First-order Hyperpolarizability Research Articles

Experimental and quantum chemical studies of a new organic proton transfer compound, 1H-imidazole-3-ium-3-hydroxy-2,4,6-trinitrophenolate

A new proton transfer compound, 1H-imidazole-3-ium-3-hydroxy-2,4,6-trinitrophenolate (IMHTP), was crystallized by slow evaporation-solution growth technique. 1H and 13C NMR spectral studies confirm the molecular structure of the grown crystal. Single crystal X-ray diffraction study confirms that IMHTP crystallizes in monoclinic system with space group P21/c. Thermal curves (TG/DTA) show that the material is thermally stable up to 198 °C. The crystal emits fluorescence at 510 nm, proving its utility in making green light emitting materials in optical applications. The stable molecular structure was optimized by Gaussian 09 program with B3LYP/6-311++G(d,p) level of basis set. The frontier molecular orbital study shows that the charge transfer interaction occurs within the complex. The calculated first-order hyperpolarizability value of IMHTP is 44 times higher than that the reference material, urea. The electrostatic potential map was used to probe into electrophilic and nucleophilic reactive sites present in the molecule.

Synthesis, spectroscopic characterization, first order nonlinear optical properties and DFT calculations of novel Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with 1,3-diphenyl-4-phenylazo-5-pyrazolone ligand

Novel Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) metal ions with 1,3-diphenyl-4-phenylazo-5-pyrazolone (L) have been prepared and characterized using different analytical and spectroscopic techniques. 1:1 Complexes of Mn(II), Co(II) and Zn(II) are distorted octahedral whereas Ni(II) complex is square planar and Cu(II) is distorted trigonal bipyramid. 1:2 Complexes of Mn(II), Co(II), Cu(II) and Zn(II) are distorted trigonal bipyramid whereas Ni(II) complex is distorted tetrahedral. All complexes behave as non-ionic in dimethyl formamide (DMF). The electronic structure and nonlinear optical parameters (NLO) of the complexes were investigated theoretically at the B3LYP/GEN level of theory. Molecular stability and bond strengths have been investigated by applying natural bond orbital (NBO) analysis. The geometries of the studied complexes are non-planner. DFT calculations have been also carried out to calculate the global properties; hardness (η), global softness (S) and electronegativity (χ). The calculated small energy gap between HOMO and LUMO energies shows that the charge transfer occurs within the complexes. The total static dipole moment (μtot), the mean polarizability (<α>), the anisotropy of the polarizability (Δα) and the mean first-order hyperpolarizability (<β>) were calculated and compared with urea as a reference material. The complexes show implying optical properties.

Insight into the theoretical and experimental studies of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone N(4)-methyl-N(4)- phenylthiosemicarbazone - A potential NLO material

The synthesis, geometrical parameters, spectroscopic studies, optimised molecular structure, vibrational analysis, Mullikan population analysis, MEP, NBO, frontier molecular orbitals and NLO effects of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone N-(4)-methyl-N-(4)-phenylthiosemicarbazone, C25H23N5OS (L1) have been communicated in this paper. A combined experimental and theoretical approach was used to explore the structure and properties of the compound. For computational studies, Gaussian 09 program was used. Starting geometry of molecule was taken from X-ray refinement data and has been optimized by using DFT (B3LYP) method with the 6-31+G (d, p) basis sets. NBO analysis gave insight into the strongly delocalized structure, responsible for the nonlinearity and hence the stability of the molecule. Frontier molecular orbitals have been defined to forecast the global reactivity descriptors of L1. The computed first-order hyperpolarizability (β) of the compound is 2 times higher than that of urea and this account for its nonlinear optical property. Simultaneously, a molecular docking study of the compound was performed using GLIDE Program. For this, three biological enzymes, histone deacetylase, ribonucleotide reductase and DNA methyl transferase, were selected as receptor molecules.

Charge transport, optical and nonlinear optical properties of $$\hbox {CF}_{3}$$ CF 3 -substituted acene compounds: a DFT study

We present a density functional study to investigate the charge transport properties of $$-\hbox {CF} _{3}$$ -substituted pentacenes (TFMPEN) and tetracenes (TFMTET). Calculated charge carrier mobilities at different relative orientations of the dimers showed that at 3.7 A translational spacing, the hole mobilities ( $$\mu _{\text{ h }}$$ ) for TFMTET and TFMPEN molecules were found in the range of 1.43–2.16 and $$1.55{-}2.17\,\hbox {cm}^{{2}}$$ /Vs, respectively, whereas the value of electron mobility ( $$\mu _{\text{ e }}$$ ) for TFMTET and TFMPEN molecules was found in the range of $$0.63{-}1.08\,\hbox {cm}^{{2}}$$ /Vs. Also at the tilting angle of $$45{^\circ }$$ , $$\mu _{\text{ e }}$$ for di- and tetra-TFMPEN was found to be more than $$\mu _{\text{ h }}$$ by an order of $$0.2{-}0.5\,\hbox {cm}^{2}$$ /Vs indicating an enhancement in the n-type character in TFMPEN molecule for such configuration. In addition, the difference in electron and hole reorganization energy reduces with the increase of $$-\hbox {CF}_{3}$$ substituents, inferring an enhancement in the n-type character in the compounds. Computed optical absorption spectra of the TFMTET and TFMPEN molecules appear in both the ultraviolet (UV) and visible regions, and the associated electronic transitions are mostly $$\pi \rightarrow \pi ^{*}$$ in nature, and on moving from TFMTET to TFMPEN molecules, a bathochromic shift of about $$25{-}30\,\hbox {nm}$$ in the UV region and $$110{-}140\,\hbox {nm}$$ in the visible region was noted at all computational levels. Values of averaged polarizability and polarizability anisotropy are found to be enhanced with substitution of $$-\hbox {CF}_{{3}}$$ group as well as with increase of acene rings. However, first-order hyperpolarizabilities are found to be comparatively larger in mono- and hexa- $$\hbox {CF}_{{3}}$$ -substituted molecules than di- and tetra-CF 3-substituted molecules.

Molecular structures, spectroscopic (FT–IR, NMR, UV) studies, NBO analysis and NLO properties for tautomeric forms of 1,3-dimethyl-5-(phenylazo)-6-aminouracil by density functional method

The equilibrium geometry, nuclear magnetic resonance (NMR) and UV–Vis analysis, and vibrational frequencies for the azo and hydrazone isomers of 1,3-dimethyl-5-(phenylazo)-6-aminouracil have been performed using density functional theory (DFT/B3LYP) method with 6–311G(d,p) basis set. A detailed interpretation of the vibrational spectra has been made on the basis of the calculated potential energy distribution (PED) obtained from the Vibrational Energy Distribution Analysis (VEDA4) program. The 1H NMR chemical shifts with respect to TMS were calculated by the gauge independent atomic orbital (GIAO) method and compared with the experimental data. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. Using the TD-DFT method, electronic absorption spectra in CHCl3 solvent of the title compound have been predicted, and good agreement is determined with the experimental one. The NLO properties such as mean polarizability (⟨α⟩), the anisotropy of the polarizability (⟨Δα⟩) and the mean first-order hyperpolarizability (⟨β⟩) were computed by using finite field method. The computed values of μ, α and β for the azo and hydrazone forms of the title molecule are 5.4717 and 3.8905 D, 2.7773×10−23 and 2.7598×10−23esu, and 3.4499×10–30 and 6.8504×10–30esu, respectively. The high β values and non-zero values of μ indicate that the title compound might be a good candidate for NLO material.

Quantum mechanical and spectroscopic (FT-IR, FT-Raman) study, NBO analysis, HOMO-LUMO, first order hyperpolarizability and molecular docking study of methyl[(3R)-3-(2-methylphenoxy)-3-phenylpropyl]amine by density functional method

Quantum chemical techniques such as density functional theory (DFT) have become a powerful tool in the investigation of the molecular structure and vibrational spectrum and are finding increasing use in application related to biological systems. The Fourier transform infrared (FT-IR) and Fourier transform Raman (FT-Raman) techniques are employed to characterize the title compound. The vibrational frequencies were obtained by DFT/B3LYP calculations with 6-31G(d,p) and 6-311++G(d,p) as basis sets. The geometry of the title compound was optimized. The vibrational assignments and the calculation of Potential Energy Distribution (PED) were carried out using the Vibrational Energy Distribution Analysis (VEDA) software. Molecular electrostatic potential was calculated for the title compound to predict the reactive sites for electrophilic and nucleophilic attack. In addition, the first-order hyperpolarizability, HOMO and LUMO energies, Fukui function and NBO were computed. The thermodynamic properties of the title compound were calculated at different temperatures, revealing the correlations between heat capacity (C), entropy (S) and enthalpy changes (H) with temperatures. Molecular docking studies were also conducted as part of this study. The paper further explains the experimental results which are in line with the theoretical calculations and provide optimistic evidence through molecular docking that the title compound can act as a good antidepressant. It also provides sufficient justification for the title compound to be selected as a good candidate for further studies related to NLO properties.

The spectroscopic investigation, NLO, NBO, NMR, HOMO–LUMO and molecular docking analysis on Clonazepam

The geometry and the vibrational frequency of Clonazepam (CPM) were elucidated with the help of structure optimisation and normal coordinate force field computations based on DFT method. Fourier Transform Infra red spectrum has been recorded in the range 4000–400 cm−1 and analysed. The non-linear optical parameters like electric dipole moment, first-order hyperpolarisability and polarisability for CPM were computed. The DFT-based NMR calculation procedure has been used for assigning the 1H and 13C NMR chemical shift of CPM. The Mulliken atomic charges were computed and interpreted. HOMO and LUMO energies have been calculated. Natural bond orbital analyses have been used for interpreting intramolecular interaction. To investigate the biotic behaviour of the compound, molecular docking (ligand and protein) stimulations have been studied and the results were discussed in detail.

Density functional modelling studies of chloride-substituted Schiff bases as corrosion inhibitors: Optimized geometries, atomic charges, solvent and non-linear optical effects

The anti-corrosive properties, optimized geometrical structures, atomic charges, molecular electrostatic potential (MEP) surfaces and non-linear optical (NLO) effects of some chloride-substituted Schiff bases salicylaldimine (R), N-(2-chlorophenyl)salicyaldimine (2Cl–R), N-(3-chlorophenyl)salicyaldimine (3Cl–R) and N-(4-chlorophenyl)salicyaldimine (4Cl–R) have been investigated by using density functional modelling calculations. The quantum chemical parameters, such as the highest occupied molecular orbital, the lowest unoccupied molecular orbital, gap energy and other parameters, including electronegativity, global hardness, the total charges on the whole molecules and the total energies have been calculated and discussed to obtain information about the relationships between the molecular and electronic structures of the studied inhibitors and their experimental corrosion inhibition efficiencies. The linear polarizability (α), and the firstorder hyperpolarizability (β) have been also predicted by the density functional theory (DFT) with different base sets 6-31G(d), 6-31+G(d,p), 6-31++G(d,p), 6-311+G(d) and 6-311++G(d,p) for investigating the effects of basis sets on the NLO properties.

Quantum Computational and Molecular docking studies of 2-{2-[(2,6-dichlorophenyl)amino]phenyl}acetic acid based on density functional theory

In this study, FT-Raman and FTIR spectroscopy have been applied to the vibrational characterization of diclofenac (DCF). The vibrational analysis was aided by DFT calculation based on B3LYP/6-31G(d,p) basis set. The optimized geometries, IR and Raman intensities and harmonic vibrational frequencies were computed. The complete vibrational assignments were performed based on potential energy distribution (PED). The correlation between entropy, enthalpy and Heat capacity at different temperatures has been studied. In addition, the first-order hyperpolarisability, NBO, HOMO and LUMO energies, Fukui function and molecular electrostatic potential were computed. Molecular docking studies suggest that the title compound exhibit anti-inflammatory activity.

Studies on synthesis, structural, luminescent and thermal properties of a new non-linear optical crystal: 4-amino-4H-1,2,4-triazol-1-ium-3-hydroxy-2,4,6-trinitrophenolate

A new organic proton transfer complex having NLO activity, 4-amino-4H-1,2,4-triazol-1-ium-3-hydroxy-2,4,6-trinitrophenolate (ATHTP), was crystallized to investigate the factors which stabilize the structure of the crystal. The compound crystallizes in triclinic system with space group P-1. Elemental analysis, thermal analysis, UV–Vis–NIR, FT-IR and NMR spectral analyses were carried out to characterize the crystal. Optical, spectral and thermal properties of the title crystal were analyzed to recommend the material for optical applications. Z-scan was used to measure the effective third-order nonlinear optical susceptibility and nonlinear refractive index. The crystal structure was determined using single crystal XRD method and the structure was optimized using Gaussian 09 program at B3LYP/6-311++G(d,p) level of basis set. This hydrogen bond interactions led to the increase in first-order hyperpolarizability of ATHTP and was 30 times greater than that of urea. Hirshfeld analyses surface analysis was carried out to explore intermolecular interactions in the crystalline state.

The important role of the isolation group (TBDPS) in designing efficient organic nonlinear optical FTC type chromophores

Highly efficient and thermally stable nonlinear optical chromophores based on the same thiophene π-conjugation and tricyanofuran acceptor (TCF) possessing different isolation groups attached to electron-donating moiety have been synthesized and systematically investigated in this paper. Density functional theory (DFT) was used to calculate the HOMO–LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. These new chromophores showed excellent thermal stability with their decomposition temperatures all above 250 °C. Most importantly, the molecular hyperpolarizability of these chromophores can be effectively translated into large electro-optic (EO) coefficients (r33) in poled polymers. The doped films-B containing 25 wt % chromophore F1 displayed an r33 value of 52 pm/V at 1310 nm, and the doped films-C containing F2 showed a value of 91 pm/V at the concentration of 35 wt %. These values are all much higher than the traditional FTC chromophore (39 pm/V). These results revealed that the introduced isolation group can reduce intermolecular electrostatic interactions thus enhance the macroscopic EO activity. Besides, the position of the isolation group plays an equally important role in achieving the ultra large EO coefficients of materials. These properties, together with the good solubility, suggest the potential use of these new chromophores as advanced materials devices.

Performance of Hybrid DFT Compared to MP2 Methods in Calculating Nonlinear Optical Properties of Divinylpyrene Derivative Molecules.

A series of divinyl-pyrene derivatives of the form D-vinyl-pyrene-vinyl-A, in which D corresponds to an electron donor group and A to an electron acceptor group, were studied in this work. The first purpose was to determine the optimal HF % exchange as incorporated in a range of hybrid functionals (M06HF, M062X, M06L, CAM-B3LYP, PBE0, BMK, and B3LYP) capable to produce, reliably and as close as possible to those obtained from MP2 calculations, NLO parameters and, in particular, first-order static hyperpolarizabilities. The CAM-B3LYP functional was revealed to be the most suitable one. The pair N(CH3)2/NO2 was then determined as the most efficient pair of groups in producing appreciable NLO responses. The effect of the substitution position on the pyrene moiety was also investigated, whereby aligning the two substituents involving the D and A groups in the direction of the dipole moment as in the (1,6 DVP) derivatives was shown to be most favorable for increasing the NLO parameters.

Acridine-1, 8-diones – A new class of thermally stable NLOphores: Photophysical, (hyper)polarizability and TD-DFT studies

Linear and non-linear optical properties of a series of new acridine-1, 8-dione derivatives are investigated in different solvents by using solvatochromic and computational methods. Values of first-order hyperpolarizabilities (βCT or β0) obtained using solvatochromic and computational methods are compared with the reported values for urea and 3-aminoxanthone. The new materials under study show first hyperpolarizability values 2.3 to 5.6 times larger than that of urea and 2 to 15.6 times more than that of 3-aminoxanthone. The dyes possess very high thermal stabilities. The dyes are prepared using one pot multicomponent reaction between dimedone, various aromatic aldehydes and amino acids, and characterized by spectroscopic techniques.

Pyrrole-thiazole based push-pull chromophores: An experimental and theoretical approach to structural, spectroscopic and NLO properties of the novel styryl dyes

Novel push-pull fluorophores constituted by two donors (substituted pyrrole and morpholine) linked to acceptor through thiazole electron spacer have been synthesized. The fluorophores are investigated for linear and non-linear optical properties by UV-VIS absorption and fluorescence spectroscopies, and by means of TD-DFT (B3LYP/6-31G(d)) method, with the aim of elucidating the ability of the morpholine/pyrrole-donor-thiazole-spacer based D-π-A fluorophores as organic NLO materials. The bond length alternation and generalized Mulliken-Hush (GMH) analysis is performed to understand the involvement of the donor in effective transfer of the charge to acceptor. Values of first-order hyperpolarizabilities (βCT or β0), obtained by the solvatochromic method (Lippert Mataga model), and the transition dipole moments (μeg) used to characterize and evaluate the non-linear optical performances of the D-π-A fluorophores in various microenvironments. The D-π-A fluorophores possess good values of βCT or β0 in different organic solvents and hold high thermal stabilities therefore can be used as potential organic NLO materials.

EO polymer at cryogenic temperatures

Electro-optic (EO) properties at 7 K of a guest–host type nonlinear poled polymer system consisting of AJLZ53 chromophores in an amorphous polycarbonate host are reported for the first time. A modified attenuated total reflection method that takes into account multilayer structure is used to accurately characterise linear and nonlinear optical properties. At the telecommunication wavelength of 1550 nm, <10% drop of the EO coefficient r 33 at 7 K is observed compared with that at 300 K, while n 3 r 33 only decreases <5% because of increased anisotropic indices of refraction at low temperatures. This decrease of the r 33 at 7 K indicates that the EO activity of nonlinear polymers at room temperatures is not of pure electronic origin because of vibrational mode contributions to the first-order hyperpolarisability.

Synthesis of chromophores with ultrahigh electro-optic activity: Rational combination of the bridge, donor and acceptor groups

A series of high performance chromophores P1P3, based on N-(4-dibutylaminophenyl) tetrahydroquinolinyl or julolidinyl donors, and phenyl-trifluoromethyl-tricyanofuran acceptors linked together via π-conjugation through thiophene or vinylene moieties as the bridges, have been designed and synthesized. Density functional theory (DFT) was used to calculate the HOMO-LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. Chromophores P1 and P3 had good thermal stabilities with glass transition temperature higher than 110 °C. Most importantly, the high molecular hyperpolarizability of these chromophores can be effectively translated into large electro-optic (EO) coefficients (r33) in poled polymers with rational chromophore designs. In electro-optic activities, the poled films of P1/APC, P2/APC and P3/APC afforded r33 values of 223, 283 and 278 pmV−1, respectively, at 1310 nm at the doping concentration of 25 wt%, which showed significant enhancement over the similar EO polymer systems previously reported.

Crystal growth and DFT insight on sodium para-nitrophenolate para-nitrophenol dihydrate single crystal for NLO applications

Single crystals of sodium para-nitrophenolate para-nitrophenol dihydrate (SPPD) were grown by slow evaporation technique and its structure has been studied by FT-IR, FT-Raman and single crystal X-ray diffraction techniques. The optical and electrical properties were characterized by UV-Vis spectrum, and dielectric studies respectively. SPPD was thermally stable up to 128 °C as determined by TG-DTA curves. Using the Kurtz-Perry powder method, the second-harmonic generation efficiency was found to be five times to that of KDP. Third-order nonlinear response was studied using Z-scan technique with a He-Ne laser (632.8 nm) and NLO parameters such as intensity dependent refractive index, nonlinear absorption coefficient and third-order susceptibility were also estimated. The molecular geometry from X-ray experiment in the ground state has been compared using density functional theory (DFT) with appropriate basis set. The first-order hyperpolarizability also calculated using DFT approaches. Stability of the molecule arising from hyperconjugative interactions leading to its nonlinear optical activity and charge delocalization were analyzed using natural bond orbital technique. HOMO-LUMO energy gap value suggests the possibility of charge transfer within the molecule. Based on optimized ground state geometries, Natural bond orbital (NBO) analysis was performed to study donor-acceptor interactions.

Growth, thermal, vibrational studies and quantum chemical calculations of 2,6-dibromo-4-nitrophenol: a new nonlinear optical crystal

Good-quality single crystals of 2,6-dibromo-4-nitrophenol have been grown by slow evaporation solution growth technique using ethanol as solvent. The lattice parameters of the grown crystal were confirmed from single-crystal XRD analysis. Quantum chemical calculations were carried out using DFT /B3LYP/6-31 G(d,p) method. The optimized geometrical parameters have been obtained from the computational technique, and the result shows good agreement with the experimental XRD data. Both the experimental and theoretical vibrational spectrum confirms the presence of functional groups. Optical absorption behaviour of the grown crystal was examined by recording the optical spectrum and band gap energy was also estimated. Theoretical investigation shows that the title compound exhibits non-zero first-order hyperpolarizability values and has microscopic non-linear optical behaviour which is 22 times more than that of urea. The calculated HOMO and LUMO energies reveal the charge transfer characteristic of the title compound. Frequency conversion property of the grown crystal was investigated using Kurtz and Perry powder technique.

Solvatochromic effect on UV–vis absorption and fluorescence emission spectra, second- and third-order nonlinear optical properties of dicyanovinyl-substituted thienylpyrroles: DFT and TDDFT study

The nonlinear optical properties of dicyanovinyl-thienylpyrroles 1–6 compounds were investigated by the determining of the first-order molecular static hyperpolarizability (β) and the second-order molecular static hyperpolarizability (γ) in the ground state by using the HSEh1PBE/6-311G(d,p) level of density functional theory (DFT). The photophysical behavior of compounds 1 and 5 in polar and non-polar solvents was studied by using UV–vis absorption and fluorescence emission spectroscopies. In order to investigate the effects of these solvents, the time-dependent density functional theory (TD-DFT) calculations with the polarizable continuum model (PCM) in the excited state were performed. The UV–Vis absorption and fluorescence emission spectra for compound 5 were also simulated using TD-HSEh1PBE/6-311G(d,p) level, and the major contributions to the electronic transitions for compounds 1–6 were obtained. The β0 value (18.74×10−30esu) calculated by using HSEh1PBE/6-311G(d,p) for compound 2 is 1.49 times lower than the experimental value (28×10−30esu), and 2.34 times greater than pNA value (8×10−30esu). The β and γ parameters for compound 2 is lower than 1 and 3–6 due to electron donating pyrrole ring and electron accepting dicyanovinyl group. Moreover, we used the hybrid DFT methods (B3LYP, M062X, CAM-B3LYP and BHandHLYP) to show the accuracy for first static hyperpolarizability values for compounds 1–6. The β0 parameter for compound 5 in both polar and non-polar solvents was examined by using two level model.

Structural and spectroscopic characterization oF N’-[(1E)-(4-fluorophenyl)methylidene]thiophene-2-carbohydrazide, a potential precursor to bioactive agents

In this study, vibrational spectral analysis of the title compound was carried out using FT-IR and FT-Raman spectroscopy in the range of 500−4000 cm−1. The vibrational analysis was aided by an electronic structure calculation based on the B3LYP/6-311++G(d,p) basis set. The molecular equilibrium geometries, IR and Raman intensities and harmonic vibrational frequencies were computed. The assignments were based on the experimental IR and Raman spectra, and a complete assignment of the observed spectra was proposed. The complete vibrational assignments were performed based on the potential energy distribution (PED). The thermodynamic properties of the title compound were calculated at different temperatures, revealing the correlations between heat capacity (C), entropy (S) and enthalpy changes (H) with temperatures. In addition, the first-order hyperpolarizability, NBO, HOMO and LUMO energies, Fukui function and the molecular electrostatic potential were computed.