Boron Nitride Nanotubes for Curcumin Delivery as an Anticancer Drug: A DFT Investigation

The electrical properties and characteristics of the armchair boron nitride nanotube (BNNT) that interacts with the curcumin molecule as an anticancer drug were studied using ab initio calculations based on density functional theory (DFT). In this study, a (5,5) armchair BNNT was employed, and two different interactions were investigated, including the interaction of the curcumin molecule with the outer and inner surfaces of the BNNT. The adsorption of curcumin molecules on the investigated BNNT inside the surface is a more favorable process than adsorption on the outside surface, and the more persistent and stronger connection correlates with curcumin molecule adsorption in this case. Furthermore, analysis of the HOMO–LUMO gap after the adsorption process showed that the HOMO value increased marginally while the LUMO value decreased dramatically in the curcumin-BNNT complexes. As a result, the energy gaps between HOMO and LUMO (Eg) are narrowed, emphasizing the stronger intermolecular bonds. As a result, BNNTs can be employed as a drug carrier in biological systems to transport curcumin, an anticancer medication, and thereby improve its bioavailability.

Theoretical studies on the two-photon absorption of II–VI semiconductor nano clusters

Semiconductor clusters, ZnnOn, ZnnSn, and CdnSn (n = 2–8), were optimized and the corresponding stable structures were acquired. The symmetry, bond length, bond angle, and energy gap between HOMO and LUMO were analyzed. According to reasonable calculation and comparative analysis for small clusters Zn2O2, Zn2S2, and Cd2S2, an effective method based on density function theory (DFT) and basis set which lay the foundation for the calculation of the large clusters have been obtained. The two-photon absorption (TPA) results show that for the nano clusters with planar configuration, sizes play important role on the TPA cross section, while symmetries determine the TPA cross section under circumstance of 3D stable structures. All our conclusions provide theoretical support for the development of related experiments.

Crystal structure, Hirshfeld surface analysis, and DFT studies of N-(2-chlorophenylcarbamothioyl)cyclohexanecarboxamide

N-(2-Chlorophenylcarbamothioyl)cyclohexanecarboxamide was characterized by a single crystal X-ray diffraction study. Crystal data for this compound, C14H17ClN2OS; Monoclinic, space group P21/n with Z = 4, a = 5.2385(10) Å, b = 17.902(4) Å, c = 15.021(3) Å, β = 90.86(3)°, V = 1408.5(5) Å3, T = 153(2) K, μ(MoKα) = 0.413 mm-1, Dcalc = 1.400 g/cm3, 9840 reflections measured (7.082° ≤ 2Θ ≤ 50.378°), 2519 unique (Rint = 0.0406, Rsigma = 0.0335) which were used in all calculations. The final R1 was 0.0397 (I > 2σ(I)) and wR2 was 0.0887 (all data). The puckering parameters (q2 = 0.019(3) Å, q3 = 0.578(3) Å, θ = 1.0(3)° and φ = 51(8)°) of the title compound show that the cyclohexane ring adopts a chair conformation. The molecular conformation of the title compound is stabilized by intramolecular hydrogen bonds (N2-H2⋅⋅⋅Cl1, N2-H2⋅⋅⋅O1, and C2-H2A⋅⋅⋅S1) and intermolecular hydrogen bonds (N1-H1⋅⋅⋅S1i and C9-HA⋅⋅⋅S1ii: 2-x, 2-y, 1-z). The intramolecular hydrogen bonds (N2-H2⋅⋅⋅O1 and C2-H2A⋅⋅⋅S1) are also form two pseudo-six-membered rings. Density functional theory optimized structure in the gaseous phase at B3LYP/6-311G(d,p) level of theory has been compared with the experimentally defined molecular structure. The molecular orbitals HOMO and LUMO with the energy gap for the title compound are calculated and the estimated energy gap (ΔE) between the HOMO and LUMO energies levels of the title compound is 3.5399 eV, which implies that the title molecule is very reactive. The Hirshfeld surface analysis reveals that the most important contributions to crystal packing are from H···H (49.0%), H···C/C···H (12.5%), H···Cl/Cl···H (10.9%), and H···S/S···H (10.0%) interactions. The energy-framework calculations are used to analyze and visualize the three-dimensional topology of the crystal packing. The intermolecular energy analysis confirmed a significant contribution of dispersion to the stabilization of molecular packings in the title compound.

GEOMETRY OPTIMIZATION OF COUPLING ALLIN -METFORMIN USING DFT/B3LYP MOLECULAR MODELLING TECHNIQUE

This researchpaper includes the incorporation of Alliin at various energy levels and angles With Metformin using Gaussian 09 and Gaussian view 06. Two computers were used in this work. Samples were generated to draw, integrate, simulate and measure the value of the potential energy surface by means of which the lowest energy value was (-1227.408au). The best correlation compound was achieved between Alliin and Metformin through the low energy values where the best place for metformin to bind was through (CH2-). This is considered to be very useful for the industrial application of drugs. This level of calculation was used for physical and quantum properties such as total energy, HOMO and LUMO orbitals energies, and power gap. Besides, the calculation of FT-IR spectra in the range 400-4000 cm-1 was calculated in addition to the essential vibrational frequencies and the intensity of the vibrational bands. Moreover, the chemical displacement of the 1H and 13C NMR of the compound in the ground state was studied.

Fluorescent Indolo[2,3-b]quinoxalin-2-yl)(Phenyl)methanone Dyes: Photophysical, Aie Activity, Electrochemical, and Theoretical Studies

Herein, we have synthesized four indolo[2,3-b]quinoxalin-2-yl)(phenyl)methanone derivatives 1−4 by cyclocondensation. The photophysical studies of dyes in various solvents and neat solid film exhibit typical electronic spectra with inbuilt intramolecular charge transfer (ICT) (λmax: 397‒490 nm) confirming donor-acceptor architecture. Herein, dyes fluoresce in the blue-orange region (λEmax: 435–614) on excitation at their ICT maxima in toluene, ethyl acetate, chloroform, DMSO, and neat solid film. 1 and 2 which exhibit good emission intensity in all mediums, were studied for aggregation-induced emission (AIE) effect. Electrochemical studies indicate 1−4 possess relatively low lying LUMO (‒3.65 to ‒3.98 eV) comparable to reported n-type/electron-transporting materials. The HOMO and LUMO energy levels in 1−4 were evaluated by DFT and TD-DFT calculations. TGA analysis shows 1−4 exhibit good thermal stability. The characteristic optoelectronic properties and thermal stability signify these dyes are potential candidate for their application in optoelectronics.

Some Nitrogen Rich Energetic Material Synthesis by Nucleophilic Substitution Reaction from Polynitro Aromatic Compounds

Three new nitrogen-rich energetic compounds, N-(5-chloro-2,4-dinitrophenyl)hydrazine (1), N-(5-chloro-2,4-dinitrophenyl) guanidine (2) and N-(5-chloro-2,4-dinitrophenyl)-4-aminopyrazole (3) prepared by the nucleophilic substitution reaction of 1,3-dichloro-4,6-dinitrobenzene with hydrazine, guanidinium carbonate and 4-aminopyrazole. The compounds were characterized by 1H NMR, 13C NMR, IR and mass spectroscopy. Only compound 2 could be prepared in a suitable crystal and molecular model was determined by X-ray analysis. Compounds were investigated by TG and DSC. Thermal degradation and thermokinetic behavior were investigated by Ozawa–Flynn–Wall and Kissinger–Akahira–Sunose techniques. Compounds were observed to be prone to exothermical thermal decomposition. HOMO and LUMO levels, theoretical formation enthalpy and electrostatic maps were calculated by Gaussian09. The detonation velocity and pressure were calculated by Kamlet–Jacobs equation. The compounds were assayed for antimicrobial properties.

Influence of Structural, Electronic and Spin Properties of ND[NV] - Surface Group Conjugates on Formation of Their Biological Activity: Quantum Chemical Simulations

To estimate possible biological activity of conjugates based on nanodiamond with an NV center inside (ND[NV]), with various functional groups located on its surface, their structural, electronic, and spin properties were calculated using the PM6 method. The energy gap between HOMO and LUMO of the complex was used as a main indicator of biological activity. It has been shown that complexes with OH or H groups attached to the (111) surface are most stable in an aqueous medium. Analysis of spin density and HOMO and LUMO localization shows that complexes ND[NV] may be not just an inert carrier of a biologically active drug or means of visualizing drug delivery, but are also directly involved in the formation of the biological activity of the conjugate.

Electronic and structural features of uranium-doped graphene: DFT study

Electronic and structural features of uranium-doped models of graphene (UG) were investigated in this work by employing the density functional theory (DFT) approach. Three sizes of models were investigated based on the numbers of surrounding layers around the central U-doped region including UG1, UG2, and UG3. In this regard, stabilized structures were obtained and their electronic molecular orbital features were evaluated, accordingly. The results indicated that the stabilized structures could be obtained, in which their electronic features are indeed size-dependent. The conductivity feature was expected at a higher level for the UG3 model whereas that of the UG1 model was at a lower level. Energy levels of the highest occupied and the lowest unoccupied molecular orbitals (HOMO and LUMO) were indeed the evidence of such achievement for electronic conductivity features. As a consequence, the model size of UG could determine its electronic feature providing it for specified applications.

Structure-Property Relationships in Benzofurazan Derivatives: A Combined Experimental and DFT/TD-DFT Investigation

In this work we seek to understand and to quantify the reactivity of benzofurazan derivatives toward secondary cyclic amines, like pyrrolidine, piperidine and morpholine, acting as nucleophile groups in SNAr reactions. For this aim, physico-chemical and structural descriptors were determined experimentally and theoretically using the DFT/B3LYP/6-31+ g (d,p) methodology. Thus, different 4-X-7-nitrobenzofurazans (X = OCH3, OC6H5 and Cl) and products corresponding to the electrophilic aromatic substitution by pyrrolidine, piperidine and morpholine, were investigated. Particularly, the HOMO and LUMO energy levels of the studied compounds, determined by Cyclic Voltammetry (CV) and DFT calculations, were used to evaluate the electrophilicity index (ω). The latter was exploited, according to Parr’s approach, to develop a relationship which rationalizes the kinetic data previously reported for the reactions of the 4-X-7-nitrobenzofurazans with nucleophiles cited above. Moreover, the Parr’s electrophilicity index (ω) of these benzofurazans determined in this work were combined with their electrophilicity parameters (E), reported in preceding papers, was found to predict the unknown electrophilicity parameters E of 4-piperidino, 4-morpholino and 4-pyrrolidino-7-nitrobenzofurazan. In addition, the relationship between the Parr’s electrophilicity index (ω) and Hammett constants σ, has been used as a good model to predict the electronic effect of the nucleophile groups. Finally, we will subsequently compare the electrophilicity index (ω) and the electrophilicity parameters (E) of these series of 7-X-4-nitrobenzofurazans with the calculated dipole moment (μ) in order to elucidate general relationships between E, ω and μ.

Physicochemical Characterization of the Loganic Acid–IR, Raman, UV-Vis and Luminescence Spectra Analyzed in Terms of Quantum Chemical DFT Approach

The molecular structure and vibrational spectra of loganic acid (LA) were calculated using B3LYP density functional theory, the 6–311G(2d,2p) basis set, and the GAUSSIAN 03W program. The solid-phase FTIR and FT-Raman spectra of LA were recorded in the 100–4000 cm−1 range. The assignment of the observed bands to the respective normal modes was proposed on the basis of the PED approach. The stability of the LA molecule was considered using NBO analysis. The electron absorption and luminescence spectra were measured and discussed in terms of the calculated singlet, triplet, HOMO, and LUMO electron energies. The Stokes shift derived from the optical spectra was 20,915 cm−1.