Facile synthesis, crystal growth, characterization and computational study of new pyridine‐based halogenated hydrazones: Unveiling the stabilization behavior in terms of noncovalent interactions

Exploration of nonlinear optical properties of 4-methyl-4H-1,2,4-triazol-3-yl)thio)-N-phenylpropanamide based derivatives: experimental and DFT approach

Triazoles, nitrogen-containing heterocycles, have gained attention for their applications in medicinal chemistry, drug discovery, agrochemicals, and material sciences. In the current study, we synthesized novel derivatives of N-substituted 2-((5-(3-bromophenyl)-4-methyl-4H-1,2,4-triazol-3-yl)thio)-N-phenylpropanamide and conducted a comprehensive investigation using density functional theory (DFT). These novel structural hybrids of 1,2,4-triazole were synthesized through the multi-step chemical modifications of 3-bromobenzoic acid (1). Initially, compound 1 was converted into its methyl-3-bromobenzoate (2) which was then transformed into 3-bromobenzohydrazide (3). The final step involved the cyclization of compound 3, producing its 1,2,4-triazole derivative (4). This intermediate was then coupled with different electrophiles, resulting in the formation of the final derivatives (7a-7c). Additionally, the characterization of these triazole-based compounds (7a, 7b, and 7c) were carried out using techniques such as IR, HNMR, and UV-visible spectroscopy to understand their structural and spectroscopic properties. The DFT study utilized M06/6-311G(d,p) functional to investigate geometrical parameters, HOMO-LUMO energies, natural bond orbital analyses, transition density matrix (TDM), density of states, and nonlinear optical (NLO) properties. The FMO analysis revealed that compound 7c exhibited the lowest band gap value (4.618 eV). Notably, compound 7c exhibited significant linear polarizability (4.195 >  × 10-23) and first and second hyperpolarizabilities (6.317 >  × 10-30, 4.314 × 10-35), signifying its potential for nonlinear optical applications. These NLO characteristics imply that each of our compounds, especially 7c, plays a crucial part in fabricating materials showing promising NLO properties for optoelectronic applications.

Synthesis, Spectroscopic and Nonlinear Optical Properties, and Antimicrobial Activity of Cu(II), Co(II), and Ni(II) Complexes: Experimental and Theoretical Studies

Currently, we report the preparation of transition metal complexes Co(II), Ni(II), and Cu(II) of hydrazone Schiff base ligands, which are obtained by the condensation reaction of substituted salicylaldehyde and hydrazines. The synthesized hydrazone ligands and their metal complexes were characterized by spectroscopic methods such as Fourier transform infrared (FT-IR), UV-vis, nuclear magnetic resonance (1H NMR and C13 NMR), and mass spectrometry analyses. All of the quantum chemistry calculations were performed using DFT executed in the Gaussian 09 software package. The geometry was optimized by using the density functional theory (DFT) approximation at the B3LYP level with a basis set of 6-31G (d, p). There was excellent agreement between the FT-IR values obtained experimentally and those obtained theoretically for the test compounds. It is worth noting that none of the optimized geometries for any of the Schiff base and metal complexes had any eigenvalues that were negative, indicating that these geometries represent the true minimum feasible energy surfaces. We also analyzed the electrostatic potential of the molecule and NBO calculation at the same level of theory. Gauss View 6 was utilized for the file organization of the input data. Gauss View 6.0, Avogadro, and Chemcraft were used to determine the data. Additionally, synthesized compounds were screened for antimicrobial activity against Gram-negative bacteria (Salmonella typhi, Escherichia coli) and Gram-positive bacteria (Bacillus halodurans, Micrococcus luteus) and two fungal strains (Aspergillus flavus, Aspergillus niger). These research findings have established the potential of ligands and their metal complexes as antimicrobial agents. Additionally, the compounds demonstrated promising nonlinear optical (NLO) properties, with potential applications across a wide range of contemporary technologies.

Density Functional Theory, Molecular Dynamics and AlteQ Studies Approaches of Baimantuoluoamide A and Baimantuoluoamide B to Identify Potential Inhibitors of Mpro Proteins: a Novel Target for the Treatment of SARS COVID-19

COVID-19 has resulted in epidemi conditions over the world. Despite efforts by scientists from all over the world to develop an effective va ine against this virus, there is presently no recognized cure for COVID-19. The most succeed treatments for various ailments come from natural components found in medicinal plants, which are also rucial for the development of new medications. This study intends to understand the role of the baimantuoluoamide A and baimantuoluoamide B molecules in the treatment of Covid19. Initially, density functional theory (DFT) used to explore their electronic potentials along with the Becke3-Lee-Yang-Parr (B3LYP) 6-311 + G(d, p) basis set. A number of characteristics, including the energy gap, hardness, local softness, electronegativity, and electrophilicity, have also been calculated to discuss the reactivity of mole ules. Using natural bond orbital, the title compound's bioactive nature and stability were investigated. Further, both compounds potential inhibitors with main protease (Mpro) proteins, molecular dynamics simulations and AlteQ investigations also studied.

Supplementary Information

The online version contains supplementary material available at 10.1134/S0021364023600039.

Synthesis, Structural, and Intriguing Electronic Properties of Symmetrical Bis-Aryl-α,β-Unsaturated Ketone Derivatives

Three symmetrical bis-aryl-α,β-unsaturated ketone derivatives, 2,6-di((E)-benzylidene)-cyclohexan-1-one (DBC), 2,6-bis((E)-4-chlorobenzylidene)cyclohexan-1-one (BCC), and (1E,1'E,4E,4'E)-5,5'-(1,4-phenylene)bis(2-methyl-1-phenylpenta-1,4-dien-3-one) (PBMP), have been prepared using the aldol condensation approach toward ketones having two enolizable sites. The structures of DBC, BCC, and PBMP have been resolved via spectrometric methods. Moreover, the crystal structure of PBMP is determined by the single-crystal X-ray diffraction (SC-XRD) technique, which revealed that the PBMP molecular assembly is stabilized by the intermolecular C-H···O bonding and C-O···π and weak T-shaped offset π···π stacking interactions. The Hirshfeld surface analysis (HSA) of the PBMP crystal structure was performed as well, and the results were compared with the results of DBC and BCC. The density functional theory (DFT) study results revealed that the longer conjugated molecule of PBMP has smaller but still quite significant HOMO-LUMO gaps compared to the smaller molecules of BCC and DBC. The natural population analysis (NPA) and natural bonding orbital (NBO) analysis were performed. Accordingly, the hydrogen bonding and dipole-dipole interactions stabilize the crystal structures of these compounds. Additionally, the NBO analysis showed numerous high-energy stabilizing interactions for the PBMP compound due to the presence of numerous delocalized and relatively easily polarizable π-electrons, thus implying its significant thermodynamic stability. According to the global reactivity parameter (GRP) analysis, the compounds BCC and DBC are relatively stable in redox processes and have high thermodynamic stability and relatively lower reactivity in general. The molecular electrostatic potential (MEP) analysis results imply potential formation of the intermolecular hydrogen bonding and dispersion interactions, which stabilizes the crystal structures of these compounds.

Exploration of Photophysical and Nonlinear Properties of Salicylaldehyde-Based Functionalized Materials: A Facile Synthetic and DFT Approach

The current research presents the synthesis of novel salicylaldehyde thiosemicarbazones (1-6) and their spectroscopic characterization employing UV-visible, Fourier transform infrared spectroscopy, and NMR techniques. Experimental results are compared and validated with the results obtained theoretically by employing density functional theory at the M06 level with the 6-311G (d,p) basis set. Further, various parameters [natural bond orbital (NBO)], linear and nonlinear optical (NLO) properties, and global reactivity parameters (GRPs) are computationally calculated. The NBO approach has confirmed the stability of compounds on account of charge delocalization and hyper conjugative interaction network. Frontier molecular orbital analysis has explained the charge transfer and chemical reactivity capability, while GRPs have led to the analysis of kinetic stability of the studied molecules. Further, the probability of being NLO-active has been theoretically proved by the HOMO/LUMO energy difference (4.133-4.186 eV) and β values (192.778-501.709 a.u). These findings suggest that the studied compounds possess potential NLO applications as they have shown larger NLO values in comparison with that of the urea molecule, and such distinct properties prove their technological importance.

Green Synthesis, SC-XRD, Non-Covalent Interactive Potential and Electronic Communication via DFT Exploration of Pyridine-Based Hydrazone

Ultrasound-based synthesis at room temperature produces valuable compounds greener and safer than most other methods. This study presents the sonochemical fabrication and characterization of a pyridine-based halogenated hydrazone, (E)-2-((6-chloropyridin-2-yl)oxy)-N′-(2-hydroxybenzylidene) acetohydrazide (HBPAH). The NMR spectroscopic technique was used to determine the structure, while SC-XRD confirmed its crystalline nature. Our structural studies revealed that strong, inter-molecular attractive forces stabilize this crystalline organic compound. Moreover, the compound was optimized at the B3LYP/6-311G(d,p) level using the Crystallographic Information File (CIF). Natural bonding orbital (NBO) and natural population analysis (NPA) were performed at the same level using optimized geometry. Time-dependent density functional theory (DFT) was performed at the B3LYP/6-311G (d,p) method to calculate the frontier molecular orbitals (FMOs) and molecular electrostatic potential (MEP). The global reactivity descriptors were determined using HOMO and LUMO energy gaps. Theoretical calculations based on the Quantum Theory of Atoms in Molecules (QT-AIM) and Hirshfeld analyses identified the non-covalent and covalent interactions of the HBPAH compound. Consequently, QT-AIM and Hirshfeld analyses agree with experimental results.

An Experimental and Computational Exploration on the Electronic, Spectroscopic, and Reactivity Properties of Novel Halo-Functionalized Hydrazones

Herein, halo-functionalized hydrazone derivatives "2-[(6'-chloroazin-2'-yl)oxy]-N'-(2-fluorobenzylidene) aceto-hydrazone (CPFH), 2-[(6'-chloroazin-2'-yl)oxy]-N'-(2-chlorobenzylidene) aceto-hydrazones (CCPH), 2-[(6'-chloroazin-2'-yl)oxy]-N'-(2-bromobenzylidene) aceto-hydrazones (BCPH)" were synthesized and structurally characterized using FTIR, 1H-NMR, 13C-NMR, and UV-vis spectroscopic techniques. Computational studies using density functional theory (DFT) and time dependent DFT at CAM-B3LYP/6-311G (d,p) level of theory were performed for comparison with spectroscopic data (FT-IR, UV-vis) and for elucidation of the structural parameters, natural bond orbitals (NBOs), natural population analysis, frontier molecular orbital (FMO) analysis and nonlinear optical (NLO) properties of hydrazones derivatives (CPFH, CCPH, and BCPH). Consequently, an excellent complement between the experimental data and the DFT-based results was achieved. The NBO analysis confirmed that the presence of hyper conjugative interactions was pivotal cause for stability of the investigated compounds. The energy gaps in CPFH, CCPH, and BCPH were found as 7.278, 7.241, and 7.229 eV, respectively. Furthermore, global reactivity descriptors were calculated using the FMO energies in which global hardness revealed that CPFH was more stable and less reactive as compared to BCPH and CCPH. NLO findings disclosed that CPFH, CCPH, and BCPH have superior properties as compared to the prototype standard compound, which unveiled their potential applications for optoelectronic technology.

Exploration of Noncovalent Interactions, Chemical Reactivity, and Nonlinear Optical Properties of Piperidone Derivatives: A Concise Theoretical Approach

The organic compounds with a π-bond system lead to electric charge delocalization which enables them to reveal fascinating nonlinear optical properties. Mono-carbonyl curcuminoids also have an appealing skeleton from the conjugation view point. Interesting chemical structures of the 3,5-bis(arylidene)-N-benzenesulfonyl-4-piperidone derivatives motivated us to perform density functional theory (DFT)-based studies. Therefore, computations using the B3LYP/6-311G(d,p) functional of DFT were executed to explore geometric parameters, highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energies, and natural bond orbital (NBO) analyses. Moreover, three different functionals such as HF, B3LYP, and M06 with the 6-311G(d,p) basis set were used to investigate the average polarizability ⟨α⟩ and first hyperpolarizability (β_tot)-based properties of all compounds. A good concurrence among calculated and experimental parameters was obtained through root mean square error calculations. The molecular stability of piperidone derivatives was examined using the Hirshfeld surface and NBO analyses. Natural population analysis was also performed to obtain insights about atomic charges. Calculated HOMO-LUMO energies showed that charge transfer interactions take place within the molecules. Moreover, global reactivity parameters including electronegativity, chemical hardness, softness, ionization potential, and electrophilicity were calculated using the HOMO and LUMO energies. The average polarizability ⟨α⟩ and first hyperpolarizability (β_tot) values of all compounds were observed to be larger in magnitude at the aforesaid functional than the standard compound.