Acta Chimica Slovenica最新文献

In this paper, six new salts of 2-formylpyridine N4-allylthiosemicarbazone ([H2L]X⸱nH2O, where X is NO3- (1), NH2SO3- (2), Cl- (3), Cl3CCOO- (4), Cl2CHCOO- (5), ClCH2COO- (6); n = 0 (1, 3, 5, 6), 1 (2, 4)) were synthesized and physico-chemically characterized by elemental analysis, molar conductivity measurements, FT-IR studies, 1H and 13C NMR. The crystal structures of compounds 1-5 were determined by single-crystal X-ray diffraction. Analysis of crystal data shows that the structures of these compounds consist of protonated thiosemicarbazone H2L+, anions of acid residue and water molecules in 2 and 4. These compounds manifest antiradical activity toward ABTS•+ cation radicals that exceeds the activity of non-protonated thiosemicarbazone HL and trolox, that is used in medicine. The most active one is compound [H2L]Cl (3) with IC50 value 9.9 μmol/L. Density Functional Theory calculations showed that the electronic structure of cation H2L+ is more favorable for electron acceptation if compared with HL.

Reaction of 2-chlorobenzaldehyde with 3-trifluoromethylbenzohydrazide, 3,5-dimethoxybenzohydrazide, 4-trifluoromethylbenzohydrazide and 2-bromobenzohydrazide, respectively, in methanol afforded four new aroylhydrazones. The newly synthesized compounds were characterized by means of elemental analysis, IR and 1H NMR spectroscopy, and their structures were further confirmed by X-ray single crystal determination. The compounds were assayed for their antibacterial activities against E. coli, P. aeruginosa, B. subtilis, and S. aureus and show interesting results.

Two mononuclear zinc(II) complexes [ZnCl2(HL)] (1) and [ZnBr2(HL)] (2), and a polymeric zinc(II) complex [Zn(dca)L] (3), where HL is the zwitterionic form of the Schiff base 2,4-difluoro-6-(((2-pyrrolidin-1-yl)ethylimino)methyl)phenol (HL), L is the monoanionic form of HL, and dca is dicyanoamide, were prepared and characterized by elemental analysis and infrared spectroscopy, as well as X-ray single crystal determination. Complexes 1 and 2 are isostructural, in which the Zn atoms are in tetrahedral coordination. The Schiff base ligands in both complexes are coordinate to the Zn atoms through phenolate oxygen and imino nitrogen. The zinc atoms in complex 3 are in tetrahedral coordination and are bridged by dicyanoamide ligands. The Schiff base ligand in this complex is coordinates to the zinc atom through phenolate oxygen, imino nitrogen and pyrrolidine nitrogen. Molecules of the three complexes are stabilized by hydrogen bonds. The biological assay indicates that the complexes have good antimicrobial activities on the bacteria strains Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi and Staphylococcus aureus.

In this study, the rapid, simple and sensitive voltammetric method has been developed for the quantification of leuprolide acetate in the presence of anionic surfactant on a glassy carbon electrode. The effect of surfactant types, pH of the medium, scan rate on the voltammetric response of leuprolide acetate were evaluated. The oxidation peak currents of leuprolide acetate were enhanced in the presence of 8.0 x 10-5 M sodium dodecyl sulfate. The monomer structure of sodium dodecyl sulfate can be attracted to amino moieties in drug structure via the electrostatic interaction. The voltammetric behavior of leuprolide acetate exhibited irreversible and diffusion-adsorption mix controlled processes by cyclic voltammetry. Under optimized conditions, the proposed method exhibits linearity in the concentration range of 3.64 x 10-9 - 2.00 x 10-7 M with a nano-level detection limit of 4.70 x 10-10 M by adsorptive stripping square wave voltammetry. The developed method was applied to an injectable dosage form for the determination of leuprolide acetate with satisfactory accuracy and precision.

The increasing demand for sustainable and efficient energy conversion technologies requires ongoing exploration of new materials and methods. Flash Joule Heating (FJH) emerges as a promising technique for large-scale graphene production, boasting advantages over conventional methods. FJH rapidly heats carbon-based precursors to extreme temperatures using high electric currents, forming flash graphene upon rapid cooling. This approach offers rapid processing, high throughput, and can utilize diverse carbon sources, including biomass and waste, making it sustainable and cost-effective. Moreover, it generates minimal waste and yields flash graphene with enhanced conductivity, crucial for energy applications. FJH's scalability, versatility, and efficiency position it as a key method for commercializing graphene across industries, particularly in energy conversion. This review comprehensively discusses FJH synthesis principles, emphasizing efficiency, scalability, and sustainability. Additionally, it analyzes recent advancements in flash graphene-based electrocatalysts, exploring their impact on renewable energy and sustainable electrocatalysis. Challenges and opportunities are addressed, outlining future research directions. Continued advancements hold immense potential to revolutionize graphene production and integrate it into next-generation energy systems, driving the transition towards cleaner energy solutions.

The sponge is one of the potential sources of bioactive compounds. Among them, the sponge Aaptos has been a promising discovery of leading drugs including aaptamine (1). This study investigated the aaptamine (1), spectroscopically determined, from Aaptos sp. collected from Bunaken National Park, Indonesia, as an anticancer agent, specifically targeting colorectal cancers (CRCs). Compound 1 showed potent cytotoxicity against DLD-1 and Caco-2 with IC50 values of 30.3 and 236.8 µg/mL, respectively. In addition, the exposure of compound 1 on those colorectal cancer cells could promote cell cycle arrest and relatively induce necrotic cell death.

Schiff bases have various pharmacological activities due to the azomethine (-C=N-) group. Usnic acid is the most famous lichen metabolite and it contains two carbonyl groups to synthesize the Schiff base derivatives with primary amines. Therefore, in the current study, the known Schiff base derivatives (2-5) of usnic acid (1) were synthesized to explore their antidiabetic, neuroprotective, antioxidant, antidepressant and anti-Parkinson's properties.  Among the tested compounds, compound 4 exhibited the strongest antidiabetic and antidepressant activities, inhibiting α-glycosidase, α-amylase and MAO-A enzyme activities, respectively. Moreover, all of the tested compounds strongly scavenged the ABTS and DPPH radicals and the ABTS radical scavenging activities of 3 and 4 were found to be higher than the commercial antioxidants BHA and trolox. All of the tested compounds did not show any significant anti-Parkinson's and neuroprotective activities. In conclusion, compound 4 can be suggested as a drug candidate molecule for further studies due to its strong antioxidant, antidiabetic and antidepressant properties.

A novel organic-inorganic hybrid metal cadmium complex [Cd (MCA)2(Phen)(H2O)] (MCA = 3-hydroxyquinoline-4-carboxylic acid anion; Phen = 1,10-phenanthroline) was synthesized by solvothermal method and characterized by single crystal X-ray diffraction. The title complex exhibits a two-dimensional structure through hydrogen bonding and π···π packing interactions. Solid state photoluminescence spectra show that they exhibit red emission bands at 616 nm, and time-dependent density functional theory calculations show that they are ligand-to-ligand charge transfers. Solid diffuse reflection spectra show that the energy band gap of the complex is 2.32 eV.

The ternary system CuCl-allylamine-dabco (dabco = 1,4-diazabicyclo[2.2.2]octane) with an excess of HCl was explored. Starting from an ethanol solution of CuCl2·2H2O, allylamine and dabco titrated with HCl, copper(I) salts were generated by means of electrochemical alternating current synthesis. In addition to the already known (H2dabco)[CuCl3], two modifications of the (allNH3)2[Cu2Cl4] compound and some Cu(II) by-products, a new mixed ligand compound of the composition (H2dabco)2[Cu4Cl9(allNH3)] was synthesized and structurally investigated. Its structure contains unique Cu4Cl95- inorganic moiety bound via a h2-interaction allylammonium moiety and discrete (H2dabco)2+ cations. The structure is stabilized by the system of N-H···Cl hydrogen bonds.