Damghan UniversityJournal of Nano Simulation3092-77221120250601Investigating variability in PLGA monomers: A comparative study of electronic properties and their role in drug delivery systems1849210.22128/jons.2025.964.1001ENLaleh KhorshidiDepartment of Physical Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran0000-0002-7126-4551Davood FarmanzadehDepartment of Physical Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, IranSima EsmailpourFaculty of Chemistry, Shahrood University of Technology, Shahrood, IranJournal Article20250220PLGA (poly(lactic-co-glycolic) acid) is a biodegradable copolymer commonly used in drug delivery. It is composed of monomers X and Y, which influence its physical and chemical properties. Incorporating hydrophilic polymers like polyethylene glycol (PEG) into PLGA enhances the circulation half-life of nanoparticles. This study employs computational methods to investigate how variations in the number and arrangement of monomers X and Y, as well as PEG integration, affect PLGA’s properties. Using Density Functional Theory (DFT) calculations, we analyze several physicochemical characteristics, including the energy gap and dipole moment. Our results show that PEG incorporation reduces the energy gap, with configurations like XYXX-PEG-XYXX and XXYYY emerging as promising drug carrier candidates. Furthermore, an increased ratio of X to Y generally elevates the dipole moment, particularly with PEG present, which improves the dipole moment further. Noncovalent interaction analysis indicates that certain PLGA monomers may exhibit beneficial van der Waals interactions, enhancing the sustained release of therapeutic agents.https://jons.du.ac.ir/article_492_147f6ab3c025d12aae7b8184210a9328.pdfDamghan UniversityJournal of Nano Simulation3092-77221120250601Intramolecular hydrogen bond and tautomeric stability of 5-Bromo-salicylideneiminpo-ethylimino-pentan-2-one91549310.22128/jons.2025.951.1000ENVahidreza DarugarDepartment of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Iran0000-0003-4901-9389Mahmood AkbariUNESCO-UNISA-ITL/NRF Africa Chair in Nanoscience and Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P.O. Box 392, Pretoria, South AfricaAli Reza BerenjiDepartment of Chemistry, Faculty of Science, University of Gonabad, Gonabad 96919, Iran0000-0003-3488-760XJournal Article20250311The tautomerism and intramolecular hydrogen bond of 5-Bromo-salicylideneimino-ethylimino-pentan-2-one (BrSEIPO) was studied by theoretical method. The tautomeric mole fraction calculations show that the L4 and L3 forms are the more stable form of SEIPO with 99.29% and 0.71% values in gas phase and for L4 form more than 67.91% in solution phase. It can be seen that with increasing the polarity of the solvent the molar fractions of two more stable forms are changed. The molar fraction of L4 and L3 forms decreases and increases, respectively Besides, the mole fraction of L3 tautomer becomes in the range from ca. 0.87% to 33.69%, while the polarity of solvent increases.By comparing the value of the geometrical results (RO…N, RN–H, O…H, θOHN), AIM results (ρBCP, ∇2ρBCP, HBCP, H-bond energy), and spectroscopic results (νNH, γNH, δOH) it can be see that the intramolecular hydrogen bonding (IHB) of BrSEIPO is stronger than that in salicylideneimino-ethylimino-pentan-2-one (SEIPO) and 4-amino-3-penten-2-one (APO).https://jons.du.ac.ir/article_493_fda6ce475e53b2ee9702dd211798df91.pdfDamghan UniversityJournal of Nano Simulation3092-77221120250601Electronic transport behavior of 4,5-bis(2,5-dimethylthiophen-3-yl)furan-2-amine (a Diarylethene) as optical molecular switch: A first-principles approach162149410.22128/jons.2025.969.1002ENAyoub Kanaani0009-0004-4414-6690Mohammad VakiliDepartment of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad 91775-1436, IranMahmood AkbariUNESCO-UNISA-ITL/NRF Africa Chair in Nanoscience and Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P.O. Box 392, Pretoria, South Africa0000-0003-1875-2721Journal Article20250303In this study, we studied the electronic transport properties of 4,5-bis(2,5-dimethylthiophen-3-yl)furan-2-amine (a Diarylethene) by nonequilibrium green's function (NEGF) joint with density functional theory (DFT). This molecule can be converted from closed-form to open form by ultraviolet irradiation or visible light. We have studied several parameters such as I–V characteristics, electronic transmission coefficients T(E), the effect of electrode materials (Au, Ag, and Pt) on electronic transport properties, on-off ratio and spatial distribution of molecular projected self-consistent Hamiltonian (MPSH) orbitals corresponding to the closed and open forms. The physical origin of switching behavior is interpreted based on the different molecular geometries, location and size of the frontier molecular orbitals and the HOMO–LUMO gap. The results showed that as the molecule changes from closed form to open form (closed → open), conductivity changes from on state (high conductivity) to off state (low conductivity). We investigated the effect of different electrodes (Ag, Au, Pt) and various connection sites (hollow, top, bridge) on conductivity.https://jons.du.ac.ir/article_494_dfa067987a80172e1946761255592577.pdfDamghan UniversityJournal of Nano Simulation3092-77221120250601Hypoxanthine: A DFT Investigation of Tautomerism and Nonlinear Optical Behavior222949510.22128/jons.2025.979.1005ENSima EsmailpourDepartment of Physical Chemistry, Faculty of Chemistry, Shahrood University of Technology, Shahrood, IranHossein NikoofardFaculty of Chemistry, Shahrood University of Technology, Shahrood, IranMohsen SargolzaeiFaculty of Chemistry, Shahrood University of Technology, Shahrood, IranJournal Article20250313This study investigates the tautomerization process of hypoxanthine using the B3LYP/6-31G(d) theoretical approach. The energy profiles derived from calculations are supplemented by kinetic rate coefficient analyses, employing transition state theory (TST). The results demonstrate that both tautomeric forms of hypoxanthine are planar, with HX1 as the more stable isomer under the studied conditions, exhibiting spontaneous and exothermic tautomerization. Kinetic analyses reveal an increased rate constant for the lactam form's formation, enhanced by tunneling effects. Transition state calculations indicate a lower energy barrier in the gas phase compared to aqueous conditions, leading to predominantly slow tautomerization rates in the absence of catalysts. Notably, both tautomers exhibit promising nonlinear optical (NLO) properties, characterized by higher hyperpolarizability relative to para-nitroaniline (pNA), even though they display lower polarizability values. Their greater dipole moments suggest potential effectiveness in NLO applications. Natural bond orbital (NBO) analysis reveals significant differences in second-order energy perturbation between HX1 and HX2, with HX1 showing reduced electron transfer from σ and π* orbitals. Additionally, the proximity of the hydroxyl group in HX2 increases perturbation energy and electron transfer, potentially contributing to the observed elongation of the C6-O10 bond length in HX1. Collectively, these tautomers represent promising candidates for further exploration in nonlinear optics.https://jons.du.ac.ir/article_495_c0eae3d5c841a8de07ae16fd0b6e3b7a.pdfDamghan UniversityJournal of Nano Simulation3092-77221120250601DFT study on interaction of triacetin with some chemical compounds in cigarette smoke304349610.22128/jons.2025.985.1006ENAbdol Hossein Masoudi GaziChemistry department of Tirtash Tobacco Research and Eduction center, Tirtash ,Iran0009-0001-9438-9349Gholam Reza Moradi RobatiChemistry department of Tirtash Tobacco Research and Eduction center, Tirtash ,IranJournal Article20250406Triacetin (1,3-Diacetyloxypropan-2-yl acetate) serves as a plasticizer in the manufacturing of cellulose acetate cigarette filters, composed of cellulose acetate fibers, plug wrap paper, hotmelt adhesive, and triacetin. Quantum chemical calculations and thermodynamic analyses were performed using Density Functional Theory (DFT) at the B3LYP level with the 6-311++G** basis set to examine triacetin's structure and its interactions with cigarette smoke chemical components. Results, corrected for intramolecular basis set superposition error (BSSE), revealed that bond formation primarily occurs through oxygen and hydrogen atoms. Among the studied complexes, triacetin exhibited the highest stability with hydrogen cyanide and the lowest stability with carbon monoxide, based on interaction energy values. All interactions showed nonspontaneous adsorption (ΔG > 0), with positive ΔH values indicating endothermic behavior for triacetin-carbon monoxide and triacetin-benzene complexes, while other interactions were exothermic (negative ΔH). Natural Bond Orbital (NBO) analysis and Quantum Theory of Atoms in Molecules (QTAIM) demonstrated covalent characteristics for C-O, C-C, and C-H bonds in triacetin, alongside van der Waals interactions in its complexes. Notably, a unique cage critical point (CCP) was observed in the triacetin-formaldehyde complex, and a dihydrogen bond was identified in the triacetin-benzene interaction. These findings enhance our understanding of triacetin’s behavior and interactions, contributing to the optimization of cigarette filter manufacturing.https://jons.du.ac.ir/article_496_c4c5b532c3b065c8a3a770921e21cf75.pdfDamghan UniversityJournal of Nano Simulation3092-77221120250601A multiscale study of Hydrogen bonding in Geminal Dicationic Ionic liquids 1,3- bis[3-methylimidazolium-1-yl]butane Halides445649710.22128/jons.2025.947.1003ENSaeid YeganegiPhysical Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran0000-0003-0603-479XAzim SoltanabadiFaculty of Chemistry, Razi University, Kermanshah, 6714414971, IranJournal Article20250304In this study, the properties of the geminal dicationic ionic liquids (DILs) 1,3- bis[3-methylimidazolium-1-yl] butane halides ([C4(mim)2][X]2, X¯ = Cl¯, Br¯ and I¯) were studied using the molecular dynamic simulation (MD) and density functional theory (DFT). The liquid structure of [C4(mim)2][X]2 (X=Cl, Br, I) was analyzed by radial distribution function(RDF), dihedral angle distribution of n-butyl side chains in the [C4(mim)2]+2 cations, distance between two rings in the [C4(mim)2]+2, spatial distribution function (SDF) and combined distribution function (CDF). The calculated RDFs show that anions spend most of their time around the hydrogens attached to the cation rings. The calculated SDFs show that the halide anions show the highest probability densities around the hydrogen atoms of the imidazolium rings. The calculated diffusion coefficients show that the diffusivities of the anions are one order of magnitude higher than that of cations and other hydrogen atoms. The effects of anion type on the diffusion coefficient were also studied. DFT calculations show that the most stable structure of the cation in the DIL is a U-shaped form, where the rings of cation bend towards each other and anions are close to the atoms of both rings. Our results show that hydrogen bonding is crucial in the interaction between the [C4(mim)2]+2 cation and anion atoms in the most stable configurations of an ion pair. These hydrogen bonds were analyzed by the atoms in molecules (AIM) and natural bond orbital (NBO) analysis. The ion pair interactions decrease with increasing the halide atomic weight.https://jons.du.ac.ir/article_497_8099fc1bf765553db38cc0275c180d8b.pdf