Spectroscopic characterization and investigation of the dynamic of charge compensation process of supramolecular films derived from tetra-2-pyridyl-1,4-pyrazine ligand

Abstract

Este trabalho descreve a caracterização espectroscópica por infravermelho e o estudo da dinâmica de compensação de cargas do filme supramolecular FeTPPZFeCN derivado do ligante tetra-2-piridil-1,4-pirazina (TPPZ) com hexacianoferrato, bem como o filme híbrido envolvendo FeTPPZFeCN e uma matriz de polipirrol (PPy). Para o filme supramolecular, foi observado um aumento no fluxo de ânion em solução contendo K + em relação ao Li + , que parece estar relacionado ao tamanho do raio iônico cristalino do K + . O processo de eletroneutralização é discutido em termos de interação eletrostática entre cátions e centros metálicos na matriz hospedeira. A natureza do processo de compensação de carga difere de outros eletrodos modificados derivados do azul da Prússia, onde somente cátions tais como K + participam no processo de eletroneutralização. No caso do filme híbrido FeTPPZFeCN/PPy, a magnitude do fluxo de ânions é também dependente da identidade do ânion em diferentes eletrólitos de suporte.This work describes the infrared spectroscopy characterization and the charge compensation dynamics in supramolecular film FeTPPZFeCN derived from tetra-2-pyridyl-1,4-pyrazine (TPPZ) with hexacyanoferrate, as well as the hybrid film formed by FeTPPZFeCN and polypyrrole (PPy). For supramolecular film, it was found that anion flux is greater in a K + containing solution than in Li + solution, which seems to be due to the larger crystalline ionic radius of K + . The electroneutralization process is discussed in terms of electrostatic interactions between cations and metallic centers in the hosting matrix. The nature of the charge compensation process differs from others modified electrodes based on Prussian blue films, where only cations such as K + participate in the electroneutralization process. In the case of FeTPPZFeCN/PPy hybrid film, the magnitude of the anions's flux is also dependent on the identity of the anion of the supporting electrolyte.

A Chloro‐Bridged Linear Chain Imine‐Copper(II) Complex and Its Application as an Enzyme‐Free Amperometric Biosensor for Hydrogen Peroxide

“…The molecular self‐assembly of coordination polymers is a potential route to novel 1‐, 2‐ and 3D networks for applications in amperometric sensor devices 2e,4b. The preparation of polymeric complexes can be accomplished by using rationally designed polydentate ligands 13.…”

Electrochromic Properties of a Metallo-supramolecular Polymer Derived from Tetra(2-pyridyl-1,4-pyrazine) Ligands Integrated in Thin Multilayer Films

“…Here, the LbL self-assembly method has been successfully applied to the assembly of poly[Fe(TPPZ)FeCN] onto an ITO electrode surface via electrostatic attraction, but lack of electrical connectivity was observed in the function of the growth of the multilayers, leading to an irreversible electrochemical behavior and higher response times (data not shown). However, this techniques was better than that films grown using standard electropolymerization methods, 27,28 where the poly[Fe(TPPZ)FeCN] supramolecular film presented lower electrochromic stability and lower chromatic contrast.…”

“…This is the great difference of this supramolecular film when compared to PB, because when the TPPZ ligand space is used, it promotes an increase of the cavity inside the crystalline structure and facilitates the insertion and withdrawal of the sodium ions, because the radius of the sodium ions is about twice as big as the other ions depicted in the literature. 27,28,33 Moreover, we have previously shown that, for the poly[Fe(TPPZ)FeCN] film, anion transport is greater in a K + -containing solution than in Li + solution. 28 Therefore, the ionic compensation dynamics depends upon the chemical nature of the cation, specifically, on the mass/charge relationship.…”

“…It was found that, for supramolecular films of poly[Fe(TPPZ)FeCN], anion transport is faster in a solution containing K + rather than Li + . 28 In this work, we report a unique strategy to immobilize the supramolecular complex poly[Fe(TPPZ)FeCN] onto a transparent conducting substrate [indium−tin oxide (ITO)] via both the layer-by-layer (LbL) self-assembly method and the spontaneous formation of the assembled molecules on the electrode surface. This composite film showed remarkable electrochromic properties compared to the analogous com- pound PB and achieved high electrochromic efficiency, with response times measured in milliseconds and long-term cycling stability even in solutions containing Na + ions, which is opposite the results for PB electrodes.…”

Organização supramolecular da ftalocianina de cobalto(II) e seu efeito na oxidação do aminoácido cisteína

“…14,16,17 Em especial, compostos de coordenação, quando imobilizados em filmes LbL, apresentam comportamento químico diferenciado quando comparados em solução e no estado sólido, situações nas quais efeitos supramoleculares devem ser levados em consideração. 2,12,32,34,36 Neste sentido, as propriedades químicas e físicas de diversas arquiteturas supramoleculares 32,33,37,38 puderam ser melhor interpretadas por meio do entendimento da química supramolecular, que utiliza conhecimentos de processos de auto-organização e de interações específicas. 2,[32][33][34][37][38][39] Recentemente, Lehn 40 reportou que os componentes químicos que interagem em nível supramolecular podem ser estudados através da Química Dinâmica Constitucional (QDC), uma vez que as interações intermoleculares são vulneráveis e, ademais, há certo grau de reversibilidade e orientação das ligações covalentes dentro da arquitetura molecular.…”