Schiff bases represent an essential class in organic
chemistry with antitumor, antiviral, antifungal, and antibacterial
activities. The synthesis of Schiff bases requires the presence of an
organic base as a catalyst such as piperidine. Base-free synthesis of
organic compounds using a heterogeneous catalyst has recently
attracted more interest due to the facile procedure, high yield, and
reusability of the used catalyst. Herein, we present a comparative study
to synthesize new Schiff bases containing indole moieties using
piperidine as an organic base catalyst and Au@TiO2 as a heterogeneous
catalyst. In both methods, the products were isolated in high yields and
fully characterized using different spectral analysis techniques. The
catalyst was reusable four times, and the activity was slightly decreased.
The presence of Au increases the number of acidic sites of TiO2,
resulting in CO polarization. Yields of the prepared Schiff bases in the presence of Au@TiO2 and piperidine were comparable.
However, Au@TiO2 is an easily separable and recyclable catalyst, which would facilitate the synthesis of organic compounds without
applying any hazardous materials. Furthermore, the luminescence behavior of the synthesized Schiff bases exhibited spectral shape
dependence on the substituent group. Interestingly, the compounds also displayed deep-blue fluorescence with Commission
Internationale de l’Éclairage (CIE) coordinates of y < 0.1. Thus, these materials may contribute to decreasing the energy
consumption of the emitting devices.

There has been evidence of non-typical fluorescence activities in thiadiazole and oxadiazole derivatives. Also,
some coumarin compounds with tunable luminescence properties via controlling the molecular structure and its
aggregation have been recently reported. As a result, our effort concentrated on integrating these moieties in
order to improve the applicability of the target compounds through easy synthetic schemes. All the synthesized
derivatives underwent extensive spectrum analysis, including NMR, FT-IR, and mass spectroscopy. DFT calculations,
UV–visible, and luminescence spectroscopy were used to study the photophysical characteristics of three
compounds having coumarin luminescent core integrated with the thiadiazole, oxadiazole, or hydrazinecarbothioamide.
We found that manipulating the packing of a compound under specific conditions (e.g., the solid state
or moderate solution concentration of compounds containing the heterocyclic substituent “thiadiazole or oxadiazole”)
can trigger processes related to the way the molecules interact, resulting in the appearance of dual or
multiple fluorescence bands that cover the full visible range. Additionally, we deduced that the intriguing white
emission from a single component might be generated by modifying the degree of molecular aggregation to
balance the relative band intensities at short and long wavelengths. Long-wavelength emission arises from
aggregated molecules whereas short-wavelength emission results from single molecules. It is evident that this
balance is feasible in both the solid form of the thiadiazole derivative and 1 × 10–5 mol L–1 solution of the
oxadiazole derivative. Hence, this research proposes an easy method for creating the intriguing white-light
emission from a single component.

The powder form of the new indole derivative 4-(((3-chloro-1H-indol-2-yl) methylene) amino) phenol [Indol-
4Ap] was synthesized and subsequently converted to a thin film [Indol-4Ap]TF using the Sol-Gel spin coating
technique. Numerous characterization techniques, including Fourier transform infrared (FTIR), nuclear magnetic
resonance (NMR), X-ray diffraction (XRD), and ultraviolet–visible (UV–Vis) optical spectroscopy were used to
characterize [Indol-4Ap]TF. Additionally, using density functional theory (DFT), optimization tvia TD-DFTD/
Mol3 and Cambridge Serial Total Energy Bundle (TD-FDT/CASTEP) was developed. The DFT calculations
accurately matched the observed NMR and FTIR spectra and validated the molecular structure of the examined
materials. The average crystallite size of [Indol-4Ap]TF, as determined by XRD calculations, is 12.02 nm. The
optical properties of the films were determined using optical absorbance spectrophotometric measurements in
the 200–800 nm wavelength range. The optical energy bandgaps computed using Tauc’s equation for the [Indol-
4Ap]TF are 3.152 and 2.751 eV, respectively. Whereas the [Indol-4Ap]iso has a bandgap of 3.074 eV as determined
by TD-DFT/DMol3. The optical characteristics predicted by CASTEP in TD-DFT are in excellent agreement
with the experimental values. The investigated

In the recent years, interest in the synthesis of diclofenac derivatives has increased due to their excep- tional biological activity. We present here the synthesis of some novel diclofenac derivatives through simple synthetic procedures, where the acylation of carbohydrazide compound 1 with chloroacetyl chlo- ride in dioxane produced the compound 2 . Chloroacetohydrazide compound 2 was further subjected to nucleophilic substitution reactions using different nucleophiles such as: hydrazine hydrate, thiosemicar- bazide and p -aminobenzenesulfonamide to give the corresponding derivatives 3-5 , respectively. More- over, the reaction of the hydrazinyl compound 3 with active hydrogen species such as: ethyl acetoacetate and acetyl acetone in refluxed ethanol provided the corresponding pyrazolone derivatives 6 and 7 , re- spectively. Furthermore, the reaction of previously reported diclofenac ester 8 with 1,2-diaminoethane gave the amino derivative 9 . Finally, condensation reaction of the latter compound with benzaldehyde in dioxan furnished the corresponding Schiff’s base compound 10 , while its acylation with chloroacetyl chloride in dioxan produced 11 . Different spectral (IR, NMR and Mass) and elemental analysis techniques were utilized to explore the structure of the synthesized compounds. All the synthesized compounds were tested for their in-vitro antibacterial activity against different strains of bacteria showing satisfac- tory results, and molecular docking study was performed to investigate the mode of action.

Nowadays, several pathogenic strains of bacteria and fungi have become resistant against many therapeutic drugs. Therefore, using novel biologically synthesized nanomaterials as antimicrobial drugs against the human pathogens is of great concern. Consequently, here, the study was aimed to assess the antimicrobial activity of titanium dioxide nanoparticles (TiO2NPs) phycosynthesized from Spirulina platensis and some conventional antifungal (clotrimazole, itraconazole, ketoconazole, micconazole, and nystatin) and antibacterial (amoxicillin and gentamicin) drugs against both Candida parapsilosis and Prototheca ciferrii. The TiO2NPs-and clotrimazole-induced ultrastructure changes on the microbes using transmission electron microscope were also investigated. The TiO2NPs significantly inhibited the growth of C. parapsilosis. The clotrimazole and ketoconazole showed the highest inhibitory effect against …

In this study, Sargassum latifolium (S. latifolium) n-hexane extract as a novel source for insecticidal bioactive compounds was investigated. The composition of the extract was identified by using GC-MS analysis. We performed the study on four types of insects and larvae sp (Sarcophaga bullata, Tribolium castaneum, Musca domestica, and Solenopsis invicta) which cause a deleterious impact on the crops and human health. We used scanning electron microscopy to show the destructive effects of S. latifolium extract on the exoskeleton. The treatment exhibited severe morphological changes and a high mortality rate. Also, different bioinformatic approaches were utilized to investigate the possible insecticidal mechanism of the extract. Molecular docking showed the potential of the compounds to be chitin synthase inhibitors. Besides, the toxicokinetic parameters of the most promising compounds were evaluated to assess the impact of using the extract as an insecticidal agent on human health. S. latifolium extract exhibited promising insecticidal activity and acceptable toxicokinetic properties as compared to other known pesticide groups.

In this study, we utilized pomegranate peel and marine algae Ulva lactuca (U. lactuca) as rich and sustained sources of bioactive compounds to combat tomato-black spot disease. n-Hexane extracts from the peel of pomegranate (Punica granatum) (PPE) and the marine algal biomass U. lactuca (ULE) were used alone and in combinations to verify their impact against Alternaria alternata (A. alternata). The applied extracts exhibited severe destructive effects on both fungal growth and structure such as mycelia malformation, underdeveloped conidia, cell wall deformation, and shrinkage. Moreover, increased deformations and protrusions, and notch-like structures, were noticed in A. alternata mycelia treated with mixed extracts (PPE and ULE) compared to all other treatments. The protein and reduced sugar contents in tomato fruits were significantly increased in the infected fruits with A. alternata. The highest enzyme 

Metal-organic frameworks (MOFs) are promising catalysts for producing clean energy and environmental-based applications. This paper reported one-pot encapsulation of guest molecules, e.g., thiourea (TU) and D-Glucose-6-phosphate disodium salt dihydrate (G6P-Na₂), into zeolitic imidazolate frameworks (ZIF-67), denoted as S@ZIF-67 and P@ZIF-67, respectively. The organic guest molecules offered the synthesis of cobalt-based materials (e.g., Co₃O₄, CoP, and CoS), embedded heteroatoms (P, N, and S) via carbonization. The materials were tested for hydrogen generation via sodium borohydride (NaBH₄) hydrolysis. ZIF-67, S@ZIF-67, and P@ZIF-67 displayed maximum hydrogen generation rates (HGR_max) of 27,273, 24,000, and 60,000 mL_H2 g_cat⁻¹ min⁻¹, respectively, using 20 mg of the catalyst and 0.2 wt.% of NaBH₄ at 60 °C. The materials were also investigated as potential catalysts for the adsorption and catalytic degradation of water pollutants such as organic dyes, e.g., methyl orange (MO) and Congo red (CR), with degradation efficiency of 100% and 99% in a short time (30–60 min).

Heterogeneous photocatalysis is a promising technology to overcome the problems associated with the energy crisis and environmental pollution. Therefore, the design of a reusable dual function photocatalyst has been studied extensively. Herein, MIL-53 (Fe) was used to fabricate Fe₃O₄@C on which TiO₂ was deposited via a sol-gel route to form Fe₃O₄@C@TiO₂ (FCT) double core-shell nanocomposite. Thermal treatment effect on photocatalytic activity under different atmospheres (air, argon and hydrogen) has been investigated. Then, the temperature was optimized (300-400 °C) under hydrogen atmosphere. Furthermore, the photocatalytic performance of the prepared composite on Rose Bengal (RB) dye degradation and hydrogen generation via water-splitting has been evaluated. The FCT sample treated at 350 °C in H₂-atmosphere (FCT/H350) showed significant improvement in photodecomposition of 100 ppm of RB which completely disappeared within 40 min of the reaction. The apparent rate constant of FCT/H350 was 8.71 × 10⁻² min⁻¹, which is 4-folds faster than that of bare-TiO₂. Moreover, the FCT/H350 exhibited an initial hydrogen generation rate (HGR) of 1593 µmol·g⁻¹·h⁻¹. Spectroscopic and electrochemical measurements were conducted to investigate the possible photocatalytic mechanism and photogenerated charge carriers pathway. This study aims to develop a magnetically separable, high-performance, and bifunctional catalyst for photocatalytic applications.