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In this research, a DFT calculation was performed for study to investigate the encapsulation of the anticancer drug Ibrance into CNT(8,8-7) by using M062X/6-311G* level of theory in the solvent water. TD-DFT method was used to compute the electronic spectra of the Ibrance drug, CNT(8,8-7) and complex CNT(8,8-7)/Ibrance in aqueous medium for the study of non-bonded interaction effect. The non-bonded interaction effects of Ibrance drug with CNT(8,8-7) on the electronic properties and natural charges have been also studied. The results display the change in title parameters after process adsorption. According to NBO results, the molecule Ibrance and CNT(8,8-7) play as both electron donor and acceptor at the complex CNT(8,8-7)/Ibrance. Charge transfer, on the other hand, occurs between the bonding, antibonding, or nonbonding orbitals of Ibrance drug and CNT (8,8-7). According to QTAIM analysis and the LOL and ELF values, all intermolecular bonds in the complex are non-covalent in nature. As a result, CNT(8,8-7) can be thought of as a drug delivery system for transporting Ibrance as an anticancer drug within biological systems. [ABSTRACT FROM AUTHOR]

The adsorption of Doxepin (DOX) drug on the surfaces of B12N12 and Al12N12 nanoclusters was studied by using DFT and TD-DFT calculations at the B3PW91 method and 6–31 + G* basis set in the solvent (water). The adsorption effect of the DOX drug on the bond lengths, electronic properties, and dipole moment of the B12N12 and Al12N12 nanoclusters was studied. The change in λmax was assessed by an investigation of calculated UV spectra. NBO analysis displayed a charge transfer between DOX and two nanoclusters. The LOL and ELF values of the B–N bond are the greater than B–O, Al–O, and Al–N bonds, confirming stronger interaction between the boron atom of B12N12 nanocluster and the nitrogen atom of the DOX drug. It is found that the B12N12 nanocluster can be suitable as a drug carrier system for the delivery of DOX drug. The results of our study can be used to design a suitable carrier for the DOX drug. [ABSTRACT FROM AUTHOR]

Abstract In this work, density functional theory (DFT) calculations were performed to investigate the complex formation ability of Meso-2,3-dimercaptosuccinic acid (DMSA) with metal ions (Cd2+, Hg2+ and Pb2+) in water. The binding energy values and thermodynamic parameters have been calculated. Natural bond orbital and charge decomposition analyses show an effective charge transfer from the oxygen and sulfur atoms of the DMSA to metal ions. Quantum theory of atoms in molecules analysis reveals that the covalent interactions between DMSA and Pb2+ are the driving force in complex formation, while the non-covalent interactions, mainly, electrostatic interactions play an important role in the complex formation of the DMSA with Cd2+ and Hg2+. Finally, The electronic properties such as highest occupied molecular orbital, lowest unoccupied molecular orbital energies, electronic chemical hardness, electronic chemical potential and global electrophilicity were calculated to get a better insight of molecular properties. Graphical abstract Image Highlights • Charge transfer and stability of [Cd-DMSA], [Hg-DMSA] and [Pb-DMSA] complexes were studied theoretically. • [Pb-DMSA] is the more stable complex than the other complexes. • Charge transfer occurs from the oxygen and sulfur atoms of DMSA to the metal ions. • QTAIM, ELF and LOL analyses confirm that the strongest metal-DMSA interactions are related to [Pb-DMSA] complex. [ABSTRACT FROM AUTHOR]

Nowadays, 3-hydroxypyridine-4-ones (HPOs) as orally active iron chelators have been introduced for the treatment of disorders associated with iron such as iron overload in thalassemia patients. In this work, a density functional theory (DFT) study was performed on a series of HPOs constituted of the different substitutions at the different positions. Structural analysis indicates that all of the HPO derivatives bind to Fe 3+ as a two-dentate mode through the oxygen atoms of the C = O groups. It is confirmed that the HPO derivative composed of three methyl groups at the different positions (3-hydroxy-1,2,5-trimethyl-4(1H) pyridinone) forms the most stable complex with Fe 3+ . Therefore, this HPO derivative acts as a better iron chelator than other ones. The vibrational frequency analysis reveals a correlation between the iron affinity constant and C = O vibrational frequency of the HPOs. Donor-acceptor interactions show an effective charge transfer from the oxygen atoms of the HPOs towards Fe 3+ . Quantum theory of atoms in molecules analysis shows the non-covalent interactions, mainly, electrostatic interactions play an important role in the complex formation of the HPOs and Fe 3+ . Finally, some linear correlations between the electron densities of the Fe − O chemical bond and interaction energy values, the vibrational frequency of the C = O bonds and electron densities of the Fe − O chemical bond were obtained and analyzed. [ABSTRACT FROM AUTHOR]

Boron-based nanocomposites considered as one of the most promising photocatalysts, have drawn significant attention in the degradation of pollutants in aquatic environments. In this regard, density functional theory calculations were carried out on the B 12 N 12 nanocluster interacted with various lengths of (PPy) n oligomers (n = 3, 5, 7, and 9) to predict the optical, electronic, charge transfer properties as well as the optimum composition of obtained (PPy) n /B 12 N 12 nanocomposites. It was found that the most stable nanocomposite corresponds to (PPy) 3 /B 12 N 12 , which was supported by its greatest adsorption energy (−59.460 kcal mol−1) in the gas phase. The calculations in the gas phase and water showed that water as a solvent has a key role in the interaction between B 12 N 12 nanocluster and (PPy) n oligomers. The results revealed that the adsorption of (PPy) 9 oligomer on the B 12 N 12 nanocluster leads to the highest reduction (∼ 2.672 eV) in the energy gap (E g) value, while the lowest reduction (∼ 1.475 eV) was related to (PPy) 3 /B 12 N 12 nanocomposite. Moreover, the natural bond orbital analysis showed that the charge flows from (PPy) n oligomers to the B 12 N 12 nanocluster. Polarizability (α 0) and first hyperpolarizability (β 0) values revealed that the adsorption of (PPy) 9 oligomer on the surface of B 12 N 12 nanocluster has the most considerable effect on the optical response of B 12 N 12 nanocluster due to increasing the α 0 and β 0 values about 492.49 and 5070.07 a.u, respectively. The UV–Vis spectra analysis showed that the (PPy) 9 /B 12 N 12 nanocomposite has the highest bathochromic shift (∼ 245.39 nm) among other nanocomposites. Finally, quantum theory of atoms in molecules analysis showed that (PPy) n oligomers interact with B 12 N 12 nanocluster through the partial covalent interactions. [Display omitted] • DFT method was employed to development of novel (PPy) n /B 12 N 12 nanocomposites for photocatalytic applications. • The photocatalytic activities of B 12 N 12 doped with polypyrole were improved. • (PPy) 9 -doped B 12 N 12 shows the most remarkable photocatalytic activities. • (PPy) n /B 12 N 12 nanocomposites can be used in optoelectronic devices. [ABSTRACT FROM AUTHOR]

The interaction of Fe3+ with blood proteins is very important because it leads to understanding the detrimental effect in biological processes. Molecular dynamic (MD) simulations and quantum chemistry calculations were performed to investigate the complex formation between the human serum albumin (HSA) and Fe3+. MD simulation results predict two binding sites (BSs) of HSA for complex formation including Glu-Arg-Asn-Glu-Cys (BS1) and Lys-Glu-Cys-Cys-Glu-Lys (BS2) amino acids. To investigate the interaction of the corresponding binding sites with Fe3+, quantum chemistry calculations were performed at M06-2X/6-31G(d) level in the water. According to density functional theory calculations, binding constant of Fe3+ to human serum albumin in BS1 (log K = 13.33) is lower than that of BS2 (log K = 18.99), showing higher thermodynamic stability of the HSA Fe3+ complex in BS2. Natural bond orbital and quantum theory of atoms in molecules analyses demonstrate that the driving force of the complex formation is electrostatic and partially covalent interactions. The results of this research would be valuable to design a suitable iron-chelating agent for the treatment of iron overload. Unlabelled Image • MD/QM simulations were performed to determine the binding site of HSA against Fe3+. • Glu in comparison to other amino acids of HSA structure has a greater interaction with Fe3+. • HSA has two more probable binding sites for complexation with Fe3+. • Molecular topology confirmed the electrostatic and partially covalent interactions. [ABSTRACT FROM AUTHOR]