A quantum chemical investigation of electro-optical properties and spectroscopic features of propargylimine

In the present work 4,6-bis(4-fluorophenyl)-5,6-dihydropyrimidin-2(1H)-one was synthesized by condensation of (2E)-1,3-bis(4-fluorophenyl)prop-2-en-1-one with urea in basic medium. The synthesized compound was characterized by using FT-IR and 1H NMR spectroscopic techniques. To determine the molecular structure of synthesized molecule some quantum chemical calculations were carried out by density functional theory (DFT) with employing B3LYP level at 6-311++G(d,p) basis set in gas phase, water and CCl4 solvents by using Gaussian-03 package. The optimized geometrical parameters, thermochemical parameters and global reactivity descriptors have been computed. The frontier molecular orbital (FMO) and molecular electrostatic potential (MEP) analysis also performed to explore the reactivity of title molecule at same level of theory. The vibrational frequencies of title molecule were analysed and compared with the corresponding experimental data. The results show fair correlation between the calculated frequencies in gas phase and experimental frequencies. The effect of water and CCl4 solvents on vibrational frequencies and global chemical reactivity descriptors were also examined. Obtained results show that polar solvent water decreased the carbonyl stretching frequency largely while other frequencies in water and CCl4 are slightly different than gas phase. There is no significant change by solvents were observed on energy gap (∆E) and global reactivity descriptors of studied molecule.

Spectroscopic properties (FT-IR, NMR and UV) and DFT studies of amodiaquine

The rational design of multifunctional ligands with tailored reactivity is of significant interest in coordination chemistry, catalysis, and polymer science. In this work, a ligand synthesized conceptually from a melamine–formaldehyde framework and succinic (amber) acid is investigated using quantum chemical methods. Density Functional Theory (DFT) calculations were employed to analyze the electronic structure, molecular geometry, frontier molecular orbitals, global and local reactivity descriptors, and potential coordination behavior of the ligand. Optimized geometries were obtained at the B3LYP/6-31G(d,p) level of theory. Frontier orbital analysis reveals a moderate HOMO–LUMO energy gap, indicating balanced stability and chemical reactivity. Global reactivity descriptors such as chemical hardness, softness, electronegativity, and electrophilicity index were calculated to assess the ligand’s overall reactivity profile. Molecular electrostatic potential (MEP) maps and Fukui function analysis were used to identify nucleophilic and electrophilic reactive sites, particularly around the triazine nitrogen atoms and carboxylate oxygen atoms. The results suggest that the ligand exhibits strong donor capability and favorable coordination behavior toward transition metal ions, making it a promising candidate for applications in metal complex formation and functional materials. This study demonstrates the usefulness of quantum chemical analysis in predicting the reactivity and coordination potential of melamine-based ligands prior to experimental investigation.

ABSTRACTIn this work, we will express a comprehensive theoretical study on C32H12 as a new bowl-shaped structure and a sub-fullerene structure. The specific structural properties of title compound were evaluated by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) computations. A wide study of vibrational spectral analysis has been done and assignments of the fundamental modes have been proposed on the basis of peak positions. Relative frequencies, natural bond orbital (NBO) charges, HOMO–LUMO energies and several thermodynamic properties in the ground state were calculated using B3LYP/6–311++G(d,p) level of theory. The C32H12 was subjected to the analysis of simulated properties include geometries, charges, 13C NMR, 1H NMR and UV/visible spectra. Results showed that most of the modes have wavenumbers in the expected range. Global and local reactivity descriptors of the C32H12 have been computed. The theoretical IR and Raman spectra have also been constructed. NBO study explains charge delocalization of the title molecule.

Molecular structure, vibrational spectroscopy (FT-IR, Raman), solvent effects, molecular docking and DFT studies of 1-(4-chlorophenyl)-3-(4-ethoxyphenyl)-prop-2-en-1-one

The title compound (2,2'-(piperazine-1,4-diyl)bis(N'-((E)-5-chloro-2-hydroxybenzylidene) acetohydrazide) (5-ClPAH) was synthesized by reacting 1,4-Piperazinediacetic acid, 1,4-dihydrazide and 5 -Chloro-2-hydroxybenzaldehyde. Mass spectrometry, 1H, 13C-NMR, IR results of the synthesized compound were examined. Many information about physical and chemical properties of 5-ClPAH can be obtained by theoretical calculations. Density functional theory (DFT) is widely used theoretical method for predicting of chemical structures. The structure was optimized using DFT/6311G method with GAUSSIAN09. Frontier Molecular Orbitls (HOMO and LUMO) energies were calculated. Global reactivity descriptors and also electrophilic and nucleophilic regions were defined by molecular electrostatic potential surface. Antibacterial and fungal activity were evaluated.

In this study, density functional theory calculations at the wB97XD/Def2TZVPP level were performed for 3,5-dimethyl-2,6-diphenylpyridine (1) compound and its para amino phenyl (2), para nitro phenyl (3), para amino nitro phenyl (4) derivatives. Global reactivity descriptors, namely, ionization potential, electron affinity, electronegativity, chemical potential, chemical hardness, softness, and electrophilicity index, were calculated using the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies. In addition, molecular electrostatic potential surfaces, Mulliken and natural charges, natural bond orbitals were analyzed. Furthermore, ultraviolet–visible (UV–Vis) absorption characteristics and nonlinear optical parameters, viz. dipole moment, polarizability, and hyperpolarizability, were calculated. The range of the energy-gap values (ELUMO − EHOMO) was 6.9470–8.8026 eV, indicating the chemical stability of 1–4, with 4 exhibiting the smallest energy gap, lowest hardness, and most softness. According to the UV–Vis analysis, p→p* transitions dominate, and in the HOMO–LUMO transition, the wavelength increases in the order of 4 > 3 > 2 > 1. The hyperpolarizability values change drastically, with the βtotal/βurea ratio for 1, 2, 3, and 4 being 2.7, 28, 25, and 50, respectively. These materials, especially 4, are promising for optoelectronics and industrial applications.

In this study, Herniarin molecule were investigated using Density Functional Theory at the B3LYP/6-311++G(d,p) level. The optimized geometry exhibited energy of -16645.48 eV and a dipole moment of 6.57 Debye, indicating molecular polarity. The calculated bond lengths and angles showed good agreement with experimental data for coumarin analogs. Vibrational analysis confirmed C-H, C-C, C=O, and C-O stretching and bending vibrations within standard ranges. Non-covalent interaction and Reduced Density Gradient analyses revealed steric repulsion and weak van der Waals interactions, with no hydrogen bonding. Electron Localization Function and Localized Orbital Locator mappings showed strong electron localization around hydrogen and oxygen atoms and delocalization within the aromatic ring. Frontier Molecular Orbital analysis yielded HOMO and LUMO energies of -6.46 eV and -2.08 eV, respectively, with an energy gap of 4.38 eV, consistent with the 4.30 eV gap from the Density of States spectrum, confirming molecular stability. Global reactivity descriptors i.e. ionization potential (6.46 eV), electron affinity (2.08 eV), hardness (2.19 eV), and electrophilicity index (4.16 eV) indicated moderate reactivity and chemical stability. Molecular Electrostatic Potential and Electrostatic Potential maps identified oxygen atoms as electron-rich and hydrogen atoms as electron-deficient reactive sites. Mulliken charges analysis showed that all hydrogen atoms carry positive charges, all oxygen atoms carry negative charges, with C3 is the most negatively and C4 is the most positively charge. Thermodynamic parameters i.e. Hom, Som, and Cop,m increased with the rise in temperature (10-500 K), showing strong quadratic correlations (R2 > 0.99), indicated thermal stability and predictable thermodynamic behavior.

Corrosion poses significant challenges in both industrial applications and everyday life, necessitating effective corrosion control strategies to mitigate costs and enhance safety. This research investigates the anti-corrosion potentials of purine derivatives-hypoxanthine (1), xanthine (2), theophylline (3), theobromine (4), uric acid (5), and isoguanine (6)-using density functional theory (DFT) and Monte Carlo simulations. Electronic properties, including energy gaps, HOMO and LUMO energies, molecular electrostatic potential (MEP) surfaces, and global reactivity descriptors, were computed at the B3LYP/6-311 + + G(d, p) theoretical level. Monte Carlo simulations were employed to evaluate the adsorption efficacy of these compounds on Fe(110) and Cu(111) surfaces. The findings reveal significant electron charge transfer from the molecules to the metal surfaces, with uric acid (5) and isoguanine (6) exhibiting the highest inhibition efficiencies. Adsorption energy calculations indicate that compounds 3 and 4 exhibit lower adsorption energies on Fe(110), while adsorption on Cu(111) surfaces demonstrated approximately 1.5 times lower absolute values. These results highlight the potential of purine derivatives, particularly compounds 5 and 6, as effective corrosion inhibitors for metal surfaces.

Vibrational (FT-IR and FT-Raman), electronic (UV–Vis), NMR (1H and 13C) spectra and molecular docking analyses of anticancer molecule 4-hydroxy-3-methoxycinnamaldehyde

A density functional theory study of eight oxicams was carried out in order to determine their global and local reactivities. These types of reactivities were measured by means of global and local reactivity descriptors coming from the conceptual density functional theory. Net electrophilicity as a global reactivity descriptor and local hypersoftness as a local reactivity descriptor were the used tools to distinguish reactivity and selectivity among these oxicams. Globally, isoxicam presents the highest electron donating capacity; meanwhile, the highest electron accepting capacity is exhibited by droxicam. Locally, two oxicams present neither nucleophilic nor electrophilic relevant reactivity in their peripheral pyridine ring, droxicam and tenoxicam, so that their more reactive zones are found on the respective fused rings. Oxicams have been divided into two subgroups in order to facilitate the local analysis of reactivity. One group is characterized because their most important condensed values for local hypersoftnes are well-separated: 4-meloxicam, lornoxicam, meloxicam, and normeloxicam. Meanwhile, the opposite situation is found in droxicam, isoxicam, piroxicam, and tenoxicam. As a whole, the nucleophilic characteristic noticeably predominates in these eight oxicams instead of an electrophilic behavior, thus meaning a greater tendency to donate electrons rather than withdrawing them; a consequence of this behavior implies a favorable interaction with a hypothetical receptor bearing one or more electron acceptor functional groups rather than electron donor functional groups; this would imply a maximization of this interaction from the covalent point of view.

This theoretical chemical reactivity study was conducted using the Density Functional Theory (DFT) method at the B3LYP/6-311G(d,p) level of calculation. It involved a series of five (05) Benzimidazolyl-Chalcone (BZC) and allowed the prediction of the chemical reactivity of these compounds. The DFT global chemical reactivity descriptors (HOMO and LUMO energies, chemical hardness, energy, electronic chemical potential and electrophilicity) were examined to predict the relative stability and reactivity of BZCs. Thus BZC-4 which has a boundary orbital energy gap of ΔEgap = 3.650 eV is the most polarisable, most reactive, good nucleophile.and it is a soft molecule. The values of the global reactivity descriptors confirmed the high chemical reactivity of BZC-4. Local reactivity indices as well as dual descriptors were calculated to indicate the likely sites of electrophilic and nucleophilic attack of the different compounds studied. The analysis of the local indices and the dual descriptors revealed that the nitrogen heteroatom N13 is the preferential site of electrophilic attack and the carbon atom C1 should be the most reactive site with respect to a nucleophilic attack. the Hierarchical Ascending Classification analysis allowed us to group all five (5) compounds studied into three categories. The most active which are BZC-1 and BZC-5, the moderately active BZC-2, and the compounds BZC-3 and BZC-4, the least active. Moreover, this classification is consistent with the value of the Larvicide concentrations (LC100 (μg/mL)).
 Keywords : Benzimidazolyl-Chalcone (BZC), Global descriptors, Local descriptors, Dual descriptors

This study explored the electronic and structural tunability of fullerene (C60) derivatives via functionalization with heteroatoms (O, S, Se) in mono-, di-, and tri-bridged configurations, including covalently modeled dimers. Calculations were performed using density functional theory (DFT) at the B3LYP/6-31G(d,p) level. Electronic descriptors such as total dipole moments (TDMs), HOMO-LUMO energy gaps (ΔE), global reactivity descriptors, total density of states (TDOS), molecular electrostatic potential (MESP) and non-covalent interactions (NCIs) were analyzed to elucidate how functionalization alters reactivity and stability. Key findings indicate that TDM increases and ΔE decreases in all functionalized C60; for example, the TDM increased from 0 Debye for C60 to 2.156 Debye for C60-O-S-Se, and ΔE decreased from 2.762 eV (C60) to 2.532 eV (C60-Se), indicating enhanced reactivity. This aligns with global reactivity descriptors such as reduced ionization energy and hardness. Mapped MESP surfaces showed activation around heteroatom sites. Quantum theory of atoms in molecules (QTAIM) and NCI analyses revealed that while mono-bridged structures retain covalent linkages, dimeric systems such as C60-O-C60 and C60-S-C60 relax into weak, van der Waals-type interactions. OPDOS (overlap population density of states) highlighted antibonding character between the fragments in the conduction region. These results demonstrate that heteroatom functionalization enhances the electronic properties of C60, making it a promising candidate for optoelectronic, organic photovoltaic, and sensor applications.

This study explored the structural, adsorption, and electronic properties of titania nanostructures loaded with cisplatin (cis) using density functional theory (DFT) at the level of B3LYP/LANL2DZ functional in gas phase, and examined the binding potential of the cis-(TiO 2 ) n (n = 2–5) nanoclusters (NCs) with hen egg white lysozyme (HEWL) via molecular docking. Our results revealed that cisplatin adsorption on (TiO 2 ) n NCs yielded adsorption energies of −56.97, −53.84, −48.40, and −39.23 kcal mol −1 for cis-(TiO 2 ) 2 , cis-(TiO 2 ) 3 , cis-(TiO 2 ) 4 , and cis-(TiO 2 ) 5 NCs, abbreviated as NC1, NC2, NC3, and NC4, respectively. Their interatomic interactions were further evaluated using reduced density gradient (RDG) and quantum theory of atoms in molecules (QTAIM) analyses. Among the studied systems, although NC1 exhibited a less negative adsorption energy compared to the other NCs, it indicated strong surface reactivity. Further, NC1 also showed the highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) energy gap of 3.66 eV, suggesting greater charge transfer and reactivity. Additionally, dipole moment, global reactivity descriptors, molecular electrostatic potential (MEP) surface, and natural bond orbital (NBO) results of the NCs were more favorable than those of cisplatin. Based on the DFT results, the protonated NC1, i.e. (TiO 2 ) 2 H 2 was selected for further analysis of its interactions with HEWL. The docking scores of cisplatin, (TiO 2 ) 2 H 2 , and cis-(TiO 2 ) 2 H 2 with HEWL were found to be −4.41, −3.82, and −6.74 kcal mol −1 , respectively, indicating strong binding affinity and therapeutic potential of cis-(TiO 2 ) 2 H 2 . More experimental investigations are required to confirm its effectiveness.

Computational evaluation on molecular stability, reactivity, and drug potential of frovatriptan from DFT and molecular docking approach