Showing papers on "Hyperpolarizability published in 2015"
TL;DR: A series of new strategies for enhancing NLO response and electronic stability of electride and alkalide molecules are exhibited by using various complexants, which include not only the behaviors of pushed and pulled electron, size, shape, and number of coordination sites of complexants but also the number and spin state of excess electrons in these unusual NLO molecules.
Abstract: The excess electron is a kind of special anion with dispersivity, loosely bounding and with other fascinating features, which plays a pivotal role (promote to about 106 times in (H2O)3{e}) in the large first hyperpolarizabilities (β0) of dipole-bound electron clusters. This discovery opens a new perspective on the design of novel nonlinear optical (NLO) molecular materials for electro-optic device application. Significantly, doping alkali metal atoms in suitable complexants was proposed as an effective approach to obtain electride and alkalide molecules with excess electron and large NLO responses. The first hyperpolarizability is related to the characteristics of complexants and the excess electron binding states. Subsequently, a series of new strategies for enhancing NLO response and electronic stability of electride and alkalide molecules are exhibited by using various complexants. These strategies include not only the behaviors of pushed and pulled electron, size, shape, and number of coordination sit...
173 citations
TL;DR: In this paper, the molecular structure and spectroscopic properties of (E)-2-((4-hydroxy-2-methylphenylimino)methyl)-3-methoxyphenol, were characterized by X-ray diffraction, FT-IR and UV-Vis spectroscopy.
138 citations
TL;DR: In this study, FT-IR,FT-Raman, NMR and UV spectra of 1-phenyl-1-propanol, an intermediate of anti-depressant drug fluoxetine, has been investigated and NLO properties related to polarizability and hyperpolarizability are discussed.
112 citations
TL;DR: In this article, the authors focused on the donor-bridge-acceptor (Dπ-A) type of novel organic charge transport and non-linear optical material, 1-(4-bromophenyl)-3-(2,4,5-trimethoxyphenyl) prop-2-en-1-one (2, 4, 5-TMBC) to spotlight its various important properties through experimental and quantum chemical approaches.
Abstract: The current study is focused on the donor–bridge–acceptor (D–π–A) type of novel organic charge transport and non-linear optical material, 1-(4-bromophenyl)-3-(2,4,5-trimethoxyphenyl) prop-2-en-1-one (2,4,5-TMBC) to spotlight its various important properties through experimental and quantum chemical approaches. The compound 2,4,5-TMBC was synthesized via a Claisen–Schmidt condensation reaction and its single crystal was grown by a slow evaporation solution growth technique. FT-IR and FT-Raman spectra of 2,4,5-TMBC were obtained and investigated. The molecular geometry of 2,4,5-TMBC was optimized by HF, B3LYP, CAM-B3LYP, wb97xd and LC-BLYP methods using the 6-31G* basis set. The calculated geometrical parameters and vibrational spectra are in good agreement with the experimental results. Time dependent density functional theory (TD-DFT) has been applied to investigate the optical properties of the title compound. The absorption wavelength calculated at the TD-B3LYP/6-31G* level of theory in the gas phase was in good agreement with the experimental value (∼400 nm) when compared with other methods. The HOMO–LUMO energy gap was calculated at all the applied levels of theory. The total dipole moment, polarizability, anisotropy of polarizability and static first and total hyperpolarizability values of 2,4,5-TMBC were calculated at different levels of theory. The dipole moment and first hyperpolarizability values are found to be many folds (2 and 56 times calculated at B3LYP) higher than urea. It is also expected that 2,4,5-TMBC would be electron transport material due to its smaller electron reorganization energy value. The study of non-linear optical (NLO) properties shows that 2,4,5-TMBC would be an outstanding candidate for NLO device applications.
100 citations
TL;DR: By including an elongated dipolar dye (p,p'-dimethylaminonitrostilbene, DANS, a prototypical asymmetric dye with a strong NLO response) inside single-walled carbon nanotubes (SWCNTs), an ideal head-to-tail alignment in which all electric dipoles point in the same sense is naturally created.
Abstract: Asymmetric dye molecules encapsulated inside single-walled carbon nanotubes align in a head-to-tail fashion to obtain a large cooperative nonlinear optical response. Asymmetric dye molecules have unusual optical and electronic properties1,2,3. For instance, they show a strong second-order nonlinear optical (NLO) response that has attracted great interest for potential applications in electro-optic modulators for optical telecommunications and in wavelength conversion of lasers2,3. However, the strong Coulombic interaction between the large dipole moments of these molecules favours a pairwise antiparallel alignment that cancels out the NLO response when incorporated into bulk materials. Here, we show that by including an elongated dipolar dye (p,p′-dimethylaminonitrostilbene, DANS, a prototypical asymmetric dye with a strong NLO response4) inside single-walled carbon nanotubes (SWCNTs)5,6, an ideal head-to-tail alignment in which all electric dipoles point in the same sense is naturally created. We have applied this concept to synthesize solution-processible DANS-filled SWCNTs that show an extremely large total dipole moment and static hyperpolarizability (β0 = 9,800 × 10−30 e.s.u.), resulting from the coherent alignment of arrays of ∼70 DANS molecules.
91 citations
TL;DR: A comparative theoretical and experimental study of four triazine-based hydrazone derivatives, synthesized by a three step process from commercially available benzil and thiosemicarbazide, showing excellent correlations with the results obtained from X-ray diffraction studies.
Abstract: We report here a comparative theoretical and experimental study of four triazine-based hydrazone derivatives. The hydrazones are synthesized by a three step process from commercially available benzil and thiosemicarbazide. The structures of all compounds were determined by using the UV-Vis., FT-IR, NMR (1H and 13C) spectroscopic techniques and finally confirmed unequivocally by single crystal X-ray diffraction analysis. Experimental geometric parameters and spectroscopic properties of the triazine based hydrazones are compared with those obtained from density functional theory (DFT) studies. The model developed here comprises of geometry optimization at B3LYP/6-31G (d, p) level of DFT. Optimized geometric parameters of all four compounds showed excellent correlations with the results obtained from X-ray diffraction studies. The vibrational spectra show nice correlations with the experimental IR spectra. Moreover, the simulated absorption spectra also agree well with experimental results (within 10–20 nm). The molecular electrostatic potential (MEP) mapped over the entire stabilized geometries of the compounds indicated their chemical reactivates. Furthermore, frontier molecular orbital (electronic properties) and first hyperpolarizability (nonlinear optical response) were also computed at the B3LYP/6-31G (d, p) level of theory.
72 citations
TL;DR: In this paper, the number of thiophene rings in π-conjugated system influence the absorption spectra and non-linear optical properties of dyes, and the results of theoretical computation show that the absorption spectrum are gradually broadened and red-shifted (384-542 nm) with increasing number of units.
71 citations
TL;DR: In this article, a novel Mn(II) complex with 1,3-Thiazolidine-2,4-dicarboxylic acid and 1,10 phenanthroline has been synthesized, and its FT-IR, FT-Raman and UV-vis spectra have been recorded.
67 citations
TL;DR: The synthesis of (1E,4E)-1,5-di-p-tolylpenta-1,4-dien-3-one (DTDO) was done and its single crystals were grown by slow evaporation solution technique from 4-methylbenzaldehyde, acetone solution at room temperature to confirm the second harmonic generation (SHG) of the specimen responsible for nonlinear optical property.
66 citations
TL;DR: Simulated FT-IR and FT-Raman spectra showed good agreement with the observed spectra.
66 citations
TL;DR: Density functional theory calculations for the ground and excited states indicated that both the locally excited state and the intramolecular charge transfer excited state make important contributions to the luminescence behavior.
Abstract: A series of disilane-bridged donor-acceptor architectures 1-9 containing strong electron-donating and -withdrawing substituents were designed and synthesized in acceptable yields. The substituents substantially affected the fluorescence and nonlinear optical properties of the compounds. In the solid state, the compounds showed purple-blue fluorescence (λ(em) = 360-420 nm) with high quantum yields (up to 0.81). Compound 3, which had p-N,N-dimethylamino and o-cyano substituents, exhibited optical second harmonic generation (activity 2.9 times that of urea, calculated molecular hyperpolarizability β = 1.6 × 10(-30) esu) in the powder state. Density functional theory calculations for the ground and excited states indicated that both the locally excited state and the intramolecular charge transfer excited state make important contributions to the luminescence behavior.
TL;DR: Comparison of the observed fundamental vibrational frequencies of 3-TCA with calculated results by HF and DFT methods indicates that B3LYP is better to HF method for molecular vibrational problems.
TL;DR: The X-ray crystal structure revealed that the intermolecular packing was stabilized by C-H⋯O type hydrogen bonding interaction, whereas NH was not involved in hydrogen bonding due to steric hindrance.
TL;DR: Stability of the molecule arising from hyperconjugation and charge delocalization is confirmed by the natural bond orbital analysis (NBO) and electron density in the σ(∗) antibonding orbitals and E(2) energies confirms the occurrence of intramolecular charge transfer (ICT) within the molecule.
TL;DR: In this article, a new organic third-order nonlinear optical crystal from stilbazolium family 2-[2-(4-methoxy-phenyl) vinyl]-1-methyl-pyridinium tetrafluoroborate (4MSTB) has been synthesized and grown by slow evaporation method for the first time.
TL;DR: The systematic synthesis, structural, optical spectroscopic, and second-order nonlinear optical (NLO) characterization of a series of donor-acceptor poly-arylene chromophores which have heretofore unachieved π-extension and substantial twisting from planarity are reported.
Abstract: The systematic synthesis, structural, optical spectroscopic, and second-order nonlinear optical (NLO) characterization of a series of donor-acceptor poly-arylene chromophores which have heretofore unachieved π-extension and substantial twisting from planarity, are reported: specifically, two-ring 2TTMC, dicyano(4-(3,5-dimethyl-1-(2-propylheptyl)pyridin-1-ium-4-yl)-3-methylphenyl)methanide; three-ring 3TTMC, dicyano(4'-(3,5-dimethyl-1-(2-propylheptyl)pyridin-1-ium-4-yl)-2,2',3',5',6'-pentamethyl[1,1'-biphenyl]-4-yl)methanide; and four-ring 4TTMC, dicyano(4″-(3,5-dimethyl-1-(2-propylheptyl)pyridin-1-ium-4-yl)-2,2',3″,6,6'-pentamethyl[1,1':4',1″-terphenyl]-4-yl)methanide. Single-crystal X-ray diffraction, DFT-optimized geometries, and B3LYP/INDO-SOS analysis identify three key features underlying the very large NLO response: (1) For ring catenation of three or greater, sterically enforced π-system twists are only essential near the chromophore donor and acceptor sites to ensure large NLO responses. (2) For synthetic efficiency, deletion of one ortho-methyl group from o,o',o″,o‴-tetramethylbiaryl junctures, only slightly relaxes the biaryl twist angle from 89.6° to ∼80°. (3) Increased arylene catenation from two to three to four rings (2TTMC→ 3TTMC → 4TTMC) greatly enhances NLO response, zwitterionic charge localization, and thus the ground-state dipole moment, consistent with the contracted antiparallel solid-state π-π stacking distances of 8.665 → 7.883 → 7.361 A, respectively. This supports zwitterionic ground states in these chromophores as do significant optical spectroscopic solvatochromic shifts, with aryl-aryl twisting turning on significant intra-subfragment absorption. Computed molecular hyperpolarizabilities (μβ) approach an unprecedented 900,000 × 10(-48) esu, while estimated chromophore figures of merit, μβ(vec)/M(w), approach 1500 × 10(-48) esu, 1.5 times larger than the highest known values for twisted chromophores and >33 times larger than that of planar donor-acceptor chromophores.
TL;DR: Li-doped outer isomer C20H10/LiC60 can exhibit the intriguing n-type characteristic, where a high energy level containing the excess electron is introduced as the new HOMO orbital in the original gap.
Abstract: A charge transfer (CT) complex was formed between C20H10 and Li+@C60 in the ground state by the concave–convex π–π CT interaction. Herein, the structures, binding interactions, electronic absorption spectra, and first hyperpolarizabilities of a series of Li+ and Li atom in contact with C60 have been explored with density functional theory methods. It is found that independent of the doping position, doping Li atom can significantly narrow the wide gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) (Egap = 2.82 eV) of the pure C20H10/C60 in the range of 0.86–0.99 eV. Among them, the Li-doped outer isomer C20H10/LiC60 can exhibit the intriguing n-type characteristic, where a high energy level containing the excess electron is introduced as the new HOMO orbital in the original gap of C20H10/C60. Furthermore, the diffuse excess electron also brings C20H10/C60 the considerable first hyperpolarizability, which is 3.53 × 10–29 esu. When Li+ and Li were en...
TL;DR: In this article, a thiosemicarbazone compound was synthesized by refluxing equimolar amounts of 4-(4-methyl phenyl)-3-thiosemide and salicylaldehyde in presence of one drop of conc. H 2 SO 4 in ethanolic medium for one hour.
TL;DR: Ampicillin trihydrate is a semi-synthetic amino-penicillin derived from the elementary penicillin nucleus, 6-aminopenicillanic acid as discussed by the authors.
Abstract: Ampicillin trihydrate chemically associated with the empirical formula C16H19N3O4S·3H2O, is a semi-synthetic amino-penicillin derived from the elementary penicillin nucleus, 6-aminopenicillanic acid. It is a very common antibiotic that is active against an extensive range of Gram-positive and Gram-negative organisms. It is used to treat certain varieties of bacterial infections, like gonorrhea and infections of the urinary, intestinal and respiratory tracts. In the present effort, quantum chemical calculations of molecular geometries (bond lengths and bond angles) and bonding features of the monomer and dimer of ampicillin trihydrate in the ground state have been carried out due to its biological and industrial importance. The optimized geometry and wavenumber of the vibrational bands of the molecule have been calculated by ab initio density functional theory (DFT) using Becke's three-parameter hybrid functional (B3LYP) with a 6-311++G(d,p) basis set. Vibrational wavenumbers were compared with the observed FT-Raman and FT-IR spectra. Molecular electrostatic potential (MEP) has also been plotted for predicting the molecule reactivity towards positively or negatively charged reactants and it shows that electropositive potential is visualized in the vicinity of the –NH3+ group and the electropositive region is found near the H2O molecule in both monomer and dimer. HOMO–LUMO analysis has been done to describe the way the molecule interacts with other species. Natural bond orbital (NBO) analysis has been carried out to inspect the intra- and inter-molecular hydrogen-bonding, conjugative and hyperconjugative interactions and their second order stabilization energy E(2). Nonlinear optical (NLO) analysis has also been performed to study the non-linear optical properties of the molecule by computing the first hyperpolarizability (β0). The variation of thermodynamic properties with temperature has been studied. Topological parameters at bond critical points (BCP) have been evaluated by ‘Quantum theory of atoms in molecules’ (QTAIM).
TL;DR: In this article, the influence of alkali metals (Li, Na and K) interaction with Be12O12 and Mg12O 12 nanoclusters on their structural, electronic and nonlinear optical properties was investigated.
TL;DR: The calculated polarizability and first hyperpolarizability showed that the studied compound has better NLO properties than urea and the electronic transitions are predicted using the TD-DFT calculations at B3LYP/6-311++G(d,p) level of theory.
TL;DR: Novel and explanatory insights on the chemical nature and origin of intrinsic nonlinear optical properties of 2,4‐dinitrophenol derivatives and the causes of change in dipole moments are discovered through sum of Mulliken atomic charges and intermolecular charge transfer spotted in frontier molecular orbitals analysis.
Abstract: This study spotlights the fundamental insights about the structure and static first hyperpolarizability (β) of a series of 2,4-dinitrophenol derivatives (1–5), which are designed by novel bridging core modifications. The central bridging core modifications show noteworthy effects to modulate the optical and nonlinear optical properties in these derivatives. The derivative systems show significantly large amplitudes of first hyperpolarizability as compared to parent system 1, which are 4, 46, 66, and 90% larger for systems 2, 3, 4, and 5, respectively, at Moller–Plesset (MP2)/6-31G* level of theory. The static first hyperpolarizability and frequency dependent coupled-perturbed Kohn–Sham first hyperpolarizability are calculated by means of MP2 and density functional theory methods and compared with respective experimental values wherever possible. Using two-level model with full-set of parameters dependence of transition energy (ΔE), transition dipole moment (μ0) as well as change in dipole moment from ground to excited state (Δμ), the origin of increase in β amplitudes is traced from the change in dipole moment from ground to excited state. The causes of change in dipole moments are further discovered through sum of Mulliken atomic charges and intermolecular charge transfer spotted in frontier molecular orbitals analysis. Additionally, analysis of conformational isomers and UV-Visible spectra has been also performed for all designed derivatives. Thus, our present investigation provides novel and explanatory insights on the chemical nature and origin of intrinsic nonlinear optical (NLO) properties of 2,4-dinitrophenol derivatives. © 2014 Wiley Periodicals, Inc.
TL;DR: The spectral analysis of 1-phenyl-2-nitropropene is carried out using the FTIR, FT Raman, FT NMR and UV-Vis spectra with the help of quantum mechanical computations using ab-initio and density functional theories to reveal the different charge transfer possibilities within the molecule.
TL;DR: The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis and the HOMO and LUMO analysis are used to determine the charge transfer within the molecule.
TL;DR: Detailed investigation of geometrical and electronic structure in ground as well as the first excited state of 3,5-Difluoroaniline (C6H5NF2) was carried out and global and local reactivity descriptors were computed to predict reactivity and reactive sites on the molecule.
TL;DR: Electron density distribution and frontier molecular orbitals (FMOs) have been constructed at B3LYP/6-311+G(d,p) level to understand the electronic properties and the dipole moment, polarizability, and hyperpolarizability of the molecule have been reported.
TL;DR: Thermodynamic properties (heat capacity, entropy and enthalpy) of the title compound at different temperatures were calculated and stability of the molecule arising from hyper conjugative interactions, charge delocalization and intra molecular hydrogen bond-like weak interaction has been analyzed.
TL;DR: In this article, a tetraene structure with a strong dialkylaminophenyl donor and a CF3-TCF acceptor is used as the primary chromophore due to its large hyperpolarizability, and a short cyanoacetate dye with a smaller dipole moment and a very different molecular aspect ratio for dipole engineering.
Abstract: A new design of tethered binary chromophores has been studied for nonlinear optics. In this work, a push–pull tetraene structure with a strong dialkylaminophenyl donor and a CF3-TCF acceptor is used as the primary chromophore due to its large hyperpolarizability, and a short cyanoacetate dye with a smaller dipole moment and a very different molecular aspect ratio is used as a secondary dipolar structure for dipole engineering. We found that such binary chromophore systems (exemplified as chromophore C1) exhibited significantly improved poling efficiency and thermal stability in poled films of guest–host polymers and monolithic glass. A systematic study of materials' physical properties, including analyses of poling-induced order thermally stimulated depolarization and comparison with simple dipolar polyenes, correlates the improved EO performance of poled films containing C1 well with its tethered binary structure. It provides an effective electrostatic screening mechanism for excellent solution processibility of materials, and a cooperative enhancement for higher polar order of poled thin films under the force of the applied poling field. An ultrahigh r33 value of 273 pm V−1 and a high refractive index of 2.12 at the wavelength of 1300 nm have been achieved for monolithic glass of C1, which represents a record-high n3r33 figure-of-merit of 2601 pm V−1 with good temporal stability. This exceptional result is a great demonstration of the advantages offered by dynamically assisted dipolar polarization enhancement of tethered binary chromophores, for significantly improving the poling efficiency and thermal stability of organic EO materials for efficient optical modulation.
TL;DR: It is found for both urea and thiourea molecules that the influence of the polarization effects is mild for the linear polarizability, but it is marked for the dipole moment and first hyperpolarizability.
Abstract: We present theoretical results for the dipole moment, linear polarizability, and first hyperpolarizability of the urea and thiourea molecules in solid phase. The in-crystal electric properties were determined by applying a supermolecule approach in combination with an iterative electrostatic scheme, in which the surrounding molecules are represented by point charges. It is found for both urea and thiourea molecules that the influence of the polarization effects is mild for the linear polarizability, but it is marked for the dipole moment and first hyperpolarizability. The replacement of oxygen atoms by sulfur atoms increases, in general, the electric responses. Our second-order Moller-Plesset perturbation theory based iterative scheme predicts for the in-crystal dipole moment of urea and thiourea the values of 7.54 and 9.19 D which are, respectively, increased by 61% and 58%, in comparison with the corresponding isolated values. The result for urea is in agreement with the available experimental result of 6.56 D. In addition, we present an estimate of macroscopic quantities considering explicit unit cells of urea and thiourea crystals including environment polarization effects. These supermolecule calculations take into account partially the exchange and dispersion effects. The results illustrate the role played by the electrostatic interactions on the static second-order nonlinear susceptibility of the urea crystal.
TL;DR: The calculated HOMO-LUMO energy gap shows that the charge transfer occurs within the molecule, and the frontier orbital and molecular electrostatic potential surface studies have been employed to understand the active sites of fluconazole.