Molecular docking, quantum chemical computational and vibrational studies on bicyclic heterocycle "6-nitro-2,3-dihydro-1,4-benzodioxine": Anti-cancer agent

Revealing the incorporation of an NH2 group into the edge of carbon dots for H2O2 sensing via the C-N⋯H hydrogen bond interaction

We investigated hydrogen peroxide (H₂O₂) sensing on NH₂-functionalized carbon dots (Cdots) for three different -NH₂ positions, and the N atom was found to be the active site using a quantum computational approach. B3LYP and 6-31G(d,p) were used for density functional theory (DFT) ground state calculations, whereas CAM-B3LYP and the same basis set were used in time-dependent density functional theory (TD-DFT) excited state calculations. Structural optimization showed that the H₂O₂ is chemisorbed on 1-sim via a C-N⋯H hydrogen bond interaction with an adsorption energy of -10.61 kcal mol^-1. Mulliken atomic charge distributions and electrostatic potential (ESP) analysis were both used to determine reactivity of the molecules at the atomic level. For in-depth analysis of the ground states, we utilized Frontier molecular orbital (FMO) theory, quantum theory of atoms in molecules (QTAIM), and non-covalent interaction (NCI) index analysis. In addition, we also present UV-vis absorption spectra and charge transfer lengths to understand the mechanism of H₂O₂ sensing in excited states. Based on the molecular and electronic properties of the NH₂-Cdots, it was shown that 1-sim is a potential candidate for use as an electrochemical sensor for H₂O₂ sensing. Whereas 3-sim is believed to be a potential candidate for use as an optical sensor of H₂O₂ based on the UV-vis characteristics via photoinduced charge transfer.

Synthesis, spectroscopic, topological, hirshfeld surface analysis, and anti-covid-19 molecular docking investigation of isopropyl 1-benzoyl-4-(benzoyloxy)-2,6-diphenyl-1,2,5,6-tetrahydropyridine-3-carboxylate

Isopropyl 1-benzoyl-4-(benzoyloxy)-2,6-diphenyl-1,2,5,6-tetrahydropyridine-3-carboxylate (IDPC) was synthesized and characterized via spectroscopic (FT-IR and NMR) techniques. Hirshfeld surface and topological analyses were conducted to study structural and molecular properties. The energy gap (E_g), frontier orbital energies (E_HOMO, E_LUMO) and reactivity parameters (like chemical hardness and global hardness) were calculated using density functional theory with B3LYP/6–311++G (d,p) level of theory. Molecular docking of IDPC at the active sites of SARS-COVID receptors was investigated. IDPC molecule crystallized in the centrosymmetric triclinic (P1¯) space group. The topological and Hirshfeld surface analysis revealed that covalent, non-covalent and intermolecular H-bonding interactions, and electron delocalization exist in the molecular framework. Higher binding score (-6.966 kcal/mol) of IDPC at the active site of SARS-COVID main protease compared to other proteases suggests that IDPC has the potential of blocking polyprotein maturation. H-bonding and π-cationic and interactions of the phenyl ring and carbonyl oxygen of the ligand indicate the effective inhibiting potential of the compound against the virus.

Molecular docking, spectroscopic, and quantum chemical studies on aromatic heterocycle tetrakis(4-pyridyl)cyclobutane regioisomers: potential membrane-permeable inhibitors

Aromatic heterocyclic compounds are commonly used in pharmaceutical and agrochemical products. The usage has been also extended in the production of corrosion inhibitors and electronic, opto-electronic, and NLO devices. The four regioisomers of the aromatic heterocyclic molecule, tetrakis(4-pyridyl)cyclobutane (tpcb), were optimized, and their chemical, electronic, and biological properties were examined. The rctt and rtct isomers were isolated and further characterized by the infrared and Raman spectroscopic techniques, and their vibrational modes with attention on important functional groups were discussed. The theoretical vibrational data obtained by DFT/B3LYP/6-311++G(d,p) were in very good agreement with the experimental ones. The occupancy, bond polarization, hybridization of the N-C bond, bonding characteristics between the pyridyl carbon and cyclobutane moiety, and distribution of electron density for the four tpcb isomers have been explored through NBO analysis. The inversion barrier of the cyclobutane moiety was obtained based on the optimized structures of the planar and puckered configurations of the isomers. The rccc isomer exhibited the least electrophilic character compared to the other tpcb isomers. The chemical significance of tpcb has been further explained by the wave function analyses. Molecular docking results revealed that the tpcb ligand would possess a potential anti-viral and anti-bacterial activity via a membrane-permeable mechanism.