Abstract Silsesquioxane 3-n-propylpyridinium chloride (SiPy+Cl-) is a water-soluble polymer that can be used as a promising material with remarkable biological effects. SiPy+Cl- can form thin films on substrate surfaces and shows suitable adhesiveness. Besides, it has high affinity for metal ions. Considering this effect as exchanger polymer and the well-known antimicrobial and cytotoxic features of copper, the aim of this study was to perform the copper functionalization of silsesquioxane 3-n-propylpyridinium chloride Cu-SiPy+Cl-. The SiPy+Cl- was obtained by the sol-gel processing method and the incorporation of copper (II) chloride was carried out by immobilization. Its characterization was performed by spectroscopic methods of Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The FTIR spectrum of SiPy+Cl- showed symmetric and asymmetric stretching of Si-O-Si group and also exhibited vibrational bands of pyridinium ring. The FTIR spectrum of Cu-SiPy+Cl- assigned typical bands displacements of the metal coordination to nitrogen atoms. Spectroscopic data recorded by 13C and 29S NMR confirmed the chemical structures of SiPy+Cl- and Cu-SiPy+Cl-. Concerning to the in vitro susceptibility assay, the antimicrobial activity against Staphylococcus aureus, Escherichia coli and Streptococus mutans was achieved by the agar-well diffusion method. Cu-SiPy+Cl- showed similar cytotoxicity than SiPy+Cl- against Calu-3 and 3T3 cell lines by the MTT colorimetric assay. Further studies are required to investigate the use of Cu-SiPy+Cl- as a novel dental material.

O objetivo deste trabalho foi desenvolver uma metodologia alternativa para o estudo e a caracterização de propriedades cristalinas de fosfatos, diretamente associadas à sua solubilidade e disponibilidade para as plantas, em "biochar" de ossos de suínos. Foram estabelecidas algumas propriedades de simetria dos fosfatos de ossos pirolisados de suínos, por meio de espectroscopia de ressonância magnética nuclear no estado sólido, análise de componentes principais e análise multivariada de resolução de curvas, em quatro amostras pirolisadas em diferentes intensidades de carbonização. O aumento nos parâmetros de carbonização (temperatura ou tempo de residência) geram diferentes estruturas de fosfatos, com aumento de sua simetria e diminuição da polarizabilidade cruzada do par ¹H-31P, o que resultou na síntese de fosfatos, provavelmente com menor solubilidade do que os produzidos com menor intensidade de carbonização. Além disso, uma nova metodologia está sendo desenvolvida para estudar e caracterizar as propriedades cristalinas de fosfatos diretamente relacionadas à sua solubilidade e disponibilidade para as plantas.

The objective of this work was to develop an alternative methodology to study and characterize the phosphate crystalline properties, directly associated with solubility and plant availability, in biochar from swine bones. Some phosphate symmetry properties of pyrolyzed swine bones were established, using solid state nuclear magnetic resonance spectroscopy, principal component analysis, and multivariate curve resolution analysis, on four pyrolyzed samples at different carbonization intensities. Increasing carbonization parameters (temperature or residence time) generates diverse phosphate structures, increasing their symmetry and decreasing the crossed polarizability of the pair ¹H-31P, producing phosphates with, probably, lower solubility than the ones produced at lower carbonization intensity. Additionally, a new methodology is being developed to study and characterize phosphate crystalline properties directly associated with phosphate solubility and availability to plants.

O objetivo deste trabalho foi obter compostos orgânicos similares aos encontrados na matéria orgânica da terra preta de índio (TPI) por meio de procedimento de funcionalização química de carvão ativado, bem como determinar a ecotoxicidade desses compostos. A partir do estudo da matéria orgânica de TPI, um modelo orgânico foi proposto e uma tentativa de reproduzi-lo foi descrita. Realizou-se a oxidação de carvão ativado pelo uso de hipoclorito de sódio em diferentes concentrações. Recorreu-se à ressonância magnética nuclear para verificar se os espectros dos produtos formados eram similares aos de ácidos húmicos de TPI. A similaridade dos espectros indicou que os produtos obtidos eram estruturas aromáticas policondensadas, com grupos carboxílicos: um condicionador de solo capaz de contribuir com a fertilidade do solo e com a sustentabilidade de seu uso. Um teste ecotoxicológico com Daphnia similis foi realizado nas frações mais solúveis (ácidos fúlvicos) do condicionador obtido. Cloretos de arila foram formados durante a síntese dos compostos orgânicos a partir do carvão funcionalizado e parcialmente removidos por meio de um processo de purificação. Contudo, é provável que algum cloreto de arila tenha permanecido no produto final, já que o teste ecotoxicológico indicou moderada toxicidade do condicionador obtido.

The objective of this work was to obtain organic compounds similar to the ones found in the organic matter of anthropogenic dark earth of Amazonia (ADE) using a chemical functionalization procedure on activated charcoal, as well as to determine their ecotoxicity. Based on the study of the organic matter from ADE, an organic model was proposed and an attempt to reproduce it was described. Activated charcoal was oxidized with the use of sodium hypochlorite at different concentrations. Nuclear magnetic resonance was performed to verify if the spectra of the obtained products were similar to the ones of humic acids from ADE. The similarity between spectra indicated that the obtained products were polycondensed aromatic structures with carboxyl groups: a soil amendment that can contribute to soil fertility and to its sustainable use. An ecotoxicological test with Daphnia similis was performed on the more soluble fraction (fulvic acids) of the produced soil amendment. Aryl chloride was formed during the synthesis of the organic compounds from activated charcoal functionalization and partially removed through a purification process. However, it is probable that some aryl chloride remained in the final product, since the ecotoxicological test indicated that the chemical functionalized soil amendment is moderately toxic.