Enhanced Method for the Synthesis and Comprehensive Characterization of 1-(4-Phenylquinolin-2-yl)propan-1-one

We present an enhanced method for synthesizing a novel compound, 1-(4-phenylquinolin-2-yl)propan-1-one (3), through the solvent-free Friedländer quinoline synthesis using poly(phosphoric acid) as an assisting agent. The crystal structure of compound 3 is analyzed using FT-IR, and the chemical shifts of its 1H- and 13C NMR spectra are measured and calculated using B3LYP/6-311G(d,p), CAM-B3LYP/6-311G(d,p), and M06-2X/6-311G(d,p) basis sets in the gas phase. Additionally, the optimized geometry of quinoline 3 is compared with experimental X-ray diffraction values. Through density functional theory calculations, we explore various aspects of the compound's properties, including noncovalent interactions, Hirshfeld surface analysis, nonlinear optical properties, thermodynamic properties, molecular electrostatic potential, and frontier molecular orbitals. These investigations reveal chemically active sites within this quinoline derivative that contribute to its chemical reactivity.

Comprehensive analysis of crystal structure, spectroscopic properties, quantum chemical insights, and molecular docking studies of two pyrazolopyridine compounds: potential anticancer agents

In this study, two pyrazolo[3,4-b]pyridine derivatives (4a and 4b) were grown using a slow evaporation solution growth technique and characterized by FT-IR, HRMS, 1H/13C NMR spectroscopy, and X-ray crystallography. The 4a and 4b structures crystallized in monoclinic and triclinic systems with space groups P21/n and P1̄, respectively. Theoretical calculations were performed at the DFT/B3LYP level for the optimized geometries. The results were in excellent agreement with the experimental data (spectroscopic and XRD). This investigation encompasses molecular modeling studies including Hirshfeld surface analysis, energy framework calculations, and frontier molecular orbital analysis. Intermolecular interactions within the crystal structures of the compounds were explored through Hirshfeld surface analysis, which revealed the notable presence of hydrogen bonding and hydrophobic interactions. This insight provides valuable information on the structural stability and potential solubility characteristics of these compounds. The research was extended to docking analysis with eight distinct kinases (BRAF, HER2, CSF1R, MEK2, PDGFRA, JAK, AKT1, and AKT2). The results of this analysis demonstrate that both 4a and 4b interact effectively with the kinase-binding sites through a combination of hydrophobic interactions and hydrogen bonding. Compound 4a had the best affinity for proteins; this is related to the fact that the compound is not rigid and has a small size, allowing it to sit well at any binding site. This study contributes to the advancement of kinase inhibitor research and offers potential avenues for the development of new therapeutic agents for cancer treatment.

Corrosion of Titanium Electrode Used for Solar Saline Electroflotation

The solar electroflotation (EF) processes using saline electrolytes are today one of the great challenges for the development of electrochemical devices, due to the corrosion problems that are generated during the operation by being in permanent contact with Cl^- ions. This manuscript discloses the corrosion behavior of titanium electrodes using a superposition model based on mixed potential theory and the evaluation of the superficial performance of the Ti electrodes operated to 4 V/SHE solar electroflotation in contact with a solution of 0.5 M NaCl. Additionally provided is an electrochemical analysis of Ti electrodes regarding HER, ORR, OER, and CER that occur during the solar saline EF process. The non-linear superposition model by mixed potential theory gives electrochemical and corrosion parameters that complement the information published in scientific journals, the corrosion current density and corrosion potential in these conditions is 0.069 A/m² and -7.27 mV, respectively. The formation of TiO₂ and TiOCl on the anode electrode was visualized, resulting in a reduction of its weight loss of the anode electrode.

The Methylene Spacer Matters: The Structural and Luminescent Effects of Positional Isomerism of n-Methylpyridyltriazole Carboxylate Semi-Rigid Ligands in the Structure of Zn(II) Based Coordination Polymers

Two Zn(II) coordination polymers (CPs) based on n-methylpyridyltriazole carboxylate semi-rigid organic ligands (n-MPTC), with n = 3 (L1) and 4 (L2), have been prepared at the water n-butanol interphase by reacting Zn(NO₃)₂·4H₂O with NaL1 and NaL2. This allows us to systematically investigate the influence of the isomeric positional effect on their structures. The organic ligands were obtained by saponification from their respective ester precursors ethyl-5-methyl-1-(pyridin-3-ylmethyl)-1H-1,2,3-triazole-4-carboxylate (P1) and ethyl-5-methyl-1-(pyridin-4-ylmethyl)-1H-1,2,3-triazole-4-carboxylate (P2), resulting in their corresponding sodium salt forms, 3-MPTC, and 4-MPTC. The structure of the Zn(II) CPs determined by single-crystal X-ray diffraction reveals that both CPs have 2D supramolecular hydrogen bond networks. The 2D supramolecular network of [Zn(L1)]n (1) is built up by hydrogen bond interactions between oxygen and hydrogen atoms between neighboring n-methylpyridyltriazole molecules, whereas in [Zn(L2)·4H₂O]n (2) the water molecules link 1D polymeric chains forming a 2D supramolecular aggregate. The structures of 1 and 2 clearly show that the isomeric effect in the semi-rigid ligands plays a vital role in constructing the Zn(II) coordination polymers, helped by the presence of the methylene spacer group, in the final structural conformation. The structures of 1 and 2 significantly affect their luminescent properties. Thus, while 2 shows strong emission at room temperature centered at 367 nm, the emission of 1 is quenched substantially.

Piperonal chalcone derivative incorporating the pyrazolo[3,4-b]pyridine moiety; crystal structure, spectroscopic characterization and quantum chemical investigations

A single crystal of a piperonal chalcone derivative was obtained, fully characterized, and crystallized by a slow evaporation technique. The synthesized compound was characterized by UV-Visible, FT-IR, HRMS, ¹H NMR, and ¹³C NMR spectroscopic studies and X-ray crystallography, revealing that the crystal belongs to a triclinic crystal system with a P1̄ space group, Z = 2. In the present work, we focus on molecular modeling studies such as Hirshfeld surface analysis, energy framework calculations, frontier molecular orbital analysis, natural bond orbital analysis, and NLO properties of a π-conjugate system combining the chalcone and the pyrazole[3,4-b]pyridine scaffolds to describe the in-depth structural analysis thereof. Good agreement was found between the calculated results and experimental data. In addition, Hirshfeld surface analysis of the crystal structure showed that the intermolecular stabilization in the crystal packing comes mainly from H⋯H bond interactions. The chalcone crystal exhibits significant NLO properties suggesting that it could be considered a potential candidate for application in nonlinear optical devices.

Design, synthesis, theoretical study, antioxidant, and anticholinesterase activities of new pyrazolo-fused phenanthrolines

Pyrazole-fused phenanthroline compounds were obtained through several synthetic routes. NMR, HRMS, and IR techniques were used to characterize and confirm the chemical structures. Crystal structures were obtained from compounds 3a, 5b, 5j, 5k, and 5n and analyzed using X-ray diffraction. Compounds were evaluated as acetyl (AChE) and butyrylcholinesterase (BChE) inhibitors, and the results showed a moderate activity. Compound 5c presented the best activity against AChE (IC50 = 53.29 μM) and compound 5l against BChE enzyme (IC50 = 119.3 μM). Furthermore, the ability of the synthetic compounds to scavenge cationic radicals DPPH and ABTS was evaluated. Compound 5e (EC50 = 26.71 μg mL-1) presented the best results in the DPPH assay, and compounds 5e, 5f and 5g (EC50 = 11.51, 3.10 and <3 μg mL-1, respectively) showed better ABTS cationic radical scavenging results. Finally, in silico analyses indicated that 71% of the compounds show good oral availability and are within the ranges established by the Lipinski criteria.

Phenoxy- and Phenylamino-Heterocyclic Quinones: Synthesis and Preliminary Anti-Pancreatic Cancer Activity

The successful application of fragment-based drug discovery strategy for the efficient synthesis of phenoxy- or phenylamino-2-phenyl-benzofuran, -benzoxazole and -benzothiazole quinones is described. Interestingly, in the final step of the synthesis of the target compounds, unusual results were observed on the regiochemistry of the reaction of bromoquinones with phenol and aniline. A theoretical study was carried out for better understanding the factors that control the regiochemistry of these reactions. The substituted heterocyclic quinones were evaluated in vitro to determine their cytotoxicity by the MTT method in three pancreatic cancer cell lines (MIA-PaCa-2, BxPC-3, and AsPC-1). Phenoxy benzothiazole quinone 26a showed potent cytotoxic activity against BxPC-3 cell lines, while phenylamino benzoxazole quinone 20 was the most potent on MIA-PaCa-2 cells. Finally, electrochemical properties of these quinones were determined to correlate with a potential mechanism of action. All these results, indicate that the phenoxy quinone fragment led to compounds with increased activity against pancreatic cancer cells.

Evaluation of trypanocidal properties of ferrocenyl and cyrhetrenyl N-acylhydrazones with pendant 5-nitrofuryl group

Four N-acylhydrazones of general formulae [R¹-C(O)-NH-N=C(R²)(5-nitrofuryl)] with (R¹ = ferrocenyl or cyrhetrenyl and R² = H or Me) are synthesized and characterized in solution and in the solid-state. Comparative studies of their stability in solution under different experimental conditions and their electrochemical properties are reported. NMR studies reveal that the four compounds are stable in DMSO‑d₆ and complementary UV-Vis studies confirm that they also exhibit high stability in mixtures DMSO:H₂O at 37 °C. Electrochemical studies show that the half-wave potential of the nitro group of the N-acylhydrazones is smaller than that of the standard drug nifurtimox and the reduction process follows a self-protonation mechanism. In vitro studies on the antiparasitic activities of the four complexes and the nifurtimox against Trypanosoma cruzi and Trypanosoma brucei reveal that: i) the N-acylhydrazones have a potent inhibitory growth activity against both parasites [EC₅₀ in the low micromolar (in T. cruzi) or even in the nanomolar (in T. brucei) range] and ii) cyrhetrenyl derivatives are more effective than their ferrocenyl analogs. Parallel studies on the L₆ rat skeletal myoblast cell line have also been conducted, and the selectivity indexes determined. Three of the four N-acylhydrazones showed higher selectivity towards T. brucei than the standard drug nifurtimox. Additional studies suggest that the organometallic compounds are bioactivated by type I nitroreductase enzymes.

Crystallization Induced Enhanced Emission in Two New Zn(II) and Cd(II) Supramolecular Coordination Complexes with the 1-(3,4-Dimethylphenyl)-5-Methyl-1H-1,2,3-Triazole-4-Carboxylate Ligand

Two new d¹⁰ metal supramolecular metal-organic frameworks (SMOFs) with general formula [ML₂(H₂O)₂]_n (M = Zn, Cd) have been synthetized using the sodium salt of the anionic 1-(3,4-dimethylphenyl)-5-methyl-1H-1,2,3-triazole-4-carboxylate ligand (Na⁺L^-). Both SMOFs have been structurally characterized by single-crystal X-ray diffraction analysis and IR spectroscopy. The compounds are isostructural and form supramolecular aggregates via hydrogen bonds with the presence of less common dihydrogen bonds. Interestingly, they show ionic conductivity and porosity. The luminescent properties have been also studied by means of the excitation and emission spectra. Periodic DFT and molecular TD-DFT calculations have been used to unravel the emergence of luminescence in the otherwise non-emitting 1-(3,4-dimethylphenyl)-5-methyl-1H-1,2,3-triazole-4-carboxylate ligand once incorporated in the SMOFs. Our results also illustrate the importance of considering the dielectric environment in the crystal when performing excited state calculations for isolated fragments to capture the correct electronic character of the low-lying states, a practice which is not commonly adopted in the community.

Structure and Properties of (CH3NH3)3Tl2Cl9: A Thallium-Based Hybrid Perovskite-Like Compound

The new compound (CH₃NH₃)₃Tl₂Cl₉ was synthesized and fully characterized. X-ray photoelectron spectroscopy and Raman spectroscopy are consistent with the crystal structure solved by single-crystal X-ray diffraction. This compound is a semiconductor with a measured band gap of E_g = 2.91 eV. It is the first thallium-based hybrid perovskite and shows remarkably high stability to ambient conditions.

A new spodium bond driven coordination polymer constructed from mercury(ii) azide and 1,2-bis(pyridin-2-ylmethylene)hydrazine

In this manuscript, the synthesis and X-ray characterization of a new spodium bond driven coordination polymer constructed from mercury(ii) azide and 1,2-bis(pyridin-2-ylmethylene)hydrazine are reported.

Crystal structure of ethyl (Z)-(4-oxo-4-phenylbut-2-en-2-yl)glycinate, C14H17NO3

C14H17NO3, monoclinic, P21/n (no. 14), a = 11.1445(7) Å, b = 8.5442(5) Å, c = 14.2503(8) Å, β = 97.5684(11)°, V = 1345.10(14) Å3, Z = 4, Rgt(F) = 0.0668, wRref(F2) = 0.1680, T = 296(2) K.

Crystal structure of dimethyl (3aS,6R,6aS,7S)-2-pivaloyl-2,3-dihydro-1H,6H,7H-3a,6:7,9a-diepoxybenzo[de]isoquinoline-3a1,6a-dicarboxylate, C21H25NO8

C21H25NO8 , P21/n, (no. 14), a = 12.905(3) Å, b = 13.370(3) Å, c = 13.090(3) Å, β = 118.19(3)°, V = 1990.5(8) Å3, Z = 4, R gt(F) = 0.0629, wR ref(F 2) = 0.1966, T = 100(2) K.

Crystal structure of 5,4′-dihydroxy-7,3′-dimethoxyflavanone, C17H16O6

C17H16O6, orthorhombic, P212121 (no. 19), a = 5.2601(3) Å, b = 12.7161(6) Å, c = 22.0116(11) Å, V = 1472.31(13) Å3, Z = 4, R gt(F) = 0.0430, wR ref(F 2) = 0.1089, T = 296(2) K.

Hydrogen and halogen bonding in the haloetherification products in chalcone

Cooperative action of hydrogen and halogen bonding in the reaction of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-1-phenylprop-2-en-1-one with HCl or HBr in alcohol medium under microwave irradiation (20 W, 80 °C, 10 min) allows the isolation of the haloetherification products (2S,3S)-3-(3-tert-butyl-5-chloro-4-hydroxyphenyl)-2-chloro-3-ethoxy-1-phenylpropan-1-one, C₂₁H₂₄Cl₂O₃, (2S,3S)-2-bromo-3-(3-tert-butyl-5-bromo-4-hydroxyphenyl)-3-methoxy-1-phenylpropan-1-one, C₂₀H₂₂Br₂O₃, and (2S,3S)-2-bromo-3-(3-tert-butyl-5-bromo-4-hydroxyphenyl)-3-ethoxy-1-phenylpropan-1-one, C₂₁H₂₄Br₂O₃, in good yields. Both types of noncovalent interactions, e.g. hydrogen and halogen bonds, are formed to stabilize the obtained products in the solid state.

Crystal structure of dimethyl (3aS,6R,6aS,7S)-1H,3H,6H,7H-3a,6:7,9a-diepoxybenzo[de]isochromene-3a 1,6a-dicarboxylate, C16H16O7

C16H16O7, monoclinic, P21/n (no. 14), a = 12.830(3) Å, b = 8.1101(16) Å, c = 14.900(3) Å, β = 114.88(3)°, V = 1406.5(6) Å3, Z = 4, R gt(F) = 0.0578, wR ref(F 2) = 0.1799, T = 100(2) K.

The Positional Isomeric Effect on the Structural Diversity of Cd(II) Coordination Polymers, Using Flexible Positional Isomeric Ligands Containing Pyridyl, Triazole, and Carboxylate Fragments

To systematically investigate the influence of the positional isomeric effect on the structures of polymer complexes, we prepared two new polymers containing the two positional isomers ethyl 5-methyl-1-(pyridin-3-yl)-1H-1,2,3-triazole-3-carboxylate (L1) and ethyl-5-methyl-1-(pyridin-3-yl)-1H-1,2,3-triazole-4-carboxylate (L2), as well as Cd(II) ions. The structures of the metal⁻organic frameworks were determined by a single crystal XRD analysis. The compound [Cd(L1)₂·4H₂O] (1), is a hydrogen bond-induced coordination polymer, whereas the compound [Cd(L2)₄·5H₂O]_n (2) is a three-dimensional (3-D) coordination polymer. Their structures and properties are tuned by the variable N-donor positions of the ligand isomers. This work indicates that the isomeric effect of the ligand isomers plays an important role in the construction of the Cd(II) complexes. In addition, the thermal and luminescent properties are reported in detail.

Crystal structure of 4-aminopyridinium 4-acetyl-(pyridin-4-yl)-1H-1,2,3-triazol-5-olate monohydrate, C14H16N6O3

C14H16N6O3, triclinic, space group P1̅ (no. 2), a = 7.7890(5) Å, b = 8.6069(6) Å, c = 12.4753(8) Å, α = 77.064(4)°, β = 72.754(3)°, γ = 67.148(3)°, V = 730.40(9) Å3, Z = 2, R gt(F) = 0.0594, wR ref(F 2) = 0.1542, T = 297(2) K.