Mechanism of charge transport by redox metal complexes confined in polymer matrices

Abstract

<jats:p> The mechanism of charge transport by metal complexes confined in polymer matrices is reviewed. There are two possibilities, one where the charge propagates in the matrix by diffusion of redox center molecules, and the other where the charge propagates by hopping between redox center molecules. The mechanism can be decided by investigating the dependence of the charge propagation rate on the redox center concentration, since in the diffusion mechanism the rate is first-order with respect to the concentration, while in the hopping mechanism it is second-order. In the hopping mechanism the charge-hopping distance can be analyzed by assuming a random distribution of the redox center in the matrix. The mechanism of charge transport by typical redox centers such as metal porphyrins, metal phthalocyanines, [Formula: see text] and methylviologen confined in a polymer membrane is presented and the charge-hopping distance is determined. </jats:p>

Review—Tetraruthenated Porphyrins and Composites as Catalysts and Sensor Materials: A Short Review

“…The macrocycle ring itself is the catalytic site for reduction of nitrite when a closed shell transition metal ion such as Zn 2+ is coordinated to the porphyrin. 60,114 In contrast, the metal ion in CoTRuP is electrochemically active and can be oxidized activating the catalyst while providing an interaction site for nitrite, as confirmed by the shift of the Soret band, 65 and a more stable catalyst than the one based on the π-radical cation. 60 Additionally, the electrocatalytic properties of porphyrin materials have been transferred to electrodes enhancing the sensitivity for detection of many analytes such as nitrite, sulfite, ascorbic acid, glucose, and hydrogen peroxide among others.…”