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141.
Melek Hajji Hasan Mtiraoui Nesrine Amiri Moncef Msaddek Taha Guerfel 《International journal of quantum chemistry》2019,119(21):e26000
The present work arose out of a desire to fundamentally understand the molecular geometry, weak interactions, electron density delocalization, and chemical reactivity features of 1,5-benzodiazepines-containing family. Herein, a complete X-ray crystallographic study, supported by trustworthy sets of computational approaches, has been reported for two organic crystals. Quantifying intramolecular and intermolecular interactions by Hirshfeld-Becke surfaces analysis conjointly with noncovalent interaction-reduced density gradient topological study revealed that supramolecular assemblies are stabilized by N-H … O (inter) and O-H … N (intra) hydrogen bonds, Cg … Cg (π … π) and C-H(O) … π intercontacts, as well as Van der Waals interactions and steric effects. The long-range-corrected functional wB97XD, which uses Grimme's D2 dispersion model, seems to be just right for our systems. The quantum theory of atoms in molecules analysis confirms that both significant O1-H1…N1 and N2-H2A…O2 H-bonds are weak and electrostatic in nature. Furthermore, global reactivity indices computed via the conceptual density functional theory framework allows these molecules to be classified as moderate electrophiles and marginal nucleophiles. The active sites favorable for nucleophilic/electrophilic attacks were also predicted based on local Parr functions. Finally, a comparative evaluation on the aromaticity character and π-π stacking ability has been done for different (pseudo) rings. 相似文献
142.
The effect of the generalized (r, q) distribution on the non‐linear propagation of dust acoustic waves (DAWs) in a dusty plasma consisting of variable‐size dust grains is discussed. A Korteweg–de Vries (KdV) equation is derived using the reductive perturbation technique (RPT). The dust size obeys the power‐law dust size distribution (DSD). The present results reveal that rarefactive and compressive waves can propagate in the proposed plasma model. It is found that the spectral indices r and q influence the main properties of DAWs. Especially, the velocity, amplitude, and width of the DAW change drastically with r compared to changes in q. 相似文献
143.
Muhammad Ali Khalid Mohammed Khan Uzma Salar Mohammed Ashraf Muhammad Taha Abdul Wadood Sujhla Hamid Muhammad Riaz Basharat Ali Shahbaz Shamim Farman Ali Shahnaz Perveen 《Molecular diversity》2018,22(4):841-861
This study is focused on the identification of thiazole-based inhibitors for the \(\alpha \)-glucosidase enzyme. For that purpose, (E)-2-(2-(arylmethylene)hydrazinyl)-4-arylthiazole derivatives were synthesized in two steps and characterized by various spectroscopic techniques. All derivatives and intermediates were evaluated for their in vitro \(\alpha \)-glucosidase inhibitory activity. Thiosemicarbazones 20 and 35, and cyclized thiazole derivatives 2, 5–11, 13, 15, 21–24, 27–31, and 36–37 showed significant inhibitory potential in the range of \(\hbox {IC}_{50}=6.2\pm 0.19\)–\(43.6\pm 0.23~\upmu \hbox {M}\) as compared to standard acarbose (\(\hbox {IC}_{50}=37.7\pm 0.19~\upmu \hbox {M}\)). A molecular modeling study was carried out to understand the binding interactions of compounds with the active site of enzyme. 相似文献
144.
145.
Ahmed A. El-Asmy Medhat A. Hafez Eman M. Saad Fatma I. Taha 《Transition Metal Chemistry》1994,19(6):603-605
Summary The direct electrochemical oxidation of metallic iron, cobalt, nickel and copper in Me2CO solution of benzoylglycine and/or ethylphthaloylglycine gave products with high yields. For each of the complexes, the electrochemical efficiency is commensurate with the metals being divalent. Conventional physical and chemical studies were used to characterize the isolated complexes and octahedral geometry was suggested for them on the basis of magnetic and electronic spectral studies. The i.r. spectra show that the ligands coordinate in a bidentate fashion; the carboxylate ion is monodentate. The molar conductances agree with the complexes being non-electrolytes. 相似文献
146.
A complete infrared study of the mixed crystal system of AgNO3 and Fe(NO3)3 is carried out in the region 400–4000 cm?1. The study includes internal fundamental normal vibrations of the NO3? ion in the ordered and disordered phases of AgNO3 at different values of the ferric concentration, I.R. spectra, spectral band shape intensities, and frequencies of the internal modes as functions of the ferric ion concentration. Special attention is paid to bending mode, combination mode, asymmetric stretching mode, and over-tone. The rotational energy barrier is determined at different concentration of the ferric ions in the system of AgNO3-Fe(NO3)3. 相似文献
147.
The aim of the study was to investigate the solubility properties of the phosphogypsum a sideproduct of phosphor industry. Phase diagrams of potassium, calcium, hydrogen phosphates, sulphates and water are presented in order to determine equilibrium of solubility. Solid phases were investigated by X-ray diffraction, IR spectrometry and thermal analysis (DTG-DTA). 相似文献
148.
Rafat M. El-Shazly Magdy M. Bekheit Fatma I. Taha Abd-Allah Y. Tawansi 《Transition Metal Chemistry》1990,15(5):337-340
Summary The Schiff base (L), prepared by the condensation of two molecules of ethyl acetoacetate and one molecule of ethylenediamine reacts with copper(II) chloride to give poiynuclear complexes of the type Cu3L Cl6, Cu4L Cl8, Cu5L Cl10, Cu6L Cl12, Cu7L Cl14 and Cu8L Cl16. Elemental analyses, molar conductivities, magnetic susceptibilities, x-ray powder diffraction and i.r. spectral studies have been used to characterize the complexes. The i.r. spectra show that the Schiff base binds in a tetradentate manner and the spectral and magnetic studies suggest the presence of a chlorine bridge between the copper atoms. The magnetic susceptibility of the complexes follows the Curie-Weiss law. 相似文献
149.
Mohamed S. A. El‐Gaby Jehane A. Micky Nadia M. Taha Marwa A. M. Sh. El‐Sharief 《中国化学会会志》2002,49(3):407-414
Thiophosgenation of sulfonamides 1a‐c in the presence of dilute HCl at room temperature furnished the isothiocyanatosulfonamides 2a‐c and treatment with aromatic amines gave 1,3‐disubstituted thioureas 3a,b . Also, interaction of two molecules of 2c with 1,4‐phenylenediamine yielded the novel bisthiourea 4 . Cyclocondensation of 2 with ortho amino carboxylic acid compounds such as anthranilic acids 8 , 5‐amino‐1‐phenyl‐pyrazol‐4‐carboxylic acid 9 and 4,5,6,7‐tetrahydro‐2‐amino‐benzo[b]thiophene‐3‐carboxylic acid 10 furnished the fused thiopyrimidines 11a‐d, 12 and 13 , respectively. 2‐Anilinobenzoazole derivatives 15a‐c, 16a, b and 17a,b were obtained through cyclocondensation of 2 with 1,2‐dinucleophiles. 相似文献
150.
Summary A new series of thiocarbamides was prepared by the reaction of benzoylisothiocyanate with various amines namely 2-aminopyridine (H2LI), 3-aminopyridine (H2LII), 2,3-diaminopyridine (H2LIII), 2,6-diaminopyridine (H2LIV), o-phenylene diamine (H2LV), p-phenylenediamine (H2LVI) and ethylene diamine (H2LVII). The copper(II) complexes of these ligands were isolated and have been characterized by elemental analyses, molar conductivities, magnetic moments and spectral (visible, i.r.) measurements. I.r. spectra show that the ligands behave as dianionic or neutral tetradentates or as monoanionic or neutral bidentates. The [Cu(HLI)Cl]2 and Cu(H2LIV)Cl2 complexes are diamagnetic and the other complexes have normal magnetic moment at room temperature. Electronic spectral analyses show that Cu2(LIV)Ac2 is planar and the other complexes are tetragonally distorted octahedral. All the complexes are non-electrolytes. 相似文献