75:1552-1558. [PMID: 20227335 DOI: 10.1016/j.saa.2010.02.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 02/05/2010] [Accepted: 02/15/2010] [Indexed: 05/28/2023]
Abstract
In this work, the experimental and theoretical spectra of nicotinamide (C(6)H(6)N(2)O) are studied. FT-IR and FT-Raman spectra of title molecule in the liquid phase have been recorded in the region 4000-100cm(-1). The structural and spectroscopic data of the molecule in the ground state have been calculated by using Hartree-Fock and density functional method (B3LYP) with the 6-31+G*(d, p) and 6-31++G* (d, p)basis set. The vibrational frequencies have been calculated and scaled values have been compared with the experimental FT-IR and FT-Raman spectra. The observed and calculated frequencies are found in good agreement. The DFT-B3LYP/6-31++G (d, p) calculations have been found are more reliable than the ab initio HF/6-31+G (d, p) calculations for the vibrational study of nicotinamide. The optimized geometric parameters (bond lengths and bond angles) are compared with experimental values of the molecule. The alteration of vibrational bands due to the substitutions in the base molecule is also investigated from their characteristic region of linked spectrum.
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Affiliation(s)
- S Ramalingam
- Department of Physics, A.V.C. College, 14 Sivasakthi Nagar, Mappadugai, Mayiladuthurai, Nagai District 609305, India.
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Swaminathan J, Ramalingam M, Saleem H, Sethuraman V, Ameen MTN. FT-IR and FT-Raman vibrational assignment of 2-bromobenzoic acid with the help of ab initio and DFT calculations. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2009; 74:1247-1253. [PMID: 19864180 DOI: 10.1016/j.saa.2009.09.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 08/26/2009] [Accepted: 09/25/2009] [Indexed: 05/28/2023]
Abstract
The vibrational spectra of 2-bromobenzoic acid (2BBA) have been experimentally recorded (FT-IR and FT-Raman) and compared with the harmonic vibrational frequencies calculated at HF and B3LYP level of theories using 6-311+G(d,p) basis set with appropriate scaling factors. The XRD geometrical parameters show satisfactory agreement with the theoretical prediction at Hartree-Fock and B3LYP levels. 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.
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Affiliation(s)
- J Swaminathan
- Department of Chemistry, Periyar Maniammai University, Vallam, Thanjavur 613403, India
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Swaminathan J, Ramalingam M, Sethuraman V, Sundaraganesan N, Sebastian S. Vibrational spectroscopic studies and DFT calculations of 4-aminoantipyrine. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2009; 73:593-600. [PMID: 19386538 DOI: 10.1016/j.saa.2009.03.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2008] [Revised: 03/01/2009] [Accepted: 03/16/2009] [Indexed: 05/27/2023]
Abstract
The pyrazole derivative, 4-aminoantipyrine (4AAP), used as an intermediate for the synthesis of pharmaceuticals especially antipyretic and analgesic drugs has been analyzed experimentally and theoretically for its vibrational frequencies. The FTIR and FT Raman spectra of the title compound have been compared with the theoretically computed frequencies invoking the standard 6-311g(d,p) and cc-pVDZ basis sets at DFT level of theory (B3LYP). The harmonic vibrational frequencies at B3LYP/cc-pVDZ after appropriate scaling method seem to coincide satisfactorily with the experimental observations rather than B3LYP/6-311g(d,p) results. The theoretical spectrograms for FT-IR and FT-Raman spectra of 4AAP have been also constructed and compared with the experimental spectra. Additionally, thermodynamic data have also been calculated and discussed.
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Affiliation(s)
- J Swaminathan
- Department of Chemistry, Periyar Maniammai University, Vallam, Thanjavur 613403, India
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