Sol gel synthesis of 3-n-propyl(4-aminomethyl)pyridinium silsesquioxane chloride and the enhanced electrocatalytic activity of LbL films

A silsesquioxane based on a silica matrix and 4-(aminomethyl)pyridine group was successfully synthesized using the sol-gel process with the proposal of two different carbonic chain arrangments in the structure of the silica polymer, observed employing NMR techniques. The silsesquioxane proposed succeeds an improvement of the adsorption of monomer electroactive species on the surface of the electrode obtained through films assembly, this fact was attributed to the presence of two coordinating nitrogen in new silsesquioxane. In this study, the Layer-by-Layer (LbL) technique was shown suitable to be used to produce electroactive electrodes with indium tin oxide electrode (ITO) coated by tetrasulfonated nickel phthalocyanine (NiTsPc) alternated with the silsesquioxane. Voltammetric techniques were used to investigate the electrochemical behavior of the nitrite oxidation, which exhibited an enhanced current response at the modified electrode. The proposed electroddisplayed a current response which varied linearly with the concentration of nitrite in the range 0.113 to 0.860 mmol L-1 with a detection limit of 0.026 mmol L-1, a sensitivity of 32.06 A mu A (mmol L-1) and relative standard deviation of approximately 3%. [GRAPHICS] Synthesis of hybrid containing both ammoniummethyl pyridine and aminomethyl pyridinium groups. The new material allows a greater adsorption of metal phthalocyanine monomers. The electrode obtained allows the detection of 0.026 mmol L-1 nitrite.