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The special properties of organic compounds are due to the polyvalence of the carbon atom. In this research, the organic single crystal of N-(4-acetyl −5-(4-(nitro) phenyl) −4,5-dihydro-1,3,4-thiadiazol-2-yl) -N-phenylacetamide (NTDZ) was successfully synthesized and crystallized in isopropanol by using slow evaporation solution growth method. FT-IR, 1H and 13C NMR spectroscopic techniques were used to characterize the presence of various functional groups in the NTDZ molecular structure. Single crystal X-ray data have been collected and used for the structural determination of NTDZ. The title crystal crystallized in the monoclinic space group P21/c, according to X-ray analysis. Besides, quantum chemical studies were carried out using the density functional theory calculation method. The theoretical and experimental geometrical parameters were compared indicating a good accordance between them. Moreover, surface shapes were displayed using 3D-Hirshfeld surface analysis, and 2D-fingerprint graphs were used to quantify the contributions of C–H...O and C–H...N intermolecular interactions. Furthermore, the vibration spectrum of the NTDZ is calculated and compared with that obtained by FT-IR spectroscopy, and the predicted vibration assignments are made according to the potential energy distribution (PED). The chemical shifts of 1H and 13C-NMR were calculated using the GIAO approximation and compared to experimental values. Using the TD-DFT method, the theoretical UV-Vis absorption spectrum was calculated in chloroform solvent to obtain the most important electronic transitions. Frontier molecular orbitals (HOMO and LUMO) indicate the charge transfer within the molecule. The global chemical reactivity descriptors (GCRD) were calculated. In addition, the MEP was also computed showing the functional groups responsible for building interactions with other molecules. Finally, the nonlinear optical behavior was investigated by the determination of the dipole moment (μ), the polarizability (α), and the first and second hyperpolarizabilities using the same level of theory. All of these findings suggest that the NTDZ crystal may be a viable candidate for NLO applications. New 1,3,4-thiadiazol derivative was synthesized. X-ray geometry was determined and confirmed by theoretical calculation. Electronic behavior was investigated by DFT and TD-DFT. NLO properties of the compound were also computed. [ABSTRACT FROM AUTHOR]

In this work, a thiazole derivative, 5-(5-nitro furan-2-ylmethylen), 3-N-(2-methoxy phenyl),2-N'-(2-methoxyphenyl) imino thiazolidin-4-one (abbreviated by NF2MT), was characterized through Fourier transform infrared, UV–vis, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. Besides, a complete and detailed vibrational assignment have been achieved by means of density functional theory (DFT) calculations using the B3LYP theory and the 6 311G(d,p) basis set. Based on the electron density distribution, reduced density gradient and atoms-in molecules analyses have been performed to describe and identify the intra- and intermolecular interactions within the molecule. Non-covalent interactivities between non-bonded atoms were also characterized. In addition, the frontier molecular orbitals and global chemical reactivity descriptors of NF2MT were further investigated using DFT, revealing the most important electronic properties of the compound. The TD-DFT method at CAM-B3LYP/6-311G(d,p) level with the chloroform solvent and polarized continuum model was applied to obtain optical behavior as well as the electronic transitions for the molecule. On the other hand, molecular properties such as atomic charges (Mulliken and NBO) and molecular electrostatic potential were calculated to locate the most reactive sites in the molecule that promote hydrogen bond formation. Molecular docking studies were also carried out to predict and display binding sites of NF2MT with its target protein. The biological activity was tested with acetylcholinesterase and butyrylcholinesterase. [ABSTRACT FROM AUTHOR]

The spectroscopic characterization of the new synthesized heterocyclic aromatic organic compound ethyl −2-{[4-ethyl −5-(quinolin- 8-yloxymethyl) -4H- 1,2,4-triazol −3-yl] sulfanyl} acetate (abbreviated by Q-tsa) was carried out using experimental FTIR, UV–Vis, 1H, and 13C NMR techniques. To support the analytical results, theoretical calculations were performed on Q-tsa using DFT method associated with B3LYP functional with 6-31G(d,p) and 6-311G(d,p) basis sets. Furthermore, the reactivity of the title compound was studied by the investigation of frontier molecular orbitals (FMO) analysis, HOMO-LUMO energies, density of state (DOS), molecular electrostatic potential (MEP), global and local chemical reactivity descriptors. Thermodynamic properties were separately computed and discussed. The attractive, repulsive and van der Waals strong and weak interactions in Q-tsa were performed via RDG analysis followed by the investigation of topological properties via AIM theory. Similarly, the NLO activity of the studied compound was highlighted by computing the first hyperpolarizability in different available solvents. Finally, through molecular docking, the biological activity of Q-tsa was studied and discussed. [ABSTRACT FROM AUTHOR]

• The structural characterization of EMBIT was performed combining experimental and theoretical methods. • The molecular electrostatic potential and the energy gap between LUMO and HOMO molecular orbitals have been computed. • Hirshfeld surface analysis and fingerprint plots furnished a detailed information on the molecular packing and the contributions of the various interactions to the crystal lattice. • The non-linear optical (NLO) properties have been assessed by studying first and second order hyperpolarizabilities. • Molecular docking studies of EMBIT indicating favorable performance protein kinases ROCK 1 and 2 key factors in the Glaucoma disease. (E)-3-(3-(2-methoxyphenyl)-4-methylthiazol-2(3H)-ylidene) benzo[4,5] imidazo [1,2-c] thiazole-1(3H)-thione (EMBIT) was synthesized and studied thoroughly by means of X-ray diffraction and molecular modeling. In this study, geometrical analysis together with FT-IR, NMR, and UV-Vis characterizations were performed. Using density functional theory and the B3LYP/6–311G++(d,p) set, geometric parameters accurately represent the structure, showing agreement between experimental and theoretical results. Various solvents were included in the calculations of the UV–Vis spectra, frontier molecular orbitals (FMOs), and global chemical reactivity descriptors (GCRD) calculations, revealing their potential for better prediction of energy gap values. The energy gap and some chemical descriptors analysis of the title compound indicated that it would be suitable for nonlinear optical properties and biological activity. Non-covalent bond interaction studies were conducted on EMBIT to investigate the intermolecular interactions. A deeper understanding of the electronic structure and chemical bonding patterns of the structure was gained by LOL and ELF studies. The computed polarizabilities and hyperpolarizabilities indicated that the molecule has non-linear optical properties and assessed the influence of the energetic gap values and electron delocalization character on enhancing NLO proprieties. The predictions of EMBIT's biological activity suggested potential as a cure for glaucoma, and molecular docking revealed the various bonds involved against two potential critical glaucoma factors Rock1 and Rock2. Rock2 is found to have a superior binding affinity, as evidenced by its highest binding energy of -8.7 kcal/mol and a lower Ki inhibition constant of 0.97. The EMBIT ligand's effectiveness in inhibiting the Rock2 protein is highly likely, as suggested by this. [ABSTRACT FROM AUTHOR]

• The optimized geometry is computed and spectroscopic properties of DBQA using B3LYP methods. • Experimentally and Theoretically calculated by FT-IR, UV–Vis, NMR spectrum of DBQA. • Hirshfeld surface analysis and fingerprint plots were generated. • The nonlinear optical properties have been evaluated for the different conformation. • Molecular docking of MBQA against HMGCS2 main protease (Mpro) protein. In this study, we present the synthesis and characterization of a novel organic compound, (E)-N'-(3-methoxybenzylidene)-2-(quinolin-8-yloxy) acetohydrazide. Our characterization includes single crystal X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and UV–visible spectroscopy. We also conducted Hirshfeld surface (HS) analysis to investigate intermolecular interactions. The compound crystallizes in the triclinic system with space group P −1. We employed density functional theory (DFT) with the B3LYP function and the 6–311 G (d, p) basis set to calculate its electronic properties. Additionally, we explored its nonlinear optical (NLO) behavior, determining the electric dipole moment (μ), polarizability (α), and hyperpolarizability (β), second-order hyperpolarizabilities (γ) using the same basis set. To evaluate the NLO properties of MBQA, we conducted frontier molecular orbitals (FMO) analysis, examined HOMO-LUMO energies, determined the energy band gap, studied the density of states (DOS), and assessed global chemical reactivity descriptors. We also performed a molecular electrostatic potential (MEP) simulation to identify optimal sites for both electrophilic and nucleophilic attacks. Our analysis further included a reduced density gradient (RDG) analysis to investigate various types of intermolecular interactions in MBQA, such as repulsive, attractive, and Van der Waals interactions while also distinguishing between strong and weak interactions. To understand the molecular stability and interactions, we conducted natural bond orbital (NBO) analysis, which provided insights into hyperconjugative interactions, charge delocalization and electron density ED among the molecular components. Finally, we assessed the biological activity of the MBQA molecule by predicting its potential pharmacological activities using the prediction of activity spectra for substances (PASS) and conducting molecular docking analyses. This comprehensive study provides valuable insights into the structural, electronic, and biological properties of (E)-N'-(3-methoxybenzylidene)-2-(quinolin-8-yloxy) acetohydrazide (MBQA). [Display omitted] [ABSTRACT FROM AUTHOR]

• New thiazolidinone derivative was synthesized and characterized by 1H and 13C NMR. • Its molecular structure has been determined by X-ray crystallography and DFT. • To display the intermolecular interactions, the Hirshfeld surface, and RDG were used. • B3LYP and CAM- B3LYP functionals were used to study HOMO-LUMO, GRCD, and MEP. • Thermodynamic properties were calculated. • Static and dynamic nonlinear optical parameters were predicted using DFT approach. This paper describes the synthesis of a novel fluorine-substituted thiazolidin-4-one compound, (2E,5Z) -3-(4-fluorophenyl) -2-(4-fluorophenylimino) -5-((E)-3-(2-nitrophenyl) allyliden) thiazolidin-4-one, abbreviated as F2NTh. Its structure was subsequently characterized by Fourier transform infrared (FTIR), 1H and 13C nuclear magnetic resonance (NMR), UV–Visible, and single crystal X-ray diffraction (SC-XRD). For a better comprehension of the electronic structure of F2NTh, experimental data collected from the X-ray diffraction pattern were then compared to theoretical results computed by the density functional theory (DFT) using both B3LYP and CAM-B3LYP functionals with a 6–311 G (d, p) basis set. Theoretical results exhibited a good correlation with those established through the experimental analysis. To identify intra- and intermolecular interactions, Hirshfeld surface (HS) and reduced density gradient (RDG) analyses were performed. The results, including 2D fingerprint plots, indicated that H...H interactions played a major role, accounting for 23.6 % of the overall intermolecular contacts. To investigate the charge transfer and ascertain the electronic properties of F2NTh, frontier molecular orbitals and global and local chemical reactivity descriptors were studied. By simulating the molecular electrostatic potential (MEP) and using MPA, NPA, ESP, and MC5 atomic charges, reactive sites within the molecule responsible for electrophilic and nucleophilic attacks were identified. Some thermodynamic parameters and functions (enthalpy, heat capacity, and entropy) obtained from spectroscopic data were also examined in the temperature range of 100−1000 K. Finally, to test the title molecule in the non-linear optical (NLO) domain, the corresponding properties were predicted using B3LYP and CAM-B3LYP functionals. The predicted static NLO parameters (μ = 4.93 D, α = 56.23×10−24 esu, β = 28×10−30 esu, and γ = 244.98 × 10−36 esu) revealed highly promising outcomes, exhibiting the molecule's utility in NLO applications. This activity was confirmed by the dynamic NLO parameters showing a high third-order response. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel quinoline derivative was synthesized and characterized. • FT-IR, NMR, UV–Vis techniques and DFT method were used for spectroscopic analysis. • Conformational analysis was performed to determine the stable geometry. • The HS, NBO and RDG analyses explained the intramolecular hydrogen bonding. • First hyper polarizability and HOMO-LUMO energy gap were theoretically predicted. In this work, (E)-N'-(4-nitrobenzylidene)-2-(quinolin-8-yloxy) acetohydrazide monohydrate (NBQA) crystal was synthesized and its structural characterization was carried out by single-crystal X-ray diffraction. The intermolecular interactions in the crystal were investigated through the Hirshfeld surface analysis and the 2D-fingerprint plot. In the solid phase, the spectroscopic characterization was also carried out using FT-IR, 1H NMR, and 13C NMR experimental spectroscopies. To support experimental results, DFT calculations have been accomplished on the NBQA molecule in the ground state. First, theoretical calculations were performed using BPV86 and GGA-PBE functionals with the 6-311G(d,p) basis set to obtain the stable conformer of the molecule. Likewise, harmonic vibrational frequencies, 1H and 13C chemical shifts, and NBO analysis were also calculated using the same level of theory and compared to available experimental data. Furthermore, the molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis, HOMO-LUMO energies, energy band gap, density of state (DOS), global chemical reactivity descriptors, and some thermodynamic functions were studied and discussed. UV–Vis spectrum was predicted by the TD-DFT method in chloroform solvent and compared with the experimental spectrum for displaying the involved electronic transitions in the compound. The repulsive, attractive, and Van der Waals strong and weak interactions in NBQA were investigated via the RDG analysis. The NLO properties of NBQA have also investigated in different available solvents by DFT and compared to the most important compounds in the field. The first hyperpolarizability values of NBQA have been increased with increasing solvent polarity and decreasing the energy band gap. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• Crystallization and single-crystal X-ray characterization of the 4-thiazolidinone derivative "(Z)-Ethyl-2-(2-((E)−2,4-dinitrobenzylideneamino)−4-oxo-3-phenylthiazolidin-5-ylidene) acetate". • The molecular packing discloses moderate intermolecular contacts with 29.7% of C−H···O and 24.5% of H···H contacts, in addition to vdW interactions. • Structure optimization and HOMO-LUMO band gap determination were carried out by the B3LYP/DFT method. • Natural bond orbital (NBO) analysis suggests a strong π-electron delocalization in the title compound. • In-silico molecular docking targeting SARS-CoV-2 MPro. This study reports on the synthesis of a 4-thiazolidinone derivative (EN2Th), namely, (Z)-Ethyl-2-(2-((E)-2,4-dinitro benzylidene amino)-4-oxo-3-phenylthiazolidin-5-ylidene) acetate. Its crystal structure has been determined by single crystal X-ray diffraction and the spectral characterizations were carried out by means of 1H and 13C NMR, and FT-IR techniques. The molecule of EN2Th crystallizes in the monoclinic P 2 1 / c symmetry and its crystal structure consists of a herringbone packing along [100]. The density functional theory (DFT) at the B3LYP/6-311G (d,p) level has been employed for structure optimization, the results confirm a good consistency between the theoretical and the experimental geometrical data. Hirshfeld surface and 2D fingerprints indicate C−H···O (29.7%) and H···H (24.5%) as the most relevant intermolecular interactions in the crystal packing of EN2Th. According to the reduced density gradient (RDG) analysis, EN2Th exhibits vdW to weak repulsive regions with low electron densities. The theoretical electronic circular dichroism (ECD) spectrum displays an exciton coupled transitions associated with the Z-configuration of the thiazolidin-4-one moiety reflecting the steric effect of the ester group. Charge transfer inside the 4-thiazolidinone derivative EN2Th was considered via the frontier molecular orbitals (FMOs) and natural bond orbital (NBO) investigations along with molecular electrostatic potential (MEP) distribution maps. The HOMO and LUMO energies allowed the estimation of the chemical reactivity descriptors. In accordance with the NBO results, the predicted hyperpolarizabilities indicate a strong donor to acceptor π-electrons delocalization in EN2Th. The anti-viral performance of EN2Th was evaluated in silico against SARS-CoV-2 main protease (MPro) via molecular docking simulations. Finally, ADMET (absorption, distribution, metabolism, excretion and toxicity) online software tools were utilized to uncover the title compound's potential cytotoxicity. [Display omitted] [ABSTRACT FROM AUTHOR]

• The experimental structure was characterized by FT-IR, UV–Vis and NMR. • The optimized geometry of FBID molecule was computed and its spectroscopic properties were examined. • The nonlinear optical properties have been evaluated for the different conformations of the FBID molecule. • MEP and energy gaps of frontier molecular orbitals (HOMO–LUMO) have been calculated. • Hirshfeld surface analysis and fingerprint plots were carried out. In a previous study, the 1-(4-fluorobenzyl)-5-bromolindolin-2,3‑dione (FBID) molecule was synthesized by adding isatin and K 2 CO 3 to acetonitrile, followed by the addition of 4-fluorobenzyl chloride. The resulting mixture was filtered, concentrated, then solidified with n-hexane, and recrystallized in water. In the present study, a combination of theoretical and experimental methods is employed to evaluate and understand the structural and vibrational properties of FBID: FT-IR, UV–Vis as well as 1H and 13C NMR chemical shifts using GIAO approach. All calculations were performed applying the DFT method, with B3LYP functional and 6–311G(d,p) basis set. The HOMO-LUMO energy gap revealed a good charge transfer interaction in FBID molecule. Also, the HOMO and LUMO energies have been exploited to describe the global chemical reactivity. At the same method and level, it has been demonstrated that the studied compound has NLO properties. The estimated NBO, atomic charges and the molecular electrostatic potential map indicated that the sites around the oxygen atoms of the FBID molecule are the most reactive. The contribution of intermolecular interactions was analysed via Hirshfeld surface analysis. In order to identify the different types of all possible interactions in our system, the reduced density gradient (RDG) method was used to characterize and evaluate the nature of these interactions as strong repulsion (steric effect), strong attraction (hydrogen bond), or weak interaction (Van der Waals). [Display omitted] [ABSTRACT FROM AUTHOR]