Effects of Changing Substituents on the Non-Linear Optical Properties of Two Coumarin Derivatives

Multifaceted Study of a Y-Shaped Pyrimidine Compound: Assessing Structural Properties, Docking Interactions, and Third-Order Nonlinear Optics

In this study, we report the synthesis of a new compound, N4,N4-dimethyl-2-(methylsulfanyl)-N6-(4-phenoxyphenyl)pyrimidine-4,6-diamine (DMS), and its comprehensive analysis through structural and spectroscopic characterizations, reactivity parameters, and nonlinear optical properties, utilizing a combination of experimental and computational techniques. The experimental aspect of the investigation encompassed structural characterization using X-ray diffraction and spectroscopic assessments employing Fourier-transform infrared, Raman, and nuclear magnetic resonance techniques, along with thermal analysis. Our computational approach involved density functional theory (DFT) calculations and molecular dynamics (MD) simulations to examine the local reactivity properties of DMS. We employed fundamental reactivity descriptors to evaluate DMS's local reactivity and utilized MD simulations to identify DMS atoms engaging in significant interactions with water molecules. We conducted periodic DFT calculations on DMS's crystal structure to investigate the contributions of specific atoms and groups to the compound's overall stability as well as to analyze noncovalent interactions between DMS molecules. We assessed the nonlinear optical properties through dynamic second hyperpolarizability and third-order nonlinear susceptibility calculations. Additionally, we conducted a comparative analysis of the static and dynamic second hyperpolarizability for the DMS molecule within the sum-over-states framework. The obtained value for the third-order nonlinear susceptibility, (λ = 1907 nm), exceeds those of other organic materials reported in previous studies, indicating that the DMS crystal holds promise as a nonlinear optical material for potential application in photonic device fabrication. Furthermore, molecular docking studies were performed with the 3E5A, 4EUT, and 4EUU proteins, yielding binding affinities of -8.1, -8.2, and -8.3 kcal/mol, respectively, in association with the ligand.

Synthesis and application of a novel polyurethane nanoemulsion bearing coumarin derivative as a "turn-on" fluorescence sensor toward Hg2

A novel polyurethane (PU-co-HCCA) nanoemulsion bearing coumarin derivative (HCCA) was synthesized as a "turn-on" fluorescent probe and used to modify filter paper, and its sensing properties were investigated. Results showed that PU-co-HCCA nanoemulsion exhibited high selectivity and excellent sensitivity toward Hg²⁺ over other metal ions, and possessed excellent fluorescence quantum yields of 0.976, ppb-levels detection limits of 1.61 ppb and large Stokes shifts of 101 nm. Meanwhile, as an application example of as-prepared PU-co-HCCA nanoemulsion, a Hg²⁺ test paper was prepared by modifying filter paper with PU-co-HCCA nanoemulsion, and results indicated that the test paper is portable and convenient and has a wide working pH range. We believe that the PU-co-HCCA nanoemulsion and the modified filter paper can provide a new design principle for the application of fluorescence sensors for metal ions including Hg²⁺.

Study of geometric, electronic structures and vibrations of 4, 4′, 4′′, 4′′′-(porphine-5,10,15,20 tetrayl) tetrakis (benzene sulfonic acid) compound by computational and experimental techniques

The optimized geometry and vibrational frequencies of a substituted compound of tetraphenylporphine namely 4, 4[Formula: see text], 4[Formula: see text], 4[Formula: see text]-(porphine-5,10,15,20 tetrayl) tetrakis (benzene sulfonic acid) have been investigated using density functional theory. The vibrational spectra of tetraphenylporphine and its substituted complex were simulated to study the substitution effects of sulfonic acid group at the peripheral sites of tetraphenylporphine. Experimentally, vibrational properties of these molecules have been studied using infrared absorption spectroscopic technique. The vibrational frequencies obtained from the theoretical studies generally agree with the experimental values. For substituted molecules, due to a change in charge distribution, ring vibrations accompanied by the S–O motions also appear at the higher wavenumbers. In the lower region, C–H bending vibrations diminish and SO3 group vibrations arise. The electronic absorption spectra of the substituted tetraphenylporphine in different solvents have been studied using UV-vis spectroscopy. In addition to dipole-dipole and electrostatic interactions, hydrogen bonding plays a key role in molecular-solvent interactions. The energy gap between the highest occupied and lowest unoccupied molecular orbitals and natural bonding orbital analysis show the intermolecular charge transfer interactions. The molecular electrostatic potential and solvent accessible surface area analysis were made in order to study the interaction sites of the molecules. The current-voltage characteristics for the substituted molecule were also plotted. It was found that substituted tetraphenylporphine show good photoconductivity.

Synthesis and structural studies on (E)-3-(2,6-difluorophenyl)-1-(4-fluorophenyl)prop-2-en-1-one: a promising nonlinear optical material

A new fluorinated chalcone (E)-3-(2,6-difluorophenyl)-1-(4-fluorophenyl)prop-2-en-1-one was synthesized in 90% yield and crystallized by a slow evaporation technique. Its full structural characterization and purity were determined by scanning electron microscopy, infrared spectroscopy, gas chromatography-mass spectrometry, 1H, 13C and 19F nuclear magnetic resonance, thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), Raman microspectroscopy, UV-Vis absorption spectroscopy, single crystal X-ray diffraction (XRD) and Hirshfeld surface (HS) analysis. The fluorinated chalcone crystallized in centrosymmetric space group P21/c stabilized by the C-H⋯O and C-H⋯F interactions and the π⋯π contact. The crystalline environment was simulated through the supermolecule approach where a bulk with 378 000 atoms was built. The electric parameters were calculated at the DFT/CAM-B3LYP/6-311++G(d,p) level as function of the electric field frequency. The macroscopic parameters such as linear refractive index and third-order nonlinear susceptibility (χ (3)) were calculated, and the results were compared with experimental data obtained from the literature. The χ (3)-value for the chalcone crystal is 369.294 × 10-22 m2 V-2, higher than those obtained from a few similar types of molecule, showing that the chalcone crystal can be considered as a nonlinear optical material. Also, molecular theoretical calculations such as infrared spectrum assignments, frontier molecular orbital analysis and MEP were implemented, revealing that the most positive region is around the hydrogen atoms of the aromatic rings, and electrophilic attack occurs on the carbonyl group.

Y-shaped potential third-order nonlinear optical material – 3-(2-amino-2-oxoethyl)-5-methyl hexanoic acid: an analysis of structural, spectroscopic and docking studies

The merit of this work is that it has clearly established the structure and the nonlinear optical properties relationship of the title molecule and it could be helpful for developing new nonlinear optical materials.

Quantum computational study of non-linear optical properties of some phenanthrene derivatives

Non-linear optical (NLO) behavior of some phenanthrene-based organic molecules is studied using quantum computational MP2 and B3LYP methods with cc-pVDZ basis set. The design of these molecules is based on possible intramolecular charge transfer between electron donor and electron acceptor groups via an aromatic bridge. The -NO₂, -CN, -CF₃, -C(CF₃)C(CF₃)₂, -SO₃H and -C(CN)C(CN)₂ acceptors and the -NH₂, -N(CH₃)₂ and pyrrolidinyl donors have been considered. The HOMO and LUMO energies, polarizabilities and first hyperpolarizabilities are calculated for the optimized structures both in the gas phase and in the conductor-like polarizable continuum model (CPCM) of different solvents. Moreover, the energies of the vertical transitions in the UV-Vis range having large oscillator strengths and their corresponding adiabatic transition energies are calculated using TD-DFT-B3LYP/cc-pVDZ method. Also, UV-Vis and infrared spectra are simulated for these designed molecules. Results show that these phenanthrene derivatives have generally very good NLO behavior. Also, NLO properties are enhanced when (-C(CN)C(CN)₂ & -NH₂) and (-NO₂ & pyrrolidinyl) pairs of (acceptor & donor) groups are used. The approach adopted in the present quantum computational study can be used for similar studies for better description and understanding of the NLO responses of the electron donor-bridge-acceptor systems with π-conjugated bridges.

Chalcone as Potential Nonlinear Optical Material: A Combined Theoretical, Structural and Spectroscopic Study

In this work, we propose the synthesis of a novel bromine chalcone (E)-3-(2-bromophenyl)-1-(2phenylsulfonylamine)-phenyl)prop-2-en-1-one (BRC) that has been crystallized by slow evaporation technique. The second order molecular optical scattering and two-photon absorption(2PA) spectrumof the BRC molecule dissolved in Dimethyl Sulfoxide (DMSO) were evaluated by using Hyper Rayleigh Scattering and femtosecond tunable Z-Scan techniques. The first order hyperpolarizability of BRC dissolved in DMSO was estimated by using a simplified two-level model, in which one- and two-photon absorption parameters were used as input information to the model. The BRC crystal was characterized from single crystal X-ray diffraction (DRX) and spectroscopy analyzes. Also, the thermogravimetric analyses and the fluorescence spectra were obtained. In addition, an ab-initio calculation method, which includes the Møller-Plesset Perturbation Theory (MP2) and the Density Functional Theory (DFT) at CAM-B3LYP level,was used to estimate the crystal linear refractive index and the third-order electric susceptibility. Also, the average first hyperpolarizability of BRC molecules dissolved in DMSO was calculated and compared with the experimental results. The obtained values are good and qualify BRC crystal as a potential candidate for application in nonlinear optical devices.