Aid Of Normal Coordinate Analysis Research Articles

Quantum computational, Spectroscopic investigations on benzofuranylcarbonylpyrazolopyridine by DFT/TD-DFT: Synthesis, Structure, NBO and NLO research

Reaction of 4-methoxy-5-oxo-5H-furo[3,2-g] chromene-6-carboxaldehyde (1) with 5-amino-2,4-dihydro-3H-pyrazol-3-one (2) afforded the novel 5-(6-hydroxy-4-methoxy-1-benzofuran-5-ylcarbonyl)-3-hydroxy-1H-pyrazolo[3,4-b]pyridine (3, BFCPP). The experimental and theoretical quantum computations (optimized structure, IR, NMR and UV-Vis.) investigation of the current compound were performed using DFT theory at B3LYP functional and 6–311++G(d,p) basis set. The complete analysis of the vibrational spectra was taken with the aid of normal coordinate analysis followed by scaled quantum mechanical force field methodology. The theoretical NMR was achieved in DMSO-d6 as a solvent, while the IR and optimized calculations were done in the gas phase. A kind of solutions were used to discover the UV-Visible spectrum using the TD-DFT method. The stability of the current molecule occurred from hyper conjugative interactions leading to its nonlinear optical activity. Also, the charge delocalization was analyzed using natural bond orbital technique. Mulliken atomic charge and molecular electrostatic potential (MEP) are also calculated. HOMO–LUMO energy gap value indicates the probability of charge transfer within the molecule. The thermodynamic properties at different temperatures are also analyzed.

Experimental and theoretical vibrational spectral Investigations, structural conformations, DFT estimations and docking studies of antibacterial drug Nitrilotriaceticacid

Nitrilotriaceticacid (NTA) was utilised without additional purification after being bought from Sigma Aldrich Chemical Company in powdered form with 99% purity. Density Functional Theory calculations at B3LYP with a 6-311++G (d,p) level were performed to gain knowledge of molecule geometries, harmonic vibrational spectra, and molecular docking analysis. Vibrational spectral investigations have been carried out with the aid of Normal Coordinate Analysis on the basis of potential energy distribution (PED) of each mode, which helps us to attain a quantitative as well as qualitative analysis of IR and Raman spectra followed by empirical scaled quantum mechanical force field methodology. Natural bond orbital analysis, Fukui analysis, RDG analysis, and Mulliken’s net charges have also been predicted. FMO's energy gap predicts the occurrence of charge transport within molecule. UV–Visible spectral analyses of NTA have been examined by experimental and theoretical calculations. By mapping electron density isosurface with an electrostatic potential surface (ESP), information about the size, shape, charge density distribution, and site of chemical reactivity of the molecules has been acquired. ELF and LOL maps portrayed topological aspects of NTA which also have been depicted. Hyperpolarizability values are in good agreement revealing that these compounds could be employed in electro optical applications. Antibacterial activity reveals that NTA have been found to exhibit antibacterial effects. Docking simulation has been carried out for the optimized ligand molecule to identify binding energy and coupling with protein molecule. NTA molecule underwent a drug likeness test utilising Lipinski's criterion, and using ADMET contour, the molecule is recommended for inclusion in pharmaceuticals.

Hyperconjugation and Hydrogen Bonding Interactions Effect with the Nonlinear Optical Features of 4-Chlorophenoxy Acetonitrile: An Experimental and DFT Methodology

The compound 4-cholorophenoxy acetonitrile (CPAN) was examined using Nonlinear optical properties in the current study. With the aid of normal coordinate analysis and the SQMFF methodology, vibrational analysis of FT-IR and FT-Raman has been conducted. Natural bond orbital analysis is used to analyze the electronic stability of the compound created by hyper conjugative contacts and charge delocalization, and the Frontier molecular orbital energy gap confirms the molecule’s optical activity. ESP recognizes the nucleophilic and electrophilic areas of molecules, and the chemical implication of molecules was explained using ELF, LOL. Third-order nonlinear optical (NLO) investigations are carried out on a CPAN crystal using the Z-scan technique, and optical properties are established.

Exploring the antibacterial activity of 1, 2 diaminoethane hexanedionic acid by spectroscopic, electronic, ELF, LOL, RDG analysis and molecular docking studies using DFT method

Diaminoethane hexanedionic acid, selected for its antibacterial property is extensively used for spectroscopic elucidations and computational aspects using density functional methods. Self-consistent field equation has been solved iteratively to reach the equilibrium geometry corresponding to the saddle point on the potential energy surface (PES). Assignments of vibrational spectra have been carried out with the aid of Normal coordinate analysis following the SQMFF methodology. NLO analysis through first order hyperpolarizability parameter helps in finding the potential of DAHA as a good NLO candidate whereas Charge delocalization and the stability of the compound was deliberated using natural bond orbital (NBO) analysis. An explicit surface analysis was carried out using the wave function analyser Multiwfn software, in order to study the reactivity of the compound. TD-DFT approach was applied to assign the electronic transition perceived in UV–visible spectrum measured experimentally. Frontier molecular orbital energy gap confirms the bioactivity of the molecule. NCI analysis gives information about inter and intra non covalent interactions and ESP is used to recognise the nucleophilic and electrophilic regions of molecule. Molecular docking was conceded with four antibacterial proteins confirm the bioactivity of molecule and drug likeness factors were calculated to comprehend the biological assets of DAHA.

Tuning the Computational Evaluation of Spectroscopic, ELF, LOL, NCI analysis and Molecular Docking of Novel Anti COVID-19 Molecule 4-Dimethylamino Pyridinium 3, 5-Dichlorosalicylate

In this work novel antiviral compound 4-(Dimethylamino) Pyridinium 3, 5-dichlorosalicylate was synthesized and characterized by UV–vis, FT-IR, FT-Raman, 1H NMR and 13C NMR spectra. Quantum chemical computations were carried out by Density functional theory methods at B3LYP level. Electronic stability of the compound arising from hyper conjugative interactions and charge delocalization is investigated using natural bond orbital analysis. Assignments of vibrational spectra have been carried out with the aid of Normal coordinate analysis following the SQMFF methodology. TD-DFT approach was applied to assign the electronic transition observed in UV visible spectrum measured experimentally. Frontier molecular orbital energy gap affirms the bioactivity of the molecule and NCI analysis gives information about inter and intra non covalent interactions. ESP recognises the nucleophilic and electrophilic regions of molecule and the chemical implication of molecule was explained using ELF, LOL. The reactive sites of the compound were studied from the Fukui function calculations and chemical descriptors define the reactivity of the molecule. Molecular docking done with SARS and MERS proteins endorses the bioactivity of molecule and drug likeness factors were calculated to comprehend the biological assets of DADS.

Synthesis, spectra, electronic structure, molecular docking and cytotoxicity investigation on 2-(piperidin-1-ylmethyl)-isoindoline-1,3-dione – A Mannich base system

A Mannich base molecule of 2-(piperidin-1-ylmethyl)isoindoline-1,3-dione (PPF) has been synthesized using Mannich base condensation reaction. The molecular geometry of PPF molecule was optimized by B3LYP/6-311G(d,p) basis set. The vibrational frequencies have been assigned with the aid of normal coordinate analysis. Total energy distributions (TED) were used to explain each vibrational wavenumber assignments of a molecule. The 1H and 13C NMR spectroscopic analyses were predicted by using gauge independent atomic orbital (GIAO) method. The thermal stability was determined by applying the thermo gravimetric/differential scanning calorimetry (TG/DSC) studies. The HOMO-LUMO energies, population density of states (PDOS), overlap population density of states (OPDOS), reduced density gradient (RDG), Mulliken atomic charges and molecular electrostatic potential (MEP) surface were plotted to investigate the van der Waals, attraction, repulsion, non-covalent and covalent interactions of the compound. The natural bond orbital (NBO) charge analysis was used in explaining the intermolecular charge transfer and resonance stabilization energy of molecule. Besides, the molecular docking studies have been performed. The cytotoxic activity of the PPF molecule has been resolved.

Evaluation of conformational and spectral behavior and prediction of biological activity and chemical reactivity descriptors of Levosimendan

The conformational behavior and structural stability of Levosimendan (LVM) is investigated by density functional theory. The spectroscopic properties are analyzed using 1H NMR, FT-IR and Raman techniques. The 1H NMR chemical shifts of the molecule are calculated by Gauge independent atomic orbital method and compared with the experimental results. The vibrational spectra have been interpreted with the aid of normal coordinate analysis. A comparison of normal modes of both the conformers has been made in terms of change in wavenumbers, intensities and potential energy distribution. Lipophilicity and aqueous solubility have been calculated to estimate the absorption and distribution properties of drug which dictate the success or failure rate of drug discovery and development. ‘Prediction of Activity Spectra for Substances’ analysis has been done to predict the possible biological activities of LVM. Molecular docking has been performed to investigate the potential of the LVM molecule to bind with human cardiac troponin C receptor. Several chemical reactivity descriptors such as ionization energy, electron affinity, chemical potential, global hardness and electrophilicity have been evaluated to understand the molecular properties. The possible electrophilic and nucleophilic reactive sites of the molecule are studied using molecular electrostatic potential surface and Fukui function.

Growth, effect of protonation and hydrogen bonding interactions of L-Histidine nitrate monohydrate, a potential semi organic third order nonlinear optical material

Single crystal of l-Histidine Nitrate monohydrate (LHNM) has been grown from aqueous solution by evaporation technique. A comprehensive investigation of the NIR FT-Raman and FT-IR spectra was carried out with the aid of normal coordinate analysis following the scaled quantum mechanical force field methodology supported by the density functional theory (DFT) computations to analyze the effects of intramolecular charge transfer on the geometries and the vibrational modes contributing to the linear electro-optic effect of the organic NLO material. Effect of protonation and hydrogen bonding interactions has been analyzed using structural analysis, natural bond orbital analysis, and spectral analysis. The HOMO-LUMO energy gap value suggests the possibility of charge transfer within the molecule. Hyperconjugative interactions responsible for second hyperpolarizabilities have been described by NBO and AIM analyses. Hirshfeld surface analysis reveals that the van der Waals H⋯H (32.3%) contact plays a significant role in crystal packing and that a variety of NH⋯O intermolecular contacts and hydrogen bonds leads to the formation of intermolecular charge transfer occurring in LHNM. The nonlinear refractive index (n2), nonlinear absorption coefficient (β) and third-order nonlinear susceptibility (χ3) of LHNM have been determined by Z-scan technique, which points to its potential application in the field of optical limiting. The calculated value of laser damage threshold was 2.04 GW/cm2.

Electronic structure, vibrational (FT-IR and FT-Raman), UV–Vis and NMR analysis of 5-(4-(2-(5-ethylpyridin-2-yl) ethoxy) benzyl) thiazolidine-2,4-dione by quantum chemical method

Abstract The vibrations of 5-(4-(2-(5-ethylpyridin-2-yl)ethoxy)benzyl) thiazolidine-2,4-dione(C19H20N2O3S) were investigated. The solid phase FTIR and FT-Raman spectra were recorded in the region 4000–400 cm−1 and 4000–50 cm−1 respectively. The vibrational frequencies of the title compound were obtained theoretically by DFT/B3LYP method with 6–31G(d,p) and 6–311G(d,p) basis sets for optimized geometry. The theoretically predicted FT-IR and FT-Raman spectra of the title molecule have been constructed. The detailed interpretation of the vibrational spectra has been carried out with aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology. UV–Vis spectrum of the title molecule was recorded and the electronic properties such as HOMO and LUMO energies were determined by Time-Dependent Density Functional Theory approach. The electrostatic potential surfaces, polarizability, NBO and thermodynamic properties of the title compound were discussed.

Crystal structure, vibrational spectra, optical and DFT studies of poly[bis(L-methionine)-κS:O cadmium (II) di-μ-thiocyanato- κ2N:S; κ2S:N

Crystal structure, FT-Raman, IR and UV–vis spectroscopy have been applied to investigate the potential nonlinear optical (NLO) material of [Cd(SCN)2(C5H11NO2S)2]n. Crystal structure of [Cd(SCN)2(C5H11NO2S)2]n shows that the one-dimensional chain is propagated through doubly bridging thiocyanate and l-methionine (C5H11NO2S) acts as terminal ligand. These chains are linked together by mean of NH⋯N and NH⋯O hydrogen bonds. Optimized molecular geometry, atomic Mulliken charges, harmonic vibrational frequencies, energies of frontier molecular orbitals (EHOMO and ELUMO), energy band gap (EHOMO–ELUMO), chemical potential (μ), chemical hardness (η), global electrophilicity index(ω) dipole moment, linear polarizability, and first order hyperpolarizability were calculated by Density functional theory (DFT) using B3LYP method with double-zeta valence (LANL2DZ). The calculated structural parameters (bond lengths and angles) are in good agreement with the experimental XRD data. DFT is also applied to explore the nonlinear optical properties of this material. This compound exhibits non-zero static first hyperpolarizabilities values so it might have microscopic NLO behavior. A detailed interpretation of the vibrational spectra was carried out with the aid of normal coordinate analysis following the scaled quantum mechanical force field methodology. Good consistency is found between the calculated results and experimental data for the IR and Raman spectra.

Quantum chemical insight into molecular structure, density functional theory calculations, vibrational dynamics, natural population analysis, Hirshfeld analysis, and molecular docking approach to chalcone 1-4-bromophenyl-3-(2-methoxyphenyl)prop-2-en-1-one

ABSTRACTThe structure of the novel chalcone 1-4-bromophenyl-3-(2-methoxyphenyl)prop-2-en-1-one has been characterized by Fourier transform infrared and Fourier transform Raman. Density functional theory with Becke, 3-parameter, Lee-Yang-Parr functional was used for the optimization of geometry. The comprehensive assignments of the vibrational spectra have been performed with the aid of normal coordinate analysis. Stability of the molecule and intra/intermolecular charge transfer have been analyzed using natural bond orbital analysis. The existence of intermolecular C-H⋯O, blueshifted hydrogen bond was investigated by bond length variation. Hirshfeld and two-dimensional fingerprint plot analyses have been performed to study the nature of interactions present in the molecule. The docked complex gives a constancy of −8.2 kcal/mol toward the androgen receptor.

Quantum chemical computation by DFT application of NLO molecule 2-aminopyridinium p-toluenesulphonate

In the present work, we have reported a theoretical study on molecular structure and vibrational spectra of organic nonlinear optical 2-aminopyridinium p-toluenesulphonate (APPTS). The molecular geometry, electrostatic potential surface and vibrational wave numbers with Raman intensities and infrared absorption intensities in the ground state have been calculated by density functional theory (DFT) method using various basis sets and Beckes three-parameter hybrid functional (B3LYP). Finally, the results were applied to simulate infrared and Raman spectra of the title compound. The assignments of the vibrational spectra have been carried out with the aid of normal coordinate analysis.

Spectroscopic (FT-IR, FT-Raman), first order hyperpolarizabilities, NBO, Fukui function and molecular docking study of N-(4-Chloro-3-methylphenyl)-2-phenylacetamide

The Fourier transform infrared (FT-IR) and Fourier transform Raman (FT-Raman) of N-(4-Chloro-3-methylphenyl)-2-phenylacetamide (N4C3M2P) were recorded in the regions 4000–400cm−1 and 4000–100cm−1 respectively, in the solid phase. The molecular structures, vibrational wave numbers, infrared intensities, Raman scattering activities were calculated using DFT method with B3LYP/6–311++G(d,p) basis set. Detailed interpretations of the vibrational spectra have been carried out with the aid of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field methodology. Molecular electrostatic potential (MEP) and HOMO-LUMO energy levels are also constructed. The stability of molecule has been analyzed by NBO analysis. The molecule orbital contributions were studied by using the total density of states (TDOS), the sum of α and β electron density of states (αβDOS). Fukui functions, local softness and eletrophilicity indices for selected atomic sites of the title compound are determined. To study the biological activity of the investigation molecule, molecular docking (ligand-protein) stimulations are performed by using autoDock 4.2.6. The hydrogen bond lengths and binding energy values are determined. Finally, the thermal behaviors of the N4C3M2P compound have been calculated by different temperature.

Antimycobacterial, antimicrobial activity, experimental (FT-IR, FT-Raman, NMR, UV-Vis, DSC) and DFT (transition state, chemical reactivity, NBO, NLO) studies on pyrrole-isonicotinyl hydrazone

As part of a study of pyrrole hydrazone, we have investigated quantum chemical calculations, molecular geometry, relative energy, vibrational properties and antimycobacterial/antimicrobial activity of pyrrole-2-carboxaldehyde isonicotinyl hydrazone (PCINH), by applying the density functional theory (DFT) and Hartree Fock (HF). Good reproduction of experimental values is obtained and with small percentage error in majority of the cases in comparison to theoretical result (DFT). The experimental FT-IR and Raman wavenumbers were compared with the respective theoretical values obtained from DFT calculations and found to agree well. In crystal structure studies the hydrated PCINH (syn-syn conformer) shows different conformation than from anhydrous form (syn-anti conformer). The rotational barrier between syn-syn and syn-anti conformers of PCINH is 12.7kcal/mol in the gas phase. In this work, use of FT-IR, FT-Raman, 1H NMR, 13C NMR and UV–Vis spectroscopies has been made for full characterization of PCINH. A detailed interpretation of the vibrational spectrum was carried out with the aid of normal coordinate analysis using single scaling factor. Our results support the hydrogen bonding pattern proposed by reported crystalline structure. The calculated nature of electronic transitions within molecule found to be π→π*. The electronic descriptors study indicates that PCINH can be used as robust synthon for synthesis of new heterocyclic compounds. The first static hyperpolarizability (β0) of PCINH is calculated as 33.89×10−30esu, (gas phase); 68.79×10−30 (CHCl3), esu; 76.76×10−30esu (CH2Cl2), 85.16×10−30esu (DMSO). The solvent induced effects on the first static hyperpolarizability were studied and found to increase as dielectric constants of the solvents increases. Investigated molecule shows better NLO value than Para nitroaniline (PNA). The compound PCINH shows good antifungal and antibacterial activity against Aspergillus niger and gram-positive bacteria Bacillus subtilis, respectively. The compound also shows good antituberculosis activity against Mycobacterium tuberculosis H37Rv using the microplate alamar blue assay (MABA).

Vibrational, electronic absorption, thermal and mechanical analyses of organic nonlinear optical material guanidinium phthalate

The FTIR and UV spectroscopic analysis have been carried out on guanidinium phthalate (GUP) crystal, an organic nonlinear optical material. The spectra are interpreted with the aid of normal coordinate analysis following structure optimizations and force field calculations based on density functional theory (DFT). The thermogravimetric (TG) and differential thermal analysis (DTA) ensures the thermal stability of the compound. Vickers microhardness values reveals the mechanical strength of the crystal.

Physico-chemical studies of the experimental and theoretical properties of organic nonlinear optical material 4-chloro-4'methoxy benzylideneaniline

The FT-IR, FT-Raman and UV–visible spectral analysis of 4-chloro 4’-methoxy benzylidene aniline were done experimentally and interpreted with the aid of normal coordinate analysis based on density functional theory (DFT) at the B3LYP/6–311++G (d, p) level of theory. Natural Bond orbital analysis was performed to understand the charge transfer interactions and reactive sites within the system. HOMO-LUMO analysis and first static and dynamic hyperpolarizability calculations were carried out in order to confirm the NLO activity of CMOBA. Photophysical characterization was done to understand the fluorescence emission and lifetime of CMOBA leading to application in blue OLEDs. The Molecular Electrostatic Potential Map was simulated to identify the active sites for electrophilic and nucleophilic attack or the active sites of the molecule which can bind to proteins. Molecular docking analysis revealed its potential as an inhibitor for different proteins which are responsible for cancer and many inflammatory diseases such as rheumatoid arthritis, inflammatory bowel disease, Crohn's disease and psoriasis. Experimental studies of invitro antiproliferative effect by MTT assay verified the anticancer properties of CMOBA.

Evaluation of structure-reactivity descriptors and biological activity spectra of 4-(6-methoxy-2-naphthyl)-2-butanone using spectroscopic techniques

The structure and several spectroscopic features along with reactivity parameters of the compound 4-(6-methoxy-2-naphthyl)-2-butanone (Nabumetone) have been studied using experimental techniques and tools derived from quantum chemical calculations. Structure optimization is followed by force field calculations based on density functional theory (DFT) at the B3LYP/6-311++G(d,p) level of theory. The vibrational spectra have been interpreted with the aid of normal coordinate analysis. UV–visible spectrum and the effect of solvent have been discussed. The electronic properties such as HOMO and LUMO energies have been determined by TD-DFT approach. In order to understand various aspects of pharmacological sciences several new chemical reactivity descriptors - chemical potential, global hardness and electrophilicity have been evaluated. Local reactivity descriptors - Fukui functions and local softnesses have also been calculated to find out the reactive sites within molecule. Aqueous solubility and lipophilicity have been calculated which are crucial for estimating transport properties of organic molecules in drug development. Estimation of biological effects, toxic/side effects has been made on the basis of prediction of activity spectra for substances (PASS) prediction results and their analysis by Pharma Expert software. Using the THz-TDS technique, the frequency-dependent absorptions of NBM have been measured in the frequency range up to 3THz.

Vibrational spectra analysis, NBO, HOMO–LUMO, and nonlinear optical behavior studies on 3-(3,4-dimethoxyphenyl)-1-(pyridin-2-yl)prop-2-en-1-one

A combined experimental and theoretical study on molecular structure, vibrational spectra, HOMO–LUMO analysis, and hyperpolarizability of organic nonlinear optical crystal 3-(3,4-dimethoxyphenyl)-1-(pyridin-2-yl)prop-2-en-1-one is reported. Vibrational wavenumbers with Raman intensities and infrared absor ption intensities have been calculated in the ground state by the density functional theory method using 6-31G(d,p) basis set and Becke’s three-parameter hybrid functional (B3LYP). Finally, the calculation results were applied to simulate infrared and Raman spectra of the title compound which showed good agreement with the observed spectra. The assignments of the vibrational spectra have been carried out with the aid of normal coordinate analysis. The natural bond orbital analysis was performed to study the intramolecular bonding, interactions among bonds, and delocalization of unpaired electrons. Electrostatic potential surface and HOMO–LUMO are reported along with global reactivity descriptors. First, hyperpolarizability of the molecule was also calculated and nonlinear behavior of the molecule analyzed using computed data.

Synthesis, crystal structure, vibrational spectral analysis and Z-scan studies of a new organic crystal N,N′dimethylurea ninhydrin: A scaled quantum mechanical force field study

A new organic material, N,N′dimethylurea ninhydrin (3a,8a-dihydroxy-1,3-dimethyl-1,3,3a,8a-tetrahydroindeno[2,1-d]imidazole-2,8-dione) (NDUN) was synthesized. Structural details were obtained from single crystal X-ray diffraction (XRD) data. A detailed interpretation of the vibrational spectra is carried out with the aid of normal coordinate analysis following the scaled quantum mechanical force field methodology. TG/DTA and 1H NMR studies were carried out. Linear optical properties were studied from UV–Vis spectra. From the open aperture Z-scan data, it is found that the molecule shows third order nonlinear optical behaviour due to two photon absorption (2PA) mechanism.

Synthesis, crystal growth, single crystal X-ray analysis and vibrational spectral studies of (2E)-3-(2-chloro-4-fluorophenyl)-1-(3,4-dimethoxyphenyl)prop-2-en-1-one: A combined DFT study

A new chalcone derivative, (2E)-3-(2-chloro-4-fluorophenyl)-1-(3,4-dimethoxyphenyl)prop-2-en-1-one (a) was synthesized and single crystals were grown by slow evaporation technique. The FT-Raman and FT-IR spectra of the sample were recorded in the region 3500–100 cm−1 and 4000–400 cm−1 respectively. The spectra were interpreted with the aid of normal coordinate analysis, following structure optimizations and force field calculations based on B3LYP/6-31G (d) level of theory. Normal coordinate calculations were performed using the DFT force field corrected by a recommended set of scaling factors yielding fairly good agreement between the observed and calculated wavenumbers. The total electron density and molecular electrostatic potential surfaces of the molecule were constructed using B3LYP/6-31G (d) method to display electrostatic potential (electron + nuclei) distribution, molecular shape, size, and dipole moments of the molecule. HOMO and LUMO energies were also calculated. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. Global and local reactivity descriptors and dipole moment (μ), static polarizability (α), first order hyperpolarizability (β) and optical gap (ΔE) were also calculated to study the NLO property of our title compound.