Síntese, caracterização e estudo de propriedades de sorção iônica de polímeros de coordenação aniônicos envolvendo policarboxilatos, aminas alifáticas e metais

Abstract

This thesis reports the synthesis, characterization, and property investigation of seven novel coordination polymers obtained through solvothermal and reflux methods using water or ethanol as solvents. The materials were prepared from combinations of polycarboxylic acids, aliphatic amines, and metal salts containing Mg²⁺, Co²⁺, Cu²⁺, and Zn²⁺, yielding six anionic and one neutral crystalline, structurally well‑defined compounds. Their characterization involved elemental analysis (CHN), thermal analysis (TG/DTA), spectroscopic techniques (FTIR and Raman), and structural determination by single‑crystal and powder X‑ray diffraction, complemented by sorption studies monitored by EDS, FAAS, and UV‑vis spectroscopy, as well as zeta potential measurements and textural analysis via N₂ adsorption at 77 K using the BET method. Three polymers belong to the iPC3D‑paMbt series (M = Mg²⁺, Co²⁺, Zn²⁺), formed by bt⁴⁻ and H₂pa²⁺, exhibiting isostructural 3D networks with pts topology, distorted octahedral metal centers, and bt⁴⁻ ligands acting in bridging bidentate and monodentate modes, with H₂pa²⁺ cations occupying the pores. The iPC3D‑paMgbt compound showed no detectable sorption of Tb³⁺ in ethanol, whereas iPC3D‑paZnbt efficiently adsorbed Cu²⁺ n alcoholic media, simulating cachaça matrices, with color change, confirmed copper incorporation, structural stability after desorption, and a maximum adsorption capacity of 0.246 mg·g⁻¹. The iPC2D‑baCobt polymer, composed of Co²⁺, bt⁴⁻, and H₂ba²⁺, forms a 2D lamellar sql‑type network with low porosity and a BET surface area of 12.5 m²·g⁻¹. The iPC2D‑DMACubt material, containing Cu²⁺ and bt⁴⁻, also displays a 2D lamellar structure with octahedral metal centers and charge compensation by in situ‑generated dimethylammonium cations. The iPC3D‑paCobta compound, formed by Co²⁺, bta⁴⁻, and H₂pa²⁺, exhibits a 3D pts‑type network and demonstrated efficient ion exchange with [Ni(H₂O)₆]²⁺ (adsorption capacity of 730 mg·g⁻¹) and incorporation of Mg²⁺ as [Mg(H₂O)₆]²⁺. Finally, the neutral polymer PC2D‑Mgbta, composed of Mg²⁺ and bta⁴⁻, presents a 2D lamellar network stabilized by extensive hydrogen bonding between coordinated and free water molecules, contributing to supramolecular cohesion.