Spectroscopic (FT-IR,1H and 13C NMR) characterization and density functional theory calculations for (Z)-5-(4-nitrobenzyliden)-3-N(2-ethoxyphenyl)-2-thioxo-thiazolidin-4-one (ARNO)

Antifungal Activities of Biogenic Silver Nanoparticles Mediated by Marine Algae: In Vitro and In Vivo Insights of Coating Tomato Fruit to Protect against Penicillium italicum Blue Mold

In an attempt to reduce such decay induced by pathogenic causes, several studies investigated the effectiveness of nanoparticles (NPs) that play a vital role in saving food products, especially fruits. Current research delves into biogenic silver nanoparticles (using marine alga Turbinaria turbinata (Tt/Ag-NPs) and their characterization using FT-IR, TEM, EDS, and zeta potential. Some pathogenic fungi, which cause fruit spoilage, were isolated. We studied the impact of using Tt/Ag-NPs to protect against isolated fungi in vitro, and the influence of Tt/Ag-NPs as a coating of tomato fruit to protect against blue mold caused by Penicillium italicum (OR770486) over 17 days of storage time. Five treatments were examined: T1, healthy fruits were used as the positive control; T2, healthy fruits sprayed with Tt/Ag-NPs; T3, fruits infected with P. italicum followed by coating with Tt/Ag-NPs (pre-coating); T4, fruits coated with Tt/Ag-NPs followed by infection by P. italicum (post-coating); and T5, the negative control, fruits infected by P. italicum. The results displayed that Tt/Ag-NPs are crystalline, spherical in shape, with size ranges between 14.5 and 39.85 nm, and negative charges. Different concentrations of Tt/Ag-NPs possessed antifungal activities against Botrytis cinerea, Rhodotorula mucilaginosa, Penicillium expansum, Alternaria alternate, and Stemphylium vesicarium. After two days of tomatoes being infected with P. italicum, 55% of the fruits were spoilage. The tomato fruit coated with Tt/Ag-NPs delayed weight loss, increased titratable acidity (TA%), antioxidant%, and polyphenol contents, and decreased pH and total soluble solids (TSSs). There were no significant results between pre-coating and post-coating except in phenol contents increased in pre-coating. A particular focus is placed on the novel and promising approach of utilizing nanoparticles to combat foodborne pathogens and preserve commodities, with a spotlight on the application of nanoparticles in safeguarding tomatoes from decay.

First and second order hyperpolarizabilities of flavonol derivatives: A density functional theory study

In this study, seventeen flavonol derivatives (1-17) were evaluated with regard to their first- and second-order hyperpolarizability parameters. For this purpose, the molecular geometries of 1-17 were optimized by using B3LYP/6-311++G(d,p) level. Spectroscopic characterizations for 1-17 were executed through the calculations of IR, UV-vis, ¹H NMR and ¹³C NMR spectra. The quantum chemical parameters such as electronegativity, chemical hardness, chemical potential and electrophilicity indexes were obtained by using the frontier molecular orbital (FMO) energies. The potential energy distribution (PED) analysis was used to provide a detailed assignment of vibrational bands. Important contributions to electronic absorption bands from FMOs were also evaluated. The distribution of FMOs to the whole molecule was investigated to determine the nature of electronic charge transfers in 1-17. The static and dynamic first- and second-order hyperpolarizability parameters for 1-17 were calculated by using B3LYP/6-311++G(d,p) level. The static β and γ were calculated at the ranges of 9.8279-0.0303 × 10^-29 esu and 80.200-268.40 × 10^-36 esu. The dynamic β and γ (ω = 532 nm) were also obtained in the field of 1.0440-71.786 × 10^-29 esu and 306.20-3607.00 × 10^-36 esu. This wide range of β and γ values indicate that flavonol derivatives with rational substitution may be promising candidates for first- and second-order NLO applications.

A density functional theory study of Fe(II)/Fe(III) distribution in single layer green rust: a cluster approach

Green rust (GR) is a potentially important compound for the reduction of heavy metal and organic pollutants in subsurface environment because of its high Fe(II) content, but many details of the actual reaction mechanism are lacking. The reductive capacity distribution within GR is a key to understand how and where the redox reaction occurs and computational chemistry can provide more details about the electronic properties of green rust. We constructed three sizes of cluster models of single layer GR (i.e., without interlayer molecules or ions) and calculated the charge distribution of these structures using density functional theory. We found that the Fe(II) and Fe(III) are distributed unevenly in the single layer GR. Within a certain range of Fe(II)/Fe(III) ratios, the outer iron atoms behave more like Fe(III) and the inner iron atoms behave more like Fe(II). These findings indicate that the interior of GR is more reductive than the outer parts and will provide new information to understand the GR redox interactions.

Synthesis of 5-(5-methyl-benzofuran-3-ylmethyl)-3H- [1, 3, 4] oxadiazole-2-thione and investigation of its spectroscopic, reactivity, optoelectronic and drug likeness properties by combined computational and experimental approach

This paper reports the synthesis of 5-(5-methyl-benzofuran-3-ylmethyl)-3H- [1, 3, 4] oxadiazole-2-thione (5MBOT) and characterization by FT-IR, FT-Raman, ¹H NMR, ¹³C NMR and UV spectral studies. The density functional theory (DFT) calculations have been executed for the 5MBOT using B3LYP/6-31++G (d, p) basis set. The fundamental modes of the vibrations were designated by the potential energy distribution (PED), and the computed and experimental values support each other. The ¹H NMR and ¹³C NMR chemical shifts of 5MBOT were estimated by gauge-including atomic orbitals (GIAO) method and compared with the experimental chemical shifts. The UV-Vis method used to study the visible absorption maxima (λ_max) by using Time-Dependent DFT. Further, the Mulliken population analysis (MPA), natural population analysis (NPA) charges, thermodynamic properties at different temperatures were presented. The calculated HOMO and LUMO energies show that charge transfer within the molecule. The natural bonds orbital (NBO) also computed. Optoelectronic properties have been carried out by combination of DFT calculations and molecular dynamics (MD) simulations, in order to assess the potential of this structure for applications in organic electronics. Further, the study encompassed calculations of reorganization energies for holes and electrons and charge transfer rates. DFT calculations have been also used in order to identify locations possibly sensitive towards the autoxidation mechanism, which correlates between bond dissociation energy for hydrogen abstraction and the mechanism. The MD simulations have been used to understand interaction of 5MBOT with water molecules. Molecular docking studies reveals the antifungal activity of 5MBOT may be due to hydrogen bonding and hydrophobic interactions with different antifungal proteins.