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.

INVESTIGASI EKSTRAK BAHAN ALAM SEBAGAI INHIBITOR KOROSI HIJAU PADA BAJA MENGGUNAKAN TEORI FUNGSIONAL KERAPATAN

Salah satu material yang ketahanannya terhadap korosi rendah adalah baja ketika berinteraksi dengan lingkungan korosif. Penggunaan green inhibitor mampu memberikan kinerja penghambatan korosi yang baik dengan efisiensi inhibisi yang tinggi pada baja. Green inhibitor yang dalam struktur senyawanya mengandung gugus heteroatom (seperti O, N, S, P) dan cincin aromatik efisien digunakan sebagai inhibitor korosi pada baja. Makalah ini memberikan tinjauan komparatif penting bagi pengembangan green inhibitor ekstrak bahan alam pada baja. Kajian DFT pada level atomik berdasarkan orbital molekuler, parameter kuantum kimia, dan karakteristik adsorpsi menunjukkan hasil yang sesuai dengan hasil eksperimen. Distribusi kerapatan elektron melalui plot Frontier Molecular Orbitals (FMO) menggambarkan prediksi situs aktif melalui distribusi daerah HOMO-LUMO molekul inhibitor yang berinteraksi dengan permukaan baja. Untuk mendapatkan korelasi antara sifat elektronik molekul inhibitor dengan potensi penghambatan (inhibisi) korosi, kalkulasi parameter kimia kuantum seperti potensial ionisasi (I), afinitas elektron (A), kekerasan global (η), elektronegativitas absolut (χ), kelembutan global (σ), fraksi elektron yang ditransfer (ΔN), elektrofilisitas global (ɷ) dan donasi balik elektron (ΔEback-donation) menunjukkan reaktivitas molekul inhibitor yang berpotensi sangat baik untuk dapat berinteraksi dan berikatan kuat dengan permukaan logam, sehingga berpotensi menghasilkan efisiensi inhibisi yang tinggi. Mekanisme inhibisi korosi dapat melalui adsorpsi kimia dan/atau adsorpsi fisika dengan membentuk senyawa kompleks antara molekul inhibitor dengan permukaan baja untuk melindungi dari lingkungan korosif. Pengembangan kajian ke depan harus dapat menampilkan mekanisme interaksi dan inhibisi dari molekul inhibitor secara lebih detail dan sistematis pada level atomik pada beberapa permukaan logam seperti Fe, Al, Cu, dan lainnya.

Crystal structure, DFT and Hirshfeld surface analysis of N-acetyl-t-3-methyl-r-2,c-6-diphenylpiperidine

In the title compound [systematic name: 1-(3-methyl-2,6-diphenylpiperidin-1-yl)ethanone], C20H23NO, the piperidine ring adopts a distorted boat conformation, while the phenyl rings subtend a dihedral angle 65.1 (2)°. In the crystal, molecules are linked by C—H...O hydrogen bonds into chains extending along the b-axis direction. The DFT/B3LYP/6–311 G(d,p) method was used to determine the HOMO–LUMO energy levels. A Hirshfeld surface analysis was conducted to verify the contributions of the different intermolecular interactions, indicating that the important contributions to the crystal packing are from H...H (73.2%), C...H (18.4%) and O...H (8.4%) interactions.

On the Spectroscopic Analyses of Polytetrafluoroethylene Coated with Nano ZnO and SiO2

On polytetrafluoroethylene (PTFE) polymer nanocomposites coated with basically two metal oxides (MOs), SiO2 and ZnO, as well as a mixture of the two MOs, density functional theory (DFT) computations were performed. The B3LYPL/LAN2DZ model was used to evaluate PTFE polymer nano composites suggested model structures. The physical and electrical properties of PTFE modified on surface with ZnO and SiO2 coated layer by layer change Total dipole moment (TDM) and HOMO/LUMO band gap energy ∆Eto be 13.0082 Debye and 0.6889 eV, respectively. Moreover, TDM and band gap energy (∆E) improved to 10.6053 Debye and 0.2727 eV, respectively, when the nanofiller was increased to 8 atoms. In addition, the results of the Molecular Electrostatic Potential (MESP) and the Quantitative Structure Activity Relationship (QSAR) showed that PTFE coated with ZnO and SiO2 improved electrical characteristics and thermal stability. As PTFE coated with ZnO and SiO2 layer by layer, all stability characteristics, including electrical and thermal stability, were enhanced. The improved PTFE can be used as a corrosion-inhibiting layer for astronaut suits, according to the predicted results.

Structures, electronic and thermodynamic properties of NiB2n (n=7-11) and their anions: A theoretical study

Based on the Crystal structure Analysis by Particle Swarm Optimization (CALYPSO) searching method and density functional theory (DFT), theoretical studies about structures, electronic and thermodynamic properties have been investigated systematically at the TPSSh/6-311+G(d) level for NiB2n0/- (n=7-11) clusters. Results found that the lowest energy structures possess a Ni atom-centered double ring tubular boron structures, NiB180/- except. Relative stabilities were analyzed via computing their vertical ionization potentials (VIP), vertical electronic affinity (VEA), adiabatic electronic affinity (AEA), HOMO-LUMO gaps and hardness. The infrared spectra, Raman spectra and photoelectron spectra were computationally simulated to facilitate their experimental characterizations. At last, aromatic properties (Nucleus independent chemical shift) and thermodynamic properties (enthalpy and entropy) with temperature were discussed in detailed for studied systems.

Deconstructive Cycloaromatization Strategy towards N,O-Bidentate Ligands and Their Four-Coordinate Organoboron Complexes

The innovative construction of novel N,O-bidentate ligands and N,O π-conjugated four-coordinate organoboron complexes represent a long-standing challenge for chemists. Here, we report an unprecedented and straightforward approach for the construction of N,O-bidentate ligands and their organoboron complexes via the merge of ring deconstruction with cycloaromatization of indolizines and cyclopropenones. Without any catalysts, our method is able to deliver a series of polyaryl 2-(pyridin-2-yl)phenol ligands, N,O π-conjugated organoboron (BF2 and BAr2) complexes with good functional-group compatibility which are difficult or even impossible to synthesize with previous methods. Importantly, the formed N,O-bidentate ligands were easy to scale up and derive with valuable drugs and active molecules. In addition, the photoluminescence measurements and the HOMO/LUMO gap have been investigated, the results have revealed that N,O π-conjugated tetracoordinate boron complexes display bright fluorescence, large Stokes shifts, and good quantum yields (Φlum = 0.15–0.45). The method proposed by the paper will inspire the development of various N,O-bidentate metal and boron complexes, which is expected to move the area of catalysis chemistry and material science forward.

DFT Study on the Substituent Effect of Anticancer Picoline-Diazido-Pt(IV) Compounds

The geometric structure of azido Pt(IV) compounds containing picoline was calculated by using density functional theory(DFT) at the LSDA/SDD level. The ESP distribution shows the possible reaction sites of the compounds. In addition, the frequency calculation results assigned the infrared spectra of these compounds, and specified important stretching and bending vibrations. The HOMO-LUMO energy gaps of these compounds are also calculated to explain the charge transfer of the molecules. The distribution of Mulliken charges and natural atomic charges of these atoms is also calculated. Natural bond orbital(NBO) analysis explains the intramolecular interactions and their electron density.

Prediction of heptagonal bipyramidal nonacoordination in highly viable [OB-M©B7O7-BO]− (M = Fe, Ru, Os) complexes

Non-spherical distributions of ligand atoms in coordination complexes are generally unfavorable due to higher repulsion than for spherical distributions. To the best of our knowledge, non-spherical heptagonal bipyramidal nonacoordination is hitherto unreported, because of extremely high repulsion among seven equatorial ligand atoms. Herein, we report the computational prediction of such nonacoordination, which is constructed by the synergetic coordination of an equatorial hepta-dentate centripetal ligand (B7O7) and two axial mono-dentate ligands (-BO) in the gear-like mono-anionic complexes [OB-M©B7O7-BO]– (M = Fe, Ru, Os). The high repulsion among seven equatorial ligand B atoms has been compensated by the strong B–O bonding. These complexes are the dynamically stable (up to 1500 K) global energy minima with the HOMO-LUMO gaps of 7.15 to 7.42 eV and first vertical detachment energies of 6.14 to 6.66 eV (being very high for anions), suggesting their high probability for experimental realization in both gas-phase and condensed phases. The high stability stems geometrically from the surrounded outer-shell oxygen atoms and electronically from meeting the 18e rule as well as possessing the σ + π + δ triple aromaticity. Remarkably, the ligand-metal interactions are governed not by the familiar donation and backdonation interactions, but by the electrostatic interactions and electron-sharing bonding.

Single excitation energies obtained from the ensemble HOMO-LUMO gap: exact results and approximations

In calculations based on density functional theory, the "HOMO-LUMO gap" (difference between the highest occupied and lowest unoccupied molecular orbital energies) is often used as a low-cost, ad hoc approximation for the lowest excitation energy. Here we show that a simple correction based on rigorous ensemble density functional theory makes the HOMO-LUMO gap exact, in principle, and significantly more accurate, in practice. The introduced perturbative ensemble density functional theory approach predicts different and useful values for singlet-singlet and singlet-triplet excitations, using semi-local and hybrid approximations. Excitation energies are of similar quality to time-dependent density functional theory, especially at high fractions of exact exchange. It therefore offers an easy-to-implement and low-cost route to robust prediction of molecular excitation energies.