Enhanced NLO response and switching self-focussing in benzodiazepine derivative with -NO2 and -Br substitution.

Optoelectronic and the cubic nonlinear optical properties of 4-(4-Bromophenyl)-2-(4-nitrophenyl)-2, 3-dihydro-1H-1, 5-benzodiazepine have been studied. Z-scan technique was used for the third-order nonlinear optical measurements namely, nonlinear absorption, nonlinear refraction, and optical power limiting behaviour employing an Nd: YAG laser of 532 nm wavelength having 5 ns Gaussian pulses. B3LYP/6-311 ++ G (d, p) level of theory was employed for structural optimization, vibrational wavenumber, frontier molecular orbitals, natural bond orbital and population analysis. The MOLVIB programme was used to perform unambiguous vibrational assignments based on potential energy distribution values acquired from normal coordinate analysis. B3LYP and CAM-B3LYP hybrid functions have been employed at the DFT level to calculate the theoretical second-order hyperpolarizability. The substitution of -NO2 and -Br in this benzodiazepine compound enhances the second-order hyperpolarizability (γ) to the order of 10-34 esu and, switching of self-defocussing to self-focussing phenomenon. The HOMO-LUMO and optical band gap analysis illustrates that polarizing nature of the molecule vary with substituents. The obtained results indicate that this compound has potential applications in optoelectronics and photonics.

Experimental and theoretical analyses and investigation of intermolecular interactions and antibacterial activity of a novel proton transfer compound:8-hydroxyquinolinium oxalate monohydrate.

A novel proton transfer compound, 8-hydroxyquinolinium oxalate monohydrate was synthesised by solid state grinding of 8-hydroxyquinoline and oxalic acid. The resulting compound is characterised by single crystal X-ray diffraction (SXRD), FT-IR, UV-Visible, TG/DTG, DTA and DSC analyses. The compound crystallizes in monoclinic crystal system with space group P21/n. The carboxylate oxygen O2 which acts as a tetrafurcated acceptor of four hydrogen bonds is the main feature of the crystal structure. The molecules are linked together by O-H⋯O, N-H⋯O and C-H⋯O hydrogen bonds. Carbonyl-carbonyl interactions play a crucial role in stabilising the crystal packing. Hirshfeld surface analysis and the associated finger print plots facilitates the comparison of intermolecular interactions. The nature of charge density distribution and topological parameters of the proton transfer region N1-H1A⋯O2 hydrogen bond reveals that the bond has considerable covalent character. Natural Bond Orbital (NBO) has been extended to analyse the nature and strength of intermolecular interactions. Topology analysis using ELF and LOL reveals electron localisation and depletion regions. ADMET analysis reveals that the compound satisfies Lipinski's rule of five and drug likeness. Antibacterial activity was screened against 3 g positive - Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus and 2 g negative strains- Klebsiella pneumonia and Salmonella typhi by employing disc diffusion method.

Chemical reactivity, molecular electrostatic potential and in-silico analysis on benzimidazole fungicide benomyl.

We are reporting theoretical concepts and biological activity of benomyl using different techniques. The molecular orbital contributions are studied by using Total Density of States (TDOS) analysis. The chemical reactivity of the molecule have been determined with the help of global reactivity descriptors. Molecular electrostatic potential is calculated by the density functional method and predicts the most reactive part in the molecule. In-silico molecular analysis is conducted for Benomyl compound.

Molecular docking, photocatalytic activity and biomedical investigations of some metal complexes.

Metal(II)-(furfural-L-his) complexes with a potentially bidentate furfural-L-his have been synthesized. Furfural-L-his and its Co/Ni/Cu/Zn(II)-(furfural-L-his) complexes have been optimized by DFT. The structural features were determined from their elemental analyses, molar conductance, magnetic, UV-Vis, IR, mass, 1H NMR and EPR spectral studies. On the basis of electronic spectral data and magnetic measurements, suitable geometry has been proposed for each complex. The redox behaviour of Cu(II)-(furfural-L-his) complex has been studied by cyclic voltammetry. Thermal decomposition profiles are consistent with the proposed formulation of Co/Ni/Cu/Zn(II)-(furfural-L-his) complexes. PXRD studies reveal that furfural-L-his and Zn(II)-(furfural-L-his) complex are of nanomeric structure. SEM images of furfural-L-his exhibit flake-like morphology. Photodegradation of methylene blue dye indicates that they are photocatalyticaly efficient. NBO and NPA shown considerable reduction in the formal charge on metal ions. Docking analysis with EGFR and cyclooxygenase-2 receptor has been performed to find the best binding energy. Antimicrobial, antioxidant and anti-inflammatory activity against standard at variable concentrations revealed that the Co/Ni/Cu/Zn(II)-(furfural-L-his) complexes show enhanced antimicrobial, free radical scavenging and anti-inflammatory activities as compared to furfural-L-his. Furfural-L-his and Cu(II)-(furfural-L-his) complex have been tested against human ovarian cancer cells, which showed that Cu(II)-(furfural-L-his) complex exhibited promising anticancer activity.Communicated by Ramaswamy H. Sarma.

Synthesis, Spectroscopic Identification and Molecular Docking of Certain N-(2-{[2-(1H-Indol-2-ylcarbonyl) Hydrazinyl](oxo)Acetylphenyl)Acetamides and N-[2-(2-{[2-(Acetylamino)Phenyl](oxo)Acetylhydrazinyl)-2-Oxoethyl]-1H-Indole-2-Carboxamides: New Antimicrobial Agents.

N-(2-{[2-(1H-Indol-2-ylcarbonyl)hydrazinyl](oxo)acetyl}phenyl)acetamides (5a⁻h) and N-[2-(2-{[2-(acetylamino)phenyl](oxo)acetyl}hydrazinyl)-2-oxoethyl]-1H-indole-2-carboxamides (5i⁻l) were synthesized and characterized with different analytical tools. N-Acetylisatines 4a⁻d were subjected to ring opening at their C2 carbons with the aid of different indole-bearing hydrazides 3a,b and 7 to afford the respective glyoxylamides 5a⁻l. The antimicrobial activity of the target compounds 5a⁻l was assessed with the aid of Diameter of the Inhibition Zone (DIZ) and Minimum Inhibitory Concentration (MIC) assays against a panel of Gram-positive and Gram-negative bacteria and certain fungal strains. The antimicrobial screening revealed that Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans are the most sensitive microorganisms towards the synthesized compounds 5a⁻l. In addition, compounds 5c and 5h emerged as the most active congeners towards Staphylococcus aureus and Candida albicans, respectively. Molecular docking studies revealed the possible binding mode of compounds 5c and 5h to their target proteins.

FT-IR and Raman spectroscopic and DFT studies of anti-cancer active molecule N-{(meta-ferrocenyl) Benzoyl} - l-alanine - glycine ethyl ester.

FT-Raman and FT-IR spectra of N-{(meta-ferrocenyl) Benzoyl} - l-alanine - glycine ethyl ester were recorded in solid phase. The optimized molecular geometry, the vibrational wavenumbers, the infrared intensities and the Raman scattering intensities were calculated by using density functional method(B3LYP) with 6-31G(d, p) basis set. Vibrational assignment of the molecule was done by using potential energy distribution analysis. Natural bond orbital analysis, Mulliken charge analysis and HOMO-LUMO energy were used to elucidate the reasons for intra molecular charge transfer. Docking studies were conducted to predict its anticancer activity.

Quantum chemical computations, vibrational spectroscopic analysis and antimicrobial studies of 2,3-Pyrazinedicarboxylic acid.

Density Functional Theory (DFT) calculations at B3PW91 level with 6-311G (d) basis sets were carried out for 2,3-Pyrazinedicarboxylic acid (PDCA) to analyze in detail the equilibrium geometries and vibrational spectra. Calculations reveal that the optimized geometry closely resembles the experimental XRD data. Vibrational spectra were analyzed on the basis of potential energy distribution (PED) of each vibrational mode, which provides quantitative as well as qualitative interpretation of IR and Raman spectra. Information about size, shape, charge density distribution and site of chemical reactivity of the molecule were obtained by mapping electron density isosurface with the electrostatic potential surface (ESP). Based on optimized ground state geometries, NBO analysis was performed to study donor-acceptor (bond-antibond) interactions. TD-DFT analysis was also performed to calculate energies, oscillator strength of electronic singlet-singlet transitions and the absorption wavelengths. The (13)C and (1)H nuclear magnetic resonance (NMR) chemical shifts of the molecule in the ground state were calculated by gauge independent atomic orbital (GIAO) method and compared with the experimental values. PDCA was screened for its antimicrobial activity and found to exhibit antifungal and antibacterial effects. Molecular docking was also performed for the different receptors.

Studies on molecular structure, vibrational spectra and molecular docking analysis of 3-Methyl-1,4-dioxo-1,4-dihydronaphthalen-2-yl 4-aminobenzoate.

The molecular structure, vibrational analysis and molecular docking analysis of the 3-Methyl-1,4-dioxo-1,4-dihydronaphthalen-2-yl 4-aminobenzoate (MDDNAB) molecule have been carried out using FT-IR and FT-Raman spectroscopic techniques and DFT method. The equilibrium geometry, harmonic vibrational wave numbers, various bonding features have been computed using density functional method. The calculated molecular geometry has been compared with experimental data. The detailed interpretation of the vibrational spectra has been carried out by using VEDA program. The hyper-conjugative interactions and charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The simulated FT-IR and FT-Raman spectra satisfactorily coincide with the experimental spectra. The PES and charge analysis have been made. The molecular docking was done to identify the binding energy and the Hydrogen bonding with the cancer protein molecule.

FT-IR spectroscopy as a sentinel technology in earthworm toxicology.

FT-IR spectroscopy is a useful tool for determining the biomolecular profile of micro-samples of body fluids such as coelomic fluid of earthworms. The present study focuses on the usefulness of the earthworm (Perionyx sansibaricus) coelomic fluid for observing pathologically induced biochemical changes. Compared to controls, appreciable changes in expression of peaks were observed in worms exposed to seven selected xenobiotics (pesticides, heavy metals, herbicides and detergents). Observation of bands in the region 1600-1690 cm(-1) indicates the presence of amide I band in all the worms. The peak at 2364 cm(-1) present as a weak band on day 7 of treatment, is shifted to 2358/2359 cm(-1) and more pronounced in most of the treated groups on day 14. Presence of band at 1663 cm(-1) in controls is attributed to CO stretching vibration representing the amino acid, glutamic acid. Under toxicological conditions vibration in this region is absent. Presence of the amino acid arginine (1633 cm(-1)) and lysine (1629 cm(-1)) and absence of glutamic acid (1663 cm(-1)) under toxicological stress were characteristic. FT-IR spectra of the coelomic fluid were similar under the sublethal and lethal concentrations of the test chemicals. The potential use of FT-IR spectral information as baseline data for toxicological studies and for monitoring the quality of the environment is recommended.

FT-Raman, FT-IR and UV-visible spectral investigations and ab initio computations of anti-epileptic drug: vigabatrin.

Vibrational analysis of anti-epileptic drug vigabatrin, a structural GABA analog was carried out using NIR FT-Raman and FTIR spectroscopic techniques. The equilibrium geometry, various bonding features and harmonic vibrational wavenumbers were studied using density functional theory method. The detailed interpretation of the vibrational spectra has been carried out with the aid of VEDA.4 program. Vibrational spectra, natural bond orbital analysis and optimized molecular structure show clear evidence for the effect of electron charge transfer on the activity of the molecule. Predicted electronic absorption spectrum from TD-DFT calculation has been compared with the UV-vis spectrum. The Mulliken population analysis on atomic charges and the HOMO-LUMO energy were also calculated. Good consistency is found between the calculated results and experimental data for the electronic absorption as well as IR and Raman spectra. The blue-shifting of the C-C stretching wavenumber reveals that the vinyl group is actively involved in the conjugation path. The NBO analysis confirms the occurrence of intramolecular hyperconjugative interactions resulting in ICT causing stabilization of the system.

Feasibility of using near infrared spectroscopy to detect and quantify an adulterant in high quality sandalwood oil.

Determination of the authenticity of essential oils has become more significant, in recent years, following some illegal adulteration and contamination scandals. The present investigative study focuses on the application of near infrared spectroscopy to detect sample authenticity and quantify economic adulteration of sandalwood oils. Several data pre-treatments are investigated for calibration and prediction using partial least square regression (PLSR). The quantitative data analysis is done using a new spectral approach - full spectrum or sequential spectrum. The optimum number of PLS components is obtained according to the lowest root mean square error of calibration (RMSEC=0.00009% v/v). The lowest root mean square error of prediction (RMSEP=0.00016% v/v) in the test set and the highest coefficient of determination (R(2)=0.99989) are used as the evaluation tools for the best model. A nonlinear method, locally weighted regression (LWR), is added to extract nonlinear information and to compare with the linear PLSR model.

Vibrational spectral investigations and density functional theory study of 4-Formylbenzoic acid.

An accurate assignment of the vibrational spectra of 4-Formylbenzoic acid in solid state was carried out. For this purpose density functional calculations (DFT) were performed to clarify wavenumber assignments of the experimentally observed bands for the first time. A scaling of the wavenumbers was carried out to improve the calculated values. Good reproduction of the experimental wavenumbers is obtained and the % error is very small in the majority of cases. The NBO analysis was carried out, and it reveals hyper conjugative interaction, ICT and stabilization of molecules.

Analysis of vibrational spectra and nonlinear optical properties of organic molecule L-alaninium formate.

Vibrational and electronic spectra of the crystallized nonlinear optical molecule L-alaninium formate have been recorded and analyzed. The equilibrium geometry, vibrational wavenumbers, and the first order hyperpolarizability of the crystal have been calculated with the help of density functional theory computations. The N-H···O bond distance shows the presence of intramolecular hydrogen bonding and the result is confirmed by the natural bond orbital analysis. The HOMO-LUMO energy gap and the first order hyperpolarizability was calculated and it supports the nonlinear optical activity of the L-alaninium formate crystal.

Vibrational spectra and first order hyperpolarizability studies of dimethyl amino pyridinium 4-nitrophenolate 4-nitrophenol.

Vibrational spectra of the organic nonlinear optical crystallized dimethyl amino pyridinium 4-nitrophenolate 4-nitrophenol have been recorded and analyzed. The spectral interpretation has been done based on the density functional theory using the standard B3LYP/LANL2DZ basis set. Total energy distribution is calculated using the scaled quantum mechanic program. Natural bond orbital analysis is also used to explain the inter and intra molecular hydrogen bonding. The relative second harmonic efficiency of the compound is found to be 15 times greater than that of KDP. The effect of intermolecular hydrogen bonding between the phenolate ion of 4-nitrophenol with N-atom of pyridine ring is sufficiently more, enhancing the ß value which is the required property of a system to be NLO active.

Intramolecular charge transfer and Z-scan studies of a semiorganic nonlinear optical material sodium acid phthalate hemihydrate: a vibrational spectroscopic study.

FT-IR and Raman spectra of the nonlinear optical material sodium acid phthalate hemihydrate crystal have been recorded and analyzed. The equilibrium geometry, bonding features, and harmonic vibrational wavenumbers have been investigated with the help of the B3LYP density functional theory method. 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. The natural bond orbital analysis confirms the occurrence of strong intermolecular hydrogen bonding in the molecule. Nonlinear optical absorption of the sample has been studied at 532 nm using single 5 ns laser pulses, employing the open-aperture Z-scan technique. It is found that the NaAPH molecule is a potential candidate for optical limiting applications.

Nonplanar property study of antifungal agent tolnaftate-spectroscopic approach.

Vibrational analysis of the thionocarbamate fungicide tolnaftate which is antidermatophytic, antitrichophytic and antimycotic agent, primarily inhibits the ergosterol biosynthesis in the fungus, was carried out using NIR FT-Raman and FTIR spectroscopic techniques. The equilibrium geometry, various bonding features, harmonic vibrational wavenumbers and torsional potential energy surface (PES) scan studies have been computed using density functional theory method. The detailed interpretation of the vibrational spectra has been carried out with the aid of VEDA.4 program. Vibrational spectra, natural bonding orbital (NBO) analysis and optimized molecular structure show the clear evidence for electronic interaction of thionocarbamate group with aromatic ring. Predicted electronic absorption spectrum from TD-DFT calculation has been compared with the UV-vis spectrum. The Mulliken population analysis on atomic charges and the HOMO-LUMO energy were also calculated. Vibrational analysis reveals that the simultaneous IR and Raman activation of the C-C stretching mode in the phenyl and naphthalene ring provide evidence for the charge transfer interaction between the donor and acceptor groups and is responsible for its bioactivity as a fungicide.

FT-IR, Raman and DFT study of 2-amino-5-fluorobenzoic acid and its biological activity with other halogen (Cl, Br) substitution.

The Fourier-transform Raman and infrared spectra of 2-amino-5-fluoro benzoic acid has been recorded and analyzed. The optimized geometry of the other halogen substitution (Cl, Br) have been computed with the help of density functional theory. The detailed interpretation of vibrational spectra of 2-amino-5-fluoro benzoic acid have performed in terms of potential energy distribution analysis. Natural bond orbital analysis on 2-amino-5-fluoro benzoic acid, 2-amino-5-chloro benzoic acid and 2-amino-5-bromo benzoic acid has been carried out for various intramolecular interactions that are responsible for the stabilization of the molecule. The pKa values of 2-amino-5-fluoro benzoic acid, 2-amino-5-chloro benzoic acid and 2-amino-5-bromo benzoic acid are computed using MOPAC and it is related with HOMO-LUMO energy difference obtained from Gaussian 03 software. The biological activity of 2-amino-5-fluoro benzoic acid has been predicted based on these values. The inhibition activity of 2-amino-5-bromo benzoic acid with the protein tyrosine kinase 3LQ8 is simulated by using Autodock software.

Density functional theory calculations and vibrational spectral analysis of 3,5-(dinitrobenzoic acid).

The FT-IR and Raman spectra of 3,5-dinitrobenzoic acid (DNBA) have been recorded and analyzed. The equilibrium geometry, various bonding and harmonic vibrational wavenumbers have been calculated with the help of density functional theory (DFT) method. Most of the vibrational modes are observed in the expected range. Mulliken population analysis shows the interactions C-N-O⋯H-C and C-O⋯H-C. The most possible interaction is explained using natural bond orbital (NBO) analysis. The strengthening and polarization of the CO bond increases due to the degree of conjugation. HOMO-LUMO energy and the thermodynamic properties are also evaluated.

Vibrational spectra and DFT study of anticancer active molecule 2-(4-Bromophenyl)-1H-benzimidazole by normal coordinate analysis.

FT-IR and FT-Raman spectra of the 2-(4-Bromophenyl)-1H-benzimidzole were recorded and analyzed in the solid phase. The optimized molecular geometry, the vibrational wavenumbers, the infrared intensities and the Raman scattering activities were calculated by using Hartree-Fock and density functional method (B3LYP) with 6-31G(d,p) basis set. The potential surface scan study was carried out for the conformation of theoretical structure. Detailed interpretation of the vibrational spectra had been carried out with the aid of the normal coordinate analysis. Chemical interpretation of hyperconjugative interaction was done by natural bond orbital analysis.

Intramolecular charge delocalization and nonlinear optical properties of push-pull chromophore 1-(4-N,N-dimethylaminopyridinium) acetic acid bromide monohydrate from vibrational spectra.

FT-Raman and FT-IR spectra of the nonlinear optical crystal 1-(4-N,N-dimethylaminopyridinium) acetic acid bromide monohydrate have been recorded and analyzed. The equilibrium geometry, vibrational wavenumbers and the first order hyperpolarizability of the crystal have been calculated with the help of density functional theory computations. The assignments of the vibrational spectra have been carried out with the help of Scaled Quantum Mechanic force field theory. Optimized geometry gives the charge transfer interaction of the pyridine ring and the amino group in the electron-donor side of the nonlinear optic chromophore. Electron-phonon coupling and O-H⋯O interactions in making the molecule nonlinear optical active have been analyzed based on the vibrational spectral features. The Natural Bond Orbital analysis confirms the occurrence of strong intermolecular O-H⋯O hydrogen bonding.