This study examines the potential use of a low-cost biosorbent - chamomile tea residues, as an alternative to traditional adsorbents for removing Pb2+ ions from aqueous solutions. The inductively coupled plasma-optical emission spectrometry (ICP-OES) was used to measure the amount of metal before and after the removal, and a scanning electron microscope (SEM) was used to examine the morphology of the residues. To ascertain the optimal operational parameters for effective metal extraction from the aqueous solutions, a range of different concentration levels, as well as the addition of acid in the solutions, was explored. The results show that lead concentration is reduced under optimized conditions, achieving an impressive nearly 50% Pb2+ ions removal with just 0.05 g of the waste material. These findings depict chamomile tea residues as promising, affordable, and highly efficient biosorbent in lead removal for environmental remediation.

New spectrophotometric methods have been developed for the determination of josamycin in pure and dosage forms based on charge transfer reactions. Method-A was based on the complexation reaction of 1,2-naphthoquinone-4-sulphonate with josamycin. Complex absorbance was measured at 454 nm. Method-B was developed by the charge transfer reaction of the amino group of josamycin with menadione. The formed orange products showed maximum absorbance at 458 nm. Lambert Beer’s law was obeyed in the range of 1.0–28.8 μg/mL. The regression plots showed good linearity with determination coefficients of 0.9997. Molar absorptivity and Sandell’s sensitivity were calculated, with a detection limit (LOD) down to 0.28 μg/mL and quantification limits (LOQ) of 0.85–0.89 μg/mL. The validity of procedures was tested for accuracy, precision, recovery and interference and the results were in accordance with ICH guidelines, with relative standard deviation (RSD %) values less than 5.0%. Determination results of josamycin in marketed formulations were in good agreement with the labelled quantities and without any interference from excipients, indicating that they can be used for quality control purposes.

This review will primarily focus on recent methods employed for the synthesis of a diverse array of chalcones with broad-ranging biological activities, with a particular emphasis on the past five years. The utilization of aromatic methyl ketones and their derivatives as starting materials for the synthesis of various heterocyclic compounds, such as chalcones, pyrazolines, dioxolanes, aminothiazoles, and more, holds significant importance in the field of synthetic organic chemistry. The synthesized heterocyclic compounds can serve as valuable subjects for testing to assess their biological activity.

The phase equilibria in the ternary La2О3–Lu2O3–Er2O3 system at 1250°C were studied by X-ray diffraction, and electron microscopy in the overall concentration range. At 1250°С in the La2О3–Lu2O3–Er2O3 system solution fields are formed based on cubic (C) modification of Lu2O3(Er2O3), hexagonal (A) modification of La2O3, as well as ordered phase structure perovskite-type LaLuO3 (LaErO3) (R). The isothermal section of the La2O3–Lu2O3–Er2O3 phase diagram at 1250°C has shown the three one-phase fields (A-La2O3, R, C-Lu2O3(Er2O3)) corresponding to solid solutions based on starting components and two dual-phase fields (C+R, A+R) between them. The refined lattice parameters of the unit cells for solid solutions and microstructures of the definite field of compositions for the systems solid were determined.

The aim of this research work was to evaluate the role of various fractions of humic substances (HS) in binding Al(III), Fe(III) and Cu(II) ions into complexes using gel chromatography. With an increase in HS concentration in Ukraine’s surface water bodies, the share of HS’ fraction with a molecular weight of 20–5 kDa increases from 37% to 59%. In the water bodies under study the HS’ fractions with molecular weight 20–5 kDa and < 1 kDa play a principal role in the studied metals’ migration. HS with molecular weight 20–5 kDa have been found to bind the smallest amount of Al(III), Fe(III) and Cu(II) in complexes, if the metals concentration bound by 1 mg fraction of HS with a certain molecular weight is calculated. Experimental results showed that, the investigated metal ions have the ability to bind into complexes mainly by HS with a molecular weight of >20 and <1 kDa. In the water bodies under study 1 mg of humic acids has a greater binding ability in relation to Al(III), Fe(III) and Cu(II) ions than 1 mg of fulvic acids. Fulvic acids and humic acids with a molecular weight of 20–5 kDa also have the lowest binding ability.

The reaction mechanism of several Williamson‟s ether syntheses have been studied using density functional theory with triple-ζ basis sets. These computations show that the synthesis of geometrically-strained epoxide from deprotonated halohydrins is due to the combined effects of favourable solvation of the products, higher bond enthalpy of C-O bonds vs. C-Cl bonds and increased vibrational entropy of the epoxide vs. the original halohydrin. Examination of the pathways leading to the formation of larger cyclic ethers revealed that the experimentally-observed preference for the formation of five-atom rings over six-atom-rings is due to the preference of the intervening methylene groups for staggered conformations, which entails that the alkyl carbon in the reactant state leading to the six-atom cyclic ether is initially not properly aligned with the attacking alkoxide. Study of the competing elimination reactions further shows that during the synthesis of five-atom cyclic ethers the competing elimination reaction is strongly disfavoured due to steric effects. The temperature dependence of both reactions favours elimination over SN2 as temperature rises, though only when the alkoxide and the halogen moieties are not part of the same carbon chain.

In a semi-review paper, it was discussed the notion of symmetry of polyatomic systems defined as invariance under transformations, and show that this important property of atomic matter is extremely vulnerable, and may undergo internal breakdown, subject to the presence of electronic degeneracy or pseudodegeneracy. First formulated by Landau, L. in 1934, later proved and published by Jahn and Teller, this Jahn-Teller effect (JTE) underwent tremendous developments with important applications in physics, chemistry, biology, and materials science. Less attention was paid to the roots of this phenomenon and its correct interpretation in the sense of its influence on observable properties. It is shown that electronic degeneracy and its extended form, called pseudodegeneracy, are actually the only source of spontaneous symmetry breaking (SSB) in nature, including all forms of matter, beginning with elementary particles, via nuclei, atoms, molecules, and solids. Theoretically, the vulnerability of the notion of symmetry is due to the fact that, following quantum mechanics, the separation of the motion of electrons and nuclei (and, similarly, the separation of motions of elementary particles) is approximate, and hence the classical notion of polyatomic space configuration is approximate too, with SSB as one of its main violation.

The degradation of diisopropyl methylphosphonate (DIMP) in aqueous solutions was studied using ultrasound irradiation with a fixed frequency of 26.2 kHz, following the first-order kinetic model. The study's primary goal was to determine the influence of the following experimental parameters: the pH (at different values of 2, 7 and 10), the initial concentration of DIMP (at different concentrations: 7, 14, 30, 50, 80 mg/L), the processing time (at different periods: 15, 30, 45, 60, 80, 90 min), and the concentration of the additive CCl4 (at different concentrations: 0.002, 0.004, 0.006, 0.008 mg/L). A DIMP removal efficiency of 98% from aqueous solution was obtained at pH 10 and 0.008 mg/L CCl4, after an ultrasound irradiation time of 45 min, pointing out the influence of the above-mentioned experimental parameters on the DIMP degradation process.

The solid-state structure of a symmetrical carbohydrazone, namely 1,5-bis(2-hydroxy-3-methoxybenzylidene)carbonohydrazide was determined by X-ray single crystal diffraction method. Compound 1 crystallizes in the monoclinic space group P21/n with unit cell parameters a= 10.1198(6), b= 22.7847(11), c= 15.1738(10) Å, β= 100.458(6)°, Z= 4, V= 3440.6(3) Å3, R1= 0.0540. Crystal structure of 1 is defined by two crystallographic independent molecules, which are bonded via N–H···O hydrogen bond. The organic molecules are as keto tautomers with respect to the carbamide fragment, and adopt the anti conformation. 1D and 2D NMR experiments have argued on the presence of the title compound in DMSO-d6 solution mostly as keto tautomer in syn conformation, and enol-imino form when considering o-vanillin residue.

In this work, taking the Pr(III) ion as a suitable case study, the authors test the capacity of a series of Gaussian Type Orbitals (GTOs) basis sets to account for the atomic spectra of lanthanide ions. An extended relevance of this assessment can be found in modeling the luminescence of lanthanide-based materials. It was selected the Pr(III) case because it shows a rather rich collection of experimental data, emerging from the f2 and fd configurations. The energy barycenters of spectral multiplets can be equated analytically in terms of the so-called Slater-Condon parameters. By multi-configurational ab initio procedures, with basis sets from existing GTO repositories, the calculated f→f transitions are moderately higher than the experimental values, while the relative energies of Fd states undergo both under- and over-estimation. The GTO shortcomings, that are impacting the accuracy, were debated, the critical perspective spreading the seeds of future development.