Chemistry, Volume 6, Issue 1 (February 2024) – 12 articles

In this study, Melia azedarach fruit extract was used as a reducing agent and copper chloride dihydrate (CuCl₂·2H₂O) was used as a precursor in the synthesis of copper oxide nanoparticles (CuO NPs). The UV–visible spectrum showed a characteristic absorption peak of CuO NPs at 350 nm. The surface properties of the adsorbent were analyzed through various techniques, indicating the successful formation of CuO NPs. The impacts of several factors, including initial pH (4 to 8), a dose of CuO NPs adsorbent (0.01–0.05 g), dye initial concentration (10–50 mg·L⁻¹), and contact times ranging from 5 to 120 min, were examined in batch adsorption studies. Based on the experimental results, the Langmuir isotherm is well-fitted, indicating MB dye monolayer capping on the CuO NPs surface with 26.738 mg·g⁻¹ as a maximum adsorption capacity Q_m value. For the pseudo-second-order kinetic model, the experimental and calculated adsorption capacity values (q_e) exhibited good agreement. Full article

The design and development of useful chemosensors for the ultra-trace detection of environmental pollutants and contaminants is a topical area of research. Herein, we report a new nanoscale emissive Zn(II) coordination polymer (TB-Zn-CP) for differential fluorescence sensing of various antibiotics in water. TB-Zn-CP was synthesized using a unique V-shaped green emitting 4-amino-1,8-naphthalimide Tröger’s base (TBNap) fluorophore. The structural and morphological features of TB-Zn-CP were characterized by various standard spectroscopic and microscopy techniques. The fluorescence titration studies in water demonstrated a remarkable sensitivity and differential fluorescence sensing properties of TB-Zn-CP for the fast detection of different antibiotics. Among different antibiotics, chloramphenicol (CRP), 1,2-dimethyl-5-nitroimidazole (DMZ), and sulfamethazine (SMZ) displayed the highest fluorescence-quenching efficiency and superior sensitivity in their detection. The differential sensing capability of TB-Zn-CP was also indicated by visualizable color changes. The Stern–Volmer quenching constant K_SV was determined to be in the order of 10³–10⁴ M⁻¹, and the sensitivity was shown to be at a nanomolar (10⁻⁹ M) level. All these results confirm that TB-Zn-CP can be a potential and practically useful polymeric sensor for differential fluorescence and visual detection of different antibiotics in water. Full article

Perovskite solar cells (PSCs) have garnered significant attention in the photovoltaic field owing to their exceptional photoelectric properties, including high light absorption, extensive carrier diffusion distance, and an adjustable band gap. Temperature is a crucial factor influencing both the preparation and performance of perovskite solar cells. The annealing temperature exerts a pronounced impact on the device structure, while the operational temperature influences carrier transport, perovskite band gap, and interface properties. This paper provides a comprehensive review of the influence of varied annealing temperatures on the hole transport layer, electron transport layer, and perovskite layer. Additionally, we present an overview of innovative annealing methods applied to perovskite materials. The effects of diverse working temperatures on the overall performance of perovskite cells are thoroughly examined and discussed in this review. In the end, different temperature conditions under ISOS testing conditions are summarized. Full article

Heterocycles, compounds featuring heteroatoms like nitrogen, sulfur, and oxygen, are integral in fields such as synthesis, pharmacology, and medicine. Among these, benzothiazoles, formed by fusing thiazole with benzene, hold significant prominence. Their unique reactivity, especially at the carbon position between nitrogen and sulfur, has sparked wide interest. Notably, 2-substituted benzothiazoles exhibit diverse biological activities, including anticonvulsant, antimicrobial, and antioxidant properties, making them valuable in drug discovery. This review unveils an array of mesmerizing methods employed by chemists to prepare these compounds using 2-aminothiophenol as one of the precursors with other varied reactants. From novel strategies to sophisticated methodologies, each section of this review provides a glimpse into the fascinating world of synthetic chemistry of 2-substituted benzothiazoles. Delving into the diverse synthetic applications of 2-substituted benzothiazoles, this paper not only enriches our understanding of their synthesis but also sparks the imagination with the possibilities for future advancements. Full article

High-temperature cooking processes like frying, baking, smoking, or drying can induce chemical transformations in conventional food ingredients, causing deteriorative modifications. These reactions, including hydrolytic, oxidative, and thermal changes, are common and can alter the food’s chemical composition. This study transformed a combination of sucrose and histidine (Su-Hi) through charring or pyrolysis. The GC-MS profiling study showed that when sucrose and histidine (Su-Hi) were exposed to high temperatures (≈240 °C), they produced carbonyl and aromatic compounds including beta-D-Glucopyranose, 1,6-anhydro (10.11%), 2-Butanone, 4,4-dimethoxy- (12.89%), 2(1H)-Quinolinone-hydrazine (5.73%), Benzenamine (6.35%), 2,5-Pyrrolidinedione, 1-[(3,4-dimethylbenzoyl)oxy]- (5.82%), Benzene-(1-ethyl-1-propenyl) (5.62%), and 4-Pyridinamine-2,6-dimethyl (5.52%). The compounds mentioned can permeate the cell membrane and contribute to the development of cell death by necrosis in human immune cells. The evidence suggests that a specific set of pyrolytic compounds may pose a risk to immune cells. This investigation reveals the complex relationship between high-temperature cooking-induced transformations, compound permeation inside the cells, and downstream cellular responses, emphasizing the significance of considering the broader health implications of food chemical contaminants. Full article

Iron is a heavy metal that often contaminates water. High iron concentrations are toxic to human health, so monitoring its presence in water is necessary. Iron in water can be detected using an optical sensor (optode). This research aims to fabricate an optode based on a cellulose triacetate membrane with a selective reagent against Fe(III). The optode was fabricated by mixing cellulose triacetate polymer, a plasticiser (a mixture of oleic acid and acetophenone), aliquot-336, and thiocyanate as a selective reagent. Membrane performance was tested based on working range, linearity, limit of detection and quantitation, precision, and accuracy. The performance of the membrane showed a linear response in the concentration range of 0.1–4 mg/L with a coefficient of determination (R²) of 0.9937, limit of detection of 0.0250 mg/L, limit of quantitation of 0.0757 mg/L, repeatability precision with a relative standard deviation of 3.31%, and an accuracy of 100.49%. Optode selectivity was good for interfering ions Cr(VI) and Pb(II). The colour complex of the optode was stable until the 10th day. The application of iron detection in water samples shows an average concentration of 0.2541 mg/L with good precision and accuracy. Full article

The thioether-functionalized 2-azabutadiene (ⁱPrS)₂C=C(H)-N=CPh₂ L ligates to CdI₂ and HgI₂ to form the chelate compounds [CdI₂{(ⁱPrS)₂C=C(H)-N=CPh₂] (1) and [HgI₂(ⁱPrS)₂C=C(H)-N=CPh₂] (2). Their crystal structures were solved via X-ray diffraction. Both crystallize in the non-centrosymmetric space groups: monoclinic P2₁ (1) and orthorhombic P2₁2₁2₁ (2), respectively. The closed-shell d¹⁰ metal centers are four-coordinated (two iodides and S and N coordinating atoms from the ligand L) in both complexes. The geometrical indexes τ indicate that a highly distorted trigonal pyramidal is adopted for 1 and a seesaw geometry for 2. The comparative nature of metal–ligand bonds is discussed on the basis of metric parameters and of QT-AIM (quantum theory of atoms in molecules) calculations. L was also treated with CuI to obtain the dinuclear species [LCu(μ₂-I₂)CuL] (3), in which the two Cu(I) centers are linked by a short metal–metal bond. The geometric and electronic properties of 3 are compared with those of 1 and 2. Full article

A new polymorph of anhydrous β-cyclodextrin (polymorph III) was obtained and characterized for the first time using powder X-ray diffraction, infrared spectroscopy, and thermal analysis. The solution enthalpy and time of dissolution in water were determined using solution calorimetry for this polymorph and compared with those of the dried commercial form of β-cyclodextrin (polymorph I), its amorphous form, and 2-hydroxypropyl-β-cyclodextrin. The specific heat capacities of polymorphs I and III were determined using differential scanning calorimetry across a wide range of temperatures, providing enthalpy and Gibbs energy values for the polymorphic transition at 298 K. The affinities of polymorph III and 2-hydroxypropyl-β-cyclodextrin for water were characterized by determining their hydration isotherms, which provided values of hydration Gibbs energy. Being energy-rich, the new-found polymorph of β-cyclodextrin has a significantly higher dissolution rate and an increased affinity for water compared with the dried commercial form of β-cyclodextrin. These properties render the new polymorph promising in industrial applications for guest inclusion in aqueous solutions and pastes, and may be a desirable alternative for water-soluble β-cyclodextrin derivatives. Full article

Polyamides (PAs) undergo local environmental degradation, leading to a decline in their mechanical properties over time. PAs can experience various forms of degradation, such as thermal degradation, oxidation, hydrothermal oxidation, UV oxidation, and hydrolysis. In order to better comprehend the degradation process of PAs, it is crucial to understand each of these degradation mechanisms individually. While this review focuses on hydrolysis, the data from degrading similar PAs under pure thermal oxidation and/or hydrothermal oxidation are also collected to grasp more perspective. This review analyzes the available characterization data and evaluates the changes in molecular weight, crystallinity, chemical structure, and mechanical properties of PAs that have aged in oxygen-free water at high temperatures. The molecular weight and mechanical strength decrease as the crystallinity ratio rises over aging time. This development is occurring at a slower rate than degradation in pure thermal oxidation. By combining the data for the changes in mechanical properties with the ones for molecular weight and crystallinity, the point of embrittlement can be not only predicted, but also modeled. This prediction is also shown to be dependent on the fibers, additives, types of PA, pH, and more. Full article

A new method for the synthesis of azido-propargyloxy derivatives of 1,3,5-triazine has been developed utilizing the nitrosation of hydrazyno-1,3,5-triazines. New hydrazines (2-hydrazino-4,6-bis(propargyloxy)-1,3,5-triazine and 2,4-dihydrazino-6-propargyloxy-1,3,5-triazine) were synthesized and characterized via FTIR, NMR spectroscopy and elemental analysis. The hyperbranched polymers with azide (diazide monomer) and propargyloxy terminal groups were obtained via the azide-alkyne polycycloaddition reaction of diazide and monoazide AB₂-type monomers. The antibacterial activity against Escherichia coli bacteria of 2,4,6-trispropargyloxy-1,3,5-triazine, 2-azido-4,6-bispropargyloxy-1,3,5-triazine, and 2,4-diazido-6-propargyloxy-1,3,5-triazine and their hyperbranched polymers was studied. Only 2,4-diazido-6-propargyloxy-1,3,5-triazine has weak antibacterial activity in comparison with ampicillin. The cytotoxicity of these compounds against M-HeLa, FetMSC, and Vero cell lines was also studied. 2,4,6-trispropargyloxy-1,3,5-triazine does not show any cytotoxic effect (IC₅₀ ≥ 280 µM). It was shown that the presence of an azide group in the compound directly affects the cytotoxic effect. Hyperbranched polymers have a less cytotoxic effect against M-HeLa (IC₅₀ > 100) in comparison with monomers (IC₅₀ = 90–99 µM). This makes it possible to use these polymers as the basis for biocompatible materials in biomedical applications. Full article