Analysis of vibrational spectra (FT-IR and FT-Raman) and nonlinear optical properties of organic 2-chloro-p-xylene

Quantum chemical calculation, performance of selective antimicrobial activity using molecular docking analysis, RDG and experimental (FT-IR, FT-Raman) investigation of 4-[{2-[3-(4-chlorophenyl)-5-(4-propan-2-yl) phenyl)-4, 5-dihydro- 1H- pyrazol-1-yl]-4-oxo-1, 3- thiazol-5(4H)-ylidene} methyl] benzonitrile

The research received a great deal of worldwide attention due to the nature of interpretation before the experimental process. Based on the systematic process the structure of thiazole -pyrazole compound 4-[{2-[3-(4-chlorophenyl)-5-(4-propan-2-yl) phenyl)-4, 5-dihydro- 1H- pyrazol-1-yl]-4-oxo-1, 3- thiazol-5(4H)-ylidene} methyl] benzonitrile [CPTBN] was investigated. In the first level, the spectral statistics on experimental FT-IR and FT- Raman was reported. At the next level, geometrical parameters was theoretically acquired from density functional theory (DFT) using B3LPY/6-31G and 6-311G basis set. The computed Wavenumber were collected and compared with the experimental data. The vibrational modes were interpreted in terms of potential energy distribution (PED) results. The FMO, MEP, and NBO analysis further validated the electrophilic and nucleophilic interaction in the molecular systems. Two grams-positive bacteria: staphylococcus aureus, Bacillus subtilis and two gram-negative bacteria: Esherichia coli, Pseudomonas aeruginosa was performed for antibacterial activity. Two fungal strain Candida albicans and Aspergillus Niger was carried out against a ligand using anti-fungal activity. The molecular docking analysis explores the antimicrobial and selective potential inhibitory nature of the binding molecule. Besides, RDG and ELF analysis were also performed to show the nature of interactions between the molecule.

Ultrasound assisted fabrication of a novel optode base on a triazine based Schiff base immobilized on TEOS for copper detection

This work introduces novel selective and sensitive optical sensor based on a nano sized triazine based Schiff base (H₂L) immbolized on a transparent glass substrate through the sol-gel process to detection of copper (II) ions in aqueous solutions. This sensor can determine the copper (II) in the range of 8.54 × 10^-8-1.0 × 10^-5 mol L^-1 with a low detection limit of 1.53 × 10^-8 mol L^-1. The optimized geometry of H₂L and its copper complex was obtained based on DFT/B3LYP levels of theory with B3LYP/6-311 + G(d,p) and LANL2DZ/6-311 + G(d,p) basis sets respectively. The calculated electronic properties of them including the molecular orbital, Mulliken population analysis, contour of electrostatic potential, and molecular electrostatic potential map confirmed the behavior of the sensor. Some advantage of the fabricated sensor such as high selectivity, sensitivity, short response time, easy production, fast regeneration, low cost, being portable and user friendly can make it a good choice to detection of Cu(II) ion in various application. The suggested sensor was revealed excellent sensitivity in the natural samples that confirmed by Inductively Coupled Plasma-Mass (ICP) spectrometry method.

A novel high performance nano chemosensor for copper (II) ion based on an ultrasound-assisted synthesized diphenylamine-based Schiff base: Design, fabrication and density functional theory calculations

A novel high selective colorimetric chemosensor was introduced based on a nano diphenyl-based Schiff base (H₂L), 2,2'-((1E,1'E)-(((hexylazanediyl)bis(4,1-phenylene))bis(methanylylidene))bis(azanylylidene))bis(4-methylphenol) that synthesized using sonochemical method. H₂L was characterized by FT-IR, MS, TGA, ¹H NMR, ¹³C NMR, SEM and elemental analysis techniques, then fabricated as the portable strips for sensing copper (II) ions in aqueous media. The binding interaction between H₂L and various metal ions was investigated by UV-Vis spectroscopic that showed favorable coordination toward Cu²⁺ ion. H₂L exhibited binding-induced color changes from yellow to pink and practically no interference in the presence of other metal ions, i.e., Cr²⁺, Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Pb²⁺, Mg²⁺ and Ca²⁺. The chemsensor showd the color change from yellow to pink in presence of copper (II) ion in aqueous media due to binging of H₂L and Cu (II). This sensor can determine the copper (II) at in the rang of 7.5 × 10^-8-1.8 × 10^-5 mol L^-1 with a correlation equation: Absorbance = 0.0450[Cu²⁺] × 10^-6 + 0.71 and R² = 0.975 and low detection limit of 1.89 × 10^-8 mol L^-1. Density functional theory (DFT) calculations were carried out at the B3LYP levels of theory with B3LYP/6-311+G(d,p) and LANL2DZ/6-311+G(d,p) basis sets for chemosensor and its copper complex respectively. The optimized geometry, harmonic vibrational frequencies, ¹H NMR and ¹³C NMR chemical, Molecular orbital (M.O.), Mulliken population analysis (MPA), contour of Electrostatic Potential (ESP) and Molecular Electrostatic Potential (MEP) map of H₂L were calculated which show good agreement with behavior of sensor for detection of Cu²⁺ ion.

Structural, electronic and optical properties of 2,5-dichloro-p-xylene: experimental and theoretical calculations using DFT method

The vibrational spectra including FT-IR and FT-Raman for 2,5-dichloro-p-xylene (DCPX) have been recorded.

Structure and nonlinear optical property analysis of L-Methioninium oxalate: a DFT approach

Infrared and FT-Raman spectra of the nonlinear optical material l-Methioninium Oxalate were recorded and analyzed. The optimized geometry, first-order hyperpolarizability and harmonic vibrational wavenumbers were calculated with the help of density functional theory method. The detailed interpretation of the vibrational spectra was carried out with the aid of normal coordinate analysis followed by scaled quantum mechanical force field methodology. Stability of the molecule arising from hyperconjugative interactions leading to its nonlinear optical activity and charge delocalization were analyzed using natural bond orbital technique. Mulliken atomic charge and molecular electrostatic potential are also predicted. HOMO-LUMO energy gap value suggests the possibility of charge transfer within the molecule. The thermodynamic properties at different temperatures are also calculated.

FT-IR and FT-Raman, NMR and UV spectroscopic investigation and hybrid computational (HF and DFT) analysis on the molecular structure of mesitylene

The spectroscopic properties of mesitylene were investigated by FT-IR, FT-Raman, UV, (1)H and (13)C NMR techniques. The geometrical parameters and energies have been obtained from density functional theory (DFT) B3LYP method and Hartree-Fock (HF) method with 6-311++G(d,p) and 6-311G(d,p) basis sets calculations. The geometry of the molecule was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (OPDOS) diagrams analysis were presented. (13)C and (1)H NMR chemical shifts were calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, oscillator strength, wavelengths, HOMO and LUMO energies, were performed by time-dependent density functional theory (TD-DFT) results complements with the experimental findings. The results of the calculations were applied to simulate spectra of the title compound, which show excellent agreement with observed spectra. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) and thermodynamic properties were performed. Reduced density gradient (RDG) of the mesitylene was also given to investigate interactions of the molecule.

Identification of structural and spectral features of synthesized cyano-stilbene dye derivatives: a comparative experimental and DFT study

The synthesized three dye derivatives of cyano-stilbene monomer were identified by experimental spectroscopic techniques and density functional approach. The optimized geometrical structure, vibrational and electronic transitions along with the nonlinear optical (NLO) properties of those compounds were presented in this study. The vibrational spectra of investigated compounds were recorded in solid state with FT-IR and FT-Raman spectrometry in the range of 4000-400 cm(-1) and 3600-50 cm(-1), respectively. The theoretical ground state equilibrium conformations and vibrational wavenumbers were carried out by using density functional method with 6-311G(d,p) basis set. Assignments of the fundamental vibrational modes were examined on the basis of the measured data and total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. The UV absorption spectra of monomers were observed in the range of 200-600 nm in chloroform, acetonitrile and toluene, and time dependent DFT method was used to obtain the electronic properties. The linear polarizability and first hyperpolarizability of the studied molecules indicates that the title compounds can be used as a good nonlinear optical material. A detailed description of spectroscopic behaviors of compounds was given based on the comparison of experimental measurements and theoretical computations.