3,4-Dimethoxy phenyl thiosemicarbazone as an effective corrosion inhibitor of copper under acidic solution: comprehensive experimental, characterization and theoretical investigations.

This study investigates the corrosion inhibition potential of 3,4-dimethoxy phenyl thiosemicarbazone (DMPTS) for copper in 1 M hydrochloric acid (HCl) solutions, aiming to disclose the mechanism behind its protective action. Through an integrative methodology encompassing electrochemical analyses-such as weight loss measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS)-we quantitatively evaluate the corrosion protection efficacy of DMPTS. It was determined that the optimal concentration of DMPTS markedly boosts the corrosion resistance of copper, achieving an impressive inhibition efficiency of up to 89% at 400 ppm. The formation of a protective layer on the copper surface, a critical aspect of DMPTS's inhibitory action, was characterized using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). These techniques provided empirical evidence of surface morphology modifications and roughness changes, affirming the formation of a protective barrier against corrosion. A significant advancement in our study was the application of Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy, which identified chemical adsorption as the definitive mechanism of corrosion inhibition by DMPTS. The ATR-FTIR results explicitly demonstrated the specific interactions between DMPTS molecules and the copper surface, indicative of a robust protective adsorbed layer formation. This mechanistic insight, crucial to understanding the inhibitory process, aligns with the protective efficacy observed in electrochemical and surface analyses. Theoretical support, provided by the Quantum Theory of Atoms in Molecules (QTAIM) and quantum chemical computations, further validated the strong molecular interaction between DMPTS and copper, corroborating the experimental findings. Collectively, this research not only confirms the superior corrosion inhibition performance of DMPTS in an acidic setting but also elucidates the chemical adsorption mechanism as the foundation of its action, offering valuable insights for the development of effective corrosion inhibitors in industrial applications.

Development of new benzil-hydrazone derivatives as anticholinesterase inhibitors: synthesis, X-ray analysis, DFT study and in vitro/in silico evaluation.

Alzheimer's disease (AD) is a complex neurodegenerative disorder affecting the central nervous system. Current drugs for AD have limited effectiveness and often come with side effects. Consequently, there is a pressing need to develop new, safe, and more effective treatments for Alzheimer's disease. In this work, two novel benzil-hydrazone compounds, abbreviated 2-ClMHB and 2-ClBHB, were synthesized for the first time by refluxing the benzil with 2-Chloro phenyl hydrazine and they have been tested for their in vitro anti-cholinesterase activities and in silico acetyl and butyryl enzymes inhibition. The resulting products were characterized using UV-Vis and IR spectroscopy, while the single-crystal X-ray diffraction investigation was successful in establishing the structures of these compounds. DFT calculations have been successfully made to correlate the experimental data. According to biological studies, the synthesized hydrazones significantly inhibited both butyrylcholinesterase (2-ClMHB: 20.95 ± 1.29 µM and 2-ClBHB: 31.21 ± 1.50 µM) and acetylcholinesterase (2-ClMHB: 21.80 ± 1.10 µM and 2-ClBHB: 10.38 ± 1.27 µM). Moreover, molecular docking was also employed to locate the molecule with the optimum interaction and stability as well as to explain the experimental findings. The compound's dynamic nature, binding interaction, and protein-ligand stability were investigated using molecular dynamics (MD) simulations. Analyzing parameters such as RMSD and RMSF indicated that the compound remained stable throughout the 100 ns MD simulation. Finally, the drugs displayed high oral bioavailability, as per projected ADME and pharmacokinetic parameters.Communicated by Ramaswamy H. Sarma.

Synthesis and crystal structures of two 1H-benzo[d]imidazole derivatives: DFT and anticorrosion studies, and Hirshfeld surface analysis.

The title benzimidazole compounds, namely, 2-(4-methoxynaphthalen-1-yl)-1H-benzo[d]imidazole, C18H14N2O (I) and 2-(4-methoxynaphthalen-1-yl)-1-[(4-methoxynaphthalen-1-yl)methyl]-1H-benzo[d]imidazole ethanol monosolvate, C30H24N2O2·C2H6O (II), were synthesized by the condensation reaction of benzene-1,2-diamine with 4-methoxynaphthalene-1-carbaldehyde in the ratios 1:1 and 1:2, respectively. In I, the mean plane of the naphthalene ring system is inclined to that of the benzimidazole ring by 39.22 (8)°, while in II, the corresponding dihedral angle is 64.76 (6)°. This difference is probably influenced by the position of the second naphthalene ring system in II; it is inclined to the benzimidazole ring mean plane by 77.68 (6)°. The two naphthalene ring systems in II are inclined to one another by 75.58 (6)°. In the crystal of I, molecules are linked by N-H...N hydrogen bonds to form chains propagating along the a-axis direction. Inversion-related molecules are also linked by a C-H...π interaction linking the chains to form layers lying parallel to the ac plane. In the crystal of II, the disordered ethanol molecule is linked to the molecule of II by an O-H...N hydrogen bond. There are a number of C-H...π interactions present, both intra- and intermolecular. Molecules related by an inversion centre are linked by C-H...π interactions, forming a dimer. The dimers are linked by further C-H...π interactions, forming ribbons propagating along the b-axis direction. The interatomic contacts in the crystal structures of both compounds were explored using Hirshfeld surface analysis. The molecular structures of I and II were determined by density functional theory (DFT) calculations at the M062X/6-311+g(d) level of theory and compared with the experimentally determined molecular structures in the solid state. Local and global reactivity descriptors were computed to predict the reactivity of the title compounds. Both compounds were shown to exhibit significant anticorrosion properties with respect to iron and copper.

The synthesis and crystal structure of (E)-2-{[(4-methoxynaphthalen-1-yl)methylidene]amino}-4-methylphenol: Hirshfeld surface analysis, DFT calculations and anticorrosion studies.

The title Schiff base compound, (E)-2-{[(4-methoxynaphthalen-1-yl)methylidene]amino}-4-methylphenol, C19H17NO2 (I), was synthesized via the reaction of 2-amino-4-methylphenol with 4-methoxynaphthalene-1-carbaldehyde. The structure of I was characterized by NMR, IR and UV-Vis spectroscopies in different solvents. The interatomic contacts in the crystal structure were explored using Hirshfeld surface analysis, which, together with the two-dimensional fingerprint plots, confirm the predominance of dispersion forces in the crystal structure. The molecule of I has a twisted conformation, with the mean plane of the naphthalene ring system being inclined to the plane of the phenol ring by 33.41 (4)°. In the crystal, molecules are linked by C-H...O hydrogen bonds to form inversion dimers. There are parallel-displaced π-π interactions present, together with C-H...π interactions, resulting in the formation of a three-dimensional structure. The anticorrosion potential of I was also investigated using density functional theory (DFT) in the gas phase and in various solvents. The compound was shown to exhibit significant anticorrosion properties for iron and copper. The molecular structure of I was determined by DFT calculations at the M062X/6-311+g(d) level of theory and compared with the crystallographically determined structure. Local and global reactivity descriptors were computed to predict the reactivity of I. Excellent agreement was observed between the calculated results and the experimental data.

2-[(4-Chloro-phen-yl)imino]-1,2-di-phenyl-ethanone.

The title Schiff base, C20H14ClNO, obtained from the reaction of 4-chloro aniline with benzil, has an approximate T shape. The dihedral angle between the phenyl rings of the benzil unit is 74.14 (15)°. The extended structure features C-H⋯O hydrogen bonds.

2,6-Di-bromo-4-methyl-aniline.

In the title compound, C7H7Br2N, the C-C-C bond angles of the benzene ring are notably distorted and two short intamolecular N-H⋯Br contacts occur. In the crystal, the mol-ecules are linked by N-H⋯N hydrogen bonds to generate C(2) chains propagating in the [100] direction.

Crystal structure and DFT study of the zwitterionic form of 3-{(E)-1-[(4-ethoxyphenyl)iminiumyl]ethyl}-6-methyl-2-oxo-2H-pyran-4-olate.

The title Schiff base compound, C16H17NO4, crystallizes as a zwitterion, with the phenolic H atom having been transferred to the imino group. The resulting iminium and hy-droxy groups are linked by an intra-molecular N-H⋯O hydrogen bond, enclosing an S(6) ring motif. The conformation about the C=N bond is E and the dihedral angle between the benzene and pyran rings is 70.49 (6)°. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming a three-dimensional supra-molecular structure. There are also C-H⋯π inter-actions and offset π-π inter-actions, involving the pyran rings [inter-centroid distance = 3.4156 (8) Å], which consolidate the three-dimensional structure. Quantum chemical calculations of the mol-ecule are in good agreement with the solid state keto-amine (NH) form of the title compound.

Crystal structure of (E)-4-hy-droxy-3-{1-[(4-hy-droxy-phen-yl)imino]-eth-yl}-6-methyl-2H-pyran-2-one.

In the title Schiff base, C14H13NO4, which adopts the phenol-imine tautomeric form, the dihedral angle between the planes of the benzene and heterocyclic (r.m.s. deviation = 0.037 Å) rings is 53.31 (11)°. An intra-molecular O-H⋯N hydrogen bond closes an S(6) ring. In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds to generate C(11) chains propagating in the [010] direction. A weak C-H⋯O link is also observed, leading to the formation of R (5) 5(32) rings extending parallel to the (101) plane.

Crystal structure of (E)-1-[4-({4-[(4-meth-oxy-benzyl-idene)amino]-phen-yl}sulfan-yl)phen-yl]ethan-1-one.

The title Schiff base compound, C22H19NO2S, crystallized with two independent mol-ecules (A and B) in the asymmetric unit. Both mol-ecules have an E conformation about the C=N bond. The two mol-ecules differ in the orientation of the aromatic rings with respect to each other. The outer 4-meth-oxy-benzene ring is inclined to the central benzene ring and the outer 4-acetyl-benzene ring by 1.80 (19) and 63.73 (19)°, respectively, in mol-ecule A, and by 6.72 (18) and 68.53 (19)°, respectively, in mol-ecule B. The two outer benzene rings are inclined to one another by 63.77 (18) and 63.19 (18)° in mol-ecules A and B, respectively. In the crystal, the individual mol-ecules stack in columns along [010], and are linked by a number of C-H⋯π inter-actions, forming slabs lying parallel to (001).

4-Hy-droxy-6-methyl-3-[3-(thio-phen-2-yl)acrylo-yl]-2H-pyran-2-one.

The title compound, C13H10O4S, crystallizes with two mol-ecules in the asymmetric unit in which the rings make dihedral angles of 3.9 (1) and 6.0 (1)°; this planarity is due in part to the presence of an intra-molecular O-H⋯O hydrogen bond, which generates an S(6) ring in each mol-ecule. Both mol-ecules represent E isomers with respect to the central C=C bond. In the crystal, mol-ecules are linked by C-H⋯O inter-actions into a three-dimensional network.

Bis(3-acetyl-6-methyl-2-oxo-2H-pyran-4-olato)bis-(dimethyl sulfoxide)nickel(II).

In the title compound, [Ni(C(8)H(7)O(4))(2){(CH(3))(2)SO}(2)], the Ni(II) atom is located on a crystallographic centre of symmetry and has a distorted octa-hedral coordination geometry of type MO(6). The bidentate dehydro-acetic acid (DHA) ligands occupy the equatorial plane of the complex in a trans configuration, and the dimethyl sulfoxide (DMSO) ligands are weakly coordinated through their O atoms in the axial positions.

Zwitterionic 6-methyl-2-oxo-3-[1-(ureido-iminio)eth-yl]-2H-pyran-4-olate monohydrate.

The title compound, C(9)H(11)N(3)O(4)·H(2)O, was prepared by the reaction of dehydro-acetic acid and semicarbazide hydro-chloride. It crystallizes in a zwitterionic form with cationic iminium and anionic enolate groups. In the crystal structure, the almost planar mol-ecules are held together by N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds, some of them involving the water molecules.