Nonlinear optical properties, synthesis, structures and spectroscopic studies of N-(4-nitrobenzylidene)-o-fluoroamine and N-(3-nitrobenzylidene)-p-fluoroamine

Exploration of linear and third-order nonlinear optical properties for donor-π-linker-acceptor chromophores derived from ATT-2 based non-fullerene molecule

In the current study, seven non-fullerene compounds abbreviated as ATTD2-ATTD8 were designed through structural tailoring and their nonlinear optical (NLO) properties were reported. The objective of this study was to explore the potential for newly configured D-π-A type non-fullerene-based compounds. Quantum chemical methods were adopted and revealed the molecules as highly efficient materials with favorable NLO characteristics for use in optoelectronic devices. The M06 functional along with the 6-311G(d,p) basis set in chloroform solvent were utilized for the natural bonding orbital (NBO) analysis, absorption spectra and computational assessments of frontier molecular orbitals (FMOs), global reactivity descriptors (GRPs), transition density matrix (TDM) and nonlinear optical properties (NLO) for ATTR1 and ATTD2-ATTD8. The HOMO-LUMO energy gap was significantly reduced in all the designed moieties compared to the reference compound in the following decreasing order: ATTR1 > ATTD8 > ATTD4 > ATTD5 > ATTD2 > ATTD7 > ATTD6 > ATTD3. All of the designed molecules (ATTD2-ATTD8) showed good NLO response. Global reactivity parameters were found to be closely associated with the band gap between the HOMO and LUMO orbitals, and the compound with the smallest energy gap, ATTD3, exhibited a lower hardness value of 1.754 eV and higher softness value of 0.570 eV with outstanding NLO response. For the reference compound and ATTD2-ATTD8 derivatives, attributes like dipole moment (μtot), average polarizability 〈α〉, first hyperpolarizability (βtot), and second hyperpolarizability γtot were calculated. Out of all the derivatives, ATTD3 revealed the highest amplitude with a βtot of 8.23 × 10-27 esu, which was consistent with the reduced band gap (1.754 eV) and suggested it was the best possibility for NLO materials in the future.

Influence of End-Capped Modifications in the Nonlinear Optical Amplitude of Nonfullerene-Based Chromophores with a D-π-A Architecture: A DFT/TDDFT Study

Nonlinear optical (NLO) materials have several uses in many fields such as solid physics, biology, medicine, nuclear physics, and material research. Therefore, a series of nonfullerene-based derivatives (CC10D1-CC10D8) with a D-π-A configuration was planned for the NLO investigation using CC10R as the reference molecule with structural alternations at acceptor moieties. Natural bonding orbital (NBO), UV-vis spectra, frontier molecular orbitals (FMOs), global reactivity parameters (GRPs), transition density matrix (TDM), and density of states (DOS) were analyzed using the M06/6-311G(d,p) functional in chloroform solvent to understand the NLO responses of CC10R and CC10D1-CC10D8. The highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) band gaps of CC10D1-CC10D6 were illustrated to be lower than that of CC10R, with the larger bathochromic shift (726.408-782.674 nm) resulting in a significant NLO response. Along with the band gap, the FMO method also identified an efficient interfacial charge transfer from D to A moieties via a π-bridge, which was further supported by the DOS and TDM map. Moreover, NBO calculations demonstrated that extended hyperconjugation and strong internal molecular interactions were important in their stabilization. The dipole moment (μ), linear polarizability ⟨α⟩, hyperpolarizability (β_total), and second-order hyperpolarizability (γ_total.) were studied for CC10R and CC10D1-CC10D8. Among all of the derivatives, CC10D2 was proven to be the most appropriate candidate because of its suitable NLO behavior such as being well-supported by a reduced band gap (2.093 eV) and having a suitable maximum absorption wavelength (782.674 nm). Therefore, CC10D2 was reported to have a greater value of first hyperpolarizability (208 659.330 a.u.) compared with other derivatives and CC10R. For the second hyperpolarizability, a greater value was obtained for CC10R (5.855 × 10⁷ a.u.), and its derivatives showed results comparable to that of the parent chromophore for γ_total. This theoretical framework reveals that structural customization with different acceptor units plays a significant role in obtaining attractive NLO materials for optoelectronic applications.

Synthesis, structure and photoresponsive properties of 4-(3-fluorobenzylideneamino)antipyrine

Organic compounds are attracting greater attention largely in the recent years owing to their potential applications in the functional materials. Herein we reported the structural and photophysical properties of 4-(3-fluorobenzylideneamino)antipyrine. The studied molecule adopts a trans configuration about the imine bond, and forms a non-planar molecular device consisted of two effectively conjugated π-electron moieties. The stronger vibrational and nonlinear optical activities are tightly related to the molecular structural characteristics revealed by the analysis on vibrational modes and frontier molecular orbitals. The intramolecular electrons can be separated by the electron-transporting with specified photon-absorbing theoretically. The total molecular dipole moment, mean linear polarizability and first-order hyperpolarizability calculated at B3LYP/6-31G(d) level are 1.5390 Debye, 35.6075 Å(3) and 1.5391×10(-29) cm(5)/esu, respectively. The reported results indicate that the compound is a promising candidate of photoresponsive materials.

DFT and experimental determination of conformations of 2-(ethoxycarbonylmethoxy)-5-(arylazo)benzaldehydes and their oximes

2-(Ethoxycarbonylmethoxy)-5-(arylazo)benzaldehydes 1-4 and their oximes 5-8 were synthesized and characterized by IR, (1)H and (13)C NMR spectroscopy. The favoured conformations of aldehydes 1-4 and oximes 5-8 were predicted theoretically. Selected geometrical parameters and charges were derived from optimized structures. IR, (1)H and (13)C NMR data were also computed using Gaussian-03 package and compared with the observed values. (15)N and (17)O chemical shifts were also determined theoretically.

Structural, proton-transfer, thermodynamic and nonlinear optical studies of (E)-2-((2-hydroxyphenyl)iminiomethyl)phenolate

Recently, the study of imine-bridged organics is interested in proton-transfer and photo-responsive material fields. Herein, we make a investigation on the structural, thermodynamic and nonlinear optical properties of (E)-2-((2-hydroxyphenyl)iminiomethyl)phenolate (HPIMP). The structural varieties of the studied compound are characterized by the X-ray single crystal diffraction and vibrational spectral techniques, as well as the vibrational spectral bands are precisely ascribed to the studied structure with the aid of DFT theoretical calculations. The experimental results of the FT-IR and X-ray measurements supply good proofs to reveal the proton-transfer procedures of HPIMP, and exhibit that the studied compound is a good proton-transfer model. In addition, the thermodynamic properties are obtained from the theoretical vibrations of the optimized HPIMP. The linear polarizability (α(0)) and first-order hyperpolarizabilities (β(0)) respectively present the values of 26.28 Å(3) and 7.41×10(-30) cm(5)/esu predicated theoretically by the DFT-B3lYP method at 6-31G(d) level, which indicates that the studied compound is a promising nonlinear optical material candidate.

DFT QUANTUM CHEMICAL STUDIES ON 1-[N-(2-PYRİDYL) AMİNOMETHYLİDENE]-2(1H)-NAPHTALENONE

Quantum chemical calculations of the structure, molecular electrostatic potential and thermodynamic functions have been performed using the density functional (DFT/B3LYP) method with the 6-311++G(d,p) basis set for the title compound 1-[N-(2-pyridyl)aminomethylidene}-2(1H)-Naphtalenone. The energetic behavior of the title compound in solvent media has been examined by applying the Onsager and the polarizable continuum model. To investigate second order nonlinear optical properties of the title compound, the electric dipole μ, the polarizability α and the first hyperpolarizability β were computed using the density functional B3LYP and CAM-B3LYP methods with the 6-311++G(d,p) basis set. According to our calculations, the title compound exhibits nonzero β value revealing second order NLO behavior. The changes of thermodynamic properties for the formation of the title compound with the temperature ranging from 200 K to 500 K have been obtained using the statistical thermodynamic method. The relationship between formation enthalpy and entropy changes has been investigated with the entropy–enthalpy compensation. Besides, natural bond orbital and frontier molecular orbital analysis of the title compound were investigated by theoretical calculations.

Synthesis, vibrational spectral and nonlinear optical studies of N-(4-hydroxy-phenyl)-2-hydroxybenzaldehyde-imine: a combined experimental and theoretical investigation

The study of imine-bridged organics has been the one hot spot of photo-responsive material sciences in recent years. Herein we make a study of the synthesis, characteristics and potential application of N-(4-hydroxy-phenyl)-2-hydroxy-benzaldehyde-imine (HPHBI), C13H11NO2. The studied compound was synthesized in one step by the condensation reaction of salicylaldehyde and 4-aminophenol in methanol solution, and characterized by single crystal X-ray diffraction, FT-IR and FT-Raman techniques with theoretical calculations at B3LYP/6-31G(d) level. The molecule adopts trans configuration about central CN bond with intramolecular hydrogen bonding, and the adjacent molecules form wave-shaped structure linked by strong intermolecular hydrogen bonding mechanism along b axis. The vibrational spectra have been precisely assigned with the aid of theoretical frequencies. Furthermore, the thermodynamic properties have been obtained by the theoretical vibrational analysis for HPHBI. The total linear polarizability and first-order hyperpolarizabilities calculated on the studied compound respectively present 25.378 Å3 and 1.655×10(-29) cm5/esu, which indicates the compound has relatively good nonlinear optical property.

Molecular structures, spectral and computational studies on nicotinohydrazides

The FT-IR and the high resolution (1)H and (13)C NMR spectra have been recorded for N'-(2-methyl-3-phenylallylidene)nicotinohydrazide (1) and N'-(2-methyl-3-phenylallylidene)isonicotinohydrazide (2) and analyzed. (1)H-(1)H COSY spectra were also recorded for the hydrazides. The spectral studies reveal that both the hydrazides exist in the keto form. Theoretical calculations were performed for some possible conformations of the hydrazide and the minimum energy conformers are predicted to be the one in which the azomethine protons are syn to N-NH bond. From the optimized structures, HOMO-LUMO energy gap and geometrical parameters were derived and these parameters were compared with the XRD measurements of hydrazide 1. The vibrational frequencies in the ground state have been calculated using DFT and HF methods and compared with the observed frequencies. Non-linear optical (NLO) behaviour of the hydrazides was investigated by the determination of the electric dipole moment mu, the polarizability alpha and the hyperpolarizability beta using B(3)LYP method.

Third-order nonlinear optical properties and structures of (E)-N-(4-nitrobenzylidene)-2,6-dimethylaniline and (E)-N-(4-nitrobenzylidene)-2,3-dimethylaniline

(E)-N-(4-Nitrobenzylidene)-2,6-dimethylaniline (1) and (E)-N-(4-nitrobenzylidene)-2,3-dimethylaniline (2) have been synthesized. The crystal structures of both compounds have been defined by X-ray diffraction analysis. The maximum one-photon absorption (OPA) wavelengths recorded by quantum mechanical computations using a configuration interaction (CI) method are estimated in the UV region to be shorter than 450nm, showing good optical transparency to the visible light. To provide an insight into the microscopic third-order nonlinear optical (NLO) properties of the investigated molecules, both dispersion-free (static) and also frequency-dependent (dynamic) linear polarizabilities (alpha) and second hyperpolarizabilities (gamma) at lambda=825-1125nm and 1050-1600nm wavelength areas have been computed using time-dependent Hartree-Fock (TDHF) method. According to the ab initio calculation results, the title molecules exhibit second hyperpolarizabilities with non-zero values, implying microscopic third-order NLO behavior.

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

Three antipyrine derivatives of o-, m- and p-chlorobenzylideneaminoantipyrines were characterized by spectral techniques and density functional calculations. The optimized configurations are very close to the XRD values and are used as foundations to investigate the molecular properties. The spectral assignments were attempted to ascribe to the vibrational modes of the detailed substructures with the aid of theoretical calculations because of the satisfactory consistencies between the experimental and theoretical spectra for each of the studied compounds. Raman spectral ascriptions represent that the pi-conjugated moieties linked by Schiff base imines are responsible for the excellent Raman scattering activities of these compounds. The linear polarizabilities and first hyperpolarizabilities of the studied molecules indicate that the compounds are good candidates of nonlinear optical materials. The statistical thermodynamic functions and their correlations with temperatures obtained from the theoretical vibrations are similar to each other among the isomers.