Potential NLO Material Research Articles

A comprehensive investigation on one-pot synthesis of imidazole derivatives: quantum computational analysis, molecular docking, molecular dynamics simulations and antiviral activity against SARS-CoV-2

New derivatives of 4-(2-(2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-4,5-diphenyl-1H-imidazol-1-yl)ethyl)morpholine (DDIM) have been successfully synthesised and characterised using spectral methods such as FT-IR, 1H NMR, and 13C NMR. Density functional theory (DFT) with the B3LYP/6-311G (d, p) level of theory was used to determine optimised bond parameters and single crystal XRD investigations confirmed the structure of DDIM. The results of single crystal XRD measurements aligned well with the optimised geometrical parameters from DFT calculations. Frontier molecular orbital computations provided insights into the molecule's stability, chemical reactivity and charge transfer. Atomic charges were determined using mulliken population analysis. The molecular electrostatic potential (MEP) mapped to electron density surfaces identified potential reactive sites. This molecule shows promise as a potential NLO material due to its high μβ0 value. Binding affinities were determined via molecular docking against the COVID-19 major protease (Mpro: 6WCF/6Y84/6LU7). A 100 ns molecular dynamics simulation under in silico physiological conditions confirmed the stability of the complex structure formed with the COVID-19 protein, revealing a stable conformation and binding pattern in an imidazole derivative environment. Additionally, in-silico analysis predicted favourable to moderate anti-viral activity and anticipated the compound's absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiles.

2,4-dichloro-6-(1,4,5-triphenyl-1H-imidazol-2-yl) phenol: synthesis, DFT analysis, Molecular docking, molecular dynamics, ADMET properties against COVID-19 main protease (Mpro: 6WCF/6Y84/6LU7)

ABSTRACT New derivatives of 2,4-dichloro-6-(1,4,5-triphenyl-1H-imidazol-2-yl) phenol (DPIP) have been successfully synthesised and characterised using spectral methods such as FT-IR, 1H NMR and 13C NMR. Density functional theory (DFT) approach at B3LYP/6-311 G (d, p) level of theory is used to determine optimised bond parameters and single crystal XRD investigation of related derivatives confirms the structure of DPIP bond parameters. The single crystal XRD measurements and the optimised geometrical parameters produced by the DFT calculation agree well. The FT-IR bands seen in the experiment were attributed to distinct normal modes of the molecule. Frontier molecular orbital computations described the molecule stability, chemical reactivity and charge transfer. Atomic charges determined via Mulliken population analysis on the different DPIP atoms. MEP, which is mapped to the electron density surfaces, has discovered potential reactive sites of the molecule. The reported molecule is used as a potential NLO material since it has a high μβ0 value. Binding affinities were discovered using molecular docking against the COVID-19 major protease (Mpro: 6WCF/6Y84/6LU7). The behaviour of the complex structure formed by the Covid-19 protein under in silico physiological conditions was then confirmed by a 100 ns molecular dynamic simulation which looked at the structure stability over time and revealed a stable conformation and binding pattern in an environment of imidazole derivatives. Furthermore, favourable to moderate anti-viral activity was revealed by an in-silico analysis that anticipated the compound absorption, distribution, metabolism, excretion and toxicity profiles (ADMET).

In silico rationalization of piperidin-4-one analogs as anaplastic lymphoma kinase inhibitors: Integration of density functional theory, topological descriptor, molecular docking and pharmacological feature profiling

Anaplastic lymphoma kinase (ALK) was involved in the development of various cancer types. Although several ALK inhibitors have been advanced to clinical trials, the emergence of drug resistance has limited the clinical application of them. Hence, developing new ALK inhibitors which can overcome resistance is essential. Here, we designed a novel ALK inhibitor Piperidin-4-One based on the structure of the second-generation ALK inhibitor ceritinib. The target compound 1-(cyclopropanecarbonyl)-2,6-bis(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-3-methylpiperidin-4-one (CDMP) was computed using density functional theory (DFT) method. The stability and charge delocalization of the molecule was also studied by natural bond orbital (NBO) analysis. The HOMO-LUMO energies describe the charge transfer takes place within the molecule. Molecular electrostatic potential has been analyzed. The reported molecule used as a potential NLO material since it has high µβ0 value. Additionally, statistical analyses were conducted to clarify the connections between ADMET properties of CDMP and molecular descriptors based on degree, neighborhood degree, degree entropy and neighborhood degree entropy. This thorough examination seeks to uncover the complex interactions between Density Functional Theory and molecular descriptors, offering valuable insights into the relationships among CDMP drug properties. The binding mode mechanism of the title compound was investigated through molecular docking studies, focusing on cancer-related proteins such as 4TT7, 5FTO and 3AOX. Furthermore, an assessment of Drug-likeness and ADMET properties revealed favorable pharmacokinetic profiles for the compound, with no indications of toxicity observed.

Spectral, optical, and thermal analyses of tris-(thiourea) zinc sulfate nonlinear optical crystals

The current research uses a slow evaporation procedure to create Thiourea Zinc sulfate (TTZS), crystal. Powder-XRD, Fourier transforms infrared (FTIR), UV-visible, and thermal and second harmonic generation have all been used to describe the TTZS. The TTZS crystallized in an orthorhombic form, based on XRD. The functional groups and vibrational modes were validated by FTIR. The transparency over the UV-visible spectrum has been confirmed by UV spectroscopy. The SHG test illustrates the creation of second harmonic signals from samples. The thermal response of TTZS is shown by the TG/DTA. The findings suggest that TTZS might be a potential NLO material.

Comparative assessment of structure–property relationships of new Cu(II) complex in selected density functionals

In order to evaluate the structure–property relationships of Cu(II) complex by using DFT methods, the structure of the newly synthesized Cu(II) complex, [Cu(6-Brpic)2(bpy)], was investigated by XRD, FTIR, UV–Vis, and fluorescence spectroscopic methods. In addition, Hirshfeld surface and NBO analyses were fulfilled to identify possible interactions in the intermolecular and coordination environment. The five different DFT methods (HCTH, M06L, TPSSTPSS, B3LYP, and CAM-B3LYP levels), having four different functionalities (the GGA, meta-GGA, hybrid-GGA, and range-separated hybrid), were carried out so as to investigate the structure–property relationship, considering the geometric parameters (bond lengths and angles), vibrational frequencies, electronic absorption wavelengths, electronic transitions, and linear and nonlinear optical parameters. The R2 for structural and vibrational parameters, as well as MPD%, MAD, an optimal scaling factor (λ) and overall root mean square (RMS) deviation, were considered only at vibration frequencies. While it was determined that M06-L and TPSSTPSS levels gave the best results for the bond lengths and angles of the Cu(II) complex, the best results for vibrational frequencies were obtained in the HCTH method along with these methods. In NLO parameters, the static and dynamic first-order hyperpolarizability (<β(0;0,0)> and β(−ω;ω,0)/<β(−2ω;ω,ω)>) values, the largest values were obtained in the HCTH method (38.817 × 10−30 and 437.86 × 10−30/201.55 × 10−30 esu), whereas the smallest values were found to be in the CAM–B3LYP/TPSSTPSS levels (6.118 × 10−30 esu, 8.270 × 10−30/11.730 × 10−30 esu). By regarding the static γ (<γ(0;0,0,0)>) and dynamic (<γ(−ω;ω,0,0)> parameters, the largest values were calculated in the M06L (232.101 × 10−36) and HCTH (1711.52 × 10−36) methods and the smallest values were obtained in the CAM–B3LYP (43.281 × 10−36 and 60.844 × 10−36) method. In fact, it is obviously seen that the β and γ values obtained by the aforementioned DFT levels are many times higher than that of the standard molecule of urea. These results indicate that the Cu(II) complex may be used as a potential NLO material to evolve optoelectronic devices.

Computational Quantum Chemical Study, Insilco Molecular Docking and ADMET Study of (3E,5E)-3,5-Bis((1H-Indol-3-yl)Methylene)-1-Benzylpiperidin-4-One Derivatives

The title compound (3E,5E)-3,5-bis((1H-indol-3-yl)methylene)-1-benzylpiperidin-4-one (BIMBP) was deliberated optimal structure, data were calculated using the density functional theory (DFT) B3LYP method on 6-31 G (d, p) basis set and the experimental bond length and bond angles are compared with experimental data. The six-member piperidin-4-one ring adopts a chair conformation with the benzyl group occupying an equatorial position and the olefinic double bonds possessing an E configuration by DFT method. The stability and charge delocalization of the molecule were also studied by natural bond orbital (NBO) analysis. The calculated energies for the Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO) showed the stability and reactivity of the title compound. The molecular electrostatic potential (MEP) picture was drawn using the same level of theory to visualize the chemical reactivity and charge distribution on the molecule. The reported BIMBP molecule used as a potential NLO material since it has high μβ0 value. Molecular docking study performed for the synthesized compound revealed an efficient interaction with the antibacterial protease and resulted in good activities. Virtual ADMET studies were carried out as well and a relationship between biological, electronic, and physicochemical qualifications of the target compound was determined. Toxicity prediction by computational technique for the title compound was also carried out.

N'-(3,4-dimethoxybenzylidene)-4-methylbenzenesulfonohydrazide derivatives: Synthesis, quantum chemical method, in silico ADMET, molecular docking and molecular dynamic simulations

A new N'-(3,4-dimethoxybenzylidene)-4-methylbenzenesulfonohydrazide derivatives were prepared from a condensation reaction between 4-methylbenzenesulfonohydrazide and 3,4-dimethoxybenzaldehyde. The structure of DMSH was elucidated using various spectral techniques including FT-IR, 1HNMR and 13CNMR. The structure of DMSH bond parameters also confirmed by single crystal XRD analysis of related derivatives and optimized bond parameters are calculated by density functional theory (DFT) method at B3LYP/6–311 G (d, p) level of theory. The optimized geometrical parameters obtained by DFT calculation are in good agreement with single crystal XRD data. The experimentally observed FT-IR bands were assigned to different normal modes of the molecule. The results show a good agreement with each other when these computed bond parameters are compared to XRD values of related compounds. The stability, chemical reactivity and charge transfer within the molecule was explained by frontier molecular orbital calculations. Atomic charges on the various atoms of DMSH obtained by Mulliken population analysis. Potential reactive sites of the DMSH compound have been identified by MEP which is mapped to the electron density surfaces. The reported molecule is used as a potential NLO material since it has a high μβ0 value. The theoretical UV–vis spectrum of the compound is used to study the visible absorption maxima (λ max). The molecular docking mechanism between DMSH ligand and COVID-19/6WCF and COVID-19/6Y84 receptors were studied to investigate the binding modes of this compound at the active sites. Molecular docking outcomes have shown that the DMSH molecule can be considered as a potential agent against COVID-19/6WCF-6Y84 receptors. In addition, the theoretical parameters of the bioactive molecules were calculated to establish their drug-likeness qualities and ADME/T analysis was carried out to examine the drug properties of the synthesized compound. Molecular dynamics simulation was performed for COVID-19 main protease (Mpro: 6WCF/6Y84) to understand the elements governing the inhibitory effect and the stability of interaction under dynamic conditions. The resultant complex structures were subjected to 100 ns simulation run to estimate their binding stabilities using GROMACS. The molecular dynamics simulation studies provided essential evidence that the systems were stable during the progression of 100 ns simulation run.

Idiosyncratic photoluminescence of europium added sulfamic acid single crystal a potential NLO material for optoelectronics and devise applications

Idiosyncratic photoluminescence of europium added sulfamic acid single crystal a potential NLO material for optoelectronics and devise applications

AIEgens-NLOphores coumarin-triphenylamine chalcone derivatives: Synthesis, photophysical properties and DFT computational study

Three coumarin-triphenylamine chalcone derivatives (5a-c) with push-pull structures of type A-π-D and D-π-A-π-D were synthesized, varying the substituent at position 7 of coumarin. The characterization of the final compounds as for the intermediates was conducted using 1H and 13C NMR, FT-IR, and HRMS. The study of the photophysical properties of 5a-c revealed a strong solvatochromism, mainly in fluorescent emission, due to the formation of a twisted intramolecular charge transfer (TICT) state. Moreover, aggregation-induced emission (AIE) in MeCNH2O mixtures was notably observed, as well as a strong red emission in the solid state. Computational studies by DFT methods allowed to elucidate the molecular geometries of the ground (S0) and excited states (S1), assign vibrational modes and electronic transitions of IR and UV–Vis spectra, respectively, to describe the reactivity and the electronic distribution from the molecular electrostatic potential (MEP) and the HOMO-LUMO orbitals. Computationally calculated first and second-order hyperpolarizabilities show chalcones 5a-c as potential NLO materials.

Two Mixed Alkali-Metal Borates Templated from Cations to Clusters

Two mixed alkali-metal borates, K0.5Li[B6O10]·0.5H3O (1) and [(μ5-OH)@(Na4Li)]0.5[B6O10]·0.5B(OH)3 (2), have been prepared under solvothermal conditions. Both of them are obtained in the same synthetic system and contain a B6O138- cluster as the structural-building unit (SBU) but exhibit quite different structural features. 1 is a centric three-dimensional (3D) oxoboron (B-O) framework, where templated mixed K+ and Li+ cations occupied the cavities of the structure. 2 crystallizes in an acentric space group under the templating effect of a unique acentric alkali-metal cluster [(μ5-OH)@(Na4Li)]4+. The SBU of 2 is also the B6O138- cluster, which acts as six-connected nodes linked together to form a 3D B-O framework, showing different characters from 1 because of two types of templates; the acentric [(μ5-OH)@(Na4Li)]4+ clusters and the electroneutral B (OH)3 groups fill in two different cages in the framework and further connect each other via Na-O-B bonds to build a novel two-dimensional (2D) wavy bricklike network, resulting in a 3D B-O framework interpenetrated by a 2D [(μ5-OH)@(Na4Li)]-B(OH)3 network. As a crystal material with an acentric space group, 2 shows a good second harmonic generation response of about 2.8 times that of KDP (KH2PO4) and has a cutoff edge below 190 nm, which suggests that 2 is a potential deep-UV NLO material.

PO(CH2CH2CF3)3: an organic ultraviolet nonlinear optical material without any anionic group.

Researchers have focused on inorganic compounds to design deep ultraviolet (UV) nonlinear optical (NLO) materials according to anionic group theory, such as CO32−, NO3−, SO42− and PO43− anions. Here we provide a new route to design an UV NLO material using a pure organic compound without any anions. Compound PO(CH2CH2CF3)31, an UV NLO material, has light transmittance up to 83% in the UV spectral region which is larger than most inorganic UV NLO materials. It also displays a wide transparent band, a SHG response of 0.30 × KH2PO4, and a cut-off edge below 200 nm. It displays ladder-like nonlinear optical properties weakened by 1.4 times at around Tc, making compound 1 a potential temperature-controlled UV NLO material. Theoretical analyses reveal that the nonlinear optical properties are primarily due to O-2p, P-2p and F-2p.

One-pot synthesis, Spectral, X-ray crystal structure, Hirshfeld surface and computational study on potential inhibitory action of novel 1-benzyl-2-(4-methoxynaphthalen-1-yl)-4,5-diphenyl-1H-imidazole derivatives against COVID-19 main protease (Mpro: 6WCF/6Y84)

A novel compound of 1-benzyl-2-(4-methoxynaphthalen-1-yl)-4,5-diphenyl-1H-imidazole (BMNDPI) are conveniently synthesized and characterized by spectral analysis FT-IR, 1H NMR, 13C NMR, Mass spectral and density functional theory (DFT/B3LYP/6–31 G (d, p) computations. The compound BMNDPI was also confirmed by single crystal XRD. The calculated geometric parameters are consistent with XRD data. To explore the intermolecular interactions, the generated Hirshfeld surface has been investigated along with 2D-fingerprint plots. The NBO results reflect the charge transfer is mainly by the orbital overlap between n (LPN54/LPO56) and σ * C1-N55/C43-C48 bond orbital which results intra-molecular charge transfer (ICT) causing stabilization of the system. Stability and charge transfer within the compound was explained by frontier molecular orbital calculations. Atomic charges on the various atoms of BMNDPI obtained by Mulliken population analysis. Potential reactive sites of the BMNDPI compound have been identified by MEP which is mapped to the electron density surfaces. The reported molecule is used as a potential NLO material since it has a high μβ0 value. The molecular docking mechanism between BMNDPI ligand and COVID-19/6WCF and COVID-19/6Y84 receptors were studied to investigate the binding modes of these compounds at the active sites. Molecular docking outcomes have shown that the BMNDPI molecule can be considered as a potential agent against COVID-19/6WCF-6Y84 receptors.

Optical and NLO properties of zigzag carbon nanobelt compounds

• Photophysical properties of CNBs were firstly studied. • The electron transition properties of CNBs were assigned. • The relation between substitutions and photophysical properties was established. • CNBs that introduce substituents from the perspective of breaking centrosymmetric may become potential second-order NLO materials with excellent performance. Zigzag carbon nanobelts (CNBs) attracted great attention from researchers with their potential applications in materials science and supramolecular chemistry. Photophysical properties of the reported CNB and five new designed substituted CNBs are investigated with the aid of density functional theory. Studies show that different substituents have different effects on the electronic structure, electronic transition and first hyperpolarizability. The introduction of electron donors and electron acceptors in a way like CNB 6 is an feasible way to obtain the smallest band gap and cause obvious charge separation in FMOs, and the introduction of different substituents makes the low-energy absorption band produce a significant red shift, and the insertion of substituents from the perspective of breaking centrosymmetric is the most effective method to enhance second-order NLO properties. In view of strong second-order NLO response of CNBs 5 and 6 , they may have the probability to be candidates used as excellent second-order NLO materials. Photophysical properties of the studied CNBs were studied with the help of the DFT calculations.

Molecular modeling and biological activity analysis of new organic-inorganic hybrid: 2-(3,4-dihydroxyphenyl) ethanaminium nitrate

In this paper, experimental and theoretical results of 2-(3, 4-dihydroxyphenyl) ethanaminium nitrate (2DOPN) have been investigated. From DFT calculations, molecular geometry and optimized parameters of 2-(3, 4-dihydroxyphenyl) ethanaminium nitrate have been obtained at B3LYP/ 6–311 ++ G(d, p) level of theory and compared with the available X-ray data. The non covalent interactions of the crystal structure were investigated by QTAIM analysis, ELF, LOL and Hirsfeld surfaces. In addition to study the weak interaction, a visualized approach known as RDG has been carried out. Mulliken atomic charge has been used to describe the process of electronegativity equalization and charge transfer in chemical reactions. NBO analysis was also performed to find the charge transfer within the molecule and their stabilization energy. Electronic proprieties such as MEP, ESP and the frontier molecular orbital analysis HOMO-LUMO of molecule were studied. The dipole moment (µ) and the first hyperpolarisability (β0) have been calculated and found that our compound is a potential NLO material. Thermal behavior (TGA and DTA) of C8H12NO2 (NO3) have also been undertaken and reported. The biological activity of 2DOPN through ligand and proteins interactions has been confirmed theoretically for the treatment of Parkinson disease with respect to chosen proteins. The activities of our molecule with divers proteins were studied in accordance with literature survey and the results were presented here.

Synthesis, spectral characterization, crystal examination, DFT method and molecular docking studies of 1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-2-(thiophen-2-yl)-1H-phenanthro[9,10-d]imidazole

We report a novel synthesis of 1-(2,3-dihydrobenzo[b][1,4]dioxin-7-yl)-2-(thiophen-2-yl)-1H-phenanthro [9,10-d]imidazole ( DDTP ) compound are conveniently found in one pot reaction. The novel compound DDTP had been characterized by FT-IR, 1 H-NMR and 13 C-NMR spectral techniques. The compound was also confirmed by single crystal XRD. The geometrical structure were optimized by density functional theory (DFT) method at B3LYP/6-31G (d,p) level of theory. The optimized geometrical parameters obtained by DFT calculation are in good agreement with single crystal XRD data. The stability and charge delocalization of the molecule were also studied by natural bond orbital (NBO) analysis. The HOMO-LUMO energies describe the charge transfer takes place within the molecule. Molecular electrostatic potential has been analyzed. The reported molecule used as a potential NLO material since it has high μβ 0 value. Hirshfeld surface analysis was carried out to detect the intermolecular interactions in the crystal structure. Molecular docking studies are performed to analyst the biological activity of the DDTP compound against standard drugs namely tetracycline, fluconazole and adriamycin with E.coli DNA gyrase, Cytochrome P450 14 alpha-sterol dimethylase (CYP51) and oxidised quinone reductase-2 inhibitors.

Contemporary studies on growth and characterization of Magnesium doped γ-glycine – A potential optoelectronic NLO material

The optical quality magnesium doped γ-glycine single crystal has been grown by slow evaporation method. The grown crystal was identified as P31 space group based on single crystal X-ray diffraction analysis. The obtained unit cell dimensions a = 7.05 Å, b =7.05 Å, c =5.51Å and α = β = 90o and γ =120o showed that the crystal is hexagonal. The transmittance of the crystal is measured and the UV cut off wavelength was found to be 340 nm and band gap of the crystal is found to be 3.5hν. The various functional groups associated with the grown single crystal have been characterized by FT-IR studies, measured in the range from 450-4000 cm−1. The hardness number and Mayer index value calculated using Microhardness studies established the good mechanical strength of the grown crystal. Simple harmonic generation studies showed that the crystal is having NLO nature. To get the knowledge of crystal surface morphology, SEM studies were carried out. The decomposition temperature of the crystal was identified using TG-DSC studies which indicated that the crystal is thermally stable up to 492.5°C. The laser damage threshold (LDT) studies also supported the suitability of the crystal towards non linear optical applications. Etching studies indicated the minimal dislocations in the crystal growth mechanism. The present study clearly shows that the grown crystal is having potential applications in NLO-optoelectronic devices.

Prediction of Novel van der Waals Boron Oxides with Superior Deep-Ultraviolet Nonlinear Optical Performance.

Deep-ultraviolet nonlinear optical (DUV NLO) materials are attracting increasing attention because of their structural diversity and complexity. Using the two-dimensional (2D) crystal structure prediction method combined with the first-principles calculations, here we propose layered 18-membered-ring (18MR) boron oxide B2 O3 polymorphs as high-performance NLO materials. 18MR-B2 O3 with the AA and AB stackings are potential DUV NLO materials. The superior performing 18MR-B2 O3 AB has an unprecedentedly high second harmonic generation coefficient of 1.63 pm V-1 , the largest among the DUV NLO materials, three times larger than that of the advanced DUV NLO material KBe2 BO3 F2 and comparable to that of β-BaB2 O4 . Its unusually large birefringence of 0.196 at 400 nm guarantees the phase-matching wavelength λPM to reach this material's extreme absorption edge of ≈154 nm.

Prediction of Novel van der Waals Boron Oxides with Superior Deep‐Ultraviolet Nonlinear Optical Performance

AbstractDeep‐ultraviolet nonlinear optical (DUV NLO) materials are attracting increasing attention because of their structural diversity and complexity. Using the two‐dimensional (2D) crystal structure prediction method combined with the first‐principles calculations, here we propose layered 18‐membered‐ring (18MR) boron oxide B2O3 polymorphs as high‐performance NLO materials. 18MR‐B2O3 with the AA and AB stackings are potential DUV NLO materials. The superior performing 18MR‐B2O3AB has an unprecedentedly high second harmonic generation coefficient of 1.63 pm V−1, the largest among the DUV NLO materials, three times larger than that of the advanced DUV NLO material KBe2BO3F2 and comparable to that of β‐BaB2O4. Its unusually large birefringence of 0.196 at 400 nm guarantees the phase‐matching wavelength λPM to reach this material's extreme absorption edge of ≈154 nm.

External electric field modulated second-order nonlinear optical response and visible transparency in hexalithiobenzene.

External electric fields (EEFs) offer a unique opportunity to tune certain activity of molecules by orienting the alignment of the electric field along the specific axis. The second-order NLO response of hexalithiobenzene (C6Li6) is very poor due to its first mean hyperpolarizability of 0.5a.u. Therefore, we have analyzed the effect of EEFs on the structural, electronic properties, and NLO response of C6Li6 using a density functional approach. We notice that the structure of the C6Li6 molecule remains planar, with the slight change in C-C and C-Li bond lengths, but their stability is increased under the effect of EEFs. By applying EEFs, the conductivity or reactivity of C6Li6 is increased as their HOMO-LUMO energy gap is decreased. Furthermore, C6Li6 attains a finite dipole moment in the presence of EEF, which increases linearly as the EEF increases. More interestingly, the firststatic hyperpolarizability of C6Li6 is significantly enhanced, becoming as high as 3.4 × 104a.u. for EEF = 50 × 10-4a.u. This suggests the EEF as an effective way to enhance the second-order NLO responses, leading to the design of potential NLO materials. Nevertheless, the visible transparency of C6Li6 with and without EEF may suggest its possible applications in optical devices.

The second-order nonlinear optical property of hydrazones-based photochromic complexes: A DFT study

A family of hydrazone-based photochromic derivatives consisting a hydrazone switching and phenyl groups with R1 and R2 (R = H, -NO2 and -NMe2) can be induced by light to form two isomers (Z-type and E-type). In this paper, we discussed detailedly the impacts of structural change on UV–Vis absorption spectra, electronic transition properties and the first hyperpolarizability (βtot) by using density functional theory (DFT) methods. The calculation results showed that second-order NLO responses of Z-type complexes are stronger than that of corresponding E-type complexes due to the red-shift of absorption spectra, the smaller electronic transition energy (ΔEge) and the narrower energy band gap (Egap) of frontier molecular orbital. Furthermore, the push-pull complexes 4 may be potential NLO materials due to the larger βtot values, for example, the βtot values of 4Z and 4E are 1.6 × 104 a.u. and 9.3 × 103 a.u., respectively. It is that the donor (D) and acceptor (A) groups are dominated by the interaction of D and A group via intramolecular charge transition (CT). We hope that this research will introduce a new relation between the structure and the photochromic nonlinear optical activity.