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Öğe A pyrazinamide-benzenesulfonohydrazide hybrid N'-(phenylsulfonyl)pyrazine-2-carbohydrazonamide: Experimental and theoretical insights(Elsevier Ltd, 2024) Alizadeh, Vali; Garcia Santos, Isabel; Castiñeiras, Alfonso; Mahmoudi, Ghodrat; Safin, Damir AA pyrazinamide-benzenesulfonohydrazide hybrid N'-(phenylsulfonyl)pyrazine-2-carbohydrazonamide (1), which was studied by physical measurements and computational tools, is reported. Compound 1 was synthesized using a metallic Na-assisted interaction of 2-cyanopyrazine with benzenesulfonylhydrazine in dry methanol. Our newly developed synthetic approach allowed to obtain the title compound witht the yield of 74%, which is more than twice higher in comparison to the previously reported synthesis using pyrazine-2-carbohydrazonamide and benzenesulfonyl chloride. Molecules of the title compound are linked via N–H⋯O, C–H⋯Ph, S=O⋯2-pyrazine and π⋯π interactions. As it was found by the Hirshfeld surface analysis, molecules of 1 interact through H⋯X (X = H, C, N and O) contacts. Electronic properties of 1 were revealed using the Density Functional Theory (DFT) computations. 1 was expected to be a fourth-class toxicity, and it does not penetrate the blood-brain barrier, while can potentially be absorbed by the gastrointestinal tract. It was predicted that compound 1, which demonstrated the strongest activity against PLpro, Nsp3_range 207–379 MES and Nsp16_SAM site, are of interest to suppress activity of the SARS-CoV-2 proteins. Although the Ki value is slightly higher, the ligand efficiency scores for complex PLpro–1 were found to be characteristic for a Hit. © 2024 Elsevier LtdÖğe Aerial carbon dioxide conversion to carbonate mediated by a lead(ii) complex with tridentate bipyridine containing a hydrazide ligand under electrochemical conditions yielding single-component white-light-emitting phosphors(Royal Society of Chemistry, 2024) Mahmoudi, Ghodrat; Garcia Santos, Isabel; Labisbal, Elena; Castiñeiras, Alfonso; Alizadeh, Vali; Gomila, Rosa M.; Frontera, Antonio; Safin, Damir A.A novel tetranuclear complex [Pb4L4(CO3)2]·4H2O (1·4H2O) is reported, which was obtained through the electrochemical oxidation of a lead anode under an ambient atmosphere in a CH3CN : MeOH solution of N’-isonicotinoylpicolinohydrazonamide (HL). CO32− anions were formed through the conversion of aerial CO2via the Pb2+-L complex system under electrochemical conditions. The ligand L links two Pb2+ cations through the carbonyl oxygen atom, while the CO32− anion links two Pb2+ cations through two monodentate and one bidentate oxygen atoms. The molecular structure of 1 is stabilized by a pair of Pb⋯O tetrel bonds formed with the bidentate oxygen atom of the CO32− anion, while molecules of 1 are interlinked through reciprocal π(chelate ring)⋯π(chelate ring), π(chelate ring)⋯π(noncovalent ring) and Pb⋯π(noncovalent ring) interactions, yielding a 1D supramolecular chain. The same reaction but under a nitrogen atmosphere yielded a novel mononuclear complex [PbL2]·MeOH·2H2O (2·MeOH·2H2O). In the structure of 2, each ligand L exhibits a tridentate coordination mode. Molecules of 2 are also interlinked through reciprocal π(chelate ring)⋯π(chelate ring), π(chelate ring)⋯π(noncovalent ring) and Pb⋯π(noncovalent ring) interactions, similar to 1, yielding a 1D supramolecular chain. The energetic features of these assemblies were studied using DFT calculations. Additionally, QTAIM analysis was employed to characterize noncovalent contacts, including intermolecular Pb⋯N tetrel bonds. These tetrel bonds were further analyzed using the ELF and Laplacian of electron density 2D maps, which confirmed their noncovalent nature. The optical properties of the complexes were revealed using UV-vis and diffuse reflectance spectroscopy and spectrofluorometry. Both complexes were found to be emissive in a solution of MeOH. CIE-1931 chromaticity coordinates of (0.38, 0.37) and (0.31, 0.32) for 1·4H2O and 2·MeOH·2H2O, respectively, fall within the white gamut of the chromaticity diagram. © 2024 The Royal Society of Chemistry.Öğe Novel benzoyl and acetyl pyrazine-2-carbohydrazonamide hybrid derivatives: Experimental and theoretical insights(Elsevier B.V., 2024) Mahmoudi, Ghodrat; Garcia Santos, Isabel; Castiñeiras, Alfonso; Servati Gargari, Masoumeh; Frontera, Antonio; Safin, Damir A.A series of novel benzoyl and acetyl pyrazine-2-carbohydrazonamide hybrid derivatives, namely N’-benzoylpyrazine-2-carbohydrazonamide (1), N’-(4-methylbenzoyl)pyrazine-2-carbohydrazonamide (2), N’-(2-phenylacetyl)pyrazine-2-carbohydrazonamide (3) and N’-(2-(1H-indol-3-yl)acetyl)pyrazine-2-carbohydrazonamide (4), were readily obtained using a metallic Na-assisted interaction of 2-cyanopyrazine with benzohydrazide, 4-methylbenzohydrazide, 2-phenylacetohydrazide or 2-(1H-indol-3-yl)acetohydrazide in dry MeOH. Compounds 1–4 were studied by a set of physical measurements, including FTIR, 1H NMR and UV–vis spectroscopy, while their crystal structures were elucidated by single crystal X-ray diffraction and the corresponding crystal packing was further studied in detail using the Hirshfeld surface analysis. Compounds 3 and 4 were found to adopt both the E- and Z-isomeric forms in DMSO‑d6. Molecules of the title compounds are linked via N[sbnd]H⋯O and N[sbnd]H⋯N hydrogen bonds and π⋯π interactions, yielding supramolecular aggregates. As it was found by the Hirshfeld surface analysis, molecules of 1–4 mainly interact through the H⋯X (X = H, C, N and O) and C⋯X (X = C and N) contacts. The molecular interactions were quantified and compared using DFT calculations, molecular electrostatic potential (MEP) analysis and quantum theory of atoms in molecules (QTAIM) analysis, highlighting the dominant role of hydrogen bonding interactions in governing the crystal packing. © 2024 The Author(s)Öğe Synthesis and characterization of a series of lead complexes with (pyrazinyl)benzohydrazone ligand and theoretical studies of their supramolecular dimerization in solid state(Elsevier b.v., 2025) Mahmoudi, Ghodrat; Garcia-Santos, Isabel; Novikov, Alexander S.; Kornilov, Dmitry A.; Fernández-Vazquez, Roi; Castiñeiras, Alfonso; Zangrando, EnnioWe have synthesized a series of lead complexes with pyrazinyl-4-methylbenzoylhydrazone (HPyz) and different anions as ancillary ligands, namely [Pb(HPyz)Cl2] (1), [Pb(Pyz)(NO2)] (2), [Pb(Pyz)(NO3)(H2O)] (3), [Pb(Pyz) (NO2)0.5(NO3)0.5(H2O)] (4), and [Pb(Pyz)(SCN)(H2O)] (5). These complexes have been characterized by 1H NMR, IR, and X-ray diffraction techniques. All the complexes show a comparable coordination mode of the organic ligand while the supramolecular crystal structure is addressed by the anions and coordinated water molecules when present. In fact, the solid state is characterized by it-stacking interactions between pyrazine and phenyl rings. In particular, inspection of X-ray data reveals dimerization of centrosymmetric related species of these lead complexes via various noncovalent interactions. To assess the nature of these intermolecular interactions, the Hirshfeld surface analysis and DFT calculations, followed by topological analysis of the electron density distribution within the QTAIM approach and NCI analysis, have been carried out for the model structures based on the experimental X-ray diffraction analysis data. The Hirshfeld surface analysis for the X-ray structures reveals that in all cases crystal packing is determined primarily by intermolecular contacts involving hydrogen atoms. The QTAIM analysis of model structures demonstrates the presence of bond critical points for various intermolecular interactions responsible for the supramolecular dimerization of the studied lead complexes in solid state.
