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Despite the significant role of ciclopirox as a novel anticancer agent to treat various cancers such as breast, liver, colorectal and bladder, it has some adverse effects and poor solubility in water. Hence, the enhancement of ciclopirox polarity is crucial in biological systems. In this work, the effect of selenium decoration on the interaction of ciclopirox drug molecule with B12N12 was investigated using density functional theory (DFT) calculations. Based on structural analysis, C O group of ciclopirox was chemisorbed on the boron and selenium atoms of B12N12 and Se-B12N12 nanoclusters, respectively. It was found that the selenium decoration significantly improves the reactivity of B12N12 toward ciclopirox. A short recovery time (~2.13 s) was predicted for ciclopirox desorption from the Se-B12N12 nanocluster surface. The vibrational frequency analysis was conducted to survey the vibration frequencies of bonds formed in the CPX/nanocluster complex. The charge transfer process was studied using charge decomposition analysis (CDA). Furthermore, Quantum theory of atoms in molecules (QTAIM) analysis revealed that the non-covalent interactions between CPX and nanoclusters are essential for the delivery process. Finally, electronic properties analysis showed that energy band gap of Se-B12N12 nanocluster is significantly reduced from 0.2835 to 0.2121 a.u after ciclopirox adsorption.

In the current work, density functional theory calculations were carried out to evaluate the potential ability of apomorphine, dopamine, hinokitiol and deferiprone chelating agents to coordinate Mn2+, Fe3+ and Zn2+ metal ions with a 1:1 ratio in water solution. The binding energy values reveal that Zn2+/chelating agent complexes are more stable compared to Mn2+/chelating agent and Fe3+/chelating agent complexes. In order to evaluate the parameters that describe the affinity between the metal ions and chelating agents, the metal ion/chelating agent interactions were analyzed by CDA, NBO, QTAIM, FMO analyses. Interestingly, it was found that the Fe O interactions in all complexes and Mn O interactions in [Mn-DFP]+ complex are mainly electrostatic, whereas other interactions have a covalent character. Moreover, TD-DFT studies showed n → π* and π → π* transitions in the absorption spectra of the complexes.

Two new bis-1,3,4-oxadiazole derivatives have been synthesized and characterized. The crystal structure of both compounds were solved by single crystal X-ray diffraction analysis and a detailed quantitative analysis of the weak non-covalent interactions have been performed by using the Hirshfeld surface analysis and DFT calculations. The results indicate that both molecules showed different crystal packing. Compound 1 shows C-H···N and C-H···O hydrogen bonds and the structure is also stabilized by C-H···π, π···π stacking and lone pair (S)···π interactions, while the crystal structure of 2 is mainly stabilized by C-H···N and weak C-H···S contacts. The Hirshfeld surfaces, QTAIM analysis and NCI plots were used to study the nature and the extent of different intermolecular interactions observed in these structures. The AChE inhibitory activity of 1 and 2 was evaluated with reference to standard drug Galantamine. The AChE inhibitory activity of compound 1 showed better inhibitory activity (IC50 = 36.34 µg/mL) as compared to compound 2 (IC50 = 47.34 µg/mL). The molecular docking analysis of the inhibitors was performed to identify the putative binding modes and interactions inside the active pocket of the enzymes. This analysis also indicates that the studied compounds could act as “bulky”-blockers of the normal ionic substrate (ACh) entrance into the active site gorge of AChE.

In this study, density functional theory (DFT) calculations were used to investigate the interaction of the B12N12 and Al12N12 nano-cages with alprazolam (ALP) in the gas phase and water at the B3LYP/6-31G(d,p) level of the theory. According to the obtained results, B12N12 nano-cage can be able to form a more stable complex with ALP in comparison to Al12N12. The stability of ALP/B12N12 and ALP/Al12N12 complexes was increased in the water as a simulation of the body condition. Natural bond orbital (NBO) analysis revealed an effective charge transfer from the nitrogen atoms of ALP to the boron atoms of nano-cages. Quantum theory of atoms in molecules (QTAIM) analysis indicated that the non-covalent interactions between Al12N12 and ALP are the main driving force in the complex formation, whereas ALP/B12N12 interaction is mainly electrostatic and partial covalent in nature. Moreover, there is an intra-molecular hydrogen bond between nitrogen atom of the nano-cages and hydrogen atom of ALP. Finally frontier molecular orbital (FMO) analysis was performed to get a better insight of the reactivity and stability of ALP/nano-cage complexes in the gas phase and water. Based on FMO analysis, B12N12 nano-cage is a better biosensor for the detection of ALP drug in comparison to Al12N12 due to the higher changes in its band gap.

In this study, the two new azomethine derivatives: have been investigated by using density functional theory (DFT: B3LYP/LanL2DZ and B3LYP/MidiX) in solvent water for the first time. After quantum-chemical calculations, two new azomethine derivatives were synthesized. The HOMO and LUMO orbitals, MEP, excitation energies, natural charges, oscillator strengths for the molecules have also been calculated. NBO analysis has been calculated in order to elucidate the intramolecular, rehybridization and delocalization of electron density and investigation. The electronic spectra of the new derivatives in solvent water were performed by the time-dependent DFT (TD-DFT) method. FT-IR, NMR and UV/Vis absorption spectra of the complexes were measured and discussed.

In the given research, the molecular structures of the two new benzo[d]oxazole derivatives including H-1 and H-2: have been studied with the use of density functional theory (DFT/B3LYP and M062X) in dimethylformamide (DMF) for the first time. The electronic spectra of the new compounds in a DMF solvent were carried out by temporally dependent density functional theory (TD-DFT) method. The computed absorption spectral data of the title compounds are in good agreement with the experimental data, thus allowing an assignment of the UV/Vis spectra. The equilibrium geometry, the HOMO and LUMO molecular orbitals, excitation energies, oscillator strengths and Natural Bond Orbital (NBO) analysis for the two new molecules have also been calculated and presented. Based on polyvinyl alcohol (PVA) and synthesized molecules polarizers for UV/Vis region of the spectrum have been developed.

Background: In the present study, the interaction between new drug Rubraca and CNT(4,4-8) nanotube by Density Functional Theory (DFT) calculations in an aqueous medium for first time have been investigated. Method and Results: According to calculations, the intermolecular hydrogen bonds take place between active positions of the molecule Rubraca and hydrogen atoms of the nanotube that plays an important role in the stability of the complex CNT(4,4- 8)/Rubraca. The non-bonded interaction effects of the molecule Rubraca with CNT(4,4- 8) nanotube on the electronic properties, chemical shift tensors and natural charge have been also detected. The natural bond orbital (NBO) analysis suggested that the molecule Rubraca as an electron donor and the CNT(4,4-8) nanotube plays the role an electron acceptor at the complex CNT(4,4-8)/Rubraca. The electronic spectra of the Rubraca drug and the complex CNT(4,4-8)/Rubraca were also calculated by Time Dependent Density Functional Theory (TD-DFT) for the investigation of adsorption effect of the Rubraca drug over nanotube. Conclusion: The use of CNT(4,4-8) nanotube for Rubraca delivery to the diseased cells have been established.

In the present work, the quantum theoretical calculations of the molecular structures of the three newly synthesized azomethine dyes: have been predicted using Density Functional Theory (DFT) in solvent dimethylformamide (DMF). The geometries of the azomethine dyes were optimized using the PBE1PBE/6-31+G level of the theory. In addition, the electronic spectra of these compounds in solvent DMF were carried out using the TDPBE1PBE, TDPBEPBE, TDB3LYP methods with 6-31G, 6-31+G, 6-31+G*, 6-31++G* basis sets. After quantum-chemical calculations three new azomethine dyes for optoelectronic applications were synthesized. Based on polyvinyl alcohol (PVA) and the new synthesized azomethine dyes polarizing films for UV/Vis regions of the spectrum were developed. The main optical parameters of polarizing PVA-films (Transmittance and Polarization Efficiency) have been measured and discussed. Anisotropy of electrical and thermal conductivity of the PVA-films has been investigated.

The adsorption of OCN − (cyanato anion) on boron nitride (B 12 N 12 and B 16 N 16 ) and boron phosphide nano-cages (B 12 P 12 and B 16 P 16 ) in terms of energetic, geometric, and electronic properties are studied using density functional theory calculations. Our study results indicated that the first OCN − strongly prefers to be adsorbed from its N atom upon B atoms of the nano-cages than the O atoms of OCN − . These findings have been rationalized using frontier molecular orbitals and total electron density plots. The energy gap of the B 12 P 12 is significantly reduced upon the adsorption of OCN − compared to B 12 N 12 , thus leading to the increase in electrical conductance of nano-cage.

The unique structure of adamantane is reflected in its highly unusual physical and chemical properties, which can have many applications including drug design and drug delivery. Tripeptide Tyr-Aaa-Gly is methionine-enkephalin analogues [Aaa = (R,S)-(1-adamantyl)glycine]. In this research, according to Quantum-mechanical calculations nuclear, shielding parameters of Tripeptide Tyr-AaaGly, such as chemical shift isotropic value (σ iso ) and the anisotropy shielding (σ aniso , ∆σ), and other parameter such as δ, ρ and atomic charge water have been taken into account using GIAO method at the HF method with the 3-21G, 6-31G and 6-31G* basis sets and at the B3LYP method with the 3-21G, 6-31G and STO-3G basis sets in the gas phase and in different solvents such as, DMSO, methanol, ethanol and dichloromethane.

M@Si/Al (where M = Mn(III), Co(II) and Fe(III) supported on nanosized SiO2/Al2O3) is applied as an efficient, highly reusable and heterogeneous catalyst for the regiospecific synthesis of 1-aryl-5-amino-1H-tetrazole in dimethylformamide (DMF) as a solvent. The arylaminotetrazoles were efficiently synthesized from the reaction of cyanamides and sodium azide in the presence of a catalytic amount of nano metal catalyst under thermal conditions. 1-Aryl-5-amino-1H-tetrazoles (B isomer) can be obtained from the arylcyanamides carrying electron releasing substituents on the aryl ring, while with electron withdrawing groups, 5-arylamino-1H-tetrazole (A isomer) will be obtained. The advantages of this method include high yields, relatively short reaction times, easy work-up, recovery and reusability of the catalyst and high TON of catalyst. The nano catalyst can be easily recovered and reused several times without considerable loss of activity. The quantum theoretical calculations for the synthesized components were performed by density functional theory (DFT) methods using the 6-31G basis set, geometry and thermodynamic parameters, frontier molecular orbitals (FMOs) as well as by using molecular electrostatic potentials (MEPs).

The density functional theory (DFT) calculations at the level of B3LYP/6-31G was carried out on the structure 4(5)-Imidazole-carbaldehyde-N(5)-phenylthiosemicarbazone (ImTPh) in gas phase using Gaussian 03. Dipole moment (Debye), energy of structure formation (HF; kcal/mol) and point group, NMR parameters such as isotropic shielding (σ iso ) and anisotropic shielding (σ aniso ), σ 11 , σ 22 and σ33 obtained. Also thermodynamic properties and natural bond orbitals (NBO) were calculated. Besides, the frontier molecular orbital (FMO) analysis and the molecular electrostatic potential (MEP) of the compound were investigated by theoretical calculations.

In the given research, the molecular structures of the four new azomethine compounds: have been studied with the use of density functional theory (DFT/RPBE1PBE/MidiX) in dimethylformamide (DMF) for the first time. The electronic spectra of the new compounds in a DMF solvent were carried out by temporally dependent density functional theory (TD-DFT) method. The computed absorption spectral data of the title compounds are in good agreement with the experimental data, thus allowing an assignment of the UV/Vis spectra. The equilibrium geometry, the HOMO and LUMO molecular orbitals, excitation energies, oscillator strengths for the molecules have also been calculated and presented. FT-IR spectra of the title molecules are recorded and discussed. On the basis of polyvinyl alcohol (PVA) and synthesized molecules polarizer for UV/Vis region of the spectrum has been developed.

The strength of the O-H···O hydrogen bridge in acetylacetone (AA) and acetylacetone derivatives is depending on the nature and size of the substitute groups and on the substitution position. We investigated the effect of electron-pull and electron-donor substitute on the formation of intramolecular hydrogen bonding at 3-substituted acetylacetone derivatives such as nitroacetylacetone (NAA) and methylacetylacetone (MAA). In this research NAA and MAA structures were fully optimized with B3LYP/6-31G*, 6-31G** and 6-311G**. From the electronic data we found that intramolecular hydrogen bonding in NAA is stronger than MAA.