Epoxidation of soybean oil was investigated using 1-n-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6] ionic liquid as biphasic medium with molybdenum(VI) acetylacetonate complex and tert-butyl hydroperoxide TBHP as oxidizing agent. Reaction conditions were molar ratio TBHP:number of double bonds of oil:catalyst of 100:100:1, reaction temperature of 60 ºC and reaction time between 2 and 24 h. The proposed system showed catalytic activity for epoxidation reactions under tested conditions. Reuse of ionic liquid/catalyst system for epoxidation reactions was also investigated. Evaluation of epoxidation observed in this catalytic system was done by quantitative ¹H NMR data.

O efeito da complexação com metais sobre a atividade antimicrobiana de 1,4-naftoquinonas foi investigado. Complexos contendo níquel, cromo, ferro, cobre e cobalto da 5-amino-8-hidroxi-1,4-naftoquinona (2) e seus acil-derivados (3-8) foram sintetizados e caracterizados e sua atividade antimicrobiana foi avaliada. Dados de espectroscopia de infravermelho indicaram que as naftoquinonas coordenam os metais através dos átomos de oxigênio e nitrogênio para 2 e através de átomos de oxigênio, quando os ligantes são os acil-derivados 3-8. Testes de sensibilidade antimicrobiana demonstraram que 2 e seus derivados foram efetivos na inibição do crescimento de bactérias patogênicas como Staphylococcus aureus, Streptococcus uberis e Bacillus cereus, mas não apresentaram efeito contra bactérias Gram-negativas. A complexação de metais geralmente causou diminuição da atividade biológica. O complexo de níquel de 2 foi o mais eficaz contra bactérias Gram-positivas, apresentando valores de MIC de, 375 a 1400 µg/mL. Os complexos metálicos podem ser ferramentas úteis para o estudo do mecanismo antimicrobiano de 1,4-naftoquinonas nestas bactérias.

The effect of metal complexation on the antimicrobial activity of 1,4-naphthoquinones was investigated. Nickel-, chromium-, iron-, copper-, and cobalt-containing metal chelates of 5-amino-8-hydroxy-1,4-naphtoquinone (2) and its acyl-derivatives (3-8) were synthesized and characterized, and their antimicrobial activity was evaluated. Data from infrared spectroscopy indicate that naphthoquinones coordinate through oxygen and nitrogen atoms for 2, and through oxygen atoms when ligands were acyl derivatives 3-8. Susceptibility tests for antimicrobial activity showed that 2 and its acyl derivatives were effective on inhibiting the growth of pathogenic bacteria such as Staphylococcus aureus, Streptococcus uberis and Bacillus cereus, but not Gram-negative bacteria. The metal complexation often caused decrease of biological activity. Nickel complex of 2 was the most effective against Gram-positive bacteria, showing MIC values ranging from 375 to 1400 mg/ml. Metal chelates may be useful tools for the understanding of the antimicrobial mechanism of 1,4-naphthoquinones on these bacteria.