Synthesis, characterization, DFT, and TD-DFT studies of (E)-5-((4,6-dichloro-1,3,5-triazin-2-yl)amino)-4-hydroxy-3-(phenyldiazenyl)naphthalene-2,7-diylbis(hydrogen sulfite)

Synthesis, crystal structure analysis, computational modelling and evaluation of anti-cervical cancer activity of novel 1,5-dicyclooctyl thiocarbohydrazone

Thiocarbazones are widely used as bioactive and pharmaceutical intermediates in medicinal chemistry and have been shown to exhibit diverse biological and pharmacological activities such as antimicrobial, anticancer, anti-viral, anti-convulsant and anti-inflammatory etc. In continuation of our interest in biologically active heterocycles and in an attempt to synthesize a spiro derivative, 1,2,4,5-tetraazaspiro[5.7]tridecane-3-thione, herein, the synthesis of 1,5-dicyclooctyl thiocarbohydrazone (3) has been reported via reaction of the cyclooctanone and thiocarbohydrazide. The structure was assigned on the basis of detailed spectral analysis and also confirmed by X-ray crystal studies. The Hirshfeld surface analysis indicates that the most significant interaction is S⋯H (12.7%). The presentation of mechanistic aspects regarding the plausible route of its formation has also been included. The first hyperpolarizability (β0) was found to be 10.22 × 10-30 esu, which indicates that the compound exhibits good non-linear optical properties. The density functional theory (DFT) method has been used to characterize the spectroscopic properties and vibrational analysis of 1,5-dicyclooctyl thiocarbohydrazone (3) theoretically. The compound and cisplatin (standard) were screened for their antiproliferative activity against the human cervical cancer cell line (SiHa) and they exhibited significant activity with IC50 values of 250 μM and 15 μM, respectively. The inhibitory nature of the title compound against viral oncoprotein E6 was confirmed by studies using molecular docking analysis. The results of biological activity and in silico analysis indicate that the synthesized molecule could act as a precursor for the synthesis of new heterocyclic derivatives of medicinal importance.

A robust computational quest: Discovering potential hits to improve the treatment of pyrazinamide-resistant Mycobacterium tuberculosis

The rise of pyrazinamide (PZA)-resistant strains of Mycobacterium tuberculosis (MTB) poses a major challenge to conventional tuberculosis (TB) treatments. PZA, a cornerstone of TB therapy, must be activated by the mycobacterial enzyme pyrazinamidase (PZase) to convert its active form, pyrazinoic acid, which targets the ribosomal protein S1. Resistance, often associated with mutations in the RpsA protein, complicates treatment and highlights a critical gap in the understanding of structural dynamics and mechanisms of resistance, particularly in the context of the G97D mutation. This study utilizes a novel integration of computational techniques, including multiscale biomolecular and molecular dynamics simulations, physicochemical and medicinal chemistry predictions, quantum computations and virtual screening from the ZINC and Chembridge databases, to elucidate the resistance mechanism and identify lead compounds that have the potential to improve treatment outcomes for PZA-resistant MTB, namely ZINC15913786, ZINC20735155, Chem10269711, Chem10279789 and Chem10295790. These computational methods offer a cost-effective, rapid alternative to traditional drug trials by bypassing the need for organic subjects while providing highly accurate insight into the binding sites and efficacy of new drug candidates. The need for rapid and appropriate drug development emphasizes the need for robust computational analysis to justify further validation through in vitro and in vivo experiments.

Design of Zr-MOFs by Introducing Multiple Ligands for Efficient and Selective Capturing of Pb(II) from Aqueous Solutions

The existence of lead ions seriously affects the quality of many metal products in metallurgical enterprises. Currently, the various methods of lead-ion removal tried by researchers will affect valuable metals in the removal process, thus resulting in low economic efficiency. In this study, a novel metal-organic framework adsorbent (UiO-FHD) which efficiently and selectively captures lead ions is developed by introducing multiple ligands. The maximum adsorption capacity of lead ions is 433.15 mg/g at pH 5. The adsorption process accords with the pseudo-second-order kinetic and the Langmuir isotherm models at room temperature. Thermodynamic experiments indicate that the removal of Pb(II) is facilitated by appropriate temperature reduction. The performance tests indicate that UiO-FHD maintains a high removal rate of 90.35% for Pb(II) after four consecutive adsorption-desorption cycles. The distribution coefficient of lead ions (26.7 L/g) shows that UiO-FHD has excellent selective adsorption for lead ions. It is revealed that the chelation of the sulfhydryl groups and the electrostatic interaction of the hydroxyl groups are the dominant factors to improve the removal rate of Pb(II) by density functional theory calculations. This study clarifies the value of self-designed novel organic ligands in metal-organic framework materials that selectively capture heavy-metal ions.

Synthesis, spectral characterization, and theoretical investigation of the photovoltaic properties of (E)-6-(4-(dimethylamino)phenyl)diazenyl)-2-octyl-benzoisoquinoline-1, 3-dione

This research work focuses on the synthesis, characterization through spectra (FT-IR, UV-vis, and ¹H-NMR) investigations, and the use of density functional theory (DFT) along with time-dependent density functional theory (TD-DFT) to investigate the electronic, structural, reactivity, photophysical properties, and the photovoltaic properties of a novel (E)-6-(4-(dimethylamino)phenyl)diazenyl)-2-octyl-benzoisoquinoline-1,3-dione. The structure of the synthesized compound was modeled using the Gaussian09W and GaussView6.0.16 softwares employing B3LYP and 6-31 + G(d) basis set. The DFT studies was performed in order to investigate the Frontier Molecular Orbital (FMO), Natural Bond Orbital (NBO), charge distribution, Nonlinear Optics (NLO), and stability of the titled molecule. The HOMO-LUMO energy gap which corresponds to the difference between HOMO and LUMO energies of the studied compound was found to be 2.806 eV indicating stiff and smooth nature of the titled molecule. This accounts for the less stability and high chemical reactivity of the compound. The photovoltaic properties were conducted to evaluate the light harvesting efficiency (LHE), short circuit current density (J_SC), Gibbs free energy of injection ([Formula: see text]), open cycled voltage (V_OC) and Gibbs free energy regeneration ([Formula: see text]) and solar cell conversion efficiency. Interestingly, the results obtained were found to be in good agreement with other experimental and computational findings.

Experimental and theoretical studies of the influence of alkyl groups on the photovoltaic properties of (E)-6-((2, 3-dihydroxylnaphthalene)diazenyl)-1H-benzoisoquinoline-1,3-dione-based organic solar cell

The manipulation of the active dye material for application in dye-sensitized solar cell (DSSC) using simple or bulky group substituents is necessary for improved dye performance. Herein, we carried out a combined experimental and theoretical studies of different alkylated novel reactive (E)-6-(2,3-dihydroxyl naphthalene diazinyl)-1H-benzoisoquinoline-1,3-dione azo-based dyes using spectral (FTIR, UV-visible, and NMR) analysis and electronic structure theory method based first principle density functional theory (DFT) calculations to investigate the molecular electronic properties, structural analysis, excitation behavior, and the theoretical potential application in photovoltaic cell. The synthesized azo dye (azoD) was theoretically modeled by varying the number of alkyl chains denoted as AzoD₁, AzoD₂, AzoD₃, and AzoD₄ to represent azo dyes having ten (10), twelve (12), fourteen (14), and sixteen (16) alkyl chain length respectively. From the natural bond orbital (NBO) analysis, the higher stabilization energies, 227.80 and 227.77 kcal/mol respectively, recorded for AzoD₁ and AzoD₄ may be due to extra orbital contribution by π*(N₂₁-N₂₂) to π*C₅₄-C₅₆ 31.19 eV for AzoD₁ and π*(N₂₁-N₂₂) → π*(C₅₃-C₅₅) 31.43 eV AzoD₄ confirming that chain length affected the orbital interaction of the molecules. The driving force (ΔG_inject) of electron injection into the TiO₂ surface (- 1.92 to - 1.93) shown in this study is indicative that alkylated azo dyes are good for improved DSSCs performance. Again, the open circuit voltage (V_oc) of 1.090 (AzoD₁), 1.092 (AzoD₂), 1.093 (AzoD₃), and 1.095 (AzoD₄) are also evidence of the suitability of azo dyes as photosensitizers. All the spectroscopic analysis, FTIR, UV-visible, and NMR combined with theoretical calculations, provided accurate data for characterizing the titled azo dye compound and showed that it has good photophysical properties. The presence of alkyl groups and chain length promoted the stability of the dyes thereby making them suitable for application in DSSCs. Increase in chain length as well enhanced the electron injection into the conduction band of the semiconductor.

Experimental and theoretical study of the dye-sensitized solar cells using Hibiscus sabdariffa plant pigment coupled with polyaniline/graphite counter electrode

In this research work, the extraction, characterization, device fabrication, and theoretical investigation of Hibiscus sabdariffa plant extract, for possible application in solid DSSCs, are reported. The plant extract was analyzed using FT-IR and UV–Vis spectrophotometry. Polyaniline on graphene was used as the counter electrode whereas titanium (IV) oxide was used as the photo anode for the fabricated DSSCs. The experimental results obtained for the open circuit voltage, short circuit current density, field factor, maximum power and conversion efficiency are 0.925 V, 0.073 A/cm2, 1.43, 1.04 W, and 0.044 % respectively. The excited states of anthocyanin (delphinidin) and quercetin, the most stable structures of Hibiscus sabdariffa plant extract, were studied using density functional theory method. In addition, the theoretical open circuit voltage, light harvesting efficiency, coupling constant, free energy change, and HOMO–LUMO energy gap were predicted for the photovoltaic properties. The theoretical results suggest that quercetin has relatively better photovoltaic properties and, hence, potentially a better dye for solar cell application.

Evaluation of the excited state dynamics, photophysical properties, and the influence of donor substitution in a donor-[Formula: see text]-acceptor system

There have been numerous attempts for the theoretical design of a better donor-[Formula: see text]-acceptor structural framework with improved absorption and emission properties. However, for effective dye designing, it is necessary to understand the electronic and photophysical properties of the dye systems. In this work, we report a detailed density functional theory (DFT) and time-dependent density functional theory (TD-DFT) investigations of the excited state characteristics and the influence of various groups (-HCO, =CH₂, (-CH₃)₂, (HCO)₂, and (-OCH₃)₂) attached to the donor group (-NH₂) in a p-nitroaniline D-[Formula: see text]-A system which are symbolized respectively as p-nitroaniline (A), N,N-dimethylnitroaniline (A2), N,N-dicarbonylnitroaniline (A3), N-methylenenitroaniline (A4), and N,N-dimethoxynitroaniline (A5). The first principles DFT and TD-DFT calculations from the ground state (S₀) to the first five excited states: (S₀→S₁), (S₀→S₂), (S₀→S₃), (S₀→S₄), and (S₀→S₅) were utilized to explore the reactivity of D-[Formula: see text]-A system using the conceptual DFT approach, characterization of electron excitation using the hole-electron analysis, visual study of the various real space functions in the hole-electron framework, density of states (DOS), measurement of charge transfer (CT) length of electron excitation ([Formula: see text]), measurement of the overlapping degrees of hole and electron of electron excitation ([Formula: see text]), interfragment charge transfer (IFCT) during electron excitation, and the second-order perturbation energy analysis from the natural bond orbitals (NBO) computation. Results of the excitation studies show that all the studied compounds exhibited an n→[Formula: see text]* localized type for first excitations (S₀→S₁) on -NO₂ group in A, A2, A4, and A5 and -NCl₂ in A3. [Formula: see text]→[Formula: see text]* charge transfer excitations were confirmed for S₀→S₂/S₄/S₅ in A and A2, S₀→S₃/S₄/S₅ in A3 and A5, and S₀→S₄/S₅ in A4. The NBO second-order perturbation energy analysis suggest that the most significant hyperconjugative interactions were [Formula: see text] (54.43kcal/mol), [Formula: see text] (40.82kcal/mol), [Formula: see text] (11.67kcal/mol), [Formula: see text] (29.52kcal/mol), [Formula: see text] (11.55kcal/mol), [Formula: see text] (23.40kcal/mol), and [Formula: see text] (24.88kcal/mol) [Formula: see text](24.64kcal/mol), which respectively corresponds to the A, A2, A3, A4, and A5 D-[Formula: see text]-A systems under investigation, and these strong interactions stabilize the systems.

Synthesis, characterization, and theoretical studies of the photovoltaic properties of novel reactive azonitrobenzaldehyde derivatives

All dyes conduct but at different degrees of absorption; it is interesting to study the degree of conductivity and absorptivity of novel reactive azo-dyes in respect to dye-sensitized solar cells (DSSCs) to ascertain their viability for such applications. In this study, four novel reactive azo-dyes were experimentally synthesized from p-aminobenzaldehyde, 4-amino-3-nitrobenzaldehyde, and aniline through series of condensation and coupling reactions. The various functional groups, molecular connectivities, and molecular weight of the various fragments of the synthesized dyes were elucidated using the GC-MS, FT-IR, UV-vis, and NMR respectively. The experimentally determined structures were modeled and investigated using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) approaches to computationally compute the electronic structure properties, reactivity, absorption and solvatochromism in four different phases: gas, ethanol, acetone, and water, and the photovoltaic properties for possible applications in dye-sensitized solar cells (DSSCs). By comparing the HOMO (E H) and the LUMO (E L) energies from the results obtained demonstrates that dye D has the highest E L energy value of -2.48 eV with a relatively lowest E H energy value of -5.63 eV such that it lies underneath the conduction band edge of TiO2 which is necessary to enable charge regeneration. Pi-electron delocalization was observed from the natural bond orbital (NBO) calculations between the different aromatic rings with dye B and A having the relatively highest and least second-order stabilization energies between σ* → σ* and LP* → LP interacting orbitals respectively. It is also observed in all the solvents that the Gibbs free energy of injection (ΔG inject) is greater than 0.2 eV and hence, all the studied azo structures in the four phases provided efficient electron injection and light harvesting efficiency (LHE), however, the value of ΔG inject for dyes B and D is greatest in all the four phases and thus, provided the highest electron injection of all the dyes. From the fact-findings of quantum theory of atoms-in-molecules (QTAIM), dyes A and C have extra-stability due to their relatively high numbers of intramolecular H-bond interactions along with some additional intra-atomic bonding between atoms within the studied compounds. Hence, all the four dyes are good for DSSCs applications.