Spectroscopic studies, quantum chemical investigations, and in silico and in vitro scrutiny of the diuretic drug trichlormethiazide adsorbed on AuNPs

Experimental and theoretical study was employed to study the adsorption of the diuretic drug, trichlormethiazide (TCM) molecule on AuNPs (TCMA). The stereoelectronic properties of the molecular structure of most stable conformers of TCM and TCMA were studied using DFT/B3LYP-6-311++G (d, p) together with LANL2DZ methodology. The Fourier transform Raman and Infrared spectra of TCM were recorded and analyzed. Quantum chemical calculations of TCM and TCMA molecules were used to evaluate the stability of the molecule, hyper-conjugative interactions, electron delocalization, and binding interactions. The calculated and experimentally observed vibrational frequencies of the molecule were assigned and compared. The shifting and intensity enhancement of the CCl₂ band manifests the back-donation and conjugation effect, which are the result of the presence of nitrogen atom adjoining the dichloromethyl groups and the oxygen in the sulfur dioxide group attached among the amino group and the chlorophenyl ring, respectively, which enhances bioactivity. Anticancer activity was examined based on molecular docking analysis, and it was identified that TCM and TCMA molecules act as good inhibitors against lung cancer. SERS analysis and MTT assay confirmed the molecular docking analysis results.

Study of the modified magnetic, dielectric, ferroelectric and optical properties in Ni substituted GdFe1-xNixO3orthoferrites

Polycrystalline GdFe_1-xNi_xO₃(x = 0.00, 0.02, 0.04) samples was synthesised using a glycine assisted sol-gel method to investigate the enhanced magnetic and electric properties of Ni substituted GdFeO₃systems. TG-DSC analysis of prepared samples confirms that GdFe_1-xNi_xO₃have good thermal stability in high temperatures. The system has been stabilized in an orthorhombic structure with space group Pbnm.The elemental composition of GdFe_1-xNi_xO₃has been estimated from EDAX spectrum. The results showed oxygen deficiency on increasing the Ni substitution and it has been supported by Rietveld refinement. FE-SEM images and Brunauer-Emmett-Teller analysis reveals that GdFe_1-xNi_xO₃is a highly porous material and its porosity and specific area increases with Ni substitution. Magnetic measurements indicates that the system exhibited ferrimagnetic behaviour at low temperatures and canted antiferromagnetic behaviour at room temperature. Forx = 0.04 Ni content, magnetization reversal for applied field of 25 Oe has been observed. Increased coercivity of GdFeO₃with Ni substitution has been attributed to the grain size effect. From electrical point of view, dielectric permittivity of GdFeO₃has been enhanced with Ni substitution. This enhancement has been attributed to the cumulative effects of hopping of Fe²⁺-Fe³⁺ions, grain-grain boundary contribution, and space charge polarization. The role of grain-grain boundary contribution is evident from electric modulus spectrum. The space charge effect has been realized in both impedance spectrum and dielectric loss. Temperature-dependent dielectric studies were conducted to understand the mechanisms and various aspects that contribute to the dielectric enhancement. A highly lossy capacitive nature in theP-Eloop also suggests space charge effects due to Ni substitution in Fe sites. Availability of free charge carrier concentration is correlated with the optical properties of GdFe_1-xNi_xO₃. The decrease of optical band gap (2.5-2.21 eV) on increasing Ni content suggests the increasing electronic contribution in the system.

Spectroscopic, density functional theoretical study, molecular docking, and in vitro studies based on anticancer activity studies against A549 lung cancer cell line of diphenylhydantoin adsorbed on AuNPs surface

The optimized geometry, FT-Raman, FT-IR, surface-enhanced Raman scattering, UV-Vis spectra, frontier molecular orbital analysis, molecular electrostatic potential analysis, and local and global reactivity descriptors of diphenylhydantoin (DPH) and diphenylhydantoin@AuNPs (DPHA) molecule have been investigated with the help of density functional theory method (B3LYP/6-31++G [d,p] together with LANL2DZ) and was compared and analyzed with the corresponding experimental data in order to identify their structural and bonding features responsible for their bioactivity. In-silico (molecular docking) biological activity screening of the molecules together with the in-vitro (SERS and MTT assay) analysis confirms the anticancer activity of DPH and DPHA molecules. The results of the structure-activity studies and bioactivity studies signify that the DPHA molecule is more active than the DPH molecule against lung cancer.

Anticancer activity of indapamide adsorbed on gold nanoparticles: DFT, in-silico, and in-vitro analysis

The adsorption properties of the lung cancer agent indapamide (IND) on gold nanoparticles (AuNPs), were studied with the help of surface-enhanced Raman scattering techniques. The structure-activity of the IND and INDA molecule has been studied using DFT/B3LYP methodology. NBO analysis reveals that, both the molecules are stabilized by a C─H^… O intramolecular hydrogen bonding, apart from the conjugative and intramolecular charge transfer interactions. The analysis of the electron density of frontier molecular orbital analysis gives a comparative idea of the reactivity, the low kinetic stability, and low value of energy gap indicating the electron transport in the molecule and thereby its bioactivity. The molecular electrostatic potential, local and global reactivity indicators predict the reactive site of the molecules. FT-IR, FT-Raman, and surface-enhanced Raman scattering have been investigated and compared with the theoretical prediction. Effective in-silico (molecular docking) biological activity screening of the molecules was checked on lung cancer cells. In-vitro (surface-enhanced Raman scattering techniques and MTT assay) analysis confirms the results from the in-silico analysis. This study promotes the potential of SERS agents for targeted drug delivery and photothermal therapy and the novelty of the IND and INDA molecule against lung cancer activity.

Investigations of Dianhydro-D-glucitol adsorbed on AuNPs surface: In silico and in vitro approach based on anticancer activity studies against A549 lung cancer cell lines

The adsorption behavior of a lung cancer agent, Dianhydro-D-glucitol (DIS) on gold nanoparticles (AuNPs) was studied using surface-enhanced Raman scattering techniques. The stabilized geometry, inter- and intra-molecular hydrogen bond, and harmonic vibrational wavenumbers of DIS and DIS adsorbed on AuNPs (DISA) surface have been investigated with the help of the density functional theory (DFT) method. The stability of the molecules arising from stereoelectronic interactions, leading to its bioactivity, has been confirmed using natural bond orbital (NBO) analysis, which was further substantiated by the narrow HOMO LUMO energy gap obtained for DISA, from frontier molecular orbital analysis as well as electronic spectral analysis. The molecular electrostatic potential analysis along with local and global reactivity descriptors predicts the reactive site of the molecules. Molecular docking study was performed to obtain information about protein-ligand reactions for DIS and DISA, with different cancer proteins. This study enlightens the potential of SERS agents for targeted drug delivery and photothermal. The in vitro cytotoxic effects of DPH and DPHA molecules on lung cancer cell lines were analyzed using the MTT assay and the SERS method.

Adsorption and photocatalytic activity of biosynthesised ZnO nanoparticles using Aloe Vera leaf extract

In this article, we demonstrates the growth of phase pure ZnO nanostructures from Aloe-Vera leaf extract and degradation of an organic dye-Malachite Green (MG)- from aqueous medium using the same as catalyst. Adsorption mechanisms were evaluated using Lagergren’s pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models. X-Ray diffraction data showed that the synthesised ZnO is crystalline with hexagonal wurtzite phase. Average crystallite size and lattice strain was estimated from Scherrer equation and Williamson-Hall analysis with the help of Rietveld refinement data. Crystallite size obtained from Scherrer method is 12.62 nm while that from Williamson-Hall analysis is 19.27 nm. Uniform growth of ZnO nano-sheets were confirmed by FE-SEM analysis. Optical characterisation was carried by UV-Visible spectroscopy and the band gap ZnO nanoparticles was found to be 3.19 eV. Zn-O stretching vibrations were recorded at 550 cm−1 using FTIR spectrophotometer. Results showed that biosynthesised ZnO nanosheets are particularly effective for the degradation of MG dye.

Computational analysis of vibrational spectroscopic properties and hyperpolarizability of silver adsorbed organic molecule, N,N' Dimethyl Urea Ninhydrin

The effect of adsorption of silver atoms to the nonlinear optical (NLO) active compound N,N' dimethyl urea ninhydrin (NDUN), has been analysed by computational methods. Single, double or triple silver atoms are added to the NDUN structure at an appropriate site and the geometry optimization, vibrational spectral and the natural bond orbital analyses, and hyperpolarizability calculations are done using B3LYP functional with LANL2DZ basis set. A comparison of IR spectra of the Ag-adsorbed NDUN (NDUN-Ag) is made to study the effect of the addition of silver atoms in the vibrational motions of the molecule. The NBO analysis gives an account of the interactions between atoms of the chosen molecule. The effect on NLO properties of NDUN is characterized by the polarizability, and the first and the second hyperpolarizability calculations.

Molecular structure, NLO properties and vibrational analysis of l-Histidine tetra fluro borate by experimental and computational spectroscopic techniques

l-histidine tetra fluroborate (L-HTFB) is a semi-organic NLO material. Ab-initio computations were performed at CAM-B3LYP/ 6-311++g(d,p) level of theory to arrive at the structures, energies, and vibrational wave numbers. The experimental FT-IR and FT-Raman spectra of L-HTFB have been recorded and analyzed. It is compared with the simulated spectra. The scaled wave numbers obtained are in good agreement with the experimental values. Hirshfeld surface analysis represented in the 2D fingerprint plot reveals the interaction within the compound. Optimized geometry reveals that the complexes l -histidine (L-H) and tetrafluoroborate (TFB) are linked by H-F bond which provides inter and intra molecular hydrogen bonded interactions such as N₁₀-H₁₆⋯F₂₅, N₁₁-H₁₇⋯F₂₂, N₁₁-H₁₄⋯F₂₄, N₁₁-H₁₄⋯N₁₀ and N₁₁-H₁₅⋯O₁₂. The inter-molecular distances H₁₇⋯F₂₂, H₁₄⋯F₂₄ and H₁₆⋯F₂₅ are in between 1.82 Å and 2.53 Å. The intra molecular distances H₁₄⋯N₁₀ and H₁₅⋯O₁₂ are found to be at 2.17 Å and 1.71 Å which stabilizes lone pair electron of N₁₀ and O₁₂ with energies 11.89 and 59.91 KJ/mol respectively. The intra and inter molecular hyperconjugations responsible for the stability of the molecule are well identified theoretically using the NBO analysis. Third order optical nonlinearity is measured by means of the open aperture Z-scan technique which reveals that the crystal has optical limiting property. Photoluminescence results clearly indicate the use of L-HTFB as a new violet-light emitting material.

Directional growth, physicochemical and quantum chemical investigations on pyridinium 2-carboxylate: 4-nitrophenol (P2C4N) single crystal for nonlinear optical (NLO) applications

An organic nonlinear optical (NLO) single crystal of pyridinium 2-carboxylate: 4-nitrophenol (P2C4N) was grown by the Sankaranarayanan-Ramasamy (SR) method using the (1 1 −1) plane.

Electronic structure, vibrational spectral and intervening orbital interactions studies of NLO material: guanidinium 4-nitrobenzoate

Single crystals of guanidinium 4-nitrobenzoate (GPNB) have been grown by slow evaporation method. Grown crystals were characterized by FT-IR, FT-Raman, UV-Vis absorption and UV-Vis transmission spectroscopies. Crystal defects and surface morphology were studied by etching method. Dielectric properties of the crystal such as dielectric constant, dielectric loss and AC electrical conductivity as function of frequency (50 Hz-5 MHz) at two temperatures (35°C and 100°C) were measured. The frequency and temperature dependence of dielectric behaviour were investigated. The equilibrium geometry, vibrational spectral analysis, intramolecular charge transfer interactions using NBO method, first order hyperpolarizability, molecular electrostatic potential and frontier molecular orbital analysis for GPNB have been studied using density functional theory at B3LYP/cc-pVTZ level. Vibrational spectral study reveals the presence of moderate and weak N-H⋯O bonds in GPNB. NBO analysis also confirms the presence of intramolecular N-H⋯O hydrogen bonding and investigates the stability as well as the intervening orbital interactions. The electronic absorption spectrum of the gas and water phases of GPNB were simulated using time dependent density functional theory and NBO transitions for the three lowest excited states were assigned and studied.

Twisted intramolecular charge transfer and its contribution to the NLO activity of Diglycine Picrate: a vibrational spectroscopic study

Single crystals of Diglycine Picrate (DGLP) were grown by slow evaporation technique and the vibrational spectral analysis is carried out using FT Raman and FT-IR spectroscopy, supported by Density Functional Theoretical (DFT) computations to derive equilibrium geometry, vibrational wavenumbers and first hyperpolarizability. The vibrational spectra confirm the existence of NH3(+) in DGLP. The influence of Twisted Intramolecular Charge Transfer (TICT) caused by the strong ionic ground state hydrogen bonding between charged species making DGLP crystal to have the non-centrosymmetric structure has been discussed. The Natural Bond Orbital (NBO) analysis confirms the occurrence of strong intermolecular N-H⋯O hydrogen bond. The HOMO-LUMO energy gap and the first order hyperpolarizability were calculated and it supports the nonlinear optical activity of the Diglycine Picrate crystal.

Growth, molecular structure, NBO analysis and vibrational spectral analysis of l-tartaric acid single crystal

Single crystal of l-tartaric acid (LTA) has been grown by slow evaporation technique. The experimental and theoretical studies on molecular structure, vibrational spectra, electronic absorption spectra and non-linear optical property of the crystal are studied. The FT-IR, FT-Raman and UV-Vis-NIR experimental spectra of LTA crystal have been recorded in the range 400-4000cm(-1), 100-3700cm(-1) and 190-1100nm, respectively. Density functional theory calculations with B3LYP/6-311++G(d,p) basis sets was used to determine ground state molecular geometries, vibrational frequencies, ICT interactions, Mulliken population analysis on atomic charge, HOMO-LUMO analysis, non-linear optical response properties and thermodynamic properties for LTA and the results were discussed. Vibrational analysis confirms the formation of intramolecular OH⋯O hydrogen bonding. The stability of the molecule has been analyzed using NBO analysis. The results of electronic absorptions in gas phase and water phase LTA were calculated using TD-DFT method. The third-order nonlinear absorption behaviour of LTA was studied using open aperture Z-scan technique, with 5ns laser pulses at 532nm and the nonlinear absorption coefficient of the grown crystal was measured. The predicted NLO properties, UV absorption and Z-scan studies indicate that LTA is an attractive material for laser frequency doubling and optical limiting applications.

Molecular conformational analysis, vibrational spectra and normal coordinate analysis of trans-1,2-bis(3,5-dimethoxy phenyl)-ethene based on density functional theory calculations

The conformational behavior and structural stability of trans-1,2-bis(3,5-dimethoxy phenyl)-ethene (TDBE) were investigated by using density functional theory (DFT) method with the B3LYP/6-311++G(d,p) basis set combination. The vibrational wavenumbers of TDBE were computed at DFT level and complete vibrational assignments were made on the basis of normal coordinate analysis calculations (NCA). The DFT force field transformed to natural internal coordinates was corrected by a well-established set of scale factors that were found to be transferable to the title compound. The infrared and Raman spectra were also predicted from the calculated intensities. The observed Fourier transform infrared (FTIR) and Fourier transform (FT) Raman vibrational wavenumbers were analyzed and compared with the theoretically predicted vibrational spectra. Comparison of the simulated spectra with the experimental spectra provides important information about the ability of the computational method to describe the vibrational modes. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential surfaces (ESP).

Vibrational spectral investigation and natural bond orbital analysis of pharmaceutical compound 7-Amino-2,4-dimethylquinolinium formate - DFT approach

The molecular geometry, the normal mode frequencies and corresponding vibrational assignments, natural bond orbital analysis and the HOMO-LUMO analysis of 7-Amino-2,4-dimethylquinolinium formate in the ground state were performed by B3LYP levels of theory using the 6-31G(d) basis set. The optimised bond lengths and bond angles are in good agreement with the X-ray data. The vibrational spectra of the title compound which is calculated by DFT method, reproduces vibrational wave numbers and intensities with an accuracy which allows reliable vibrational assignments. The possibility of N-H⋯O hydrogen bonding was identified using NBO analysis. Natural bond orbital analysis confirms the presence of intramolecular charge transfer and the hydrogen bonding interaction.

Molecular structure, NBO analysis, electronic absorption and vibrational spectral analysis of 2-Hydroxy-4-Methoxybenzophenone: reassignment of fundamental modes

Vibrational frequencies of 2-Hydroxy-4-Methoxybenzophenone (HMB) have been reassigned with the aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The conformational analyses were performed and the energies of the different possible conformers were determined. The geometry of different conformers of the compounds were optimized with B3LYP method using 6-311++G(d,p) basis set to characterize all stationary points as minima. The optimized structural parameters of the most stable conformer were used in the vibrational frequency calculations. The force constants obtained from the B3LYP/6-311++G(d,p) method have been utilized in the normal coordinate analysis. The temperature dependence of the thermodynamic properties, heat capacity at constant pressure (Cp), entropy (S) and enthalpy change (ΔH) for the compound was also determined by B3LYP/6-311++G(d,p) method. The total electron density and Molecular electrostatic potential surfaces of the molecules were constructed by Natural Bond Orbital analysis using B3LYP/6-311++G(d,p) method to display electrostatic potential (electron+nuclei) distribution, molecular shape, size, and dipole moments of the molecule. The electronic properties, HOMO and LUMO energies were measured.

Density functional theory study, FT-IR and FT-Raman spectra and SQM force field calculation for vibrational analysis of 1, 3-Bis (hydroxymethyl) benzimidazolin-2-one

FT-IR and FT-Raman spectra of 1, 3-Bis (hydroxymethyl) benzimidazolin-2-one were recorded and analyzed in the solid phase. The optimized molecular geometry and vibrational wavenumbers have also been calculated in optimized structure by using DFT method. Scaled quantum mechanical force fields have also been used to calculate potential energy distributions in order to make conspicuous vibrational assignments. The red shifting of the O-H stretching wavenumber is due to the formation of O-H···O intermolecular hydrogen bonding. The lowering and splitting of the carbonyl stretching vibrational modes is assigned to the intermolecular association based on C=O···H type hydrogen bonding in the molecule. Chemical interpretation of hyperconjugative interactions was done by natural bond orbital analysis.

Crystal growth, spectral, optical and thermal properties of semiorganic nonlinear optical material: picolinic acid hydrochloride

The bulk single crystal of 2-picolinic acid hydrochloride (PHCL) (a semi-organic nonlinear optical material of dimensions 25×15×10 mm(3)) was successfully grown by slow solvent evaporation technique. The XRD results revealed the cell parameters and the centrosymmetric nature of the crystal structure. FT-IR spectral study identified the functional groups, nature of bonding and their bond strength. The UV-Vis-NIR studies recognized the optical transmittance window and the lower cut off wavelength of the PHCL crystal and thus it could be performed as a NLO material. (1)H NMR and (13)CNMR spectra were correlated with the XRD standard for the molecular structure reveals harmony of the materials. Thermal properties of the crystal were studied by thermo gravimetric analysis (TGA) and differential thermal analysis (DTA); the derived kinetic parameter values support the intuitive association of picolinicacid and HCl leads to the spontaneous formation of PHCL with a first order reaction. The presence of a proton and a proton acceptor groups provide the necessary stability to induce charge asymmetry in the PHCL structure. The load dependent hardness values of the crystal were measured by microhardness testing.

Structural conformations and density functional study on the intramolecular charge transfer based on vibrational spectra of 2,4-dihydroxy-N'-(4-methoxybenzylidene)benzohydrazide

The NIR-FT Raman and FT-IR spectra of 2,4-dihydroxy-N'-(methoxybenzylidene) benzohydrazide (DMBBH) molecule have been recorded and analyzed. Density functional theory (DFT) calculations at the B3LYP/6-31G(d) level has been used to compute energies of different conformers of DMBBH to find out their stability, the optimized geometry of the most stable conformer and its vibrational spectrum. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential surfaces (ESP). A complete vibrational analysis has been attempted on the basis of experimental infrared and Raman spectra and calculated vibrational modes and potential energy distribution over the internal coordinates. The vibrational analysis confirm the charge transfer interaction between the phenyl rings through C=N-N skeleton. The broadening of the band at 1631 cm(-1) and the appearance of the band at 1556 cm(-1) strongly suggests the existence of proton equilibrium.

Ultrafast optical nonlinearity, electronic absorption, vibrational spectra and solvent effect studies of ninhydrin

FT-IR, FT-Raman and UV-Vis spectra of the nonlinear optical molecule ninhydrin have been recorded and analyzed. The equilibrium geometry, bonding features, and harmonic vibrational wavenumbers have been investigated with the help of B3LYP density functional theory method. 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. Solvent effects have been calculated using time-dependent density functional theory in combination with the polarized continuum model. Natural bond orbital analysis confirms the occurrence of strong intermolecular hydrogen bonding in the molecule. Employing the open-aperture z-scan technique, nonlinear optical absorption of the sample has been studied in the ultrafast and short-pulse excitation regimes, using 100 fs and 5 ns laser pulses respectively. It is found that ninhydrin exhibits optical limiting for both excitations, indicating potential photonic applications.

Multi-photon absorption effect and intra-molecular charge transfer of donor-π-acceptor chromophore ethyl p-amino benzoate

Fourier transform (FT)-Raman and infrared (IR) spectra of the nonlinear optical (NLO) material ethyl p-amino benzoate (EPAB) have been recorded and analyzed. The geometry and harmonic vibrational wavenumbers are calculated with the help of B3LYP density functional theory method. The detailed interpretation of the vibrational spectra has been carried out with the aid of normal coordinate analysis following the scaled quantum mechanical force field methodology. Stability of the molecule arising from hyperconjugative interactions leading to its NLO activity and charge delocalization have been analyzed using natural bond orbital (NBO) analysis. Employing the open-aperture z-scan technique, NLO absorption of the sample has been studied in two excitation regimes, using 100 fs and 5 ns laser pulses respectively. It is found that EPAB is a three-photon absorber for 100 fs pulses at the excitation wavelength of 800 nm. For ns pulses at 532 nm it exhibits strong optical limiting, indicating possible photonics applications.

Three-photon absorption and vibrational spectroscopic study of 2-methylamino-5-chlorobenzophenone

In this paper, the vibrational spectral analysis and three-photon absorption properties of an organic material of 2-methylamino-5-chlorobenzophenone have been reported. The geometry and harmonic vibrational wavenumbers are calculated with the help of B3LYP density functional theory method. The detailed interpretation of the vibrational spectra has been carried out with the aid of normal coordinate analysis following the scaled quantum mechanical force field methodology (SQM). SQM force fields have also been used to calculate potential energy distribution (PED) in order to make conspicuous vibrational assignments. The nonlinear absorption properties have been investigated in ethanol solution at 532nm using the Z-scan technique employing laser pulses of 5ns duration. Open aperture Z-scan data reveal the presence of effective three-photon absorption for ns pulses at 532nm resulting in a strong optical limiting behavior, indicating possible photonic applications.

Vibrational spectral investigation and Natural Bond Orbital analysis of anti-rheumatoid drug ethyl 4-nitrophenylacetate--DFT approach

Vibrational analysis of ethyl 4-nitrophenylacetate (ENPA) molecule was carried out using FT-IR and FT-Raman spectroscopic techniques. The equilibrium geometry, harmonic vibrational wave numbers, various bonding features have been computed using density functional theory. The calculated molecular geometry parameters have been compared with XRD data. The detailed interpretation of the vibrational spectra has been carried out by computing Potential Energy Distribution (PED). Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using Natural Bond Orbital (NBO) analysis. The results show that the charge in the electron density (ED) in the σ(*) and π(*) antibonding orbitals and second order delocalization energies (E(2)) confirm the occurrence of ICT (intramolecular charge transfer) within the molecule. The simulated spectra satisfactorily coincide with the experimental spectra.

Vibrational spectra, structural conformations, scaled quantum chemical calculations and NBO analysis of 3-acetyl-7-methoxycoumarin

The powder form NIR-FT Raman and FT-IR spectra of 3-acetyl-7-methoxycoumarin (3A7MC) have been recorded in the regions 4000-400 and 3500-100 cm(-1), respectively. The equilibrium geometry, vibrational frequencies, band intensities, NMR spectra, NBO analysis and UV-Vis spectral studies of the most stable conformer have been calculated by density functional B3LYP method with the 6-311G(d,p) basis set. A complete vibrational analysis has been attempted on the basis of experimental infrared and Raman spectra, the calculated wavenumber and intensity of the vibrational bands and the potential energy distribution over the internal coordinates. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping the electron density isosurface with electrostatic potential surfaces (ESP). Natural bond orbital analysis has been carried out to understand the nature of different interactions responsible for the electron delocalization and the intramolecular charge transfer between the orbitals (n→π(∗), n→σ(∗), π→π(∗)).

Synthesis, growth and vibrational spectroscopic study of a novel coumarinoylthiazole

An efficient route was developed for the synthesis of novel 3-(2-morpholinyl-4-phenylthiazol-5-oyl)coumarin (MPTC). FT-IR spectrum of MPTC was recorded and analyzed. The crystal structure data are also described. The vibrational wavenumbers were computed theoretically using the Gaussian03 package of programs using HF/6-31G(d) and B3LYP/6-31G(d) levels of theory. The data obtained from vibrational wave number calculations are used to assign vibrational bands observed in the infrared spectra of MPTC. The first hyperpolarizability, infrared absorption band intensities and intensities of raman active bands are reported. The calculated first hyperpolarizability is comparable with the values reported for compounds of similar structure. The structural parameters of MPTC obtained from XRD studies are in agreement with the calculated values. The unit cell parameters of crystals of MPTC are: a=8.6017(10)Å, b=9.9735(5)Å, c=13.3870(13)Å, α=111.123(6)°, β=90.102(9)°, γ=110.246(6)°, and Z=2,1.397 Mg/m(3).

Synthesis, growth, spectral and thermal properties of a new organic crystal: 2-carboxypyridin-1-ium trichloroacetate

A novel organic optical material complex of 2-carboxypyridin-1-ium trichloroacetate has been synthesized and crystals were grown from aqueous solution employing the technique of controlled evaporation. The crystal structure has been determined using single crystal X-ray diffraction studies. The single crystals were successfully grown by the slow evaporation method with dimensions 12 × 8 × 3 mm(3). FT IR spectral investigation has been carried out to identify the various functional groups present in the grown crystal. Molecular structure was confirmed by NMR spectral analysis. Melting point was found using thermal measurements.

Spectral, thermal and optical properties of adenosinium picrate: a nonlinear optical single crystal

A new organic nonlinear optical material adenosinium picrate (C10H14N5O4+, C6 H2 N3 O7-) was synthesized. The single crystal X-ray diffraction revealed the non-centrosymmetric crystal structure, which is an essential criterion for second harmonic generation. The crystalline nature of the grown crystals was confirmed using powder XRD techniques. Molecular structure was confirmed by NMR spectral analysis and functional groups were identified by FT-IR spectral analysis. The optical transmittance window and the lower cutoff wavelength of the AP have been identified by UV-vis-NIR studies. Thermo gravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study its thermal properties. Powder test with Nd:YAG laser radiation shows second harmonic generation.

DFT-based molecular modeling, NBO analysis and vibrational spectroscopic study of 3-(bromoacetyl)coumarin

The NIR-FT Raman and FT-IR spectra of 3-(bromoacetyl)coumarin (BAC) molecule have been recorded and analyzed. Density functional theory (DFT) calculation of two BAC conformers has been performed to find the optimized structures and computed vibrational wavenumbers of the most stable one. The obtained vibrational wavenumbers and optimized geometric parameters were seen to be in good agreement with the experimental data. Characteristic vibrational bands of the pyrone ring and methylene and carbonyl groups have been identified. The lowering of HOMO-LUMO energy gap clearly explains the charge transfer interactions taking place within the molecule.

Spectral, thermal and optical properties of L-tryptophanium picrate: a nonlinear optical single crystal

A new organic nonlinear optical material L-tryptophanium picrate was synthesized. From the powder XRD pattern the various planes of reflections were identified. The grown crystals were subjected to FT-IR and (1)H NMR spectral analyses to confirm the synthesized compound. Thermal properties of the crystals were investigated using thermo gravimetric (TG) and differential thermal analyses (DTA). The second harmonic generation (SHG) efficiency of the title compound was found using the modified experimental setup of Kurtz and Perry.

Natural bond orbital analysis, electronic structure, non-linear properties and vibrational spectral analysis of L-histidinium bromide monohydrate: a density functional theory

The spectroscopic properties of the crystallized nonlinear optical molecule L-histidinium bromide monohydrate (abbreviated as L-HBr-mh) have been recorded and analyzed by FT-IR, FT-Raman and UV techniques. The equilibrium geometry, vibrational wavenumbers and the first order hyperpolarizability of the crystal were calculated with the help of density functional theory computations. The optimized geometric bond lengths and bond angles obtained by using DFT (B3LYP/6-311++G(d,p)) show good agreement with the experimental data. The complete assignments of fundamental vibrations were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. The natural bond orbital (NBO) analysis confirms the occurrence of strong intra and intermolecular N-H⋯O hydrogen bonding.