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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]

(E)-4-(4-methoxyphenyl)-1-((E)-3(2nitrophenyl) allylidene) thiosemicarbazide was synthesised and screened for nonlinear optical properties. The novel compound has been characterized by infrared spectroscopy, 1H and 13C nuclear magnetic resonance. The experimental and theoretical optical gap energy is obtained using the Tauc method and density functional theory and has been estimated to be around 2.72 and 2.69 eV, respectively. The synthesized thiosemicarbazide exhibits efficiency hyper-Rayleigh scattering hyperpolarizability is calculated to be 6794.51 a.u. at the PBE0 functional. A direct relationship of the hyper-Rayleigh scattering hyperpolarizability with the optical band gap and between the hyper-Rayleigh scattering hyperpolarizability and electric field-induced second harmonic generation is found. The study showed the potential of the novel thiosemicarbazide as nonlinear optical candidates. [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]

In this work, 2-thioxo -3 N-(2-ethoxyphenyl -5[4′-methyl -3′N-(2′-ethoxyphenyl) thiazol-2′(3′H)-ylidene] thiazolidin-4-one (E2Th2) was synthesized and its molecular structure determined by FT-IR, UV-Vis and NMR spectroscopic techniques along with a single crystal X-ray diffraction study. Quantum chemical calculations were performed to better understand its structural, spectroscopic and electronic properties such as HOMO and LUMO energy gap, MEP and global reactivity descriptors. Theoretical calculations were performed using density functional theory (DFT) based on the B3LYP/6-311G (d,p). Vibrational frequencies were assigned on the basis of PED and electronic transitions are calculated according to time-dependent density functional theory (TD-DFT). The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. The NLO activity evaluation was based on the determination of the dipole moment, polarizability (α), first-order hyperpolarizability (β) and the second-order hyperpolarizability (γ) which were calculated using the same level of theory. The hyper-hardness descriptor (Γ) was explored and correlated with the NLO properties. Additionally, the stability of the molecule occurring from hyper-conjugative interaction, intramolecular hydrogen bond and charge delocalization were quantified using NBO analysis. The repulsive, attractive, and van der Waals strong and weak interactions were revealed by RDG and HS analyses. Finally, results have shown that the title compound can be used as attractive future NLO material. [ABSTRACT FROM AUTHOR]

The synthesis of a series of atropisomeric iminothiazolines is carried out by using methoxy precursors. The reaction provides insight into stereodynamics of hydrogen bond between the proton of the OH group and the nitrogen of the imino group.