A fast method for preparing aqueous graphene oxide (GO) dispersions by electrochemical oxidation of a graphite anode without preliminary intercalation with oxidizing agents is proposed. Ultrasonic probing was used in the modulation mode of ultrasonic waves (work/rest) for more efficient graphite oxidation–exfoliation. It is shown that the 4/2 s mode of ultrasonic modulation is the most effective due to the probe material’s low corrosion while maintaining the optimum synthesis temperature not exceeding 30–35 °C and achieving the best characteristics of the resulting product. Three cases of anodic oxidation of graphite to obtain graphene oxide were considered: (1) a combined cathode–anode compartment, (2) a split cathode–anode salt-bridged compartment, and (3) separated anode compartment with a 3.5 kDa dialysis membrane. It was determined that the approach to synthesis with a divided cathode–anode compartment makes it possible to obtain GO sheets with fewer defects compared to chemical methods or methods with a combined cathode–anode compartment and makes it possible to control the oxidation degree of the material (C:O ratio) by varying the current density. The prepared samples showed good stability for more than six months. The spectral and morphological characteristics were studied. Using chemiluminometry in the luminol/Co(II)/H₂O₂ system, the antioxidant properties concerning three key reactive oxygen species (H₂O₂, superoxide anion radical, and hydroxyl radical) were demonstrated. It was also shown that the prepared GO dispersions do not induce lipid and phospholipid peroxidation.

The feasibility of saturating aqueous anoxic solutions with in situ-generated high-purity nitric oxide (NO) is shown herein. A methemoglobin assay estimated the average nitric oxide concentration to be ca. 20 ± 3 µM. Graphene oxide aqueous dispersions were prepared by ultrasound-assisted extra exfoliation. These dispersions, including unpurified (pristine) samples and samples purified from transition metal impurities (bulk) fractions (bulkGO) and (nano) separated fractions (nanoGO) in a range of 0.5 to 14 kDa were prepared with ppm level concentrations. A robust and reproducible chemiluminescence (CL) assay validated the interaction between graphene oxide and NO in a luminol-based system. The results showed a significant increase in NO scavenging activity within the bulkGO fractions to nanofractions ranging from 14 to 3.5 kDa. The different reaction pathways underlying the transformation of nitric oxide are being evaluated, focusing on understanding how its presence or absence affects these processes. Our kinetic model suggests a significant difference in nitric oxide regulation; nanoGO demonstrates an interception rate seventy-times higher than that achieved through CL quenching.

A new type of dimerization of dimethyl (β-styryl)malonates in the presence of TiCl₄ accompanied by elimination of a methanol molecule was discovered. Selective methods for the synthesis of substituted trimethyl 4-hydroxy-[1,1′-biaryl]-3,3,5(2H)-tricarboxylates and trimethyl 7-hydroxy-9,10-dihydro-5,9-methanobenzo[8]annulene-6,8,8(5H)-tricarboxylates were developed. The regularities of the occurring processes were determined and a similar reaction of β-styrylmalonate with benzylidenemalonate in the presence of TiCl₄ was performed in the scope of the suggested mechanism.

Zinc is an essential micronutrient in agricultural systems, fulfilling vital roles in both plant physiology and modern fertilizer formulations. Despite its importance, zinc deficiency has emerged as one of the most prevalent micronutrient limitations in global agriculture. Humic acids (HA) can serve as effective transporters of trace elements for crops, including in foliar fertilization. Our investigation addressed two key aspects: (1) the synthesis of HA-stabilized ZnO nanoparticles, and (2) the assessment of nanoparticle efficacy as zinc sources for foliar fertilization. ZnO and HA-coated ZnO nanoparticles were synthesized via a chemical deposition method and characterized by FTIR, XRD, DLS, ELS, UV-Vis spectroscopy, and TEM. The penetration ability of the nanoparticles through plant leaves was investigated using wheat sprouts. After 24 h of saturation, the plants were dried, and their leaves and seedlings were dissolved in nitric acid; the solution was analyzed by ICP-AES. HA-coated ZnO nanoparticles showed competitive performance compared to conventional zinc chelates used in agriculture. Wheat leaf studies confirmed that nanoparticle accumulation and uptake are pH-dependent, with acidic conditions favoring HA-coated ZnO nanoparticles. These findings provide valuable insights for developing advanced zinc-containing formulations for foliar crop fertilization. The demonstrated effectiveness of HA-stabilized ZnO nanoparticles suggests they represent a promising alternative to traditional zinc supplements in agriculture.