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Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) have been used to investigate the nonlinear optical (NLO) properties of phenolic N-pyrimidinyl stilbazolium cationic chromophore in its corresponding noncentrosymmetric crystals. Such a cationic chromophore, the OPR (4-(4-hydroxystyryl)-1-(pyrimidin-2-yl)pyridinium), consists of a strong electron donor, the 4-hydroxyphenyl group, and a strong electron acceptor, the N-pyrimidinylpyridinium group based on two electron-withdrawing groups. The in-crystal NLO properties were determined by applying a supermolecule approach in combination with an iterative electrostatic scheme, in which the surrounding molecules of a unit cell are represented by point charges. With CAM-B3LYP, our absolute estimates for the largest diagonal component of the second-order nonlinear susceptibility tensor of OPR-based crystals range from 64.00 to 80.34 pm/V in the static regime and from 162.09 to 175.52 pm/V at 1907 nm. These values are significant when compared to those of benchmark stilbazolium-based crystals. Furthermore, the third-order susceptibility, which is related to the nonlinear optical process of the intensity-dependent refractive index, is also significant compared to the results for other organic crystals, such as chalcone derivatives. With TD-CAM-B3LYP, the two-state model effectively explains the similarity in the first hyperpolarizability values in the crystalline phase. This similarity arises from the combination of the oscillator strength and the charge transfer of the crucial transition. Therefore, phenolic organic salt crystals show great promise for various nonlinear optical applications.
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The linear polarizability, first and second hyperpolarizabilities of the asymmetric unit of DAPSH crystal are studied and compared with available experimental results. The polarization effects are included using an iterative polarization procedure, which ensures the convergence of the dipole moment of DAPSH embedded within a polarization field generated by the surrounding asymmetric units whose atomic sites are considered as point charges. We estimate macroscopic susceptibilities from the results of the polarized asymmetric units in the unit cell, considering the significant contribution of the electrostatic interactions in crystal packing. The results show that the influence of the polarization effects leads to a marked decrease of the first hyperpolarizability, compared with the respective isolated counterpart, which improves the concordance with the experiment. There is a minor influence of polarization effects on the second hyperpolarizability but our estimated result for the third-order susceptibility, related to the NLO process of the intensity dependent refractive index, is significant as compared with the results for other organic crystals, such as chalcone-derivatives. In addition, supermolecule calculations are conducted for explicit dimers in presence of the electrostatic embedding to illustrate the role played by the electrostatic interactions in the hyperpolarizabilities of the DAPSH crystal.
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A novel 4(1H) quinolinone derivative (QBCP) was synthesized and characterized with single crystal X-ray diffraction. Hirshfeld surfaces (HS) analyses were employed as a complementary tool to evaluate the crystal intermolecular interactions. The molecular global reactivity parameters of QBCP were studied using HOMO and LUMO energies. In addition, the molecular electrostatic potential (MEP) and the UV-Vis absorption and emission spectra were obtained and analyzed. The supermolecule (SM) approach was employed to build a bulk with 474,552 atoms to simulate the crystalline environment polarization effect on the asymmetric unit of the compound. The nonlinear optical properties were investigated using the density functional method (DFT/CAM-B3LYP) with the Pople's 6-311++G(d,p) basis set. The quantum DFT results of the linear polarizability, the average second-order hyperpolarizability and the third-order nonlinear susceptibility values were computed and analyzed. The results showed that the organic compound (QBCP) has great potential for application as a third-order nonlinear optical material.
Assuntos
Teoria Quântica , Cristalografia por Raios X , Modelos Moleculares , Conformação Molecular , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade EstáticaRESUMO
In this study, a combined experimental and theoretical study of the nonlinear optical properties (NLO) of two chalcone derivatives, (E)-3-(2-methoxyphenyl)-1-(2-(phenylsulfonylamine)phenyl)prop-2-en-1-one (MPSP) and (E)-3-(3-nitrophenyl)-1-(2-(phenylsulfonylamine)phenyl)prop-2-en-1-one (NPSP), in DMSO is reported. The single crystal structures of the compounds, which differ only by the type and position of one substituent, were grown using the slow evaporation technique, and the main structural differences are discussed. The two-photon absorption and first-order hyperpolarizability measurements were performed via the Z-scan technique and hyper-Rayleigh scattering experiment in DMSO. The theoretical calculations were performed using the Density Functional Theory (DFT) at the CAM-B3LYP/6-311++G(d,p) level, and the sum-over-states (SOS) approach in both static and dynamic cases. Besides the electron conjugation achieved by the aromatic rings, olefins, and carbonyl groups, both compounds have a nearly flat chalcone backbone, which is believed to contribute to the nonlinear optical properties. MPSP and NPSP have different positions, even though they have roughly the same conformation and form C-HO interactions. For several studied frequencies, the HRS first hyperpolarizability values for MPSP are greater than those for NPSP, indicating that in most cases the NLO properties of MPSP are better. The comparison among the theoretical and experimental HRS first hyperpolarizability results showed a good agreement. In addition, the two-dimensional second order nonlinear optical spectra obtained from the sum-over-states model indicate good second-order NLO responses of the two chalcone derivatives under external fields. Our findings are important not only to show the potential nonlinear optical application of the two new compounds but also to gain an insight into how different chemical compositions might affect the crystal structures and physico-chemical properties.
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Abstract The use of organic as nonlinear optical materials has been intensively explored in the recent years due to the ease of manipulation of the molecular structure and the synthetic flexibility regarding the change of substituent groups. In the present work, the linear and nonlinear properties of two chalcones derivatives (E)-1-(4-methylphenyl)-3-phenylprop-2-en-1-one (4MP3P) and (E)-1-(4-Nitrophenyl)-3-phenylprop-2-en-1-one (4NP3P), that differ by the substituent position at the phenyl ring, were studied in the presence of protic and aprotic solvents simulated by the Polarizable Continuum Model (PCM) at DFT/B3LYP/6-311+G(d) level. The static and dynamic (1064 nm) molecular parameters as the dipole moment, linear polarizability, first and second hyperpolarizabilities were studied as function of the solvent dielectric constant value. The geometrical behavior as the chemical bond angles, torsion angles, and partial charges distribution of the compounds were studied, including calculations of gap energies in various solvents. The obtained results revealed that the substituent change of CH3 (4MP3P) to NO2 (4NP3P) benefits the nonlinear optical properties of the compounds in the presence of the solvent media, the absolute values of the parallel first hyperpolarizability were the ones that present the greater variation.
Resumen El uso de materiales orgánicos como materiales ópticos no lineales se ha explorado intensamente en los últimos años, debido a la facilidad de manipulación de estas estructuras moleculares y la flexibilidad de síntesis en relación con el cambio de grupos sustituyentes. En el presente trabajo, las propiedades lineales y no lineales de dos derivados de chalcona (E)-1-(4-metilfenil)-3-fenilprop-2-en-1-ona (4MP3P) y (E)-1-(4-nitrofenil)-3-fenilprop-2-en-1-ona (4NP3P), los cuales difieren en la posición del sustituyente en el anillo de fenilo, se estudiaron en presencia de disolventes próticos y apróticos simulados por el Modelo Continuo Polarizable a nivel DFT/B3LYP/6-311+G(d). Además, se estudiaron parámetros moleculares estáticos y dinámicos (1064 nm) como el momento dipolar, la polarización lineal y la primera y la segunda hiperpolarización en función del valor constante dieléctrico del disolvente. El comportamiento geométrico se estudió como ángulos de enlace químico, ángulos de torsión y distribución de carga parcial de compuestos, incluidos los cálculos de energía de huecos en varios solventes. Los resultados mostraron que el cambio del sustituyente CH3 (4MP3P) a NO2 (4NP3P) beneficia las propiedades ópticas no lineales de los compuestos en presencia del medio solvente, los valores absolutos de la primera hiperpolarizabilidad paralela fueron los que presentaron la mayor variación.
Resumo O uso de materiais orgânicos como materiais ópticos não lineares tem sido intensamente explorado nos últimos anos, devido à facilidade de manipulação dessas estruturas moleculares e à flexibilidade de síntese em relação à mudança de grupos substituintes. No presente trabalho, as propriedades lineares e não lineares de dois derivados de chalconas (E)-1-(4-metilfenil)-3-fenilprop-2-en-1-ona (4MP3P) e (E)-1-(4-nitrofenil)-3-fenilprop-2-en-1-ona (4NP3P), que diferem pela posição do substituinte no anel fenil, foram estudados na presença de solventes próticos e apróticos simulados pelo Modelo Continuo Polarizável (PCM) no nível DFT/B3LYP/6-311+G(d). Os parâmetros moleculares estáticos e dinâmicos (1064 nm) como momento dipolar, polarizabilidade linear, primeira e segunda hiperpolarizabilidades foram estudados em função do valor da constante dielétrica do solvente. Estudou-se o comportamento geométrico como ângulos de ligação química, ângulos de torção e distribuição parcial de cargas dos compostos, incluindo cálculos de energias de gap em vários solventes. Os resultados obtidos revelaram que a mudança do substituinte de CH3 (4MP3P) para NO2 (4NP3P) beneficia as propriedades ópticas não lineares dos compostos na presença do meio solvente, os valores absolutos da primeira hiperpolarizabilidade paralela foram os que apresentaram a maior variação.
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In this work, the nonlinear optical (NLO) properties of two heterocyclic chalcones, (E)-1-(5-chlorothiophen-2-yl)-3-(thiophen-2yl)-2-propen-1-one (CLTT) and (E)-1-(5-methylfuran-2-yl)-3-(5-methylthiophen-2-yl)prop-2en-1-one (2MFT), are investigated. Using an iterative electrostatic embedding approach via the Møller-Plesset perturbation (MP2) theory, the chalcone crystals were simulated and the polarization effects on the isolated molecules are investigated. The electrical parameters of CLTT and 2MFT as dipole moment and linear polarizability were calculated via MP2/6-311++G(d) and the second hyperpolarizability was obtained via DFT/CAM-B3-LYP/6-311++G(d) level. A significant influence of the molecular packing on the chalcone electric parameters was observed. The static linear refractive index and the third-order electric susceptibility of the compounds were calculated and compared with experimental results available for other chalcone derivatives, indicating the CLTT crystal as a promising candidate for NLO applications in photonic and optoelectronic devices. The Hirshfeld surface analysis has been used to quantify the intermolecular interactions of the molecular crystals. Additionally, the solvent medium effects on the electrical properties of the heterocyclic chalcones were also studied.
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The application of organic crystals on nonlinear optical (NLO) materials has been increasing in recent years, and compounds like chalcones are interesting due to their significant third-order nonlinear properties. Hereof, we describe the synthesis, molecular structure, supramolecular arrangement, and theoretical calculations for a bromine-chalcone 3-(4-bromophenyl)-1-[3-(2-oxo-2-phenylethoxy)phenyl]-propenone (BC), which crystallized into noncentrosymmetric space group Pc. Also, a comprehensive topological analysis performed by QTAIM highlights the observed halogen bonds on solid state. In addition, the thermal stability was studied in temperatures smaller than 800 °C showing BC crystal as potential optical devices at temperatures up to 250 °C. Finally, the NLO properties indicate a photonic application based on strong third-order nonlinear response.