Experimental and theoretical studies on o-, m- and p-chlorobenzylideneaminoantipyrines

Computational Studies on Optoelectronic and Nonlinear Properties of Octaphyrin Derivatives

The electronic and nonlinear optical (NLO) properties of octaphyrin derivatives were studied by employing the DFT/TDFT at CAM-B3LYP/6-311++G (2d, 2p) level of the theory. Thiophene, phenyl, methyl and cyano moieties were substituted on the molecular framework of octaphyrin core, in order to observe the change in optoelectronic and nonlinear response of these systems. The frontier molecular orbital studies and values of electron affinity reveals that the studied compounds are stable against the oxygen and moisture present in air. The calculated ionization energies, adiabatic electron affinity and reorganization energy values indicate that octaphyrin derivatives can be employed as effective n-type material for Organic Light Emitting Diodes (OLEDs). This character shows an enhancement with the introduction of an electron withdrawing group in the octaphyrin framework. The polarizability and hyperpolarizability values of octaphyrin derivatives demonstrate that they are good candidates for NLO devices. The nonlinear response of these systems shows enhancement on the introduction of electron donating groups on octaphyrin moiety. However, these claims needs further experimental verification.

Screening and design of high-performance indoline-based dyes for DSSCs

The photophysical properties of three D–A–π–A dyes (WS-2, WS-92 and WS-95) were calculated based on DFT and TDDFT.

Synthesis, crystal growth, physicochemical properties and quantum chemical investigations of a D–π–A type organic single crystal: 2-amino-5-nitropyridinium p-phenolsulfonate (2A5NPP) for nonlinear optical (NLO) applications

Efficient organic NLO 2A5NPP single crystals have been grown by slow cooling method.

Double-anchoring organic dyes for dye-sensitized solar cells: the opto-electronic property and performance

A series of A–D–π–D–A multi-anchoring organic dyes (MA-201–MA-206) with different core spacers was designed to investigate optoelectronic properties and to develop utility for solar cells.

Structural, spectroscopic (FT-IR, FT-Raman, NMR) and computational analysis (DOS, NBO, Fukui) of 3,5-dimethylisoxazole and 4-(chloromethyl)-3,5-dimethylisoxazole: A DFT study

The theoretical and computational analysis of two isoxazole derivatives 3,5-dimethylisoxazole and 4-chloromethyl-3,5-dimethylisoxazole were carried out along with some of the experimental evidences. The density functional theory calculations of these compounds were done with DFT/B3LYP/6-31+G(d,p) basis set using Gaussian 09 software. From the DFT calculations, the optimization geometry, vibrational analysis, electronic properties, local reactivity descriptors, natural bond orbitals, and other structural properties of the title compounds were elucidated. The chemical shifts of every C and H atom of the title compounds were calculated using Gauge Independent Atomic orbitals (GIAO) method for both proton and carbon NMR spectra. The molecular electrostatic potential of DMI has been found out and the difference in MEP on addition of chloromethyl group is also discussed. The hyperpolarizability calculations of the investigated molecules shows that the nonlinear optical activity of CDMI is greater when compared to DMI.

Spectroscopic and nonlinear optical properties of new chalcone fluorescent probes for bioimaging applications: a theoretical and experimental study

In this study, the newly synthesized non-centrosymmetric, 4-dimethylamino-3'-isothiocyanatochalcone (PKA) compound was presented. This compound belongs to the chalcone group, and its main purpose is to be used in biomedical imaging as a fluorescence dye. For this reason, the linear and nonlinear properties in solvents of different polarity were thoroughly studied. In accordance with the requirements for a fluorochrome, the PKA compound is characterized by strong absorption, large Stokes' shifts, relatively high fluorescence quantum yields and high nonlinear optical response. Moreover, the isothiocyanate reactive probe was conjugated with Concanavalin A. Conventional fluorescence microscopy imaging of Candida albicans cells incubated with the PKA-Concanavalin A, is presented. The results of this study show that the novel conjugate PKA-Concanavalin A could be a promising new probe for cellular labelling in biological and biomedical research. Graphical abstract Spectroscopic behavior of the PKA dye.

Experimental and theoretical study of ornidazole

The Fourier transform infrared (FT-IR) and the Fourier transform Raman (FT-Raman) spectra of the title molecule in solid phase were recorded in the region 4000-400 cm(-1) and 4000-100 cm(-1) respectively. The geometrical parameters and energies were investigated with the help of Density Functional Theory (DFT) employing B3LYP method and 6-31G (d, p) basis set. The analysis was supported by electrostatic potential maps and calculation of HOMO-LUMO. UV, FT-IR and FT-Raman spectra of ornidazole were calculated and compared with experimental results. Thermodynamic properties like entropy, heat capacity, have been calculated for the molecule. The predicted first hyperpolarizability also shows that the molecule might have a reasonably good non-linear optical (NLO) behavior. The intramolecular contacts have been interpreted using natural bond orbital (NBO) and natural localized molecular orbital (NLMO) analysis.

Ab initio and density functional theory calculations of molecular structure and vibrational spectra of 4-(2-Hydroxyethyl) piperazine-1-ethanesulfonic acid

The FTIR and FT-Raman spectra of 4-(2-Hydroxyethyl) piperazine-1-ethanesulfonic acid were recorded and the structural and spectroscopic data of the molecule in the ground state were calculated using Hartree-Fock and Density Functional Method (B3LYP). The most stable conformer was optimized and the structural and vibrational parameters were determined. With the observed FTIR and FT-Raman data, a complete vibrational band assignment and analysis of the fundamental modes of the compound were carried out. Thermodynamic properties, Mulliken and natural atomic charge distribution were calculated using both Hartree-Fock and Density Functional Method and compared. UV-Visible and HOMO-LUMO analysis were carried out. (1)H and (13)C NMR chemical shifts of the molecule were calculated using gauge including atomic orbital method and were compared with experimental results. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using natural bond orbital analysis. The first order hyperpolarizability (β) and molecular electrostatic potential of the molecule was computed using DFT calculations. The electron density based local reactivity descriptor such as Fukui functions were calculated to explain the chemically reactive site in the molecule.

Eight membered cyclic-borasiloxanes: synthesis, structural, photophysical, steric strain and DFT calculations

A series of eight membered cyclic borasiloxanes were synthesized and structurally characterized. The photophysical properties were investigated. HOMO–LUMO, hyperpolarizability and steric strain were computed by B3LYP/6-31+G** method.

Synthesis, electronic structure investigation of 3-pentyl-2,6-di(furan-2-yl)piperidin-4-one by FT-IR, FT-Raman and UV-Visible spectral studies and ab initio/DFT calculations

FT-IR and FT-Raman spectra of 3-pentyl-2,6-di(furan-2-yl) piperidin-4-one (3-PFPO) were recorded in the solid phase. The structural and spectroscopic analyses of 3-PFPO were made by using B3LYP/HF level with 6-311++G(d, p) basis set. The fundamental vibrations are assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. Comparison of the observed fundamental vibrational frequencies of 3-PFPO with calculated results by HF and DFT methods indicates that B3LYP is superior to HF method for molecular vibrational problems. The electronic properties such as excitation energies, oscillator strength, wavelengths and HOMO-LUMO energies were obtained by time-dependent DFT (TD-DFT) approach. The polarizability and first order hyperpolarizability of the title molecule were calculated and interpreted. The hyperconjugative interaction energy (E((2))) and electron densities of donor (i) and acceptor (j) bonds were calculated using NBO analysis. In addition, MEP and atomic charges of carbon, nitrogen, oxygen and hydrogen were calculated using B3LYP/6-311++G(d, p) level theory. Moreover, thermodynamic properties (heat capacities, entropy and enthalpy) of the title compound at different temperatures were calculated in gas phase.

Molecular structure, spectroscopic characterization, HOMO and LUMO analysis of 3,3'-diaminobenzidine with DFT quantum chemical calculations

In this work, infrared, Raman and UV spectra of 3,3'-diaminobenzidine (3,3-DAB) were carried out by using density functional theory (DFT)/B3LYP method with 6-311G(d,p) basis set. FT-IR and FT-Raman spectra were recorded in the region 4000-400 and 4000-50 cm(-1), respectively. The geometrical parameters, energies and wavenumbers were obtained and fundamental vibrations were assigned on the basis of the potential energy distribution (PED) of the vibrational modes. The UV spectrum of the investigated compound was recorded in the range of 200-400 nm in ethanol and water solutions. The electronic properties, such as excitation energies, absorption wavelengths, HOMO and LUMO energies were performed by DFT/B3LYP approach and the results were compared with experimental observations. Thermodynamic properties, Mulliken atomic charges and molecular electrostatic potential (MEP) were calculated for the title molecule. Also the nonlinear optical properties of 3,3-DAB molecule were explored theoretically. As a result, the calculated results were compared with the observed values and generally found to be in good agreement.

Synthesis, spectroscopic (FT-IR, FT-Raman, UV and NMR) and computational studies on 3t-pentyl-2r,6c-diphenylpiperidin-4-one semicarbazone

The structural and spectroscopic studies of 3t-pentyl-2r,6c-diphenylpiperidin-4-one semicarbazone (PDPOSC) were made by adopting B3LYP/HF levels theory using 6-311++G(d,p) basis set. The FT-IR and Raman spectra were recorded in solid phase, the fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. DFT method indicates that B3LYP is superior to HF method for molecular vibrational analysis. UV-vis spectrum of the compound was recorded in different solvents in the region of 200-800 nm and the electronic properties such as excitation energies, oscillator strength, wavelengths, HOMO and LUMO energies were evaluated by time-dependent DFT (TD-DFT) approach. The polarizability and first order hyperpolarizability of the title molecule were calculated and interpreted. The hyperconjugative interaction energy (E((2))) and electron densities of donor (i) and acceptor (j) bonds were calculated using NBO analysis. In addition, MEP and atomic charges of carbon, nitrogen and oxygen were calculated using B3LYP/6-311++G(d,p) level theory. Moreover, thermodynamic properties of the title compound were calculated by B3LYP/HF, levels using 6-311++G(d,p) basis set. The (1)H and (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.

Synthesis, structural characterization and theoretical approach of the tri(2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) cobalt(II)

The crystal structure of a new coordination compound tri(2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) Co(II) complex ([Co(dcpip)3]Cl2) was measured with X-ray diffraction measurements. The compound is crystallizes triclinic, Pī space group. The ligand, 2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline(dcpip), binds to Co(II) ions with a bis-dentate mode, and each Co(II) ion with a distorted octahedral coordination geometry. The calculated interaction energies of Co(II) with coordination atoms N are between 101.7-206.5 kJ/mol and 115.3-230.9 kJ/mol for B3LYP/6-31+G(∗) and PBE1PBE/6-31+G(∗) theoretical methods, respectively. The experimental Fourier transform infrared spectrum was assigned. The calculated IR based on B3LYP/6-31+G(∗) and PBE1PBE/6-31+G(∗) methods were performed and compared with experimental results. The UV-Vis experimental spectrum of [Co(dcpip)3]Cl2 was measured in methanol solution. The calculated electronic spectrum was performed with TD/B3LYP and TD/PBE1PBE methods with 6-31+G(∗) basis set. The first and second order hyperpolarizability for the compound was calculated. The calculated values of γtot are -1.5551344 × 10(-33) esu for B3LYP method and -1.3323259 × 10(-33) esu for PBE1PBE method. The nature bond orbital analysis and temperature dependence of the thermodynamic properties were calculated with the same methods.

Spectroscopic (FT-IR/FT-Raman) and computational (HF/DFT) investigation and HOMO/LUMO/MEP analysis on 1,1-difluoro-2-vinyl-cyclopropane

All the computational calculations were made in the ground state using the HF and DFT (B3LYP) methods with 6-31++G (d,p) and 6-311++G (d,p) basis sets. Making use of the recorded data, the complete vibrational assignments were made and analysis of the observed fundamental bands of molecule was carried out. The shifting of the frequencies in the vibrational pattern of the title molecule due to the substitutions; CHCH₂ and F were deeply investigated by the vibrational analysis. Moreover, (13)C NMR and (1)H NMR chemical shifts were calculated by using the gauge independent atomic orbital (GIAO) method with HF/B3LYP methods with 6-311++G (d,p). A study on the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. Mulliken charges of the 1DF2VCP were also calculated and interpreted. The thermodynamic properties (heat capacity, entropy, and enthalpy) of the title compound at different temperatures were calculated in gas phase.

Synthesis and investigation of the properties of novel azocalix[4]arenes

The azocalix[4]arenes molecules such as methylphenylazocalix[4]aren (MPcalix[4]) and methoxyphenylazocalix[4]aren (MOPcalix[4]) have been synthesized and characterized by experimental FT-IR and (1)H NMR spectral analyses. The fundamental vibrational transitions have been addressed by experimental FT-IR (4000-400 cm(-1)) technique and density functional theory (DFT) employing B3LYP level with the 6-31G(d) and 6-311G(d,p) basis sets. The (1)H NMR spectra of the studied compounds have been recorded in chloroform, and compared with computed data obtained by using gauge including atomic orbital (GIAO) method. Furthermore, thermodynamic properties (heat capacity, entropy, and enthalpy changes) and frontier molecular orbitals of the molecules in the ground state have been calculated by using the same method and basis sets. The non-linear optical properties such as the first order hyperpolarizability (β0), related properties (α0 and Δα) are also computed. Information about the charge density distribution of the molecules and its chemical reactivity has been studied by mapping molecular electrostatic potential surface (MEPs). The scaled vibrational frequency values have been compared with experimental FT-IR spectroscopic data. The correlations between the observed and calculated frequencies are in good agreement with each other as well as the correlation of NMR data. The linear polarizability and first hyperpolarizability of the studied molecules indicate that the compounds are a good candidate of nonlinear optical materials.

Study on molecular structure, spectroscopic behavior, NBO, and NLO analysis of 3-methylbezothiazole-2-thione

Experimentally observed spectral data (FT-TR and FT-Raman) of 3-methylbezothiazole-2-thione (3MBT2T) were compared with the spectral data obtained by DFT/B3LYP method using 6-311++G(d,p) basis set. UV-Vis spectrum of the title compound was recorded and the electronic properties, such as frontier molecular orbitals and band gap energies were calculated by TD-DFT approach. The molecular properties like dipole moment, polarizability, first static hyperpolarizability, molecular electrostatic potential surface (MEPs), and contour map were calculated to get a better comprehension of the properties of the title molecule. Natural bond orbital (NBO) analysis was applied to investigate the stability of the molecule arising from charge delocalization. Global and local reactivity descriptors were also computed to predict reactivity and reactive sites on the molecule.

Time-dependent density functional theory calculations of the solvatochromism of some azo sulfonamide fluorochromes

The absorption and emission spectra of three azo sulfonamide compounds in different solvents were investigated theoretically by using response functions combined with density functional theory (DFT), while the solvent effect on the structure and the electronic transitions was determined using the integral equation formalism for the polarizable continuum model (IEF-PCM). The results show that the applied different exchange-correlation functionals can reproduce the experimental values well. DFT calculations of the title compounds showed that the H-bond formed between the solute and solvent molecules is one of the major causes of the reversible solvatochromism observed in measured spectra. This is due to a better stabilization of the neutral form than the zwitterionic form in the polar protic solvents, which is characteristic of the hypsochromic shift. On the other hand, the molecules considered exhibit a monotonic behavior regarding the polarity of the low-lying excited state (Δμg-CT) as a function of the solvent polarity. This dependence occurs in the case of the positive solvatochromism and confirms the thesis regarding the H-bond solute-solvent interactions. Theoretically determined values of the two-photon cross section revealed that the (σOF(2)) shows similar trends with changes in λabs, in contrast to <δ(OF)> values. In conclusion, the results demonstrate that the investigated molecules can be used successfully as fluorochromes in bioimaging.

Molecular structure, spectroscopic characterization of (S)-2-Oxopyrrolidin-1-yl Butanamide and ab initio, DFT based quantum chemical calculations

The experimental and theoretical spectra of (S)-2-Oxopyrrolidin-1-yl Butanamide (S2OPB) were studied. FT-IR and FT-Raman spectra of S2OPB in the solid phase were recorded and analyzed in the range 4000-450 and 5000-50 cm(-1) respectively. The structural and spectroscopic analyses of S2OPB were calculated using ab initio Hartree Fock (HF) and density functional theory calculations (B3PW91, B3LYP) with 6-31G(d,p) basis set. A complete vibrational interpretation has been made on the basis of the calculated Potential Energy Distribution (PED). The HF, B3LYP and B3PW91 methods based NMR calculation has been used to assign the (1)H NMR and (13)C NMR chemical shift of S2OPB. Comparative study on UV-Vis spectral analysis between the experimental and theoretical (B3PW91, B3LYP) methods and the global chemical parameters and local descriptor of reactivity through the Fukui function were performed. Finally the thermodynamic properties of S2OPB were calculated at different temperatures and the corresponding relations between the properties and temperature were also studied.

Normal co-ordinate analysis, molecular structural, non-linear optical, second order perturbation studies of Tizanidine by density functional theory

The spectroscopic techniques and semi-empirical molecular calculations have been utilized to analyze the drug Tizanidine (5CDIBTA). The solid phase Fourier Transform Infrared (FTIR) and Fourier Transform Raman (FTR) spectral analysis of 5CDIBTA is carried out along with density functional theory (DFT) calculations (B3LYP) with the 6-311++G(d,p) basis set. Detailed interpretation of the vibrational spectra of the compound has been made on the basis of the calculated potential energy distribution (PED). The individual atomic charges by NPA using B3LYP method is studied. A study on the Mulliken atomic charges, frontier molecular orbitals (HOMO-LUMO), molecular electrostatic potential (MEP) and thermodynamic properties were performed. The electric dipole moment (μ) and the first hyperpolarizability (α) values of the investigated molecule were also computed.

Vibrational spectra (FT-IR, FT-Raman), frontier molecular orbital, first hyperpolarizability, NBO analysis and thermodynamics properties of Piroxicam by HF and DFT methods

The solid phase FT-IR and FT-Raman spectra of 4-Hydroxy-2-methyl-N-(2-pyridinyl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide (Piroxicam) have been recorded in the region 4000-400 and 4000-100cm(-1) respectively. The molecular geometry, harmonic vibrational frequencies and bonding features of piroxicam in the ground state have been calculated by Hartree-Fock (HF) and density functional theory (DFT) methods using 6-311++G(d,p) basis set. The calculated harmonic vibrational frequencies are scaled and they are compared with experimental obtained by FT-IR and FT-Raman spectra. A detailed interpretation of the vibrational spectra of the title compound has been made on the basis of the calculated potential energy distribution (PED). The electronic properties, such as HOMO and LUMO energies, molecular electrostatic potential (MESP) are also performed. The linear polarizability (α) and the first order hyper polarizability (β) values of the title compound have been computed. The molecular stability arising from hyper conjugative interaction, charge delocalization has been analyzed using natural bond orbital (NBO) analysis.

Crystal growth and properties of NLO optical crystal - Butylated Hydroxy Toluene (BHT)

Crystallographic, experimental and theoretical density functional theory (DFT) of Butylated Hydroxy Toluene (BHT) are investigated. The grown crystals were identified by single crystal X-ray analysis. The first order hyperpolarizability (β0) and related properties (β, α0 and Δα) of BHT is calculated using B3LYP/6-31G(d,p) method on the finite-field approach. The stability of molecule has been analyzed by using NBO/NLMO analysis. The molecular electrostatic potential (MESP) mapping is very useful in the investigation of the molecular structure with its physiochemical property relationship. The calculated HOMO and LUMO energies show that charge transfer occurs within these molecules. Mulliken population analysis on atomic charge is also calculated. Because of vibrational analysis, the thermodynamic properties of the title compound at different temperatures have been calculated. Finally, the UV-Vis spectra and electronic absorption properties are explained and illustrated from the frontier molecular orbitals. The grown crystals were characterized by measuring their thermal properties by Differential Thermal Analysis (DTA) and Thermo Gravimetric Analysis (TGA) measurements.

DFT electronic structure calculations, spectroscopic studies, and normal coordinate analysis of 2-[(5-nitro-1,3-thiazol-2-yl)carbamoyl]phenyl acetate

The solid phase FTIR and FT-Raman spectra of 2-[(5-nitro-1,3-thiazol-2-yl)carbamoyl]phenyl acetate (25N2LCPA) have been recorded 450-4000cm(-1) and 100-4000cm(-1) respectively. The normal coordinate analysis was carried out to confirm the precision of the assignments. DFT calculations have been performed giving energies, optimized structures, harmonic vibrational frequencies and IR intensities. The structure of the molecule was optimized and the structural characteristics were determined by density functional theory (DFT) using B3LYP method with 6-31+G(d,p) basis set. The detailed interpretation of the vibrational spectra has been carried out with aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology. The Vibrational frequencies are calculated in the above method and are compared with experimental frequencies which yield good agreement between observed and calculated frequencies. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. In addition, Frontiers molecular orbital and molecular electrostatic potential were computed by using Density Functional Theory (DFT) B3LYP/6-31+G(d,p) basis set. The calculated HOMO and LUMO energies show that charge transfer occurs in the molecule.

Conformational stability, vibrational (FT-IR and FT-Raman) spectra and computational analysis of m-trifluoromethyl benzoic acid

In this work, the vibrational characteristics of m-trifluoromethyl benzoic acid have been investigated and both the experimental and theoretical vibrational data indicate the presence of functional groups in the title molecule. The density functional theoretical (DFT) computations were performed at the B3LYP/6-31G (d, p), LSDA/6-31G (d, p), MP2/6-31G (d, p) levels to derive the optimized geometry, vibrational wavenumbers. Furthermore, the molecular orbital calculations such as natural bond orbitals (NBO), HOMO-LUMO energy gap and Mapped molecular electrostatic potential (MEP) surfaces, The Mulliken charges, the first-order hyperpolarizability were also performed with the same level of DFT. The thermal flexibility of molecule in associated with vibrational temperature was also illustrated on the basis of correlation graphs. The detailed interpretation of the vibrational spectra has been carried out with the aid of potential energy distribution (PED) results obtained from MOLVIB program. The delocalization of electron density of various constituents of the molecule has been discussed with the aid of NBO and HOMO-LUMO energy gap analysis.