Electrochemical behaviour of 9-methylcaffeinium iodide and in situ electrochemical synthesis of hymeniacidin

9-Methylcaffeinium iodide, a bio-based salt obtained by reaction of caffeine with methyl iodide, is an imidazolium salt. The electrochemical behaviour of 9-methylcaffeinium iodide was studied by means of cyclic voltammetry, differential pulse voltammetry and electrolysis. Its behaviour revealed to be very similar to that of common imidazolium salts. In fact, its cathodic reduction yielded the corresponding N-heterocyclic carbene, which was evidenced by its reaction products with dioxygen and with sulfur, although in low amounts. In fact, this electrogenerated carbene was very unstable and prone to add water, yielding a ring opening product (hymeniacidin) in high yield. Hymeniacidin is a natural product from the marine sponge Hymeniacidon sp. The voltammetric behaviour of isolated hymeniacidin confirmed the in situ formation of this ring opening product, by comparison of the voltammetric peak potentials of starting caffeinium salt and hymeniacidin. This study allowed to determine that hymeniacidin derives from NHC, and not by hydrolysis of the caffeinium salt

Cellulose nanomaterials: extraction, synthesis, characterization and applications

Due to their renewability, sustainability, and eco-friendliness, cellulose nanomaterials are capturing the interest of the research world. In this work, nanocellulose was extracted from different natural sources and used to produce new multifunctional nanocomposite materials, which can intervene such as mechanical reinforcement, optical shielding, and antibacterial coatings, useful, for example, as a consolidating agent for degraded cellulosic artworks or as a carrier for drug delivery for plants

Electrochemical synthesis and amidation of benzoin: benzamides from benzaldehydes

The benzoin condensation starting from benzaldehyde and the subsequent benzoin amidation to benzamide can be efficiently carried out under very mild conditions in an electrolysis cell. Among the advantages of using electrochemistry to generate our active reagents, the use of the easily dosed and non pollutant electron, instead of stoichiometric amounts of redox reagents or bases, usually renders the electrochemical methodology “greener” than classical organic reactions. Benzoin is obtained in good yield (85 %) carrying out the reaction in the room temperature ionic liquid BMIm-BF4. In this electrochemical reaction this liquid salt assumes the double role of solvent-supporting electrolyte system and precatalyst, yielding the corresponding N-heterocyclic carbene. The subsequent benzoin amidation is carried out by electrochemically generated superoxide anion, in the presence of an aliphatic primary or secondary amine. In this case the system superoxide/molecular oxygen acts as base and oxidant, yielding very good yields of benzamides (up to 89 %)

Impacto de programa de educação em saúde no conhecimento de idosos sobre doenças cardiovasculares

Objetivo Verificar o impacto de um programa de educação em saúde no conhecimento de idosos sobre doenças cardiovasculares.Métodos: Pesquisa qualitativa, com abordagem participativa. A população foi composta por sete idosos que realizaram oito intervenções educativas sobre temas vinculados à saúde cardiovascular. Os dados foram tratados por análise de conteúdo temática.Resultados A análise do conteúdo evidenciou que as intervenções participativas promoveram ampliação dos conhecimentos e que, após as intervenções, os sujeitos se mostraram mais seguros quanto às atitudes preventivas mais adequadas para evitar riscos cardiovasculares. Constatou-se, ainda, que a educação em saúde com abordagem participativa impacta positivamente na formação de sujeitos mais críticos, capacitados a argumentar e fazer escolhas mais saudáveis.Conclusão O estudo evidenciou que a abordagem participativa é uma estratégia eficaz quando se pretende agregar conhecimento significativo para minimizar os riscos à saúde

Electrochemical studies of new donor‐acceptor oligothiophenes

Electrochemical studies on a series of new conjugated oligothiophene derivatives are reported. The molecular architectures (D−A and A−D−A) of these compounds present different donor cores (thiophene, bithiophene) with different numbers of 3‐octylthiophene units (that act as π‐bridge and solubilizing components). The acceptor end groups adopted were, in all the cases, ethyl cyanoacrylate units. The results from voltammetric experiments confirm the close relationship between the structure of these oligothiophenes and their electrochemical behavior. Furthermore, we carried out quantum mechanical calculations to be able to obtain the HOMO/LUMO characteristics of some of our compounds in order to confirm our hypotheses on their electrochemical behavior. Moreover, the roles of the oligothiophene backbone and the ethyl cyanoacrylate group in cyclic voltammetry were elucidated by carrying out two different electrolyses at anodic and cathodic peak potentials. In particular, we were successful in the anodic dimerization of a tetrathiophene (D−A) to an octithiophene (A−D−A) (in high yield) with a considerable shortening of the chemical synthesis