Acta Chimica Slovenica最新文献

Efficiency of time use is a key factor in chemistry calculation tasks, affecting both, personal and professional domains. This study is dedicated to finding the fastest methods for accomplishing chemistry tasks. Our investigation delves into the comparative temporal outlays made by students as they engage three different approaches: using an electronic calculator, a basic calculator app on a smartphone, and a desktop computer calculator. As part of our research, we examine a cohort of 52 Slovenian university students, preservice teachers who were actively enrolled in chemistry and related science programs, spanning the academic years of 2019 and 2022.  The results from 2019 show that students can solve the chemistry tasks most quickly using electronic calculator and take the most time to calculate the tasks using smartphones (Δmean = 133 s; ΔSD = 5 s; Δmin = 97 s; Δmax = 131 s). An even larger difference is observed from the 2022 study year (Δmean = 189 s; ΔSD = 129 s; Δmin = 170 s; Δmax = 625 s). In summary, although smartphones are recognised as a multitasking device, replacing traditional single-purpose devices, they have not been able to outperform them.

It is well known that the guanidinium group in Arginine plays an important role in noncovalent interactions. However, its role is not well documented since the selection of its global minimum structure is still controversial. The main difficulties on obtaining accurate results lie on:  neutral Arginine can occur in 3 forms, two of which are canonical and one is zwitterion; each form has degenerate enantiomers D- and L-; its numerous degrees of freedom make it challenging to perform a thorough study; the short-range interactions require higher levels of theory to correctly describe them. Thus, we have performed a meticulous global minimum search. We performed optimizations of the systems at the PBE0 /Def2TZVP level of theory and single point calculations at the DLPNO-CCSD(T)/Def2TZVP level with zero-point corrections at PBE0 /Def2TZVP. We also analyzed Thermal Populations and IR Spectra of the systems to fully understand Arginine's behavior. The results show the energy minima structures strongly rely on its internal nitrogen-rich groups.

In 2020, around 19.3 million new cancer cases resulted in 3.5 million deaths. It is estimated that there will be 28.4 million cases by 2040. Plant-derived natural products, such as alkaloids, flavonoids, terpenoids, and phenolic compounds, offer a wide range of chemical structures and biological activities that can be explored for their potential in cancer research. In a particular study, researchers investigated the potential anticancer effects of Fallopia flower extracts on cancer induced by TAA (a carcinogen). They examined the extracts to identify specific amino acids with antioxidant properties and assessed their impact on liver function and tissue structure. The results showed that the plant extracts had positive effects on the histological section of the TAA-treated group. Additionally, the group of male rats treated with TAA and a chemotherapy drug called MMC displayed positive effects. Similarly, the group of male rats treated with TAA, flower plant extract, and MMC also showed positive effects. These findings suggest that the extract from Fallopia flowers could be considered as a traditional therapy with potential anticancer properties.

Presently, there is a necessity to design novel methods because of quercetin's significant biological relevance. Therefore, we developed the rose petal-derived graphene quantum dots embedded zinc metal organic frameworks (RP-GQDs@Zn-MOFs) based fluorescence "On-Off-On" nanoprobe for quercetin sensing. Initially, RP-GQDs were synthesized using rose petal waste and then subjected to embedding into Zn-MOFs. Herein, the addition of copper ions (Cu2+) results in fluorescence "Switch Off" whereas quercetin inclusion resulted in the formation of the quercetin-Cu2+ complex. It regains the RP-GQDs@Zn-MOFs quenched fluorescence termed as "Switch On" because of the static quenching mechanism. It demonstrated a wide concentration range and low detection limit of 100 ng/mL to 1400 ng/mL (R2=0.99) and 37.84 ng/mL, respectively. The selectivity study shows the high specificity for quercetin in presence of interfering compounds because of Cu2+ coordination between the carbonyl oxygen atom and the 3-OH group of quercetin. Moreover, the designed probe shows good stability, repeatability, and real-time analysis possibility.

This work summarizes our research on synthesis, characterization and toxicity of selected UV-A filters and their antioxidant shield in commercial formulation - resveratrol. Benzophenone type of UV filters react under disinfection conditions with chlorine and form different mono- and dichlorinated products, while dibenzoylmethane derivatives, such as avobenzone, react with chlorine and form two main bridge chlorinated products followed by numerous chlorinated species at the advanced stages of the process. Resveratrol showed three main susceptible centers to chlorination, starting from the electrophilic addition to the double bond and continuing with the chlorination of the phenolic moieties. Several experiments conducted under different disinfection conditions (pool/sea water, addition of salts, irradiation) showed basically similar chlorination patters with some variations in terms of product formation. The results of toxicity assessment using different test organisms (Vibrio fischeri, microalgae, daphnids) have shown different sensitivity of testing organisms to the parent UV filters in comparison with chlorinated products as well as different toxicity for specific UV filter in comparison to the others. As the closing loop of all experiments in the laboratory, an up-scaling to the real human skin is presented.

The research focuses on investigating the cytotoxic effects of Cu(II) complexes bearing isatine groups on cancer cells. These complexes were tested against lung carcinoma (A549) and breast carcinoma (MCF-7) cell lines using the MTT assay, with cisplatin as a positive control. Additionally, their effects on human normal cell line 3T3 were assessed. The Cu(L1)2 complex exhibited significant inhibitory effects on tumor cells in a dose-dependent manner, although not as potent as cisplatin. The cytotoxic selectivity indices (SI) indicated acceptable selectivity levels for both cancer cell lines, indicating potential for selective lethality. The crystal structure of one compound was confirmed, revealing van der Waals interactions and hydrogen bonding in the packing.

Benzodiazepines and their derivatives belong to a category of new psychoactive substances that have been introduced into the continually expanding illicit market. However, there is a notable absence of available pharmacological data for these substances. To gain a deeper understanding of their pharmacology, we employed the Monte Carlo optimization conformation-independent method as a tool for developing QSAR models. These models were built using optimal molecular descriptors derived from both SMILES notation and molecular graph representations. The resulting QSAR model demonstrated robustness and a high degree of predictability, proving to be very reliable. Moreover, we were able to identify specific molecular fragments that exerted both positive and negative effects on binding activity. This discovery paves the way for the swift prediction of binding activity for emerging benzodiazepines, offering a faster and more cost-effective alternative to traditional in vitro/in vivo analyses.

The antioxidant interactions between several natural phenolic and non-phenolic compounds (catechin, quercetin, rutin, resveratrol, gallic acid and ascorbic acid) and organic acids (tartaric, citric and dihydroxyfumaric acids) have been investigated through the DPPH method. Main additive and antagonistic interactions have been found for the combinations of catechin, quercetin, resveratrol and gallic acid with tartaric and citric acids; such behavoir can be due to the enhanced stability of the phenolic compounds in the acidic media. Rutin and ascorbic acid demonstrated good synergistic effects with tartaric and citric organic acids, which may rely on the polymerization processes for rutin, and change of the mechanism of action in case of ascorbic acid. In combination with dihydroxyfumaric acid, the mixtures showed dose - dependent synergistic, additive or antagonistic antioxidant interactions. Good synergystic effects have been registered for the binari mixtures of dihydroxyfumaric acid with ascorbic acid, catechin and rutin.

The reaction of 2-benzimidazolethiole (2-BIT) with copper dichloride in the presence of two equivalents of triphenylphosphine led to a binuclear complex of the type [Cu(µ-S-2-BIT)2(Ph3P)2Cl2]: dichloridobis(μ-1,3-dihydro-2H-benzimidazole-2-thione)bis(triphenylphosphi ne)-di-copper. The Cu(I) compound has been fully identified by elemental analysis, molar conductivity, FT-IR, UV/Vis, and single-crystal X-ray diffraction (XRD). The XRD study reveals that the complex has distorted tetrahedral geometry around the Cu(I)center, which contains two bridge sulfur atoms. The Hirshfeld surface mapped over dnorm, shape index, and curvature revealed important H...H, H... C/C...H, and H... Cl/Cl...H intermolecular interactions as the main contributors to crystal packing. The natural bond orbital (NBO) was applied to understand the strength of nucleophilic and electrophilic attack between ligands and Cu(I) ions. Furthermore, density functional theory (DFT) was employed to demonstrate the molecular reactivity and stability of the ligands and copper complex.

Two new polythioamides were prepared through the polycondensation reaction between thiourea monomers and terephthaloyl dichloride, while the thiourea monomers were synthesized by the interaction of aromatic (4,4'-diaminophenylsulfone) or alicyclic (1,2-cyclohexanediamine) diamine with ammonium thiocyanate. The elemental composition of polythioamides was confirmed through CHN microanalysis. The structure and properties of thiourea monomers and polythioamides were determined through proton NMR, UV-Vis, FT-IR spectroscopy, fluorescence, TGA/DTA and SEM. The polythioamides indicated high thermal stabilities which were assessed from their Tmax (temperature indicating highest rate of weight loss) values (670 °C and 346 °C) observed in their DTG graphs. The thioureas and polythioamides were fluorescent and showed multicolor (violet, green, yellow, orange and red) emissions at different excitation wavelengths. All the synthesized compounds were also tested for their antifungal and antibacterial functions and showed antibacterial activity against Salmonella typhi, Bacillus subtilis and Staphylococcus aureus, and antifungal activity against Candida albicans.