Spectral investigations, DFT based global reactivity descriptors, Inhibition efficiency and analysis of 5-chloro-2-nitroanisole as π-spacer with donor-acceptor variations effect for DSSCs performance

Molecular modeling analysis for functionalized graphene/sodium alginate composite

This study examined the functionalization of graphene with easily ionizable elements, such as lithium, and subsequently its interaction with the biopolymer sodium alginate (SA), to highlight its potential for biomedical applications. Utilizing Density Functional Theory (DFT), the research comprehensively investigated the structural, electronic, and spectroscopic properties of these graphene-based composites. The electronic properties of functionalized graphene were investigated using DFT at the B3LYP/6-31G(d,p) level. Among the various configurations studied, graphene exhibited weak interaction with two lithium atoms, displaying the highest reactivity in terms of total dipole moment (TDM) at 5.967 Debye and a HOMO/LUMO energy gap (ΔE) of 0.748 eV. Electrostatic potential mapping revealed that graphene when enhanced with lithium and three units of SA, exhibited an augmented potential density on its surface, a finding corroborated by other investigated physical properties. Notably, the configuration of graphene/3SA/Li, with weak interaction occurring at two side carbons, demonstrated the highest reactivity with a TDM of 15.509 Debye and ΔE of 0.280 eV. Additionally, a shift in the spectral characteristics of graphene towards lower wavenumbers was observed as lithium and SA interacted with the graphene substrate. The PDOS plot for Graphene/3SA/Li, showed the highest contribution in the HOMO orbitals was equally from lithium, sodium, hydrogen, and oxygen, while the lowest contribution was from carbon. This computational analysis provides comprehensive insights into the functionalized graphene systems, aiding in their further development and optimization for practical biomedical use.

Study of the microscopic mechanism of stepwise charge injection in co-sensitive DSSCs in the framework of a D-π-A dye and chlorophyll

The newly synthesized dye molecules TY6 and CXC22 were selected to explain the influence of anthracene and acetylene groups on the power conversion efficiency (PCE) of the molecules at the microscopic level. Theoretical simulation was carried out to understand the properties of the two molecules, including frontier molecular orbitals, absorption spectra, light absorption efficiency, intramolecular charge transfer (ICT), dye regeneration, I-V prediction, etc. The results suggest that for CXC22, adding an anthracene and acetylene group in the conjugate bridge greatly enhances the molecule's absorption wavelength and molar extinction coefficient; CXC22 also has significant advantages in the intramolecular charge transfer and comparatively better dye regeneration and electron injection. These parameters cause CXC22 to have a higher PCE. Subsequently, CXC22 and the chlorophyll molecule (CHL7) were selected for co-sensitization to regulate performance. The stable structure in the co-sensitization configuration was screened, and the absorption spectrum characteristics and charge transfer mechanisms were revealed for the co-sensitization system. The designed evaluation model predicted that the PCE of CO1 (the cosensitive system of CXC22 and TY6 in H-H configuration is referred to as CO1) could reach 16.78%. This work provides an idea for developing an efficient dye-sensitized solar cell system.

Influence of acceptors on the optical nonlinearity of 5H-4-oxa-1,6,9-trithia-cyclopenta[b]-as-indacene-based chromophores with a push-pull assembly: a DFT approach

Herein, a series of compounds (TPD1-TPD6) having a D-π-A architecture was quantum chemically designed via the structural modulation of TPR. Quantum chemical calculations were employed to gain a comprehensive insight into the structural and optoelectronic properties of the designed molecules at the M06/6-311G(d,p) level. Interestingly, all the designed chromophores displayed narrow energy gaps (2.123-1.788 eV) and wider absorption spectra (λmax = 833.619-719.709 nm) with a bathochromic shift in comparison to the reference compound (λmax = 749.602 nm and Egap = 3.177 eV). Further, Egap values were utilized to evaluate global reactivity parameters (GRPs), which indicate that all the chromophores expressed higher softness (σ = 0.134-0.559 eV-1) and lower hardness (η = 4.155-4.543 eV) values than the reference chromophore. Efficient charge transfer from donors towards acceptors was noted through FMOs, which was also supported by DOS and TDM analyses. Overall, the TPD3 derivative exhibited a remarkable reduction in the HOMO-LUMO band gap (1.788 eV) with a red shift as λmax = 833.619 nm. Furthermore, it exhibited prominent linear and non-linear characteristics such as μtotal = 24.1731 D, 〈α〉 = 2.89 × 10-22 esu, and βtotal = 7.24 × 10-27 esu, among all derivatives. The above findings revealed that significant non-linear optical materials could be achieved through structural tailoring with studied efficient acceptors.

Charge Transfer Complex between O-Phenylenediamine and 2, 3-Dichloro-5, 6-Dicyano-1, 4-Benzoquinone: Synthesis, Spectrophotometric, Characterization, Computational Analysis, and its Biological Applications

UV-vis electronic absorption spectroscopy was used to investigate the new molecular charge transfer complex (CTC) interaction between electron donor O-phenylenediamine (OPD) and electron acceptor 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ). The CTC solution state analysis was carried out by two different polarities. The stoichiometry of the prepared CTC was determined by using Job's, photometric, and conductometric titration methods and was detemined to be 1:1 in both solvents (at 298 K). The formation constant and molar extinction coefficient were determined by applying the modified (1:1) Benesi-Hildebrand equation. The thermodynamic parameter ΔG° result indicated that the charge transfer reaction was spontaneous.The stability of the synthesized CTC was evaluated by using different spectroscopic parameters like the energy, ionization potential, oscillator strength, resonance energy, dissociation energy, and transition dipole moment. The synthesized solid CTC was characterized by using different analytical methods, including elemental analysis, Fourier transform infrared, nuclear magnetic resonance, TGA-DTA, and powder X-ray diffraction. The biological evolution of the charge transfer (CT) complex was studied by using DNA binding and antibacterial analysis. The CT complex binding with calf thymus DNA through an intercalative mode was observed from UV-vis spectral study. The CT complex produced a good binding constant value (6.0 × 10⁵ L.mol^-1). The antibacterial activity of the CT complex shows notable activity compared to the standard drug, tetracycline. These results reveal that the CT complex may in future be used as a bioactive drug. The hypothetical DFT estimations of the CT complex supported the experimental studies.

Photovoltaic performance and power conversion efficiency prediction of double fence porphyrins

To explore high efficiency dye-sensitized solar cells (DSSCs), two experimentally derived (single fence and double fence porphyrins) and two theoretically designed zinc porphyrin molecules with D-D-π-A-A configurations were studied. Density functional theory and time-dependent density functional theory were employed to simulate these two experimental dyes and dye@TiO₂ systems to understand why the double fence porphyrin molecule exhibits better photovoltaic performance than the single fence porphyrin molecule. For the short-circuit current (J_SC), the various parameters that affected the experimental magnitude of J_SC were analyzed from different aspects of absorption, charge transfer and chemical parameters as well as an electron injection process. The almost equal open-circuit voltages (V_OC) in the experiment were predicted by theoretical V_OC calculations. Our model predicted power conversion efficiencies (PCEs) of 1.993% and 10.866% for the single and double fence molecules, respectively, which are in accordance with the experimental values of 3.48% and 10.69%, respectively. In addition, one designed two new molecules based on the double fence porphyrin molecule with a 2-methyl-2H-benzo[d][1,2,3]triazole (BTA) unit bearing one fluorine and two fluorine atoms as the guest acceptor, respectively. Compared to the original molecules, the engineered molecules significantly improved the photovoltaic parameters, J_SC and V_OC, thereby causing excellent PCEs. The most outstanding designed molecule reached a PCE of 12.155%, and is considered a candidate dye for high-efficiency DSSC. This study provides insights into the photoelectric properties of single and double fence porphyrins. It also demonstrated that the strong electron-withdrawing ability of fluorine atoms would enhance the photovoltaic performance and provide a guideline for the further design of double fence porphyrins.

Chitosan and chitosan/PEG nanoparticles loaded with indole-3-carbinol: Characterization, computational study and potential effect on human bladder cancer cells

Indole-3-carbinol (I3C) is a plant molecule known to be active against several types of cancer, but some chemical characteristics limit its clinical applications. In order to overcome these limitations, polymeric nanoparticles can be used as carrier systems for targeted delivery of I3C. In this study, chitosan and chitosan/polyethylene glycol nanoparticles (CS NP and CS/PEG NP, respectively) were prepared to encapsulate I3C by ionic gelation method. The polymeric nanoparticles were characterized by Dynamic Scattering Light (DLS), Zeta Potential (ZP), Fourier Transform Infrared (FTIR) spetroscopy, X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Field Emission Gun Scanning Electron Microscopy (FEG-SEM). I3C release testing was performed at an acidic media and the interactions between I3C and chitosan or PEG were evaluated by Density Functional Theory (DFT). Cytotoxicity of nanoparticles in bladder cancer T24 cell line was evaluated by the Methyl-thiazolyl-tetrazolium (MTT) colorimetric assay. The average size of the nanoparticles was observed to be in the range from 133.3 ± 3.7 nm to 180.4 ± 2.7 nm with a relatively homogeneous distribution. Samples had relatively high positive zeta potential values (between +20.3 ± 0.5 mV and + 24.3 ± 0.5 mV). Similar encapsulation efficiencies (about 80%) for both nanoparticles were obtained. Physicochemical and thermal characterizations pointed to the encapsulation of I3c. electron microscopy showed spherical particles with smooth or ragged surface characteristics, depending on the presence of PEG. The mathematical fitting of the release profile demonstrated that I3C-CS NP followed the Higuchi model whereas I3C-CS/PEG NP the Korsmeyer-Peppas model. Chemical differences between the nanoparticles as based on the I3C/CS or I3C/PEG interactions were demonstrate by computational characterization. The assessment of cell viability by the MTT test showed that the presence of both free I3C and I3C-loaded nanoparticles lead to statistically significant reduction in T24 cells viability in the concentrations from 500 to 2000 μM, when comparison to the control group after 24 h of exposure. Thus, CS and CS/PEG nanoparticles present as feasible I3C carrier systems for cancer therapy.

Spiro-Indole-Coumarin Hybrids: Synthesis, ADME, DFT, NBO Studies and In Silico Screening through Molecular Docking on DNA G-Quadruplex

New series of hybrids were synthesized by combination of 4-hydroxycoumarin with spiro[indol-indazole-thiazolidine]-diones and spiro[indol-pyrazole-thiazolidine]-diones, via hitherto unknown Schiff bases. The effects of substituents, such as -F, -Br and -CH3, on the crucial characteristics pertaining to the hybrids were investigated through computational studies. In silico or virtual screening through molecular docking studies on the library of 22 compounds, including reference compounds, precursors, non-hybrid and hybrid derivatives, was performed on DNA G-quadruplex of the human genome. All six freshly synthesized hybrids showed high binding energy as compared to non-hybrids as well as reference compounds. The presence of substituents at 5-position of indole enhanced the binding tendency of the ligand. ADME studies indicated good oral bioavailability and absorption of these compounds. Density Functional Theory (DFT) calculations of hybrids were done at B3LYP/6-311G++(d,p) level of computation. Their HOMO and LUMO energy plots reflected the presence of high charge transfer and chemical potential. Natural bond order (NBO) calculations predicted hyperconjugative interactions. The Molecular Electrostatic Potential (MEP) surface plots showed possible electrophilic and nucleophilic attacking sites of the hybrids. Compound 10 a (5-fluoro-spiro[indol-indazole-thiazolidine]-dione-coumarin hybrid), on the basis of global reactivity descriptors, was filtered to be chemically most reactive with the highest binding energy of -8.23 kcal/mol with DNA G-quadruplex. The synthesized hybrid coumarin derivatives in correlation with theoretical docking studies validate that hybrid derivatives are more reactive compared to their non-hybrid counterparts.

DFT studies on global parameters, antioxidant mechanism and molecular docking of amlodipine besylate

Amlodipine besylate (AMB) is a synthetic dihydropyridine calcium channel blocker with antihypertensive and anti-anginal effects. Quantum computational investigations on AMB were done using DFT/B3LYP/6-311++G (d, p) level of theory, to study the molecular structural properties, nonlinear properties and antioxidant properties of AMB. The electrophilic and nucleophilic sites along with complete NBO analysis helps to locate the intermolecular electronic interactions and their stabilization energies. Complete NBO analysis was additionally done to locate the intermolecular electronic interactions and their stabilization energies. Charge distributions of Mulliken population, NBO and MEP are correlated. Also, the antioxidant properties of AMB were assessed to check whether these antioxidant effects contribute to the effects of antioxidant therapy. Further, the molecular docking studies of these compounds demonstrated a good selectivity profile with Monoamine oxidase B with better binding affinity and confirms AMB is a potent antioxidant.