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Deferoxamine (DFO) is one of the most potent iron ion complexing agent belonging to a class of trihydroxamic acids. The extremely high stability constant of the DFO–Fe complex (log β = 30.6) prompts the use of deferoxamine as a targeted receptor for scavenging Fe(III) ions. The following study aimed at deferoxamine immobilization on three different supports: poly(methyl vinyl ether- alt -maleic anhydride), silica particles, and magnetite nanoparticles, leading to a class of hybrid materials exhibiting effectiveness in ferric ion adsorption. The formed deferoxamine-loaded hybrid materials were characterized with several analytical techniques. Their adsorptive properties toward Fe(III) ions in aqueous samples, including pH-dependence, isothermal, kinetic, and thermodynamic experiments, were investigated. The materials were described with high values of maximal adsorption capacity q m , which varied between 87.41 and 140.65 mg g –1 , indicating the high adsorptive potential of the DFO-functionalized materials. The adsorption processes were also described as intense, endothermic, and spontaneous. Moreover, an exemplary magnetically active deferoxamine-modified material has been proven for competitive in vitro binding of ferric ions from the biological complex protoporphyrin IX–Fe(III), which may lead to a further examination of the materials’ biological or medical applicability.

Adsorptive materials demand meeting several criteria, including the versatility of applications, synthetic easiness, reusability, eco-friendliness, and low-cost production. Therefore, the following study aimed at the synthesis of dual-polymeric material containing biocompatible poly­(methyl vinyl ether−alt−maleic anhydride) (PMVEAMA) matrix functionalized with multifunctional and branched poly­(amidoamine) (PAMAM) dendrimer. The obtained PMVEAMA−PAMAM material was characterized with several analytical techniques and investigated as an adsorbent of several analytes, which belong to a class of either water contaminants or bioactive molecules. Adsorption isothermal studies have been performed, using aqueous solutions of analytes (conditions: distilled water or phosphate buffer pH 8.0 solutions of concentration ranging between 0.1 and 1 mM; room temperature; 24 h incubation), which revealed highly satisfactory results of the maximal adsorption capacity q m values, e.g. 367.65 and 304.88 mg g–1 for Congo Red and folic acid, respectively. The studies aiming to a description of the material–dye complexes included also adsorption kinetic studies and 5 cycles of adsorption/desorption steps, showing fast and intense dye adsorption and high reusability of the material toward dye scavenging. Moreover, PMVEAMA−PAMAM has been investigated for the drug delivery of four biocompounds. The release studies performed in three different media showed that material–drug complexes dissociate to the highest extent at pH 2.0, reaching maximally 94.90% for salicylic acid. The performed experiments indicate the versatility of PMVEAMA−PAMAM applications, including chemical analysis, environmental protection, and in vitro biomedical application.

The study of various forms of pharmaceutical substances with specific physicochemical properties suitable for putting them on the market is one of the elements of research in the pharmaceutical industry. A large proportion of active pharmaceutical ingredients (APIs) occur in the salt form. The use of an acidic coformer with a given structure and a suitable pK a value towards purine alkaloids containing a basic imidazole N atom can lead to salt formation. In this work, 2,6-dihydroxybenzoic acid (26DHBA) was used for cocrystallization of theobromine (TBR) and caffeine (CAF). Two novel salts, namely, theobrominium 2,6-dihydroxybenzoate, C7H9N4O2 +·C7H5O4 − (I), and caffeinium 2,6-dihydroxybenzoate, C8H11N4O2 +·C7H5O4 − (II), were synthesized. Both salts were obtained independently by slow evaporation from solution, by neat grinding and also by microwave-assisted slurry cocrystallization. Powder X-ray diffraction measurements proved the formation of the new substances. Single-crystal X-ray diffraction studies confirmed proton transfer between the given alkaloid and 26DHBA, and the formation of N—H...O hydrogen bonds in both I and II. Unlike the caffeine cations in II, the theobromine cations in I are paired by noncovalent N—H...O=C interactions and a cyclic array is observed. As expected, the two hydroxy groups in the 26DHBA anion in both salts are involved in two intramolecular O—H...O hydrogen bonds. C—H...O and π–π interactions further stabilize the crystal structures of both compounds. Steady-state UV–Vis spectroscopy showed changes in the water solubility of xanthines after ionizable complex formation. The obtained salts I and II were also characterized by theoretical calculations, Fourier-transform IR spectroscopy (FT–IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and elemental analysis.

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The functional silica-based materials functionalized with a strong nitrogen base TBD (SiO2-TBD) deposited via a linker or with a basic poly(amidoamine) dendrimer containing multiple terminal amine groups -NH2 (SiO2-EDA) and functional polymers containing a strong phosphazene base (Polymer-Phosphazene) or another basic poly(amidoamine) dendrimer (PMVEAMA-PAMAM) were tested as sorbents dedicated to a mixture of nitrophenols (p-nitrophenol and 2-methoxy-5-nitrophenol), which are analogs of nitrophenols used in plant growth biostimulants. The adsorptive potential of the studied materials reached 0.102, 0.089, 0.140, and 0.074 g of the nitrophenols g−1, for SiO2-TBD, SiO2-EDA, polymer-phosphazene, and PMVEAMA-PAMAM, respectively. The sorptive efficiency of the analytes, i.e., their adsorption on the functional materials, the desorption from the obtained [(sorbent)H+ − nitrophenolates–] complexes, and interactions with the used soil, were monitored using mass spectrometry (MS) technique with electrospray (ESI) and flowing atmosphere-pressure afterglow (FAPA) ionizations, for the analysis of the aqueous solutions and the solids, respectively. The results showed that the adsorption/desorption progress is determined by the structures of the terminal basic domains anchored to the materials, which are connected with the strength of the proton exchange between the sorbents and nitrophenols. Moreover, the conducted comprehensive MS analyses, performed for both solid and aqueous samples, gave a broad insight into the interactions of the biostimulants and the presented functional materials.