Porfirinas pentacianoferrato e estruturas supramoleculares auto-organizadas / New pentacyanoferrate porphyrin and supramolecular self-assembled structures

AUTOR(ES)

Herbert Winnischofer

DATA DE PUBLICAÇÃO

2000

RESUMO

The present work describes the synthesis and spectroscopic and electrochemical properties of meso-{tetrakis-(3 pyridylpentacyanoferrate)} porphyrin (PPCF) and its Prussian Blue type materiais, obtained by self-assembly reaction between the new porphyrin and transition metal ions. The new materiais were characterized by Mass, UV -Vis, Infrared, Resonance Raman, and 57Fe Mossbauer spectroscopy, chronoamperometry, cyclic and differential pulse voltametry, electrochemical impedance spectroscopy and spectroelectrochemistry. The meso-{tetrakis-(3-pyridylpentacyanoferrate)} porphyrin (PPCF) was obtained by the reaction of 3-TPyP with [Fe(CN)5(NH3)]3--in a 2,2,2-trifluoroethanol/water solution. The supramolecular porphyrin exhibits characteristic properties of the pentacyanoferrate complexes, such as high solubility in aqueous solutions and formation of highly insoluble solids with transition metal ions, like Ni2+, Zn2 + or Fe3 +. The spectroscopic and electrochemical data indicated the coordination of the pentacyanoferrate complex to the pyridyl residues of 3-TPyP. They also suggested a stronger π back-bonding interaction between 3-TPyP and the iron complex than in the related compound [Fe(CN)5py]3--· The Prussian Blue type materiais were used as nickel and carbon paste electrodes modifiers. The electrochemical behavior is dependent of the electrolyte. For example, when NaNO3 was used instead of KNO3 the waves became broad and the intensity decreased, indicating that the charges generated in the redox reactions are compensated by the diffusion of the hydrated cation through the material. Stable and quite homogeneous films of the new porphyrin were grown galvanostatically (6.7 mC.cm-2 ) on nickel surfaces. The PPCF nickel modified electrodes exhibited fast photoresponse and a reproducible photocurrent.

ASSUNTO(S)

pentacyanoferrate química inorgânica prússia blue porfirinas azul da prússia inorganic chemistry eletrodos modificados modified electrodes porphyrin pentacianoferrato

Documentos Relacionados

• Estudos de multicamadas auto-organizadas de ácidos fosfônicos por difração dispersiva em energia
• Eletrodos modificados com monocamadas auto-organizadas de alcanotióis: uma abordagem sobre a transferência eletrônica
• Desenvolvimento de sensor biomimetico empregando monocamadas auto-organizadas de tiois sobre eletrodos de ouro
• Supramolecular self-assembled fullerene nanostructures
• Desenvolvimento de estruturas do tipo bi-camada baseadas em camadas auto-organizadas e polianilina para a proteção contra a corrosão de ligas de alumínio