FT-IR, FT-Raman and DFT calculations of 4-chloro-2-(3,4-dichlorophenylcarbamoyl)phenyl acetate

Preliminary anticancer evaluation of new Pd(II) complexes bearing NNO donor ligands

In this study we presented a novel series of NNO tridentate ligands generating imino, amido and oxo donor pocket for Pd(II) coordination. All the compounds were meticulously characterized by elemental analysis and advanced spectroscopic techniques, including FTIR, proton and carbon NMR. The synthesized compounds underwent rigorous evaluation for their potential as anti-cancer agents, utilizing the aggressive breast cancer cell lines MDA-MB (ATCC) and MCF-7 as a crucial model for assessing growth inhibition in cancer cells. Remarkably, the MTT assay unveiled the robust anti-cancer activity for all palladium complexes against MDA-MB-231 and MCF-7 cells. Particularly, complex [Pd(L1)(CH3CN)] exhibited exceptional potency with an IC50 value of 25.50 ± 0.30 µM (MDA-MB-231) and 20.76 ± 0.30 µM (MCF-7), compared to respective 27.00 ± 0.80 µM and 24.10 ± 0.80 µM for cisplatin, underscoring its promising therapeutic potential. Furthermore, to elucidate the mechanistic basis for the anti-cancer effects, molecular docking studies on tyrosine kinases, an integral target in cancer research, were carried out. The outcome of these investigations further substantiated the remarkable anticancer properties inherent to these innovative compounds. This research offers a compelling perspective on the development of potent anti-cancer agents rooted in the synergy between ligands and Pd(II) complexes and presenting a promising avenue for future cancer therapy endeavors.

Synthesis, Structural Elucidation and Pharmacological Applications of Cu(II) Heteroleptic Carboxylates

Six heteroleptic Cu(II) carboxylates (1-6) were prepared by reacting 2-chlorophenyl acetic acid (L¹), 3-chlorophenyl acetic acid (L²), and substituted pyridine (2-cyanopyridine and 2-chlorocyanopyridine). The solid-state behavior of the complexes was described via vibrational spectroscopy (FT-IR), which revealed that the carboxylate moieties adopted different coordination modes around the Cu(II) center. A paddlewheel dinuclear structure with distorted square pyramidal geometry was elucidated from the crystal data for complexes 2 and 5 with substituted pyridine moieties at the axial positions. The presence of irreversible metal-centered oxidation reduction peaks confirms the electroactive nature of the complexes. A relatively higher binding affinity was observed for the interaction of SS-DNA with complexes 2-6 compared to L¹ and L². The findings of the DNA interaction study indicate an intercalative mode of interaction. The maximum inhibition against acetylcholinesterase enzyme was caused for complex 2 (IC₅₀ = 2 µg/mL) compared to the standard drug Glutamine (IC₅₀ = 2.10 µg/mL) while the maximum inhibition was found for butyrylcholinesterase enzyme by complex 4 (IC₅₀ = 3 µg/mL) compared to the standard drug Glutamine (IC₅₀ = 3.40 µg/mL). The findings of the enzymatic activity suggest that the under study compounds have potential for curing of Alzheimer's disease. Similarly, complexes 2 and 4 possess the maximum inhibition as revealed from the free radical scavenging activity performed against DPPH and H₂O₂.

Molecular structure determination, spectroscopic, quantum computational studies and molecular docking of 4-(E)-[2-(benzylamino)phenylimino) methyl-2]ethoxy phenol

A Schiff base compound 4-(E)-[2-(benzylamino)phenylimino)methyl-2]ethoxy phenol (4BPM2EP) was synthesized and spectroscopic characterization was performed using experimental methods such as FT-IR, FT-Raman and UV-Vis spectroscopy. Density functional theory (DFT/B3LYP/6-311++G(d,p)) computation was used to investigate the optimized molecular geometry, harmonic vibrational wavenumber, NMR chemical shifts, natural bond orbital (NBO) analysis, non-linear optical (NLO) properties, molecular electrostatic potential (MEP) map and Mulliken atomic charges of 4BPM2EP molecule. TD-DFT calculations have been carried out on the optimized geometry at gaseous phase, DMSO and ethanol to further understand the electronic transitions and solvents effect on the UV-Vis spectra of the compound. The assignments of vibrational modes were performed on the basis of total energy distribution (TED) using VEDA 4 program and were compared with experimental data. Molecular docking study was performed using Glide program to establish the information about the interactions between the topoisomerase DNA gyrase enzymes and the novel compound in order to explore the biological behaviour of the examined compound. The compound screened against four pathogens two gram positive, two gram negative and two fungal strains had shown good anti-bacterial and antifungal behaviour. Furthermore the compound was subjected to in-silico ADMET studies.Communicated by Ramaswamy H. Sarma.

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.

Quantum chemical calculation, performance of selective antimicrobial activity using molecular docking analysis, RDG and experimental (FT-IR, FT-Raman) investigation of 4-[{2-[3-(4-chlorophenyl)-5-(4-propan-2-yl) phenyl)-4, 5-dihydro- 1H- pyrazol-1-yl]-4-oxo-1, 3- thiazol-5(4H)-ylidene} methyl] benzonitrile

The research received a great deal of worldwide attention due to the nature of interpretation before the experimental process. Based on the systematic process the structure of thiazole -pyrazole compound 4-[{2-[3-(4-chlorophenyl)-5-(4-propan-2-yl) phenyl)-4, 5-dihydro- 1H- pyrazol-1-yl]-4-oxo-1, 3- thiazol-5(4H)-ylidene} methyl] benzonitrile [CPTBN] was investigated. In the first level, the spectral statistics on experimental FT-IR and FT- Raman was reported. At the next level, geometrical parameters was theoretically acquired from density functional theory (DFT) using B3LPY/6-31G and 6-311G basis set. The computed Wavenumber were collected and compared with the experimental data. The vibrational modes were interpreted in terms of potential energy distribution (PED) results. The FMO, MEP, and NBO analysis further validated the electrophilic and nucleophilic interaction in the molecular systems. Two grams-positive bacteria: staphylococcus aureus, Bacillus subtilis and two gram-negative bacteria: Esherichia coli, Pseudomonas aeruginosa was performed for antibacterial activity. Two fungal strain Candida albicans and Aspergillus Niger was carried out against a ligand using anti-fungal activity. The molecular docking analysis explores the antimicrobial and selective potential inhibitory nature of the binding molecule. Besides, RDG and ELF analysis were also performed to show the nature of interactions between the molecule.

Tailored activity of Cu–Fe bimetallic Beta zeolite with promising C3H6 resistance for NH3-SCR

The introduction of Cu has inhibited the polymerization of C₃H₆ and promoted the oxidation of C₃H₆, which alleviated competitive adsorption between C₃H₆ and NO_x, therefore results in the enhanced NH₃-SCR performance in the presence of C₃H₆.

Spectroscopic (FT-IR, FT-Raman, UV, 1H and 13C NMR) insights, electronic profiling and DFT computations on ({(E)-[3-(1H-imidazol-1-yl)-1-phenylpropylidene] amino}oxy)(4-nitrophenyl)methanone, an imidazole-bearing anti-Candida agent

The anti-Candida agent, ({(E)-[3-(1H-imidazol-1-yl)-1-phenylpropylidene]amnio}oxy(4-nitropheny) methanone (IPAONM), was subjected to comprehensive spectroscopic (FT-IR, FT-Raman, UV–Vis 1H and 13C NMR) characterization as well as Hartree Fock and density functional theory computation studies. The selected optimized geometric bond lengths and bond angles of the IPAONM molecule were compared with the experimental values. The calculated wavenumbers have been scaled and compared with the experimental spectra. Mulliken charges and natural bond orbital analysis of the title molecule were calculated and interpreted. The energy and oscillator strengths of the IPAONM molecule were calculated by time-dependent density functional theory (TD-DFT). In addition, frontier molecular orbitals and molecular electrostatic potential diagram of the title compound were computed and analyzed. A study on the electronic properties, such as HOMO, HOMO-1, LUMO and LUMO+1 energies was carried out using TD-DFT approach. The 1H and 13C NMR chemical shift values of the title compound were calculated by the gauge independent atomic orbital method and compared with the experimental results.

Spectroscopic (FT-IR, FT-Raman and UV) investigation, NLO, NBO, molecular orbital and MESP analysis of 2-{2-[(2,6-dichlorophenyl)amino]phenyl}acetic acid

In this work, FT-IR and FT-Raman spectra of 2-{2-[(2,6-dichlorophenyl)amino]phenyl}acetic acid (abbreviated as 2DCPAPAA) have been reported in the regions 4000-450cm(-1) and 4000-50cm(-1), respectively. The molecular structure, geometry optimization, intensities, vibrational frequencies were obtained by the ab initio and DFT levels of theory B3LYP with 6-311++G(d,p) standard basis set and a different scaling of the calculated wave numbers. 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 harmonic frequencies were calculated and the scaled values were compared with experimental FT-IR and FT-Raman data. The observed and the calculated frequencies are found to be in good agreement. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The thermodynamic properties of the title compound at different temperature reveal the correlations between standard heat capacities (C) standard entropies (S) standard enthalpy changes (ΔH). The important non-linear optical properties such as electric dipole momentum, polarizability and first hyperpolarizability of 2DCPAPAA have been computed using B3LYP/6-311++G(d,p) quantum chemical calculations. The Natural charges, HOMO, LUMO, chemical hardness (η), chemical potential (μ), Electro negativity (χ) and electrophilicity values (ω) are calculated and reported. The oscillator's strength, wave length, and energy calculated by TD-DFT and 2DCPAPAA is approach complement with the experimental findings. The molecular electrostatic potential (MESP) surfaces of the molecule were constructed.

The effects of electronegative substituent atoms on structural, vibrational, electronic and NLO properties of some 4-nitrostilbene derivates

Organic compounds which have one or more aromatic systems in conjugated positions show charge transfer interactions which are responsible for the non-linear properties of the compounds. A conjugated π electron system enables a pathway for the entire length of conjugation under the perturbation of an external electric field. When electron donating and withdrawing moieties are located at terminal position of conjugated backbone, nonlinear optical (NLO) properties have been increased significantly which involve the correlated and high delocalized π electron states. Recently synthesized organic complexes, 1-(4-fluorostyryl)-4-nitrostilbene (1), 4-Chloro 4-nitrostilbene (2), 4-Bromo 4-nitrostilbene (3) and 4-Iodo 4-nitrostilbene (4), were simulated using density functional theory (DFT). Based on the optimized geometries, spectroscopic and NLO properties of these complexes were discussed as compared with each other.

FT-IR, NBO, HOMO-LUMO, MEP analysis and molecular docking study of 1-[3-(4-Fluorophenyl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl]ethanone

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 1-[3-(4-fluorophenyl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl]ethanone have been investigated experimentally and theoretically. The geometrical parameters are in agreement with XRD data. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. From the MEP it is evident that the negative charge covers the carbonyl group and the positive region is over the remaining groups. The more electronegativity in the carbonyl group makes it the most reactive part in the molecule. First hyperpolarizability is calculated in order to find its role in nonlinear optics. From the molecular docking studies, it is evident that the fluorine atom attached to benzene ring and ethanone attached to the pyrazoline ring are crucial for binding and the compound might exhibit inhibitory activity against TPII and may act as anti-neoplastic agent.

Spectroscopic (FTIR, FT-Raman), molecular electrostatic potential, NBO and HOMO-LUMO analysis of P-bromobenzene sulfonyl chloride based on DFT calculations

The FTIR and FT-Raman spectra of P-bromobenzene sulfonyl chloride (P-BBSC) have been recorded in the regions 4000-400 cm(-1) and 3500-50 cm(-1), respectively. Utilizing the observed FTIR and FT-Raman data, a complete vibrational assignment and analysis of the fundamental modes of the compound were carried out. The optimum molecular geometry, harmonic vibrational frequencies, infrared intensities and Raman scattering activities, were calculated by density functional theory (DFT/B3LYP) method. A good agreement between experimental and calculated normal modes of vibrations has been observed. A detailed interpretation of the infrared and Raman spectra of P-BBSC is also reported based on total energy distribution (TED). Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The MEP map shows the negative potential sites are on oxygen atoms as well as the positive potential sites are around the hydrogen atoms. The UV-vis spectral analysis of P-BBSC has also been done which confirms the charge transfer of the molecule.

Molecular structure, FT-IR, NBO, HOMO and LUMO, MEP and first order hyperpolarizability of (2E)-1-(2,4-Dichlorophenyl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one by HF and density functional methods

(2E)-1-(2,4-Dichlorophenyl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one is synthesized by using 2,4-dichloroacetophenone and 3,4,5-trimethoxybenzaldehyde in ethanol. The structure of the compound was confirmed by IR and single crystal X-ray diffraction studies. FT-IR spectrum of (2E)-1-(2,4-dichloro-phenyl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one was recorded and analyzed. The crystal structure is also described. The vibrational wavenumbers were computed using HF and DFT methods and are assigned with the help of potential energy distribution method. The first hyperpolarizability and infrared intensities are also reported. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated (DFT) values. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. MEP was performed by the DFT method. From the MEP map of the title molecule, negative region is mainly localized over the electronegative oxygen atoms, in the carbonyl group and the oxygen atom O4 of the methoxy group and the maximum positive region is localized on the phenyl rings.

FT-IR, molecular structure, first order hyperpolarizability, MEP, HOMO and LUMO analysis and NBO analysis of 4-[(3-acetylphenyl)amino]-2-methylidene-4-oxobutanoic acid

4-[(3-Acetylphenyl)amino]-2-methylidene-4-oxobutanoic acid is synthesized and the structure of the compound was confirmed by IR, (1)H NMR and single crystal X-ray diffraction studies. FT-IR spectrum of 4-[(3-acetylphenyl)amino]-2-methylidene-4-oxobutanoic acid was recorded and analyzed. The crystal structure is also described. The vibrational wavenumbers were computed using HF and DFT methods are assigned with the help of potential energy distribution analysis. The NH stretching frequency is red shifted in the IR spectrum with a strong intensity from the computed frequency, which indicates the weakening of the NH bond resulting in proton transfer to the neighboring oxygen atom. The first hyperpolarizability and infrared intensities are also reported. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. Molecular electrostatic potential map was performed by the DFT method. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated (DFT) values.

Vibrational spectra and normal coordinate analysis of 2-hydroxy-3-(2-methoxyphenoxy) propyl carbamate

In this work, the vibrational spectral analysis was carried out by using FT-Raman and FTIR spectroscopy in the range 50-4000 cm(-1) and 450-4000 cm(-1) respectively, for 2-hydroxy-3-(2-methoxyphenoxy) propyl carbamate (2H3MPPLC) molecule. The molecular structure, fundamental vibrational frequencies and intensities of the vibrational bands were interpreted with the aid of structure optimizations and normal coordinate force field calculations based on density functional theory (DFT) and ab initio HF methods with 6-31G(d,p) basis set. The complete vibrational assignments of wave numbers were made on the basis of potential energy distribution (PED). The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The scaled B3LYP/6-31G(d,p) results show the best agreement with the experimental values over the other method. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results confirm the occurrence of intramolecular charge-transfer (ICT) within the molecule. The dipole moment (μ), polarizability (α) and hyperpolarizability (β) of the investigated molecule has been computed using B3LYP/6-31G(d,p) method. Mulliken population analysis on atomic charges was also calculated. Besides, frontier molecular orbitals, molecular electrostatic potential (MEP) and thermodynamic properties were performed.

Vibrational (FT-IR and FT-Raman), electronic (UV-Vis), NMR (1H and 13C) spectra and reactivity analyses of 4,5-dimethyl-o-phenylenediamine

The structure of 4,5-dimethyl-o-phenylenediamine (C8H12N2, DMPDA) was investigated on the basis of spectroscopic data and theoretical calculations. The sterochemical structure was determined by FT-IR, FT-Raman, UV, 1H and 13C NMR spectra. An experimental study and a theoretical analysis were associated by using the B3LYP method with Gaussian09 package program. FT-IR and FT-Raman spectra were recorded in the region of 4000-400 cm(-1) and 4000-10 cm(-1), respectively. The vibrational spectra were calculated by DFT method and the fundamental vibrations were assigned on the basis of the total energy distribution (TED), calculated with scaled quantum mechanics (SQM) method with Parallel Quantum Solutions (PQS) program. The UV absorption spectrum of the compound that dissolved in ethanol solution were recorded in the range of 190-400 nm. Total density of state (TDOS) and partial density of state (PDOS) of the DMPDA in terms of HOMOs and LUMOs were calculated and analyzed. Chemical shifts were reported in ppm relative to tetramethylsilane (TMS) for 1H and 13C NMR spectra. The compound was dissolved in dimethyl sulfoxide (DMSO). Also, 1H and 13C chemical shifts calculated using the gauge independent atomic orbital (GIAO) method. Mullikan atomic charges and other thermo-dynamical parameters were investigated with the help of B3LYP (DFT) method using 6-311++G** basis set. On the basis of the thermodynamic properties of the title compound at different temperatures have been carried out, revealing the correlations between heat capacity (C), entropy (S), enthalpy changes (H) and temperatures. The optimized bond lengths, bond angles, chemical shifts and vibrational wavenumbers showed the best agreement with the experimental results.

Molecular structure, FT-IR, first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis of 2-(4-chlorophenyl)-2-oxoethyl 3-methylbenzoate by HF and density functional methods

2-(4-Chlorophenyl)-2-oxoethyl 3-methylbenzoate is synthesized by reacting 4-chlorophenacyl bromide with 2-methylbenzoic acid using a slight excess of potassium or sodium carbonate in DMF medium at room temperature. The structure of the compound was confirmed by IR and single-crystal X-ray diffraction studies. FT-IR spectrum of 2-(4-chlorophenyl)-2-oxoethyl-3-nitrobenzoate was recorded and analyzed. The crystal structure is also described. The vibrational wavenumbers were computed using HF and DFT methods and are assigned with the help of potential energy distribution method. The first hyperpolarizability and infrared intensities are also reported. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated (DFT) values. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. MEP was performed by the DFT method.

Vibrational spectroscopy (FT-IR and Laser-Raman) investigation, and computational (M06-2X and B3LYP) analysis on the structure of 4-(3-fluorophenyl)-1-(propan-2-ylidene)-thiosemicarbazone

In this study, the experimental and theoretical vibrational spectral analysis of 4-(3-fluorophenyl)-1-(propan-2-ylidene)-thiosemicarbazone have been carried out. The experimental FT-IR (4000-400 cm(-1)) and Laser-Raman spectra (4000-100 cm(-1)) have been recorded for the solid state samples. The theoretical vibrational frequencies and the optimized geometric parameters (bond lengths and angles) have been calculated for gas phase using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr) and M06-2X (the highly parametrized, empirical exchange correlation function) quantum chemical methods with 6-311++G(d,p) basis set. The diversity in molecular geometry of fluorophenyl substituted thiosemicarbazones has been discussed based on the X-ray crystal structure reports and theoretical calculation results from the literature. The assignments of the vibrational frequencies have been done on the basis of potential energy distribution (PED) analysis by using VEDA4 software. A good correlation was found between the computed and experimental geometric and vibrational data. In addition, the highest occupied (HOMO) and lowest unoccupied (LUMO) molecular orbital energy levels and other related molecular energy values of the compound have been determined using the same level of theoretical calculations.

FT-IR, molecular structure, first order hyperpolarizability, HOMO and LUMO analysis, MEP and NBO analysis of 2-(4-chlorophenyl)-2-oxoethyl 3-nitrobenzoate

2-(4-Chlorophenyl)-2-oxoethyl 3-nitrobenzoate is synthesized by reacting 4-chlorophenacyl bromide with 3-nitrobenzoic acid using a slight excess of potassium or sodium carbonate in DMF medium at room temperature. The structure of the compound was confirmed by IR and single-crystal X-ray diffraction studies. FT-IR spectrum of 2-(4-chlorophenyl)-2-oxoethyl 3-nitrobenzoate was recorded and analyzed. The crystal structure is also described. The vibrational wavenumbers were computed using HF and DFT methods and are assigned with the help of potential energy distribution method. The first hyperpolarizability and infrared intensities are also reported. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated (DFT) values. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. MEP was performed by the DFT method.

Molecular structure, vibrational investigation of 2-chloro-α-α-α-trifluoro-3,5-dinitrotoluene using DFT (LSDA, B3LYP, B3PW91 and MPW1PW91) and UV-Vis absorption spectra in organic solvents: a IEF-PCM/TD-DFT study

Theoretical Spectrograms (IR and Raman) have been constructed and compared with the experimental FT-IR and FT-Raman spectra. The effect of solvent polarity on the optimized structure is studied by the density functional theory calculation (LSDA, B3LYP, B3PW91 and MPW1PW91 with 6-311++G(d,p)) in gas phase and selected solvents benzene (non-polar solvent), tetrahydrofuran THF (polar aprotic solvent), DMSO, Methanol (polar solvent) and water (protic solvent). In addition variation of dipole moment and charges on atoms in the solvents are studied. With the help of TD-DFT study, the electrostatic effects of different solvents and the energy difference between the excited electronic states noticeably depends on the size of the solute cavity used in the PCM calculations. On the basis of the thermodynamic properties of the title compound at different temperatures have been calculated in gas phase, reverling the correlations between standard heat capacities (C), standard entropies (S), standard enthalpy (H) and vibrational and rotational temperatures. The solvation influence on the geometrical parameters, atomic charges and HOMO-LUMO energies was estimated with the use of PCM method. The presence of solvent did not alter these parameters, but affected the orbital energies. The aggregation phenomena were studied with dimer and trimer structure of the title compound.

Synthesis, FT-IR investigation and computational study of 5-[(4-Bromophenyl)acetamido]-2-(4-tert-butylphenyl) benzoxazole

The synthesis and antimicrobial properties of 5-[(4-Bromophenyl)acetamido]-2-(4-tertbutylphenyl) benzoxazole are reported in the present work. The optimized molecular structure, (1)H NMR, vibrational frequencies, corresponding vibrational assignments of 5-[(4-Bromophenyl)acetamido]-2-(4-tert-butylphenyl) benzoxazole have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of the normal modes of vibrations was done using GAR2PED program. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. MEP was performed by the SDD method and the predicted infrared intensities have also been reported. The calculated geometrical parameters are in agreement with that of similar derivates. The first hyperpolarizability is high and the title compound is suitable for further NLO studies. Microbiological results indicated that the title compound possessed a broad spectrum activity against the tested Gram-positive, Gram-negative bacteria.

Spectroscopic (FT-IR, FT-Raman, UV and NMR) investigation, conformational stability, NLO properties, HOMO-LUMO and NBO analysis of hydroxyquinoline derivatives by density functional theory calculations

The FTIR and FT-Raman spectra of 2-hydroxyquinoline and its derivatives have been recorded in the region 4000-400 cm(-1) and 3500-100 cm(-1), respectively. The optimized geometry, frequency and intensity of the vibrational bands of these compounds were obtained by the density functional theory using 6-311++G(d,p) basis sets. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FTIR and FT-Raman spectra. A detailed interpretation of the infrared and Raman spectra were also reported based on total energy distribution (TED). The observed and the calculated frequencies are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically simulated spectra. (1)H and (13)C NMR spectra were recorded and its corresponding nuclear magnetic resonance chemical shifts of the molecule were also calculated using the gauge independent atomic orbital (GIAO) method. UV-visible spectrum of the compound was recorded and the electronic properties HOMO and LUMO energies were measured by time-dependent (TD-DFT) approach. Molecular stability and bond strength were investigated by applying the natural bond orbital analysis (NBO). The calculated HOMO and LUMO energies show that charge transfer occurs in the molecules. In addition, the non-linear optical properties were discussed from the dipole moment values and excitation wavelength in the UV-visible region.

Vibrational spectroscopic investigations and computational study of 5-chloro-2-[4-(trifluoromethyl)phenylcarbamoyl]phenyl acetate

The optimized molecular structure, vibrational frequencies and corresponding vibrational assignments of 5-Chloro-2-[4-(trifluoromethyl)phenylcarbamoyl]phenyl acetate have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of the normal modes of the vibrations was done using GAR2PED program. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper conjugative interaction and charge delocalization have been analyzed using NBO analysis. The calculated geometrical parameters are in agreement with that of similar derivatives. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of nonlinear optics. The red shift of the NH stretching wave number in the IR spectrum with a strong intensity from the computed wave number indicates the weakening of the NH bond resulting in proton transfer to the neighboring oxygen.

Density functional theory, comparative vibrational spectroscopic studies, HOMO-LUMO, first hyperpolarizability analyses of 2-fluoro 5-nitrotoluene and 2-bromo 5-nitrotoluene

This work deals with the vibrational spectra of 2-fluoro 5-nitrotoluene and 2-bromo 5-nitrotoluene by quantum chemical calculations. The solid phase FTIR and FT-Raman spectra of the title compounds were recorded in the regions 4000-400 cm(-1) and 4000-50 cm(-1) respectively. The spectra were interpreted with the aid of normal co-ordinate analysis based on density functional theory (DFT) using standard B3LYP/6-31G(*) basis set for the most optimized geometry. The vibrational frequencies are calculated and scaled values are compared with experimental FTIR and FT-Raman spectra. The scaled theoretical wave numbers showed very good agreement with the experimental ones. The complete vibrational assignments are performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. (13)C and (1)H NMR chemical shifts results are compared with the experimental values.

Vibrational spectroscopic (FT-IR, FT-Raman, ¹H NMR and UV) investigations and computational study of 5-nitro-2-(4-nitrobenzyl) benzoxazole

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 5-nitro-2-(4-nitrobenzyl) benzoxazole have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of the normal modes of vibrations was done using GAR2PED program. The energy and oscillator strength calculated by time dependent density functional theory almost compliments with experimental findings. Gauge-including atomic orbital (1)H NMR chemical shifts calculations were carried out by using B3LYP functional with 6-31G basis set. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization have been analyzed using NBO analysis. MEP was performed by the DFT method and the predicted infrared intensities and Raman activities have also been reported. The calculated geometrical parameters are in agreement with that of similar derivatives.

Experimental (FT-IR and FT-Raman) and theoretical (HF and DFT) investigation, NMR, NBO, electronic properties and frequency estimation analyses on 2,4,5-trichlorobenzene sulfonyl chloride

The present work deals with the structural, electronic, and vibrational analyses of the biomolecule 2,4,5-trichlorobenzene sulfonyl chloride (TCBSC). TCBSC is a novel pharmaceutical compound used in dyes, pesticides, pigments, fluorescence brighteners and intermediate for agricultural chemicals in the manufacture of insecticides. Quantum chemical calculation of geometrical structure and energies of TCBSC was carried out by density functional theory (B3LYP) and ab initio (HF) methods at 6-311+G(d,p) and 6-311++G(d,p) standard basis set. The stability of the molecule arising from hyperconjugative interaction and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. NMR analysis shows that the isotropic chemical shifts of carbon and hydrogen atom of TCBSC are giving the reasonable shielding to the molecule. Another interesting property shows nonlinear optical (NLO) behavior. Moreover, we have not only simulated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) but also determined the transition state and energy band gap.

Rotational isomers, density functional theory, vibrational spectroscopic studies, thermodynamic functions, NBO and HOMO-LUMO analyses of 2,6-Bis(chloromethyl)pyridine

The FT-IR and FT-Raman spectra of 2,6-Bis(chloromethyl)pyridine (BCMP) have been recorded in the regions 4000-400 cm(-1) and 3500-100 cm(-1), respectively. The total energy calculations of BCMP were tried for the possible rotational isomers. The molecular structure, geometry optimization, vibrational frequencies were obtained by the HF and density functional theory (DFT/B3LYP) method with 6-311+G(d,p) basis set for the most stable rotational isomer "R3". The harmonic frequencies were calculated and the scaled values were compared with experimental FT-IR and FT-Raman spectra. The observed and the calculated frequencies are found to be in good agreement. The calculated HOMO and LUMO energies show that charge transfer occurs in the molecule. The stability of the molecule was analyzed using NBO analysis. The thermodynamic functions (heat capacity, entropy, vibrational partition function and Gibbs energy) were obtained for the range of temperature 100 K-700 K.

Spectroscopic (FT-IR, FT-Raman, UV and NMR) investigation and NLO, HOMO-LUMO, NBO analysis of organic 2,4,5-trichloroaniline

In this work, the experimental and theoretical study on the molecular structure and vibrational spectra of 2,4,5-trichloroaniline (C(6)H(4)NCl(3), abbreviated as 2,4,5-TClA) were studied. The FT-IR and FT-Raman spectra were recorded. The molecular geometry and vibrational frequencies in the ground state were calculated by using the Hartree-Fock (HF) and density functional theory (DFT) methods (B3LYP) with 6-311++G(d,p) basis set. Comparison of the observed fundamental vibrational frequencies of 2,4,5-TClA with calculated results by HF and DFT indicates that B3LYP is superior to HF method for molecular vibrational problems. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small. The theoretically predicted FT-IR and FT-Raman spectra of the title molecule have been constructed. A study on the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. Besides, molecular electrostatic potential (MEP) and thermodynamic properties were performed. The electric dipole moment (μ) and the first hyperpolarizability (β) values of the investigated molecule were computed using ab initio quantum mechanical calculations. The calculated results also show that the 2,4,5-TClA molecule may have microscopic nonlinear optical (NLO) behavior with non-zero values. Mulliken atomic charges of 2,4,5-TClA was calculated and compared with aniline and chlorobenzene molecules. The (13)C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by the gauge independent atomic orbital (GIAO) method and compared with experimental results.

Vibrational spectroscopic studies, NLO, HOMO-LUMO and electronic structure calculations of α,α,α-trichlorotoluene using HF and DFT

FT-IR and FT-Raman spectra of α,α,α-trichlorotoluene have been recorded and analyzed. The geometry, fundamental vibrational frequencies are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on density functional theory (DFT) B3LYP/6-311++G(d,p) method and a comparative study between HF level and various basis sets combination. The fundamental vibrational wavenumbers as well as their intensities were calculated and a good agreement between observed and scaled calculated wavenumbers has been achieved. The complete vibrational assignments of wavenumbers are made on the basis of potential energy distribution (PED). The effects due to the substitutions of methyl group and halogen were investigated. The absorption energy and oscillator strength are calculated by time-dependent density functional theory (TD-DFT). The electric dipole moment, polarizability and the first hyperpolarizability values of the α,α,α-trichlorotoluene have been calculated. (1)H NMR chemical shifts were calculated by using the gauge independent atomic orbital (GIAO) method with HF and B3LYP methods with 6-311++G(d,p) basis set. Moreover, molecular electrostatic potential (MEP) and thermodynamic properties were performed. Mulliken and natural charges of the title molecule were also calculated and interpreted.

Density functional theory, comparative vibrational spectroscopic studies, NBO, HOMO-LUMO analyses and thermodynamic functions of N-(bromomethyl)phthalimide and N-(chloromethyl)phthalimide

Quantum mechanical calculations of energies, geometries, and vibrational wavenumbers of N-(bromomethyl)phthalimide and N-(chloromethyl)phthalimide are carried out using density functional theory (DFT/B3LYP) method with 6-31G and 6-311G(d,p) basis sets. The optimized geometrical parameters obtained by B3LYP method show good agreement with experimental data. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small. A detailed interpretation of the infrared and Raman spectra of N-(bromomethyl)phthalimide and N-(chloromethyl)phthalimide was also reported. The calculated HOMO and LUMO energies show that charge transfer occurs in the molecules. The thermodynamic functions of N-(bromomethyl)phthalimide and N-(chloromethyl)phthalimide have been performed at B3LYP/6-31G and B3LYP/6-311G(d,p) basis sets. The theoretical spectrograms for FT-IR and FT-Raman spectra of N-(bromomethyl)phthalimide and N-(chloromethyl)phthalimide have also been constructed.

Vibrational spectroscopic studies and computational calculations of 5-chloro-2-(3-chlorophenylcarbamoyl)phenylacetate

The FT-IR and FT-Raman spectra of 5-chloro-2-(3-chlorophenylcarbamoyl)phenylacetate were studied. The vibrational wave numbers and corresponding vibrational assignments were examined theoretically using the Gaussian 03 set of quantum chemistry codes and the normal modes are assigned by Potential Energy Distribution calculations. The synthesis, elemental analysis and NMR values are presented. The red shift of the NH stretching wave number in the infrared spectrum from the computed wave number indicates the weakening of the NH bond resulting in proton transfer to the neighboring oxygen atom. The first hyperpolarizability, infrared intensities and Raman activities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of nonlinear optics. The geometrical parameters of the title compound are in agreement with that of similar reported derivatives.

FT-IR, FT-Raman, ab initio, HF and DFT studies, NBO, HOMO-LUMO and electronic structure calculations on 4-chloro-3-nitrotoluene

In this work, the vibrational spectral analysis was carried out by using Raman and infrared spectroscopy in the range 100-4000 cm(-1) and 50-4000 cm(-1), respectively, for 4-chloro-3-nitrotoluene (C7H6NO2Cl) molecule. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on Hartree Fock (HF) and density functional theory (DFT) method and different basis sets combination. The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution (PED). The scaled B3LYP/6-311++G(d,p) results show the best agreement with the experimental values over the other methods. The calculated HOMO and LUMO energies shows that charge transfer within the molecule. The effects due to the substitutions of methyl group, nitro group and halogen were investigated. The results of the calculations were applied to simulate spectra of the title compound, which show excellent agreement with observed spectra. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) and thermodynamic properties were performed.