The vanadium(V) complexes have been investigated as potential anticancer agents which makes it essential to evaluate their toxicity for safe use in the clinic. The large-scale synthesis and the acute oral toxicity in mice of the oxidovanadium(V) Schiff base catecholate complex, abbreviated as [VO(HSHED)dtb] containing a redox-active ligand with tridentate Schiff base (HSHED = N-(salicylideneaminato)-N’-(2-hydroxyethyl)-1,2-ethylenediamine) and dtb = 3,5-di-(t-butyl)catechol ligands were carried out. The body weight, food consumption, water intake as well biomarkers of liver and kidney toxicity of the [VO(HSHED)dtb] were compared to the precursors, sodium orthovanadate, and free ligand. The 10-fold scale-up synthesis of the oxidovanadium(V) complex resulting in the preparation of material in improved yield leading to 2–3 g (79%) material suitable for investigating the toxicity of vanadium complex. No evidence of toxicity was observed in animals when acutely exposed to a single dose of 300 mg/kg for 14 days. The toxicological results obtained with biochemical and hematological analyses did not show significant changes in kidney and liver parameters when compared with reference values. The low oral acute toxicity of the [VO(HSHED)dtb] is attributed to redox chemistry taking place under biological conditions combined with the hydrolytic stability of the oxidovanadium(V) complex. These results document the design of oxidovanadium(V) complexes that have low toxicity but still are antioxidant and anticancer agents.

This work presents the synthesis and spectroscopic study of new homotrinuclear (TRI) systems for photonics applications. The luminescence spectroscopy shows characteristics transitions of Eu(III) and Tb(III) ions. For the Gd(III) complexes, the triplets states were determined by phosphorescence measurement. The complexes’ coordination geometries were calculated using the Sparkle/AM1 model. For the europium systems, the Sparkle/AM1 geometries were used to calculate all details involved in the energy transfer process, and the theoretical quantum yields were determined. From an energy diagram, that estimates triplet levels, it was possible to understand some experimental phenomenon, such as weak luminescence for precursor complex (without heterocyclics ligands), and ligands emission in terbium complexes. Some of these observations can also be explained by the Jablonski diagrams that describe, based on theoretical calculations, all luminescent process. The synthesized complexes showed high values of quantum yield in ethanolic environment: 50% for EuTRIDipy, 26% EuTRITerpy, and 56% for EuTRIPhen complexes.

The electrocatalytic activity of cobalt(II)-phthalocyanine immobilized in a carbon paste electrode for citric acid oxidation under a diffusion-controlled electrochemical process was employed to develop a selective flow injection amperomettric analysis method. Under optimized conditions, rapid and reliable determinations of citric acid (65 samples per hour) were achieved for analyses of commercial fruit juices with minor pretreatment of the samples. A linear response was accomplished ranging from 0.25 to 15 mmol L(-1) (r(2)=0.9979) with an estimated detection limit of 0.117 mmol L(-1). Alternatively, a very sensitive and selective assay was developed for the micromolar range, obtaining a linear response ranging from 3.81 to 91.2 μmol L(-1) (r(2)=0.9993) with an estimated detection limit of 2.54 μmol L(-1), by using square wave voltammetric methodology. The speed and simplicity of the proposed approaches compares advantageously to the all other citric acid determination methods.

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This work describes preparation of bacterial cellulose membranes and their use as filters for water remediation. The samples were tested as filters using natural specimens that were extracted from the Igarassu River basin in Pernambuco, Brazil, and using suspensions with a high load of Escherichia coli and raw industrial effluents from the dairy and textile industries. The bacterial cellulose membrane performance was compared with commercial membranes that are used in sterile environments with better results. The membranes were shown to be effective for removing E. coli and dye effluent for up to ten cycles. When the samples that were extracted from the river were studied, no microorganisms were detected after the filtrate was inoculated into a culture medium. The results reported here show that the bacterial cellulose membranes are effective for the remediation of samples with different compositions.